Cognitive Function, Depressive Symptoms and Quality of Life in Clinically Stable Kidney Transplant Recipients

Cognitive Function, Depressive Symptoms and Quality of Life in Clinically Stable Kidney Transplant Recipients | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Cognitive Function, Depressive Symptoms and Quality of Life in Clinically Stable Kidney Transplant Recipients Namolovan Călin, Bogdan Dumitru Agavriloaei, Luminita Voroneanu, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9084932/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Background Kidney transplantation improves survival in patients with end-stage kidney disease; however, cognitive and psychological outcomes after transplantation remain incompletely characterized. This study aimed to assess cognitive performance, depressive symptoms, and health-related quality of life in clinically stable kidney transplant recipients. Methods In this cross-sectional study, 201 adult kidney transplant recipients with stable graft function were evaluated. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), depressive symptoms using the Beck Depression Inventory (BDI), and quality of life using the Short Form-36 (SF-36). Associations between clinical variables and psychological outcomes were analyzed using correlation and multivariable regression analyses. Results Global cognitive performance was largely preserved, with MMSE scores within the normal range in the majority of participants. Minimal or no depressive symptoms were observed in 84.1% of patients, while mild, moderate, and severe depressive symptoms were present in 9.0%, 3.5%, and 1.5%, respectively. Quality-of-life domains showed variability across physical and mental components. Depressive symptom severity was significantly associated with reduced quality-of-life scores (p < 0.05), whereas MMSE scores showed limited correlation with depressive symptoms. Clinical variables demonstrated selective associations with psychological and quality-of-life measures. Conclusions In clinically stable kidney transplant recipients, overall cognitive performance appears preserved, although a subset of patients continues to experience depressive symptoms and impaired quality of life. These findings underscore the importance of routine psychological evaluation alongside standard clinical follow-up in transplant care. Kidney transplantation Cognitive function Depression Mini-Mental State Examination Quality of life Clinically stable recipients 1. Introduction Cognitive impairment and depressive symptoms are common complications in patients with chronic kidney disease and are strongly associated with adverse clinical outcomes, reduced quality of life, and increased mortality [ 1 ]. In patients receiving dialysis, cognitive dysfunction has been extensively documented and is attributed to a complex interplay of vascular disease, uremic toxins, inflammation, and metabolic disturbances [ 2 ]. Kidney transplantation improves survival and quality of life and is generally assumed to mitigate many of these risk factors; however, the extent to which cognitive function and mood fully recover after transplantation remains incompletely understood [ 3 ]. Cognitive impairment is a key component of frailty in patients with end-stage kidney disease and kidney transplant candidates and has been consistently associated with adverse outcomes, including increased mortality, both before and after transplantation. These observations suggest that cognitive vulnerability may persist even in clinically stable kidney transplant recipients and warrant focused cognitive evaluation in this population [ 4 ]. Cognitive dysfunction reported prevalence rates vary widely across studies. This marked heterogeneity is largely attributable to differences in study populations, time elapsed since transplantation, and, critically, the cognitive assessment tools used, with more sensitive instruments consistently identifying a higher burden of cognitive impairment than brief global screening tests [ 5 ]. Generally, kidney transplantation has been associated with significant improvements in overall neurocognitive performance compared with the dialysis period [ 6 ], but the assessment of post-transplant cognitive function remains heterogeneous and insufficiently standardized, relying on a wide range of neuropsychological instruments with variable sensitivity across studies. A meta-analysis evaluating the diagnostic accuracy of the Mini-Mental State Examination demonstrated limited sensitivity for detecting mild to moderate cognitive impairment, with a substantial proportion of affected individuals remaining unidentified in the absence of overt dementia. These findings indicate that reliance on MMSE alone may underestimate clinically relevant cognitive dysfunction, particularly in populations with preserved global functioning [ 7 ]. Depression in kidney transplant recipients is associated with impaired quality of