Integrated rehabilitation and ambulatory recovery in older adults with hip fracture according to muscle strength and sarcopenia status: a secondary analysis of a randomized controlled trial

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Although integrated multidisciplinary rehabilitation improves outcomes after hip fractures, it remains unclear whether its benefits over conventional rehabilitation differ by baseline muscle strength or sarcopenia severity. This study aimed to examine whether the functional benefits of Fragility Fracture Integrated Rehabilitation Management (FIRM) vary according to sarcopenia status and handgrip strength (HGS) in older adults after hip fracture surgery. Methods This was a secondary analysis of a multicenter randomized controlled trial comparing FIRM with conventional rehabilitation in adults aged ≥ 65 years undergoing hip fracture surgery. Independent ambulation at 12 months was the primary outcome. Sarcopenia was classified using three approaches: sarcopenia versus non-sarcopenia, a three-level classification (non-sarcopenia, possible sarcopenia, sarcopenia), and low versus normal HGS. Logistic regression models including treatment, sarcopenia status, and their interaction, were fitted with sequential adjustment for relevant covariates. Results Of the 203 randomized participants, 119 (58.6%) completed the 12-month follow-up. Although treatment-by-sarcopenia interactions were not statistically significant, stratum-specific analyses consistently showed a greater benefit of FIRM in participants with sarcopenia or low HGS. In the fully adjusted models, FIRM was associated with large absolute improvements in independent ambulation among participants with sarcopenia (odds ratio [OR], 4.01; risk difference [RD] + 32.3%) and low HGS (OR, 4.38; RD + 35.3%). Conclusions Integrated rehabilitation provides greater functional benefit than conventional rehabilitation in older adults with sarcopenia or low muscle strength after hip fracture. hip fracture older people sarcopenia rehabilitation muscle strength Figures Figure 1 Figure 2 Figure 3 Figure 4 Key summary points Aim To examine whether the functional benefits of integrated rehabilitation vary by sarcopenia status and handgrip strength in older adults with hip fracture. Findings Functional recovery differed by baseline muscle strength and sarcopenia status. Older adults with sarcopenia or low handgrip strength showed greater ambulatory improvement with integrated rehabilitation than with conventional rehabilitation. Message Low muscle strength identifies a vulnerable yet rehabilitation-responsive subgroup, and early assessment may help guide stratified rehabilitation after hip fracture. Introduction Hip fractures in older adults are associated with poor prognosis and represent a substantial clinical and socioeconomic burden [ 1 ], particularly in rapidly aging societies such as Korea [ 2 ]. As the population ages, multiple age-related factors contribute to the occurrence of fragility fractures [ 3 ], among which sarcopenia plays a critical role in both the development of hip fractures and subsequent recovery [ 3 , 4 ]. Sarcopenia, a progressive and generalized skeletal muscle disorder characterized by the loss of muscle mass and function, is common in older adults and is strongly associated with adverse clinical outcomes [ 5 ]. Its prevalence is estimated 5–10% in the general population and 10–22% in older adults [ 5 , 6 ], with higher rates reported in Asian populations (13–19%) [ 7 ], particularly in Korea, where nearly 23% of adults aged ≥ 70 years are affected [ 8 ]. Sarcopenia is more prevalent among institutionalized individuals and in specific clinical conditions, including cancer and critical illness [ 5 , 6 ]. Among patients with hip fractures, sarcopenia is markedly more common than in those with other fragility fractures, with a reported prevalence ranging from 12% to 95% in men and 18% to 64% in women [ 9 ]. Importantly, sarcopenia is a key adverse prognostic factor in this population and is associated with increased short- and long-term mortality, higher rates of postoperative complications and infections, prolonged hospitalization, and poorer functional recovery [ 10 – 12 ], thereby substantially complicating postoperative rehabilitation [ 13 ]. Integrated rehabilitation strategies, particularly resistance exercise combined with nutritional interventions, have been proposed as key approaches for improving outcomes in older adults with sarcopenia [ 5 , 14 , 15 ]. In patients with hip fractures and sarcopenia, recovery likely requires a comprehensive approach that addresses both muscle mass preservation and functional improvement [ 16 , 17 ]. Previous studies have shown that moderate- to high-intensity resistance exercise and structured intensive rehabilitation can improve function and walking ability after hip fractures in older adults, irrespective of sarcopenia status [ 18 , 19 ]. However, it remains unclear whether intensive multidisciplinary rehabilitation programs confer additional benefits over conventional rehabilitation, specifically among patients with sarcopenia. Fragility Fracture Integrated Rehabilitation Management (FIRM) is a multidisciplinary integrated rehabilitation program that has demonstrated superior functional outcomes compared with conventional rehabilitation in older adults with hip fractures during the 12-month postoperative follow-up period in a multicenter randomized controlled trial (RCT) [ 20 ]. However, the potential heterogeneity in treatment response, particularly among frail or vulnerable patients, such as those with impaired muscle strength or varying severity of sarcopenia, has not been fully explored. Therefore, in this secondary analysis of an RCT, we aimed to examine whether the effectiveness of FIRM on 12-month ambulatory recovery differs according to the baseline sarcopenia status and muscle strength compared with conventional rehabilitation in older adults undergoing hip fracture surgery. Methods Study design and participants This study was a secondary analysis of a multicenter, parallel-group, single-blind RCT comparing FIRM with conventional rehabilitation in older adults following hip fracture surgery, with 12 months of follow-up [ 20 ]. The trial was conducted between February 2017 and February 2020. The study protocol was approved by the Institutional Review Boards of XXXXX (B-1603-337-002), XXXXX (C2016117[1860]), and XXXXX (JEJUNUH 2016-11-001). All participants provided written informed consent prior to enrollment. Participants aged ≥ 65 years who underwent surgical treatment for hip fractures were randomized to receive either FIRM or conventional rehabilitation. The detailed eligibility criteria and randomization procedures have been previously reported [ 20 ]. All randomized participants were included in the secondary analysis. Participants without baseline handgrip strength (HGS) and muscle mass measurements could not be classified by sarcopenia status and were therefore excluded from sarcopenia-stratified analyses but included in the overall cohort description. Data collection Baseline sociodemographic and clinical data were collected using standardized questionnaires and review of medical records. The variables included demographic characteristics, fracture- and surgery-related factors, comorbidities assessed using the Charlson Comorbidity Index (CCI) [ 21 ], pre-fracture walking ability, length of hospital stay, time to surgery, time to transfer to the rehabilitation unit, and discharge destination. Walking ability was assessed using the Koval scale [ 22 ] and the Functional Ambulation Category (FAC) [ 23 ]. Pre-fracture independent ambulation was defined as the ability to walk outdoors without physical assistance, regardless of assistive device use (Koval score ≤ 3 and FAC score ≥ 3); failure to meet this criterion was considered pre-fracture gait impairment. Cognitive impairment was evaluated using the Mini-Mental State Examination (MMSE) [ 24 ], with cutoffs adjusted for age, sex, and education level [ 25 ]. Sarcopenia classification Muscle mass was assessed using bioelectrical impedance analysis (BIA). Appendicular skeletal muscle mass (ASM) was calculated using the lean mass from both the upper extremities and the non-fractured lower extremity to minimize bias related to postoperative edema or orthopedic implants [ 26 ]. Appendicular skeletal muscle mass index (ASMI) was calculated as ASM divided by height squared (kg/m²). BIA measurements were performed after the transfer to the rehabilitation unit using a tetrapolar system (InBody S10; Biospace, Seoul, Korea) according to standardized protocols [ 27 ]. HGS was measured using a digital dynamometer (TKK 5401 Grip-D; Takei, Niigata, Japan) according to established procedures [ 28 ]. Baseline sarcopenia was defined according to the 2025 consensus of the Asian Working Group for Sarcopenia (AWGS), using criteria for low muscle strength (HGS < 28 kg in men and < 18 kg in women) and low muscle mass (ASMI < 7.0 kg/m² in men and < 5.7 kg/m² in women [ 14 ]. Two classification approaches were applied. First, among participants with complete data, sarcopenia was defined as the concurrent presence of low HGS and muscle mass. Second, to retain participants with available HGS data but missing muscle mass data, a three-level classification was used: non-sarcopenia (normal HGS), possible sarcopenia (low HGS without muscle mass measurement), and sarcopenia (concurrent low HGS and low muscle mass). Participants with a low HGS but missing muscle mass measurements were retained in the possible sarcopenia category. Intervention Participants in the intervention group underwent FIRM, a multidisciplinary and intensive rehabilitation program that included structured physiotherapy, occupational therapy, and patient education, with linkage to community-based rehabilitation services. The conventional rehabilitation group received standard postoperative care that focused primarily on basic gait training. The detailed intervention protocols have been reported previously [ 20 ]. Outcome Independent ambulation at 12 months was defined as a FAC score ≥ 3 combined with a Koval walking ability score ≤ 3, consistent with pre-fracture ambulation criteria. Statistical analysis The baseline characteristics of the randomized cohort were summarized by treatment group using means with standard deviations for continuous variables and counts with percentages for categorical variables. The comparative effectiveness of FIRM versus conventional rehabilitation across the sarcopenia strata was evaluated using logistic regression, with independent ambulation at 12 months as the outcome. The models included the treatment group, sarcopenia status, and their interaction; treatment effects were reported as stratum-specific odds ratios (ORs) with 95% confidence intervals (CIs). Three analytical models were applied: Model 1 included participants with complete baseline HGS and muscle mass data (sarcopenia vs. non-sarcopenia); Model 2 applied a three-level AWGS-based classification among participants with available HGS (non-sarcopenia, possible sarcopenia, and sarcopenia); and Model 3 dichotomized participants by muscle strength alone (normal vs. low HGS), regardless of muscle mass availability. Stratum-specific ORs, model-based predicted probabilities, and absolute risk differences (RDs) were estimated using marginal means, and the number needed to treat (NNT) was calculated as the inverse of the RD. Analyses were sequentially adjusted (unadjusted; age and sex; further adjustment for cognitive impairment, CCI, and pre-fracture gait impairment). All tests were two-sided, with a significance level of 0.05. Analyses were conducted using the R software (version 4.4.3; R Foundation for Statistical Computing, Vienna, Austria). Results Characteristics of the participants The baseline characteristics of the randomized cohort are summarized in Table 1 , and the participant flow, including eligibility for sarcopenia-stratified analysis, is shown in Fig. 1 . A total of 203 patients were randomized to the FIRM (n = 108) or conventional rehabilitation (n = 95) group, and 119 (58.6%) completed the 12-month follow-up. As shown in Fig. 1 , nine participants lacked baseline HGS and muscle mass data, and muscle mass data were missing in an additional 75 participants. Baseline characteristics were generally comparable between the groups, except for a longer time to transfer to the rehabilitation unit in the FIRM group and a lower prevalence of cognitive impairment. Table 1 Baseline characteristics of the randomized cohort according to treatment group. Variable FIRM group (n = 108) Conventional group (n = 95) P- value Age, mean (SD), years 80.8 (7.3) 82.0 (6.0) 0.212 Sex, n (%) (female) 82 (75.9) 73 (76.8) 0.878 Height, mean (SD), cm 155.5 (8.5) 156.0 (8.5) 0.733 Weight, mean (SD), kg 53.3 (9.4 ) 55.1 (10.0) 0.188 BMI, mean (SD), kg/m 2 22.1 (3.7) 22.6 (3.4) 0.276 ASMI, mean (SD), kg/m 2 (n = 119) Male 6.3 (1.2) 6.2 (1.2) 0.778 Female 5.3 (1.0) 5.7 (1.0) 0.120 HGS, mean (SD), kg (n = 194) Male 20.6 (8.6) 22.0 (7.2) 0.561 Female 13.9 (6.0) 13.6 (6.3) 0.803 Fracture type, n (%) 0.103 Femoral neck 50 (46.3) 32 (33.7) Intertrochanteric 51 (47.2) 59 (53.6) Subtrochanteric 7 (6.5) 4 (4.2) Operation type, n (%) 0.014 Bipolar hemiarthroplasty 47 (43.5) 52 (54.7) Total hip arthroplasty 11 (10.2) 1 (1.1) Internal fixation 50 (46.3) 42 (44.2) Pre-fracture Koval, mean (SD), score 1.7 (1.2 ) 1.8 (1.1) 0.794 Pre-fracture FAC, mean (SD), score 4.6 (0.8) 4.6 (0.6) 0.562 Pre-fracture gait impairment, n (%) 12 (11.1) 8 (8.4) 0.521 Previous history of hip fracture, n (%) 7 (6.5) 5 (5.3) 0.713 Cognitive impairment, n (%) 39 (36.1) 47 (50.0) 0.046 Osteoporosis, n (%) 77 (71.3) 70 (73.7) 0.704 Charlson Comorbidity Index, n (%) 0.913 None 37 (34.3) 33 (34.7) Mild (1–2) 51 (47.2) 41 (43.2) Moderate (3–4) 9 (8.3) 9 (9.5) Severe (≥ 5) 11 (10.2) 12 (12.6) Postoperative complication, n (%) 3 (2.8) 8 (8.4) 0.076 Length of hospital stay, mean (SD), days 24.0 (6.4) 23.4 (6.3) 0.537 Days to surgery, mean (SD), 2.9 (2.3) 3.2 (3.7) 0.438 Days to rehabilitation, mean (SD), 8.4 (3.7) 7.0 (2.7) 0.003 Discharge location, n (%) 0.969 Home 56 (51.9) 49 (51.6) Institution 52 (48.1) 46 (48.4) FIRM, fragility integrated rehabilitation management; BMI, body mass index; ASMI, appendicular skeletal muscle mass index; HGS, handgrip strength; FAC, functional ambulation category. The baseline characteristics stratified by sarcopenia status are presented in Supplementary Table S1 . Participants with possible or sarcopenia were older and had a lower body mass index; poorer baseline functional status; higher comorbidity burden; and higher prevalence of pre-fracture gait impairment, prior hip fracture, cognitive impairment, and institutional discharge, indicating clinically meaningful differences across the sarcopenia spectrum. Comparative effectiveness of FIRM versus conventional rehabilitation across the sarcopenia strata Model 1: Sarcopenia vs non-sarcopenia The treatment-by-sarcopenia interaction was not statistically significant in the unadjusted or adjusted models (all P for interaction > 0.43). However, stratum-specific analyses showed a substantially greater benefit of the FIRM in participants with sarcopenia (Fig. 2 ). In the unadjusted analyses, FIRM was associated with a large absolute increase in independent ambulation at 12 months in the sarcopenia group (RD, + 28.9%; P = 0.043; NNT = 3.5), whereas the effect was small and non-significant in the non-sarcopenia group (RD, + 6.3%; P = 0.63; NNT = 16.0). This pattern persisted after adjusting for age and sex (RD, + 29.1%; P = 0.042; NNT = 3.4) and remained clinically meaningful in the fully adjusted model (RD, + 32.3%; P = 0.045; NNT = 3.1), with no significant benefit observed among participants without sarcopenia (Fig. 2 and Supplementary Figure S2). Model 2: Three-level AWGS 2025 sarcopenia classification Among participants with available baseline HGS data, the crude rate of independent ambulation at 12 months declined across the sarcopenia categories (86.1% in non-sarcopenia, 64.5% in possible sarcopenia, and 57.1% in sarcopenia; P = 0.016), indicating progressively poorer recovery with increasing sarcopenia severity (Table S1 ). Although the treatment-by-sarcopenia interaction was not statistically significant (all P for interaction > 0.70), stratum-specific analyses demonstrated greater treatment effects in participants with sarcopenia (Fig. 3 ). In the unadjusted analyses, FIRM was associated with substantial absolute improvements in independent ambulation among participants with possible sarcopenia (RD, + 34.6%; P = 0.032; NNT = 2.9) and sarcopenia (RD, + 28.9%; P = 0.043; NNT = 3.5), but not in those without sarcopenia (RD, + 7.1%; P = 0.54). After adjusting for age and sex, the benefits persisted in sarcopenia (RD, + 30.9%; P = 0.030; NNT = 3.2) and remained clinically relevant, although attenuated, in possible sarcopenia. In the fully adjusted model, the largest and most statistically significant benefit was observed in the sarcopenia group (RD, + 35.9%; P = 0.031; NNT = 2.8), whereas the effects in the non-sarcopenia and possible sarcopenia groups were smaller and non-significant (Fig. 3 and Supplementary Figure S2). Model 3: Low versus normal HGS When participants were dichotomized by baseline HGS, the treatment-by-strength interaction was not statistically significant (P for interaction = 0.41–0.55). Nevertheless, stratum-specific analyses consistently indicated that the benefit of the FIRM was concentrated among participants with low HGS (Fig. 4 ). In the unadjusted analyses, FIRM was associated with a large absolute increase in independent ambulation at 12 months among participants with low HGS (RD, + 29.9%; P = 0.006; NNT = 3.3), with no meaningful benefit observed in those with normal strength (RD, + 7.1%; P = 0.54). This finding persisted even after adjusting for age and sex (RD, + 28.9%; P = 0.007; NNT = 3.5). and remained robust in the fully adjusted model (RD = + 35.3%; P = 0.005; NNT = 2.8). The concordant stratum-specific ORs further supported the strong treatment effect in the low-strength group (OR, 4.38 vs 1.65; Fig. 4 and Supplementary Figure S2). Discussion In this secondary analysis of a multicenter RCT, we found that the functional benefit of integrated rehabilitation after hip fracture was not uniform but varied systematically with baseline muscle strength and sarcopenia severity. Although formal tests of treatment-by-sarcopenia interactions were not statistically significant, stratum-specific analyses consistently demonstrated clinically meaningful differences in treatment effects across all analytical models. In particular, older adults with low HGS or sarcopenia derived substantially greater ambulatory benefits from FIRM than from conventional rehabilitation, as evidenced by large absolute gains in independent ambulation and a low NNT at 12 months. Sarcopenia is a critical condition in older adults with hip fractures, serving as both a contributor to fracture occurrence and a major barrier to postoperative recovery. It reflects a complex multifactorial pathophysiology, including reduced mechanical loading, impaired muscle protein synthesis, chronic inflammation, and metabolic dysregulation, resulting in a concurrent decline in muscle strength and bone quality [ 3 , 29 ]. Consequently, sarcopenia impairs gait and balance, increases the risk of falls and fractures [ 3 , 29 , 30 ], and is consistently associated with delayed functional recovery and poor prognosis after hip fracture [ 10 – 13 ]. Importantly, sarcopenia is at least partially reversible [ 31 ], underscoring the clinical relevance of early identification and timely implementation of targeted interventions. Given its dual role as both a precipitating factor and modifiable determinant of recovery, sarcopenia should be considered a central therapeutic target in post–hip fracture care. Our findings suggest that baseline muscle strength and sarcopenia status are the key determinants of the most appropriate rehabilitation strategies after hip fracture surgery. Multidisciplinary, intensive, and structured rehabilitation has been shown to improve functional outcomes, reduce institutionalization, and decrease mortality in this population [ 32 , 33 ]. However, despite sarcopenia being a well-established poor prognostic factor, comparative evidence of optimal rehabilitation strategies in this population remains limited. Previous studies have largely focused on individual exercises or nutritional components as adjuncts to conventional rehabilitation, with heterogeneous designs and limited comparative scope [ 34 – 37 ]. In this context, the present study provides comparative evidence that an integrated multidisciplinary rehabilitation program confers greater functional benefits than conventional rehabilitation in older adults with hip fracture and sarcopenia or impaired muscle strength. Across multiple analytical models, this advantage was reflected in consistently larger absolute gains in independent ambulation, with the benefit of integrated rehabilitation particularly pronounced in patients with sarcopenia. Notably, despite their substantial functional vulnerability, these patients appeared to retain their rehabilitation potential when exposed to intensive integrated interventions. These findings also suggest that conventional rehabilitation alone is insufficient to achieve optimal functional recovery in patients with sarcopenia or impaired muscle strength as it may not adequately address the complex physical and functional deficits inherent to sarcopenia. This should not be interpreted as implying that integrated rehabilitation is ineffective in patients with preserved muscle strength; rather, our results emphasize that in patients with sarcopenia or low muscle strength, integrated and multidisciplinary rehabilitation is not merely advantageous, but may be essential to maximize recovery. From a clinical perspective, these data support a stratified rehabilitation approach in which patients with impaired muscle strength are proactively identified and prioritized for intensive programs, such as FIRM, to optimize ambulatory recovery after hip fracture. Recent global consensus statements have revised the conceptual framework of sarcopenia, placing greater emphasis on early case-finding and repeated assessment in high-risk populations. The updated AWGS 2025 consensus emphasizes early case-finding and repeated assessment of sarcopenia in high-risk older adults, with HGS being recommended as the first-line screening tool [ 14 ]. Even in the absence of overt muscle weakness, individuals with relevant medical risk factors are considered at risk for sarcopenia and are recommended to undergo periodic reassessment and timely muscle health interventions. Hip fracture is a prototypical geriatric syndrome in this context, functioning both as a consequence and a precipitating factor of sarcopenia, placing patients in a highly vulnerable state characterized by acute stress, immobilization, inflammation, and nutritional decline. Accordingly, older adults with hip fractures are recognized as a priority population for early evaluation and proactive intervention. Against this background, the consistent benefit of FIRM among patients with sarcopenia or low HGS across the unadjusted and adjusted models highlights muscle strength as a clinically meaningful and actionable marker for prioritizing intensive rehabilitation after hip fracture. Within the AWGS 2025 framework, low HGS without concurrent muscle mass assessment is classified as possible sarcopenia and may be interpreted as functional sarcopenia to prompt early identification and intervention. [ 14 ]. Notably, even patients identified solely by low HGS derived greater benefits from FIRM than from conventional rehabilitation. Given the limited feasibility of routine muscle mass assessment in postoperative settings [ 26 , 38 ], these findings support the use of HGS as a simple bedside screening tool to guide stratified rehabilitation, whereby patients with impaired muscle strength are prioritized for integrated programs such as FIRM to optimize functional recovery. This study had several limitations. First, this secondary analysis was not powered for