life and adverse clinical outcomes, while incident depression after transplantation remains an important determinant of increased mortality and graft failure despite an overall lower depression risk compared with patients with end-stage kidney disease [ 8 ]. Despite growing interest in cognitive outcomes after kidney transplantation, most studies rely on heterogeneous neuropsychological batteries or focus on early post-transplant periods. Data addressing cognitive performance, depressive symptoms, and quality of life simultaneously in clinically stable kidney transplant recipients, as assessed by tools commonly used in routine practice, remain limited. In this context, we aimed to evaluate global cognitive function using the MMSE, depressive symptoms, and health-related quality of life in a well-characterized cohort of stable kidney transplant recipients, and to explore their clinical correlates. 2. Materials and methods 2.1 Study design and participants This was a single-center, cross-sectional observational study conducted in a tertiary nephrology and kidney transplantation unit between October 2024 and November 2025. Patients were evaluated during routine outpatient follow-up consultations and were enrolled consecutively from the daily outpatient visit schedule. Inclusion criteria Age ≥18 years; A functional kidney transplant for a minimum of 3 months (first or subsequent graft); Clinical stability at the time of evaluation, defined as the absence of acute rejection episodes or ongoing graft dysfunction; Absence of severe visual or hearing impairment; Ability to independently complete cognitive and psychometric questionnaires. Exclusion criteria Pre-existing major neuropsychiatric disorders (e.g., severe dementia, active psychosis); Ongoing acute illness; Communication barriers that precluded reliable cognitive or psychometric testing. 2.2.Clinical and Demographic Variables Collected The following variables were recorded: Age, sex, and level of education; Time since kidney transplantation (in months); Dialysis history (modality and duration) prior to transplant; Comorbidities including hypertension, diabetes mellitus, and ischemic heart disease; Current immunosuppressive regimen. Psychometric Instruments (MMSE, BDI-II, SF-36) Mini-Mental State Examination (MMSE): Screening tool for global cognitive function (score range: 0–30). Although a cutoff of <24 is widely used in clinical practice to indicate possible cognitive impairment, it is recognized that this threshold has limited sensitivity for detecting mild cognitive deficits, particularly in populations with preserved global cognitive functioning. Beck Depression Inventory-II (BDI-II): 21-item self-report scale assessing depressive symptoms over the past two weeks (score range: 0–63). Short Form-36 Health Survey (SF-36): Assesses eight domains of health-related quality of life, with two composite scores for physical and mental components. Each domain is scored from 0 to 100. Data Collection Process Each participant underwent a single standardized evaluation session. Clinical and demographic data were collected via medical chart review and patient interview. Psychometric tests were administered in a quiet, standardized setting, and responses were self-reported, with assistance provided by trained personnel, when necessary, without influencing participant responses. Ethics approval and consent to participate: The study was conducted in accordance with the Declaration of Helsinki and was approved by the local Ethics Committee (approval no. 1796/27.02.2024). 2.3. Statistical analysis Statistical analyses were performed to describe the study population and explore associations between cognitive function, depressive symptoms, and health-related quality of life. Continuous variables were expressed as mean ± standard deviation (SD), and categorical variables as absolute numbers and percentages. Normality of distribution was assessed by visual inspection of histograms and Q–Q plots. Between-group comparisons were conducted using independent samples t-tests or one-way ANOVA for normally distributed variables, with Welch corrections applied when appropriate. For non-normally distributed variables, the Mann–Whitney U or Kruskal–Wallis test was used. Associations between categorical variables were examined using the Chi-square test or Fisher’s exact test when necessary. Correlations between continuous variables were evaluated using Pearson’s correlation coefficient. Multivariate analysis of variance (MANOVA) was performed to assess the overall effect of educational level on SF-36 domains, using Pillai’s Trace as the multivariate test statistic. Multivariable linear regression analyses were conducted to identify independent determinants of SF-36 domains. All tests were two-tailed, and a p-value < 0.05 was considered statistically significant. 