sarcopenia-stratified comparisons, which limited the statistical power of formal interaction testing. Accordingly, the treatment-by-sarcopenia interaction terms did not consistently reach statistical significance despite internally consistent and clinically meaningful stratum-specific effects and should be interpreted as exploratory. Second, muscle mass measurements were unavailable for all participants, potentially leading to misclassification of sarcopenia status. Participants with low HGS but missing muscle mass data were classified as having possible sarcopenia; such nondifferential misclassification would bias results toward the null, potentially underestimating true differences across sarcopenia severity. Third, the independent or additive effects of structured nutritional interventions could not be evaluated. Fourth, attrition during the 12-month follow-up period was substantial, and recruitment from tertiary rehabilitation centers may limit generalizability. Despite these limitations, this study suggests that integrated multidisciplinary rehabilitation provides greater functional benefits than conventional rehabilitation in older adults with hip fractures and impaired muscle strength. Low muscle strength did not indicate limited rehabilitation potential but rather identified a vulnerable subgroup more likely to benefit from intensive, integrated rehabilitation. Future prospective studies that stratify patients according to sarcopenia status and compare conventional with enhanced integrated rehabilitation protocols may help further refine optimal strategies for this high-risk population. Conclusions In this secondary analysis of a multicenter RCT, older adults with hip fractures and low HGS or sarcopenia derived substantially greater functional benefits from FIRM than from conventional rehabilitation. Impaired muscle strength did not reflect limited rehabilitation potential but instead identified patients who were particularly responsive to intensive, multidisciplinary intervention. These findings support a targeted and stratified rehabilitation strategy, in which baseline muscle strength is used to proactively identify patients most likely to benefit from integrated rehabilitation programs. Early screening for low HGS and prioritizing such patients for intensive integrated rehabilitation may optimize functional recovery and reduce the overall burden of hip fractures in older adults. Contributions Conceptualization: SK Lim, JY Lim; Project administration: JY Lim; Data curation: SK Lim, JY Lim; Formal analysis SK Lim; Funding acquisition: SK Lim; Methodology: SK Lim, JY Lim; Resources: : JY Lim, Supervision: JY Lim; Writing – original draft: SK Lim; Writing – review & editing: JY Lim; All authors have read and agreed to the published version of the manuscript. Declarations Conflict of interest The authors declare that they have no competing interest. Ethics approval The study protocol was approved by the Institutional Review Boards of XXXXX (B-1603-337-002), XXXXX (C2016117[1860]), and XXXXX (JEJUNUH 2016-11-001). All participants provided written informed consent prior to enrollment. Funding This research was supported by a grant of Patient-Centered Clinical Research Coordinating Center (PACEN) funded by the Ministry of Health & Welfare, Republic of Korea (grant number: RS-2025-02217163). Acknowledgements Not applicable. Data Availability Data are available on reasonable request. References Harris E, Clement N, MacLullich A, Farrow L The impact of an ageing population on future increases in hip fracture burden. Bone Joint J 2024;106-b(1):62 – 8. https://doi:10.1302/0301-620x.106b1.Bjj-2023-0740.R1 Jang I-Y, Lee HY, Lee E (2019) Geriatrics fact sheet in Korea 2018 from national statistics. Ann Geriatr Med Res 23(2):50. https://doi:10.4235/agmr.19.0013 Cederholm T, Cruz-Jentoft AJ, Maggi S (2013) Sarcopenia and fragility fractures. Eur J Phys Rehabil Med 49(1):111–117 Brzeszczynski F, Brzeszczynska J, Duckworth AD et al (2022) The effect of sarcopenia on outcomes following orthopaedic surgery: a systematic review. bone joint J 104(3):321–330. https://doi:10.1302/0301-620X.104B3.BJJ-2021-1052.R1 Sayer AA, Cooper R, Arai H, Sarcopenia et al (2024) Nat Rev Dis Primers 10(1):68. https://doi:10.1038/s41572-024-00550-w Yuan S, Larsson SC (2023) Epidemiology of sarcopenia: prevalence, risk factors, and consequences. Metabolism 144:155533. https://doi:10.1016/j.metabol.2023.155533 Weng SE, Huang YW, Tseng YC et al (2025) The evolving landscape of sarcopenia in Asia: a systematic review and meta-analysis following the 2019 Asian working group for sarcopenia (AWGS) diagnostic criteria. Arch Gerontol Geriatr 128:105596. https://doi:10.1016/j.archger.2024.105596 Kim M, Won CW (2020) Sarcopenia in Korean community-dwelling adults aged 70 years and older: application of screening and diagnostic tools from the Asian working group for sarcopenia 2019 update. J Am Med Dir Assoc 21(6):752–758. https://doi:10.1016/j.jamda.2020.03.018 Wong RMY, Wong H, Zhang N et al (2019) The relationship between sarcopenia and fragility fracture-a systematic review. Osteoporos Int 30(3):541–553. https://doi:10.1007/s00198-018-04828-0 Sheehan KJ, Williamson L, Alexander J et al (2018) Prognostic factors of functional outcome after hip fracture surgery: a systematic review. Age Ageing 47(5):661–670. https://doi 10.1093/ageing/afy057 Xu BY, Yan S, Low LL, Vasanwala FF, Low SG (2019) Predictors of poor functional outcomes and mortality in patients with hip fracture: a systematic review. BMC Musculoskelet Disord 20(1):568. https://doi:10.1186/s12891-019-2950-0 Wong BLL, Chan YH, O'Neill GK, Murphy D, Merchant RA (2023) Frailty, length of stay and cost in hip fracture patients. Osteoporos Int 34(1):59–68. https://doi:10.1007/s00198-022-06553-1 Boskovic K, Pantelinac S, Tomasevic-Todorovic S et al (2020) AB0889 sarcopenia and hip fracture in geriatric population. Ann Rheum Dis 79:1749. https://doi:10.1136/annrheumdis-2020-eular.5440 Chen LK, Hsiao FY, Akishita M et al (2025) A focus shift from sarcopenia to muscle health in the Asian working group for sarcopenia 2025 consensus update. Nat Aging. ;5(11):2164-75. 2025;5(11):2164–2175. https://doi:10.1038/s43587-025-01004-y Cruz-Jentoft AJ, Sayer AA (2019) Sarcopenia Lancet 393(10191):2636–2646. https://doi:10.1016/s0140-6736(19)31138-9 Wakabayashi H, Sakuma K (2014) Rehabilitation nutrition for sarcopenia with disability: a combination of both rehabilitation and nutrition care management. J Cachexia Sarcopenia Muscle 5(4):269–277. https://doi:10.1007/s13539-014-0162-x Inoue T, Maeda K, Nagano A et al (2020) Undernutrition, sarcopenia, and frailty in fragility hip fracture: advanced strategies for improving clinical outcomes. Nutrients 12(12):3743. https://doi:10.3390/nu12123743 Zhang Y, Chen L, Wu P, Lang J, Chen L (2020) Intervention with erythropoietin in sarcopenic patients with femoral intertrochanteric fracture and its potential effects on postoperative rehabilitation. Geriatr Gerontol Int 20(2):150–155. https://doi:10.1111/ggi.13845 Lim SK, Beom J, Lee SY, Lim JY (2019) Functional outcomes of fragility fracture integrated rehabilitation management in sarcopenic patients after hip fracture surgery and predictors of independent ambulation. J Nutr Health Aging 23(10):1034–1042. https://doi:10.1007/s12603-019-1289-4 Lim SK, Beom J, Lee SY et al (2025) Efficacy of fragility fracture integrated rehabilitation management in older adults with hip fractures: a randomized controlled trial with 1-year follow-up. J Am Med Dir Assoc 26(1):105321. https://doi:10.1016/j.jamda.2024.105321 Charlson ME, Pompei P, Ales KL, MacKenzie CR (1987) A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 40(5):373–383. https://doi:10.1016/0021-9681(87)90171-8 Koval KJ, Skovron ML, Aharonoff GB, Meadows SE, Zuckerman JD (1995) Ambulatory ability after hip fracture. a prospective study in geriatric patients. Clin Orthop Relat Res ;(310):150–159 Holden MK, Gill KM, Magliozzi MR, Nathan J, Piehl-Baker L (1984) Clinical gait assessment in the neurologically impaired. reliability and meaningfulness. Phys Ther 64(1):35–40. https://doi:10.1093/ptj/64.1.35 Kang Y, Na DL, Hahn S (1997) A validity study on the Korean mini-mental state examination (K-MMSE) in dementia patients. J Korean Neurol Assoc 15(2):300–308 Lee DY, Lee KU, Lee JH et al (2004) A normative study of the CERAD neuropsychological assessment battery in the Korean elderly. J Int Neuropsychol Soc 10(1):72–81. https://doi:10.1017/S1355617704101094 Kyle UG, Bosaeus I, De Lorenzo AD et al (2004) Bioelectrical impedance analysis-part II: utilization in clinical practice. Clin Nutr 23(6):1430–1453. https://doi:10.1016/j.clnu.2004.09.012 Lukaski HC, Johnson PE, Bolonchuk WW, Lykken GI (1985) Assessment of fat-free mass using bioelectrical impedance measurements of the human body. Am J Clin Nutr 41(4):810–817. https://doi:10.1093/ajcn/41.4.810 Lim SK, Beom J, Lee SY et al (2025) Standardized measurement of muscle strength and physical performance for sarcopenia: an expert-based delphi consensus. Ann Geriatr Med Res 29(2):185–198. https://doi 10.4235/agmr.25.0070 Tarantino U, Piccirilli E, Fantini M et al (2015) Sarcopenia and fragility fractures: molecular and clinical evidence of the bone-muscle interaction. J Bone Joint Surg Am 97(5):429–437. https://doi 10.2106/jbjs.N.00648 Yeung SSY, Reijnierse EM, Pham VK et al (2019) Sarcopenia and its association with falls and fractures in older adults: a systematic review and meta-analysis. J Cachexia Sarcopenia Muscle 10(3):485–500. https://doi:10.1002/jcsm.12411 Kirk B, Cawthon PM, Arai H et al (2024) The conceptual definition of sarcopenia: delphi consensus from the global leadership Initiative in sarcopenia (GLIS). Age Ageing 53(3):afae052. https://doi:10.1093/ageing/afae052 Handoll HH, Cameron ID, Mak JC, Panagoda CE, Finnegan TP (2021) Multidisciplinary rehabilitation for older people with hip fractures. Cochrane Database Syst Rev 11(11):Cd007125. https://doi:10.1002/14651858.CD007125.pub3 McDonough CM, Harris-Hayes M, Kristensen MT et al (2021) Physical therapy management of older adults with hip fracture. J Orthop Sports Phys Ther 51(2):CPG1–CPG81. https://doi:10.2519/jospt.2021.0301 Yoo JI, Ha YC, Cha Y (2022) Nutrition and exercise treatment of sarcopenia in hip fracture patients: systematic review. J Bone Metab 29(2):63–73. https://doi:10.11005/jbm.2022.29.2.63 Avola M, Mangano GRA, Testa G et al (2020) Rehabilitation strategies for patients with femoral neck fractures in sarcopenia: a narrative review. J Clin Med 9(10). https://doi:10.3390/jcm9103115 Oh MK, Yoo JI, Byun H et al (2020) Efficacy of combined antigravity treadmill and conventional rehabilitation after hip fracture in patients with sarcopenia. J Gerontol Biol Sci Med Sci 75(10):e173–e81. https://doi:10.1093/gerona/glaa158 Han Z, Ji NN, Ma JX, Dong Q, Ma XL (2022) Effect of resistance training combined with beta-hydroxy-beta-methylbutyric acid supplements in elderly patients with sarcopenia after hip replacement. Orthop Surg 14(4):704–713. https://doi:10.1111/os.13208 Hsiao PL, Hsu SF, Chen PH et al (2019) Does a spinal implant alter dual energy X-ray absorptiometry body composition measurements? PLoS ONE 14(9):e0222758. https://doi:10.1371/journal.pone.0222758 Supplementary Files Supplementarymaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major revisions 30 Apr, 2026 Reviewers agreed at journal 24 Feb, 2026 Reviewers invited by journal 23 Feb, 2026 Editor invited by journal 17 Feb, 2026 Editor assigned by journal 14 Feb, 2026 First submitted to journal 13 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8868135","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":595923643,"identity":"72b2fbac-e0d5-4e3c-a96d-208dcd626f25","order_by":0,"name":"Seung-Kyu Lim","email":"","orcid":"https://orcid.org/0000-0002-6867-2896","institution":"Soonchunhyang University College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Seung-Kyu","middleName":"","lastName":"Lim","suffix":""},{"id":595923644,"identity":"f1edbff7-590b-445e-b376-42fd1db132fc","order_by":1,"name":"Jae-young Lim","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAsUlEQVRIiWNgGAWjYDCCA8wNBxgMbGDcBGK0MAK1FKSRqIWB4cNhErTw3T7YeOiGwXl7c4kExg8/GNLyCWqRPJfYcDjH4HbizhkJzJI9DDmWDYS0GJxhBGtJMLiRwCDNwFBhQNAWqJZz9kAtzL9J0XKAccONBDagLTmEtUhCtCQnbjjzsM2yxyCNsBa+M8yHP+f8sbM3OJ58+MaPimTCWpAAKIJI0jAKRsEoGAWjACcAAFtbPz/s4JshAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-9454-0344","institution":"Seoul National University College of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Jae-young","middleName":"","lastName":"Lim","suffix":""}],"badges":[],"createdAt":"2026-02-13 06:30:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8868135/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8868135/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103576262,"identity":"567a4d0f-3182-4b36-9dd6-c27c5befe0c4","added_by":"auto","created_at":"2026-02-27 09:16:06","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":275210,"visible":true,"origin":"","legend":"\u003cp\u003eFlow of participants and availability of sarcopenia-related measurements. A total of 203 participants were randomized. At baseline, HGS was available in 194 participants; nine participants had neither HGS nor muscle mass measurements. Both HGS and muscle mass data were available in 119 participants at baseline. At the 12-month follow-up, HGS data were available for 116 participants, and both HGS and muscle mass measurements were available for 81 participants. FIRM, Fragility Fracture Integrated Rehabilitation Management; HGS, handgrip strength.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-8868135/v1/9ef1129131d92f0114ac4cd3.png"},{"id":103576261,"identity":"2aba2f8b-570e-4d7a-9060-fe8855f7fd2d","added_by":"auto","created_at":"2026-02-27 09:16:06","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":224376,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of FIRM on 12-month independent ambulation by sarcopenia status. Forest plots show the effect of FIRM compared with conventional rehabilitation on independent ambulation at 12 months, stratified by sarcopenia status. Panel A shows unadjusted estimates, and panel B shows fully adjusted estimates controlling for age, sex, cognitive impairment, Charlson Comorbidity Index, and pre-fracture gait impairment. Treatment effects are presented as odds ratios (ORs), risk differences (RDs), and numbers needed to treat (NNTs).\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-8868135/v1/caf052fa995c54833f5e4033.png"},{"id":103576263,"identity":"dc8a6edb-d76e-4f5f-b984-014a664edf34","added_by":"auto","created_at":"2026-02-27 09:16:06","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":286382,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of FIRM on 12-month independent ambulation across AWGS 2025 sarcopenia classification. Forest plots show stratum-specific treatment effects of FIRM compared with conventional rehabilitation on independent ambulation at 12 months across three sarcopenia categories (non-sarcopenia, possible sarcopenia, and sarcopenia). Panel A shows unadjusted estimates, and panel B shows fully adjusted estimates controlling for age, sex, cognitive impairment, Charlson Comorbidity Index, and pre-fracture gait impairment. Treatment effects are presented as odds ratios (ORs), risk differences (RDs), and numbers needed to treat (NNTs).\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-8868135/v1/c7ce8601cb108f3d33136950.png"},{"id":103576259,"identity":"98a646c0-9499-451c-aefb-7ebf0921fde7","added_by":"auto","created_at":"2026-02-27 09:16:06","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":212429,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of FIRM on 12-month independent ambulation by handgrip strength status. Forest plots show the effect of FIRM compared with conventional rehabilitation on independent ambulation at 12 months, stratified by baseline handgrip strength status (normal vs low). Panel A shows unadjusted estimates, and panel B shows fully adjusted estimates controlling for age, sex, cognitive impairment, Charlson Comorbidity Index, and pre-fracture gait impairment. Treatment effects are presented as stratum-specific odds ratios (ORs), risk differences (RDs), and numbers needed to treat (NNTs). HGS, handgrip strength.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-8868135/v1/b7dde7f7752789a6d4158240.png"},{"id":104399413,"identity":"a2cebd9a-2596-404b-be4f-d1dd7fce27e8","added_by":"auto","created_at":"2026-03-11 12:06:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1523775,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8868135/v1/554a0b10-f1a1-424d-8e90-abb683d05d23.pdf"},{"id":103576264,"identity":"e9a480d2-0d2e-47b6-9098-5d677dc2442c","added_by":"auto","created_at":"2026-02-27 09:16:06","extension":"docx","order_by":11,"title":"","display":"","copyAsset":false,"role":"supplement","size":337100,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-8868135/v1/5716046234290c06979a90a6.docx"}],"financialInterests":"","formattedTitle":"Integrated rehabilitation and ambulatory recovery in older adults with hip fracture according to muscle strength and sarcopenia status: a secondary analysis of a randomized controlled trial","fulltext":[{"header":"Key summary points","content":"\u003cp\u003e\u003cstrong\u003eAim\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo examine whether the functional benefits of integrated rehabilitation vary by sarcopenia status and handgrip strength in older adults with hip fracture.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFindings\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFunctional recovery differed by baseline muscle strength and sarcopenia status. Older adults with sarcopenia or low handgrip strength showed greater ambulatory improvement with integrated rehabilitation than with conventional rehabilitation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMessage\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLow muscle strength identifies a vulnerable yet rehabilitation-responsive subgroup, and early assessment may help guide stratified rehabilitation after hip fracture.\u003cstrong\u003e\u003cbr\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eHip fractures in older adults are associated with poor prognosis and represent a substantial clinical and socioeconomic burden [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], particularly in rapidly aging societies such as Korea [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. As the population ages, multiple age-related factors contribute to the occurrence of fragility fractures [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], among which sarcopenia plays a critical role in both the development of hip fractures and subsequent recovery [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSarcopenia, a progressive and generalized skeletal muscle disorder characterized by the loss of muscle mass and function, is common in older adults and is strongly associated with adverse clinical outcomes [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Its prevalence is estimated 5\u0026ndash;10% in the general population and 10\u0026ndash;22% in older adults [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], with higher rates reported in Asian populations (13\u0026ndash;19%) [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], particularly in Korea, where nearly 23% of adults aged\u0026thinsp;\u0026ge;\u0026thinsp;70 years are affected [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Sarcopenia is more prevalent among institutionalized individuals and in specific clinical conditions, including cancer and critical illness [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Among patients with hip fractures, sarcopenia is markedly more common than in those with other fragility fractures, with a reported prevalence ranging from 12% to 95% in men and 18% to 64% in women [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Importantly, sarcopenia is a key adverse prognostic factor in this population and is associated with increased short- and long-term mortality, higher rates of postoperative complications and infections, prolonged hospitalization, and poorer functional recovery [\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], thereby substantially complicating postoperative rehabilitation [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIntegrated rehabilitation strategies, particularly resistance exercise combined with nutritional interventions, have been proposed as key approaches for improving outcomes in older adults with sarcopenia [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In patients with hip fractures and sarcopenia, recovery likely requires a comprehensive approach that addresses both muscle mass preservation and functional improvement [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Previous studies have shown that moderate- to high-intensity resistance exercise and structured intensive rehabilitation can improve function and walking ability after hip fractures in older adults, irrespective of sarcopenia status [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. However, it remains unclear whether intensive multidisciplinary rehabilitation programs confer additional benefits over conventional rehabilitation, specifically among patients with sarcopenia.\u003c/p\u003e \u003cp\u003eFragility Fracture Integrated Rehabilitation Management (FIRM) is a multidisciplinary integrated rehabilitation program that has demonstrated superior functional outcomes compared with conventional rehabilitation in older adults with hip fractures during the 12-month postoperative follow-up period in a multicenter randomized controlled trial (RCT) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, the potential heterogeneity in treatment response, particularly among frail or vulnerable patients, such as those with impaired muscle strength or varying severity of sarcopenia, has not been fully explored. Therefore, in this secondary analysis of an RCT, we aimed to examine whether the effectiveness of FIRM on 12-month ambulatory recovery differs according to the baseline sarcopenia status and muscle strength compared with conventional rehabilitation in older adults undergoing hip fracture surgery.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and participants\u003c/h2\u003e \u003cp\u003eThis study was a secondary analysis of a multicenter, parallel-group, single-blind RCT comparing FIRM with conventional rehabilitation in older adults following hip fracture surgery, with 12 months of follow-up [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The trial was conducted between February 2017 and February 2020. The study protocol was approved by the Institutional Review Boards of XXXXX (B-1603-337-002), XXXXX (C2016117[1860]), and XXXXX (JEJUNUH 2016-11-001). All participants provided written informed consent prior to enrollment.\u003c/p\u003e \u003cp\u003eParticipants aged\u0026thinsp;\u0026ge;\u0026thinsp;65 years who underwent surgical treatment for hip fractures were randomized to receive either FIRM or conventional rehabilitation. The detailed eligibility criteria and randomization procedures have been previously reported [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. All randomized participants were included in the secondary analysis. Participants without baseline handgrip strength (HGS) and muscle mass measurements could not be classified by sarcopenia status and were therefore excluded from sarcopenia-stratified analyses but included in the overall cohort description.