3. Results 3.1. Baseline characteristics 3.1.1. General patient characteristics The cohort included 201 kidney transplant recipients, with a mean age of 48.2 ± 11.2 years, and a predominance of male participants (58.7%). Most patients resided in urban areas (62.2%). Deceased-donor transplantation was more frequent than living-donor transplantation. The mean graft vintage was 78.8 ± 73.3 months. Educational attainment and monthly income showed a heterogeneous distribution, with lower educational levels and income more frequently observed among patients from rural areas (Table 1). 3.1.2. Pre-transplant CKD stage and etiology of kidney disease Renal replacement therapy prior to transplantation was required in 68.2% of patients. Most patients required renal replacement therapy prior to transplantation, predominantly hemodialysis, with a mean dialysis duration of 35.9 ± 41.7 months. A minority (16.4%) of patients received immunosuppressive therapy before transplantation, most commonly corticosteroid-based regimens. ( Table 2 ). The mean duration of dialysis before transplantation was 35.9 ± 41.7 months (range 1–312). 3.1.3. Cardiovascular and metabolic comorbidities Hypertension was present in 78.6% of patients. Diabetes mellitus was observed in 15.4% of recipients, including both pre-transplant and post-transplant diabetes. Vascular disease, defined as coronary artery disease, peripheral arterial disease, or prior stroke, was documented in 5.0% of the cohort. Atrial fibrillation was present in 2.0% of patients. Comorbidity data are presented in Table 3 . 3.1.4. Laboratory Parameters Mean hemoglobin was 13.3 ± 2.2 g/dL (range 6.8–19.2). Anemia (hemoglobin <12 g/dL) was present in 24% of patients, while moderate to severe anemia (hemoglobin <10 g/dL) occurred in 7%. Laboratory data are summarized in Table 4 . 3.2. Mini-Mental State Examination (MMSE) The median MMSE score in the cohort fell within the normal range. MMSE-defined cognitive impairment was identified in 3 patients (1.5%), all classified as having mild impairment (MMSE 18–23). No cases of moderate or severe cognitive impairment were observed. The distribution of MMSE categories is shown in Table 5 . Given the very small number of participants classified as cognitively impaired by MMSE criteria, further subgroup analyses were not pursued. 3.2.1. Clinical and Sociodemographic Correlates of MMSE Scores Given the markedly unbalanced distribution of MMSE categories, with only three patients classified as cognitively impaired, statistical power for group comparisons was limited. Associations between MMSE categories and clinical or sociodemographic variables are detailed in Table S1 (Supplementary Table S1) 3.3. Beck's depression index Most participants (84.1%) reported minimal or no depressive symptoms. Mild depression was observed in 9.0% of patients, moderate depression in 3.5%, and severe depression in 1.5%. Beck Depression Inventory categories are presented in Table 6 . No statistically significant associations were identified between Beck categories and demographic, clinical, transplant-related, or biochemical variables. Beck categories were not associated with MMSE categories (χ² = 0.502, p = 0.919). 3.4. Health-Related Quality of Life Assessed by the SF-36 Mean scores for SF-36 domains are presented in Table 7 . Higher mean scores were observed for Social Functioning and Mental Health domains, while lower scores were recorded for Role–Physical and Role–Emotional domains. 3.4.1. Correlations with SF-36 Domains Age showed modest negative correlations with Physical Functioning, Role–Physical, Social Functioning, Bodily Pain, and Vitality. Graft vintage correlated positively with Role–Emotional scores. Beck Depression Inventory scores demonstrated consistent negative correlations across all SF-36 domains (all p < 0.001). Hemoglobin levels correlated positively with Social Functioning, while serum phosphate showed weak correlations with Role–Emotional and General Health domains. All statistically significant correlations are detailed in Table 8 . 3.5.Multivariate analysis In multivariate linear regression analyses examining determinants of SF-36 domains, Beck Depression Inventory score emerged as the most consistent independent predictor across all domains. Higher Beck scores were independently associated with poorer Physical Functioning, Role–Physical, Bodily Pain, and General Health scores, with adjusted R² values ranging from 0.10 to 0.17. For the Vitality domain, the multivariate model explained a larger proportion of variance. Both Beck score and hemoglobin level were identified as significant independent predictors, indicating that lower depressive symptom burden and higher hemoglobin levels were associated with better perceived vitality. Similarly, Beck score remained an independent predictor of Social Functioning, Role–Emotional, and Mental Health domains. Hemoglobin levels and immunosuppression status were not independently associated with most SF-36 domains, although hemoglobin showed a non-significant trend in the General Health domain and immunosuppression demonstrated a weak trend in the Mental Health domain. Independent determinants of SF-36 health-related quality-of-life domains: multivariate linear regression analysis were found in Table 9 . 