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData collection\u003c/h3\u003e\n\u003cp\u003eBaseline sociodemographic and clinical data were collected using standardized questionnaires and review of medical records. The variables included demographic characteristics, fracture- and surgery-related factors, comorbidities assessed using the Charlson Comorbidity Index (CCI) [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], pre-fracture walking ability, length of hospital stay, time to surgery, time to transfer to the rehabilitation unit, and discharge destination. Walking ability was assessed using the Koval scale [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] and the Functional Ambulation Category (FAC) [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Pre-fracture independent ambulation was defined as the ability to walk outdoors without physical assistance, regardless of assistive device use (Koval score\u0026thinsp;\u0026le;\u0026thinsp;3 and FAC score\u0026thinsp;\u0026ge;\u0026thinsp;3); failure to meet this criterion was considered pre-fracture gait impairment. Cognitive impairment was evaluated using the Mini-Mental State Examination (MMSE) [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], with cutoffs adjusted for age, sex, and education level [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eSarcopenia classification\u003c/h3\u003e\n\u003cp\u003eMuscle mass was assessed using bioelectrical impedance analysis (BIA). Appendicular skeletal muscle mass (ASM) was calculated using the lean mass from both the upper extremities and the non-fractured lower extremity to minimize bias related to postoperative edema or orthopedic implants [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Appendicular skeletal muscle mass index (ASMI) was calculated as ASM divided by height squared (kg/m\u0026sup2;). BIA measurements were performed after the transfer to the rehabilitation unit using a tetrapolar system (InBody S10; Biospace, Seoul, Korea) according to standardized protocols [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. HGS was measured using a digital dynamometer (TKK 5401 Grip-D; Takei, Niigata, Japan) according to established procedures [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBaseline sarcopenia was defined according to the 2025 consensus of the Asian Working Group for Sarcopenia (AWGS), using criteria for low muscle strength (HGS\u0026thinsp;\u0026lt;\u0026thinsp;28 kg in men and \u0026lt;\u0026thinsp;18 kg in women) and low muscle mass (ASMI\u0026thinsp;\u0026lt;\u0026thinsp;7.0 kg/m\u0026sup2; in men and \u0026lt;\u0026thinsp;5.7 kg/m\u0026sup2; in women [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Two classification approaches were applied. First, among participants with complete data, sarcopenia was defined as the concurrent presence of low HGS and muscle mass. Second, to retain participants with available HGS data but missing muscle mass data, a three-level classification was used: non-sarcopenia (normal HGS), possible sarcopenia (low HGS without muscle mass measurement), and sarcopenia (concurrent low HGS and low muscle mass). Participants with a low HGS but missing muscle mass measurements were retained in the possible sarcopenia category.\u003c/p\u003e\n\u003ch3\u003eIntervention\u003c/h3\u003e\n\u003cp\u003eParticipants in the intervention group underwent FIRM, a multidisciplinary and intensive rehabilitation program that included structured physiotherapy, occupational therapy, and patient education, with linkage to community-based rehabilitation services. The conventional rehabilitation group received standard postoperative care that focused primarily on basic gait training. The detailed intervention protocols have been reported previously [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eOutcome\u003c/h3\u003e\n\u003cp\u003eIndependent ambulation at 12 months was defined as a FAC score\u0026thinsp;\u0026ge;\u0026thinsp;3 combined with a Koval walking ability score\u0026thinsp;\u0026le;\u0026thinsp;3, consistent with pre-fracture ambulation criteria.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eThe baseline characteristics of the randomized cohort were summarized by treatment group using means with standard deviations for continuous variables and counts with percentages for categorical variables. The comparative effectiveness of FIRM versus conventional rehabilitation across the sarcopenia strata was evaluated using logistic regression, with independent ambulation at 12 months as the outcome. The models included the treatment group, sarcopenia status, and their interaction; treatment effects were reported as stratum-specific odds ratios (ORs) with 95% confidence intervals (CIs). Three analytical models were applied: Model 1 included participants with complete baseline HGS and muscle mass data (sarcopenia vs. non-sarcopenia); Model 2 applied a three-level AWGS-based classification among participants with available HGS (non-sarcopenia, possible sarcopenia, and sarcopenia); and Model 3 dichotomized participants by muscle strength alone (normal vs. low HGS), regardless of muscle mass availability.\u003c/p\u003e \u003cp\u003eStratum-specific ORs, model-based predicted probabilities, and absolute risk differences (RDs) were estimated using marginal means, and the number needed to treat (NNT) was calculated as the inverse of the RD. Analyses were sequentially adjusted (unadjusted; age and sex; further adjustment for cognitive impairment, CCI, and pre-fracture gait impairment). All tests were two-sided, with a significance level of 0.05. Analyses were conducted using the R software (version 4.4.3; R Foundation for Statistical Computing, Vienna, Austria).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eCharacteristics of the participants\u003c/h2\u003e \u003cp\u003eThe baseline characteristics of the randomized cohort are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, and the participant flow, including eligibility for sarcopenia-stratified analysis, is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. A total of 203 patients were randomized to the FIRM (n\u0026thinsp;=\u0026thinsp;108) or conventional rehabilitation (n\u0026thinsp;=\u0026thinsp;95) group, and 119 (58.6%) completed the 12-month follow-up. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, nine participants lacked baseline HGS and muscle mass data, and muscle mass data were missing in an additional 75 participants. Baseline characteristics were generally comparable between the groups, except for a longer time to transfer to the rehabilitation unit in the FIRM group and a lower prevalence of cognitive impairment.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBaseline characteristics of the randomized cohort according to treatment group.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFIRM group\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;108)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eConventional group\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;95)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP-\u003c/em\u003evalue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, mean (SD), years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80.8 (7.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e82.0 (6.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.212\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex, n (%) (female)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e82 (75.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e73 (76.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.878\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeight, mean (SD), cm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e155.5 (8.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e156.0 (8.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.733\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight, mean (SD), kg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53.3 (9.4 )\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e55.1 (10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.188\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI, mean (SD), kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.1 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.6 (3.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.276\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eASMI, mean (SD), kg/m\u003csup\u003e2\u003c/sup\u003e (n\u0026thinsp;=\u0026thinsp;119)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.3 (1.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.2 (1.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.778\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.3 (1.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.7 (1.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.120\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHGS, mean (SD), kg (n\u0026thinsp;=\u0026thinsp;194)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20.6 (8.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.0 (7.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.561\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.9 (6.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.6 (6.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.803\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFracture type, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.103\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemoral neck\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50 (46.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32 (33.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntertrochanteric\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51 (47.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e59 (53.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubtrochanteric\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (6.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (4.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOperation type, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.014\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBipolar hemiarthroplasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e47 (43.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52 (54.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal hip arthroplasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (10.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (1.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInternal fixation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50 (46.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42 (44.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-fracture Koval, mean (SD), score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.7 (1.2 )\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.8 (1.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.794\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-fracture FAC, mean (SD), score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.6 (0.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.6 (0.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.562\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-fracture gait impairment, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (11.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (8.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.521\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious history of hip fracture, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (6.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (5.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.713\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCognitive impairment, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e39 (36.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e47 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.046\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOsteoporosis, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e77 (71.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e70 (73.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.704\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharlson Comorbidity Index, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.913\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37 (34.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33 (34.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMild (1\u0026ndash;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51 (47.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e41 (43.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModerate (3\u0026ndash;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (8.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (9.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSevere (\u0026ge;\u0026thinsp;5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (10.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (12.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative complication, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (2.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (8.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.076\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength of hospital stay, mean (SD), days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.0 (6.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.4 (6.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.537\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDays to surgery, mean (SD),\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.9 (2.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.2 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDays to rehabilitation, mean (SD),\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.4 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.0 (2.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDischarge location, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.969\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e56 (51.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e49 (51.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInstitution\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52 (48.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e46 (48.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eFIRM, fragility integrated rehabilitation management; BMI, body mass index; ASMI, appendicular skeletal muscle mass index; HGS, handgrip strength; FAC, functional ambulation category.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe baseline characteristics stratified by sarcopenia status are presented in Supplementary Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e. Participants with possible or sarcopenia were older and had a lower body mass index; poorer baseline functional status; higher comorbidity burden; and higher prevalence of pre-fracture gait impairment, prior hip fracture, cognitive impairment, and institutional discharge, indicating clinically meaningful differences across the sarcopenia spectrum.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eComparative effectiveness of FIRM versus conventional rehabilitation across the sarcopenia strata\u003c/h2\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003eModel 1: Sarcopenia vs non-sarcopenia\u003c/h2\u003e \u003cp\u003eThe treatment-by-sarcopenia interaction was not statistically significant in the unadjusted or adjusted models (all P for interaction\u0026thinsp;\u0026gt;\u0026thinsp;0.43). However, stratum-specific analyses showed a substantially greater benefit of the FIRM in participants with sarcopenia (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the unadjusted analyses, FIRM was associated with a large absolute increase in independent ambulation at 12 months in the sarcopenia group (RD, +\u0026thinsp;28.9%; P\u0026thinsp;=\u0026thinsp;0.043; NNT\u0026thinsp;=\u0026thinsp;3.5), whereas the effect was small and non-significant in the non-sarcopenia group (RD, +\u0026thinsp;6.3%; P\u0026thinsp;=\u0026thinsp;0.63; NNT\u0026thinsp;=\u0026thinsp;16.0). This pattern persisted after adjusting for age and sex (RD, +\u0026thinsp;29.1%; P\u0026thinsp;=\u0026thinsp;0.042; NNT\u0026thinsp;=\u0026thinsp;3.4) and remained clinically meaningful in the fully adjusted model (RD, +\u0026thinsp;32.3%; P\u0026thinsp;=\u0026thinsp;0.045; NNT\u0026thinsp;=\u0026thinsp;3.1), with no significant benefit observed among participants without sarcopenia (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Supplementary Figure S2).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eModel 2: Three-level AWGS 2025 sarcopenia classification\u003c/h2\u003e \u003cp\u003eAmong participants with available baseline HGS data, the crude rate of independent ambulation at 12 months declined across the sarcopenia categories (86.1% in non-sarcopenia, 64.5% in possible sarcopenia, and 57.1% in sarcopenia; P\u0026thinsp;=\u0026thinsp;0.016), indicating progressively poorer recovery with increasing sarcopenia severity (Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAlthough the treatment-by-sarcopenia interaction was not statistically significant (all P for interaction\u0026thinsp;\u0026gt;\u0026thinsp;0.70), stratum-specific analyses demonstrated greater treatment effects in participants with sarcopenia (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). In the unadjusted analyses, FIRM was associated with substantial absolute improvements in independent ambulation among participants with possible sarcopenia (RD, +\u0026thinsp;34.6%; P\u0026thinsp;=\u0026thinsp;0.032; NNT\u0026thinsp;=\u0026thinsp;2.9) and sarcopenia (RD, +\u0026thinsp;28.9%; P\u0026thinsp;=\u0026thinsp;0.043; NNT\u0026thinsp;=\u0026thinsp;3.5), but not in those without sarcopenia (RD, +\u0026thinsp;7.1%; P\u0026thinsp;=\u0026thinsp;0.54). After adjusting for age and sex, the benefits persisted in sarcopenia (RD, +\u0026thinsp;30.9%; P\u0026thinsp;=\u0026thinsp;0.030; NNT\u0026thinsp;=\u0026thinsp;3.2) and remained clinically relevant, although attenuated, in possible sarcopenia. In the fully adjusted model, the largest and most statistically significant benefit was observed in the sarcopenia group (RD, +\u0026thinsp;35.9%; P\u0026thinsp;=\u0026thinsp;0.031; NNT\u0026thinsp;=\u0026thinsp;2.8), whereas the effects in the non-sarcopenia and possible sarcopenia groups were smaller and non-significant (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Supplementary Figure S2).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eModel 3: Low versus normal HGS\u003c/h2\u003e \u003cp\u003eWhen participants were dichotomized by baseline HGS, the treatment-by-strength interaction was not statistically significant (P for interaction\u0026thinsp;=\u0026thinsp;0.41\u0026ndash;0.55). Nevertheless, stratum-specific analyses consistently indicated that the benefit of the FIRM was concentrated among participants with low HGS (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the unadjusted analyses, FIRM was associated with a large absolute increase in independent ambulation at 12 months among participants with low HGS (RD, +\u0026thinsp;29.9%; P\u0026thinsp;=\u0026thinsp;0.006; NNT\u0026thinsp;=\u0026thinsp;3.3), with no meaningful benefit observed in those with normal strength (RD, +\u0026thinsp;7.1%; P\u0026thinsp;=\u0026thinsp;0.54). This finding persisted even after adjusting for age and sex (RD, +\u0026thinsp;28.9%; P\u0026thinsp;=\u0026thinsp;0.007; NNT\u0026thinsp;=\u0026thinsp;3.5). and remained robust in the fully adjusted model (RD\u0026thinsp;=\u0026thinsp;+\u0026thinsp;35.3%; P\u0026thinsp;=\u0026thinsp;0.005; NNT\u0026thinsp;=\u0026thinsp;2.8). The concordant stratum-specific ORs further supported the strong treatment effect in the low-strength group (OR, 4.38 vs 1.65; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and Supplementary Figure S2).\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this secondary analysis of a multicenter RCT, we found that the functional benefit of integrated rehabilitation after hip fracture was not uniform but varied systematically with baseline muscle strength and sarcopenia severity. Although formal tests of treatment-by-sarcopenia interactions were not statistically significant, stratum-specific analyses consistently demonstrated clinically meaningful differences in treatment effects across all analytical models. In particular, older adults with low HGS or sarcopenia derived substantially greater ambulatory benefits from FIRM than from conventional rehabilitation, as evidenced by large absolute gains in independent ambulation and a low NNT at 12 months.\u003c/p\u003e \u003cp\u003eSarcopenia is a critical condition in older adults with hip fractures, serving as both a contributor to fracture occurrence and a major barrier to postoperative recovery. It reflects a complex multifactorial pathophysiology, including reduced mechanical loading, impaired muscle protein synthesis, chronic inflammation, and metabolic dysregulation, resulting in a concurrent decline in muscle strength and bone quality [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Consequently, sarcopenia impairs gait and balance, increases the risk of falls and fractures [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e], and is consistently associated with delayed functional recovery and poor prognosis after hip fracture [\u003cspan additionalcitationids=\"CR11 CR12\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Importantly, sarcopenia is at least partially reversible [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e], underscoring the clinical relevance of early identification and timely implementation of targeted interventions. Given its dual role as both a precipitating factor and modifiable determinant of recovery, sarcopenia should be considered a central therapeutic target in post\u0026ndash;hip fracture care.\u003c/p\u003e \u003cp\u003eOur findings suggest that baseline muscle strength and sarcopenia status are the key determinants of the most appropriate rehabilitation strategies after hip fracture surgery. Multidisciplinary, intensive, and structured rehabilitation has been shown to improve functional outcomes, reduce institutionalization, and decrease mortality in this population [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. However, despite sarcopenia being a well-established poor prognostic factor, comparative evidence of optimal rehabilitation strategies in this population remains limited. Previous studies have largely focused on individual exercises or nutritional components as adjuncts to conventional rehabilitation, with heterogeneous designs and limited comparative scope [\u003cspan additionalcitationids=\"CR35 CR36\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. In this context, the present study provides comparative evidence that an integrated multidisciplinary rehabilitation program confers greater functional benefits than conventional rehabilitation in older adults with hip fracture and sarcopenia or impaired muscle strength. Across multiple analytical models, this advantage was reflected in consistently larger absolute gains in independent ambulation, with the benefit of integrated rehabilitation particularly pronounced in patients with sarcopenia. Notably, despite their substantial functional vulnerability, these patients appeared to retain their rehabilitation potential when exposed to intensive integrated interventions.\u003c/p\u003e \u003cp\u003eThese findings also suggest that conventional rehabilitation alone is insufficient to achieve optimal functional recovery in patients with sarcopenia or impaired muscle strength as it may not adequately address the complex physical and functional deficits inherent to sarcopenia. This should not be interpreted as implying that integrated rehabilitation is ineffective in patients with preserved muscle strength; rather, our results emphasize that in patients with sarcopenia or low muscle strength, integrated and multidisciplinary rehabilitation is not merely advantageous, but may be essential to maximize recovery. From a clinical perspective, these data support a stratified rehabilitation approach in which patients with impaired muscle strength are proactively identified and prioritized for intensive programs, such as FIRM, to optimize ambulatory recovery after hip fracture.\u003c/p\u003e \u003cp\u003eRecent global consensus statements have revised the conceptual framework of sarcopenia, placing greater emphasis on early case-finding and repeated assessment in high-risk populations. The updated AWGS 2025 consensus emphasizes early case-finding and repeated assessment of sarcopenia in high-risk older adults, with HGS being recommended as the first-line screening tool [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Even in the absence of overt muscle weakness, individuals with relevant medical risk factors are considered at risk for sarcopenia and are recommended to undergo periodic reassessment and timely muscle health interventions. Hip fracture is a prototypical geriatric syndrome in this context, functioning both as a consequence and a precipitating factor of sarcopenia, placing patients in a highly vulnerable state characterized by acute stress, immobilization, inflammation, and nutritional decline. Accordingly, older adults with hip fractures are recognized as a priority population for early evaluation and proactive intervention.\u003c/p\u003e \u003cp\u003eAgainst this background, the consistent benefit of FIRM among patients with sarcopenia or low HGS across the unadjusted and adjusted models highlights muscle strength as a clinically meaningful and actionable marker for prioritizing intensive rehabilitation after hip fracture. Within the AWGS 2025 framework, low HGS without concurrent muscle mass assessment is classified as possible sarcopenia and may be interpreted as functional sarcopenia to prompt early identification and intervention. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Notably, even patients identified solely by low HGS derived greater benefits from FIRM than from conventional rehabilitation. Given the limited feasibility of routine muscle mass assessment in postoperative settings [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], these findings support the use of HGS as a simple bedside screening tool to guide stratified rehabilitation, whereby patients with impaired muscle strength are prioritized for integrated programs such as FIRM to optimize functional recovery.\u003c/p\u003e \u003cp\u003eThis study had several limitations. First, this secondary analysis was not powered for sarcopenia-stratified comparisons, which limited the statistical power of formal interaction testing. Accordingly, the treatment-by-sarcopenia interaction terms did not consistently reach statistical significance despite internally consistent and clinically meaningful stratum-specific effects and should be interpreted as exploratory. Second, muscle mass measurements were unavailable for all participants, potentially leading to misclassification of sarcopenia status. Participants with low HGS but missing muscle mass data were classified as having possible sarcopenia; such nondifferential misclassification would bias results toward the null, potentially underestimating true differences across sarcopenia severity. Third, the independent or additive effects of structured nutritional interventions could not be evaluated. Fourth, attrition during the 12-month follow-up period was substantial, and recruitment from tertiary rehabilitation centers may limit generalizability.\u003c/p\u003e \u003cp\u003eDespite these limitations, this study suggests that integrated multidisciplinary rehabilitation provides greater functional benefits than conventional rehabilitation in older adults with hip fractures and impaired muscle strength. Low muscle strength did not indicate limited rehabilitation potential but rather identified a vulnerable subgroup more likely to benefit from intensive, integrated rehabilitation. Future prospective studies that stratify patients according to sarcopenia status and compare conventional with enhanced integrated rehabilitation protocols may help further refine optimal strategies for this high-risk population.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn this secondary analysis of a multicenter RCT, older adults with hip fractures and low HGS or sarcopenia derived substantially greater functional benefits from FIRM than from conventional rehabilitation. Impaired muscle strength did not reflect limited rehabilitation potential but instead identified patients who were particularly responsive to intensive, multidisciplinary intervention. These findings support a targeted and stratified rehabilitation strategy, in which baseline muscle strength is used to proactively identify patients most likely to benefit from integrated rehabilitation programs. Early screening for low HGS and prioritizing such patients for intensive integrated rehabilitation may optimize functional recovery and reduce the overall burden of hip fractures in older adults.\u003c/p\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eContributions\u003c/h2\u003e \u003cp\u003eConceptualization: SK Lim, JY Lim; Project administration: JY Lim; Data curation: SK Lim, JY Lim; Formal analysis SK Lim; Funding acquisition: SK Lim; Methodology: SK Lim, JY Lim; Resources: : JY Lim, Supervision: JY Lim; Writing \u0026ndash; original draft: SK Lim; Writing \u0026ndash; review \u0026amp; editing: JY Lim; All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of interest\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no competing interest.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthics approval\u003c/strong\u003e \u003cp\u003eThe study protocol was approved by the Institutional Review Boards of XXXXX (B-1603-337-002), XXXXX (C2016117[1860]), and XXXXX (JEJUNUH 2016-11-001). All participants provided written informed consent prior to enrollment.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis research was supported by a grant of Patient-Centered Clinical Research Coordinating Center (PACEN) funded by the Ministry of Health \u0026amp; Welfare, Republic of Korea (grant number: RS-2025-02217163).\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eNot applicable.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e \u003cp\u003eData are available on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHarris E, Clement N, MacLullich A, Farrow L The impact of an ageing population on future increases in hip fracture burden. Bone Joint J 2024;106-b(1):62\u0026thinsp;\u0026ndash;\u0026thinsp;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1302/0301-620x.106b1.Bjj-2023-0740.R1\u003c/span\u003e\u003cspan address=\"https://doi:10.1302/0301-620x.106b1.Bjj-2023-0740.R1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJang I-Y, Lee HY, Lee E (2019) Geriatrics fact sheet in Korea 2018 from national statistics. Ann Geriatr Med Res 23(2):50. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.4235/agmr.19.0013\u003c/span\u003e\u003cspan address=\"https://doi:10.4235/agmr.19.0013\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCederholm T, Cruz-Jentoft AJ, Maggi S (2013) Sarcopenia and fragility fractures. Eur J Phys Rehabil Med 49(1):111\u0026ndash;117\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrzeszczynski F, Brzeszczynska J, Duckworth AD et al (2022) The effect of sarcopenia on outcomes following orthopaedic surgery: a systematic review. bone joint J 104(3):321\u0026ndash;330. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1302/0301-620X.104B3.BJJ-2021-1052.R1\u003c/span\u003e\u003cspan address=\"https://doi:10.1302/0301-620X.104B3.BJJ-2021-1052.R1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSayer AA, Cooper R, Arai H, Sarcopenia et al (2024) Nat Rev Dis Primers 10(1):68. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1038/s41572-024-00550-w\u003c/span\u003e\u003cspan address=\"https://doi:10.1038/s41572-024-00550-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYuan S, Larsson SC (2023) Epidemiology of sarcopenia: prevalence, risk factors, and consequences. Metabolism 144:155533. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1016/j.metabol.2023.155533\u003c/span\u003e\u003cspan address=\"https://doi:10.1016/j.metabol.2023.155533\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeng SE, Huang YW, Tseng YC et al (2025) The evolving landscape of sarcopenia in Asia: a systematic review and meta-analysis following the 2019 Asian working group for sarcopenia (AWGS) diagnostic criteria. Arch Gerontol Geriatr 128:105596. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1016/j.archger.2024.105596\u003c/span\u003e\u003cspan address=\"https://doi:10.1016/j.archger.2024.105596\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim M, Won CW (2020) Sarcopenia in Korean community-dwelling adults aged 70 years and older: application of screening and diagnostic tools from the Asian working group for sarcopenia 2019 update. J Am Med Dir Assoc 21(6):752\u0026ndash;758. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1016/j.jamda.2020.03.018\u003c/span\u003e\u003cspan address=\"https://doi:10.1016/j.jamda.2020.03.018\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWong RMY, Wong H, Zhang N et al (2019) The relationship between sarcopenia and fragility fracture-a systematic review. Osteoporos Int 30(3):541\u0026ndash;553. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1007/s00198-018-04828-0\u003c/span\u003e\u003cspan address=\"https://doi:10.1007/s00198-018-04828-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSheehan KJ, Williamson L, Alexander J et al (2018) Prognostic factors of functional outcome after hip fracture surgery: a systematic review. Age Ageing 47(5):661\u0026ndash;670. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi\u003c/span\u003e\u003cspan address=\"https://doi\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ageing/afy057\u003c/span\u003e\u003cspan address=\"10.1093/ageing/afy057\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu BY, Yan S, Low LL, Vasanwala FF, Low SG (2019) Predictors of poor functional outcomes and mortality in patients with hip fracture: a systematic review. BMC Musculoskelet Disord 20(1):568. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1186/s12891-019-2950-0\u003c/span\u003e\u003cspan address=\"https://doi:10.1186/s12891-019-2950-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWong BLL, Chan YH, O'Neill GK, Murphy D, Merchant RA (2023) Frailty, length of stay and cost in hip fracture patients. Osteoporos Int 34(1):59\u0026ndash;68. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1007/s00198-022-06553-1\u003c/span\u003e\u003cspan address=\"https://doi:10.1007/s00198-022-06553-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoskovic K, Pantelinac S, Tomasevic-Todorovic S et al (2020) AB0889 sarcopenia and hip fracture in geriatric population. Ann Rheum Dis 79:1749. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1136/annrheumdis-2020-eular.5440\u003c/span\u003e\u003cspan address=\"https://doi:10.1136/annrheumdis-2020-eular.5440\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen LK, Hsiao FY, Akishita M et al (2025) A focus shift from sarcopenia to muscle health in the Asian working group for sarcopenia 2025 consensus update. Nat Aging. ;5(11):2164-75. 2025;5(11):2164\u0026ndash;2175. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1038/s43587-025-01004-y\u003c/span\u003e\u003cspan address=\"https://doi:10.1038/s43587-025-01004-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCruz-Jentoft AJ, Sayer AA (2019) Sarcopenia Lancet 393(10191):2636\u0026ndash;2646. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1016/s0140-6736(19)31138-9\u003c/span\u003e\u003cspan address=\"https://doi:10.1016/s0140-6736(19)31138-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWakabayashi H, Sakuma K (2014) Rehabilitation nutrition for sarcopenia with disability: a combination of both rehabilitation and nutrition care management. J Cachexia Sarcopenia Muscle 5(4):269\u0026ndash;277. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1007/s13539-014-0162-x\u003c/span\u003e\u003cspan address=\"https://doi:10.1007/s13539-014-0162-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInoue T, Maeda K, Nagano A et al (2020) Undernutrition, sarcopenia, and frailty in fragility hip fracture: advanced strategies for improving clinical outcomes. Nutrients 12(12):3743. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.3390/nu12123743\u003c/span\u003e\u003cspan address=\"https://doi:10.3390/nu12123743\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Y, Chen L, Wu P, Lang J, Chen L (2020) Intervention with erythropoietin in sarcopenic patients with femoral intertrochanteric fracture and its potential effects on postoperative rehabilitation. Geriatr Gerontol Int 20(2):150\u0026ndash;155. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1111/ggi.13845\u003c/span\u003e\u003cspan address=\"https://doi:10.1111/ggi.13845\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLim SK, Beom J, Lee SY, Lim JY (2019) Functional outcomes of fragility fracture integrated rehabilitation management in sarcopenic patients after hip fracture surgery and predictors of independent ambulation. J Nutr Health Aging 23(10):1034\u0026ndash;1042. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1007/s12603-019-1289-4\u003c/span\u003e\u003cspan address=\"https://doi:10.1007/s12603-019-1289-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLim SK, Beom J, Lee SY et al (2025) Efficacy of fragility fracture integrated rehabilitation management in older adults with hip fractures: a randomized controlled trial with 1-year follow-up. J Am Med Dir Assoc 26(1):105321. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1016/j.jamda.2024.105321\u003c/span\u003e\u003cspan address=\"https://doi:10.1016/j.jamda.2024.105321\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCharlson ME, Pompei P, Ales KL, MacKenzie CR (1987) A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 40(5):373\u0026ndash;383. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1016/0021-9681(87)90171-8\u003c/span\u003e\u003cspan address=\"https://doi:10.1016/0021-9681(87)90171-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoval KJ, Skovron ML, Aharonoff GB, Meadows SE, Zuckerman JD (1995) Ambulatory ability after hip fracture. a prospective study in geriatric patients. Clin Orthop Relat Res ;(310):150\u0026ndash;159\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHolden MK, Gill KM, Magliozzi MR, Nathan J, Piehl-Baker L (1984) Clinical gait assessment in the neurologically impaired. reliability and meaningfulness. Phys Ther 64(1):35\u0026ndash;40. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1093/ptj/64.1.35\u003c/span\u003e\u003cspan address=\"https://doi:10.1093/ptj/64.1.35\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKang Y, Na DL, Hahn S (1997) A validity study on the Korean mini-mental state examination (K-MMSE) in dementia patients. J Korean Neurol Assoc 15(2):300\u0026ndash;308\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee DY, Lee KU, Lee JH et al (2004) A normative study of the CERAD neuropsychological assessment battery in the Korean elderly. J Int Neuropsychol Soc 10(1):72\u0026ndash;81. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1017/S1355617704101094\u003c/span\u003e\u003cspan address=\"https://doi:10.1017/S1355617704101094\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKyle UG, Bosaeus I, De Lorenzo AD et al (2004) Bioelectrical impedance analysis-part II: utilization in clinical practice. Clin Nutr 23(6):1430\u0026ndash;1453. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1016/j.clnu.2004.09.012\u003c/span\u003e\u003cspan address=\"https://doi:10.1016/j.clnu.2004.09.012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLukaski HC, Johnson PE, Bolonchuk WW, Lykken GI (1985) Assessment of fat-free mass using bioelectrical impedance measurements of the human body. Am J Clin Nutr 41(4):810\u0026ndash;817. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1093/ajcn/41.4.810\u003c/span\u003e\u003cspan address=\"https://doi:10.1093/ajcn/41.4.810\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLim SK, Beom J, Lee SY et al (2025) Standardized measurement of muscle strength and physical performance for sarcopenia: an expert-based delphi consensus. Ann Geriatr Med Res 29(2):185\u0026ndash;198. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi\u003c/span\u003e\u003cspan address=\"https://doi\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.4235/agmr.25.0070\u003c/span\u003e\u003cspan address=\"10.4235/agmr.25.0070\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTarantino U, Piccirilli E, Fantini M et al (2015) Sarcopenia and fragility fractures: molecular and clinical evidence of the bone-muscle interaction. J Bone Joint Surg Am 97(5):429\u0026ndash;437. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi\u003c/span\u003e\u003cspan address=\"https://doi\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2106/jbjs.N.00648\u003c/span\u003e\u003cspan address=\"10.2106/jbjs.N.00648\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYeung SSY, Reijnierse EM, Pham VK et al (2019) Sarcopenia and its association with falls and fractures in older adults: a systematic review and meta-analysis. J Cachexia Sarcopenia Muscle 10(3):485\u0026ndash;500. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1002/jcsm.12411\u003c/span\u003e\u003cspan address=\"https://doi:10.1002/jcsm.12411\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKirk B, Cawthon PM, Arai H et al (2024) The conceptual definition of sarcopenia: delphi consensus from the global leadership Initiative in sarcopenia (GLIS). Age Ageing 53(3):afae052. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1093/ageing/afae052\u003c/span\u003e\u003cspan address=\"https://doi:10.1093/ageing/afae052\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHandoll HH, Cameron ID, Mak JC, Panagoda CE, Finnegan TP (2021) Multidisciplinary rehabilitation for older people with hip fractures. Cochrane Database Syst Rev 11(11):Cd007125. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1002/14651858.CD007125.pub3\u003c/span\u003e\u003cspan address=\"https://doi:10.1002/14651858.CD007125.pub3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcDonough CM, Harris-Hayes M, Kristensen MT et al (2021) Physical therapy management of older adults with hip fracture. J Orthop Sports Phys Ther 51(2):CPG1\u0026ndash;CPG81. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.2519/jospt.2021.0301\u003c/span\u003e\u003cspan address=\"https://doi:10.2519/jospt.2021.0301\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYoo JI, Ha YC, Cha Y (2022) Nutrition and exercise treatment of sarcopenia in hip fracture patients: systematic review. J Bone Metab 29(2):63\u0026ndash;73. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.11005/jbm.2022.29.2.63\u003c/span\u003e\u003cspan address=\"https://doi:10.11005/jbm.2022.29.2.63\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAvola M, Mangano GRA, Testa G et al (2020) Rehabilitation strategies for patients with femoral neck fractures in sarcopenia: a narrative review. J Clin Med 9(10). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.3390/jcm9103115\u003c/span\u003e\u003cspan address=\"https://doi:10.3390/jcm9103115\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOh MK, Yoo JI, Byun H et al (2020) Efficacy of combined antigravity treadmill and conventional rehabilitation after hip fracture in patients with sarcopenia. J Gerontol Biol Sci Med Sci 75(10):e173\u0026ndash;e81. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1093/gerona/glaa158\u003c/span\u003e\u003cspan address=\"https://doi:10.1093/gerona/glaa158\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHan Z, Ji NN, Ma JX, Dong Q, Ma XL (2022) Effect of resistance training combined with beta-hydroxy-beta-methylbutyric acid supplements in elderly patients with sarcopenia after hip replacement. Orthop Surg 14(4):704\u0026ndash;713. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1111/os.13208\u003c/span\u003e\u003cspan address=\"https://doi:10.1111/os.13208\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHsiao PL, Hsu SF, Chen PH et al (2019) Does a spinal implant alter dual energy X-ray absorptiometry body composition measurements? PLoS ONE 14(9):e0222758. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi:10.1371/journal.pone.0222758\u003c/span\u003e\u003cspan address=\"https://doi:10.1371/journal.pone.0222758\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-geriatric-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"EGEM","sideBox":"Learn more about [European Geriatric Medicine](https://www.springer.com/journal/41999)","snPcode":"41999","submissionUrl":"https://www.editorialmanager.com/egem/default2.aspx","title":"European Geriatric Medicine","twitterHandle":"","acdcEnabled":false,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"hip fracture, older people, sarcopenia, rehabilitation, muscle strength","lastPublishedDoi":"10.21203/rs.3.rs-8868135/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8868135/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eSarcopenia and impaired muscle strength are common in older adults with hip fracture and are strongly associated with poor functional recovery. Although integrated multidisciplinary rehabilitation improves outcomes after hip fractures, it remains unclear whether its benefits over conventional rehabilitation differ by baseline muscle strength or sarcopenia severity. This study aimed to examine whether the functional benefits of Fragility Fracture Integrated Rehabilitation Management (FIRM) vary according to sarcopenia status and handgrip strength (HGS) in older adults after hip fracture surgery.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis was a secondary analysis of a multicenter randomized controlled trial comparing FIRM with conventional rehabilitation in adults aged\u0026thinsp;\u0026ge;\u0026thinsp;65 years undergoing hip fracture surgery. Independent ambulation at 12 months was the primary outcome. Sarcopenia was classified using three approaches: sarcopenia versus non-sarcopenia, a three-level classification (non-sarcopenia, possible sarcopenia, sarcopenia), and low versus normal HGS. Logistic regression models including treatment, sarcopenia status, and their interaction, were fitted with sequential adjustment for relevant covariates.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eOf the 203 randomized participants, 119 (58.6%) completed the 12-month follow-up. Although treatment-by-sarcopenia interactions were not statistically significant, stratum-specific analyses consistently showed a greater benefit of FIRM in participants with sarcopenia or low HGS. In the fully adjusted models, FIRM was associated with large absolute improvements in independent ambulation among participants with sarcopenia (odds ratio [OR], 4.01; risk difference [RD]\u0026thinsp;+\u0026thinsp;32.3%) and low HGS (OR, 4.38; RD\u0026thinsp;+\u0026thinsp;35.3%).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eIntegrated rehabilitation provides greater functional benefit than conventional rehabilitation in older adults with sarcopenia or low muscle strength after hip fracture.\u003c/p\u003e","manuscriptTitle":"Integrated rehabilitation and ambulatory recovery in older adults with hip fracture according to muscle strength and sarcopenia status: a secondary analysis of a randomized controlled trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-27 09:16:01","doi":"10.21203/rs.3.rs-8868135/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revisions","date":"2026-04-30T19:06:22+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2026-02-24T08:26:12+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-23T23:20:26+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"European Geriatric Medicine","date":"2026-02-17T17:54:38+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-14T16:54:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Geriatric Medicine","date":"2026-02-13T23:10:09+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-geriatric-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"EGEM","sideBox":"Learn more about [European Geriatric Medicine](https://www.springer.com/journal/41999)","snPcode":"41999","submissionUrl":"https://www.editorialmanager.com/egem/default2.aspx","title":"European Geriatric Medicine","twitterHandle":"","acdcEnabled":false,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7c4fff8c-82f6-43c9-9976-55aa068d9867","owner":[],"postedDate":"February 27th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Major revisions","date":"2026-04-30T19:06:22+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-15T09:09:00+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-27 09:16:01","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8868135","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8868135","identity":"rs-8868135","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}