3.5.1. Effects of Pre-Transplant Renal Replacement Therapy Patients with pre-transplant renal replacement therapy had higher scores in Role–Physical, Role–Emotional, and Social Functioning domains compared with patients transplanted preemptively. No significant differences were observed in other SF-36 domains. Group comparisons are presented in Table 10 . 3.5.2. Influence of Educational Level Educational level showed a significant overall effect on SF-36 domain scores. In univariate analyses, significant associations were observed with Mental Health, Role–Emotional, General Health, and Social Functioning domains (Supplementary Table S2). 3.5.4. Association Between Cognitive Status and SF-36 Scores Comparisons between patients with normal MMSE scores and those with mild MMSE-defined cognitive impairment showed no significant differences across most SF-36 domains. A significant difference was observed for the Vitality domain, with higher scores in patients with normal MMSE performance. 4. Discussion 4.1. Cognitive Function Assessed by MMSE In this cross-sectional study of clinically stable kidney transplant recipients, we observed a low prevalence of MMSE-defined cognitive impairment and depressive symptoms, alongside generally preserved health-related quality of life. These findings reflect the characteristics of a carefully selected, stable transplant cohort and the use of a brief global cognitive screening instrument, rather than the absence of cognitive vulnerability after transplantation. Cognitive impairment is highly prevalent in patients with advanced chronic kidney disease and those receiving dialysis, driven by vascular disease, metabolic disturbances, and chronic inflammation [9]. Although kidney transplantation has been associated with measurable improvements in cognitive function, particularly in attention, executive function, and processing speed, post-transplant cognitive performance has been assessed using a heterogeneous range of instruments, from global screening tools such as the Mini-Mental State Examination and Montreal Cognitive Assessment to comprehensive neuropsychological batteries. Despite overall improvement, residual or domain-specific deficits are frequently reported, highlighting the lack of standardized cognitive assessment and the persistence of subtle cognitive impairment after transplantation[10]. A study published in 2011 demonstrated that the Mini-Mental State Examination has limited sensitivity for detecting mild cognitive impairment, as it inadequately captures deficits in executive function, attention, and processing speed, leading to an underestimation of clinically relevant cognitive dysfunction despite preserved global scores [11]. Consistent with this, transplant-focused studies indicate that cognitive impairment in kidney transplant recipients is frequently underrecognized, with subtle deficits persisting and being identified only through more sensitive or domain-specific assessments [12]. Our results should therefore not be interpreted as contradicting these findings, but rather as illustrating how MMSE-based screening may underestimate mild cognitive impairment in clinically stable recipients. The low prevalence observed in our cohort likely reflects both patient selection and the intrinsic characteristics of the screening instrument. Age and educational level were associated with MMSE performance, in line with established determinants of cognitive test results in both transplant and non-transplant populations. In contrast, transplant-related variables showed no strong association with MMSE scores, suggesting that global cognitive performance may remain preserved once clinical stability is achieved. However, given the very small number of patients classified as cognitively impaired by MMSE criteria, these associations should be interpreted cautiously and considered exploratory. 4.2. Depressive Symptoms and Health-Related Quality of Life Depressive symptoms were uncommon in this cohort and were predominantly mild, yet they showed consistent and clinically meaningful associations with multiple domains of health-related quality of life. This finding underscores the central role of psychological well-being in shaping patient-reported outcomes after transplantation, even in the absence of overt cognitive impairment. The lack of a strong association between depressive symptoms and MMSE scores further suggests that mood and global cognitive performance may represent partially independent dimensions of post-transplant recovery. Our findings suggest that in clinically stable kidney transplant recipients, global cognitive screening using the MMSE identifies few cases of overt impairment, whereas depressive symptoms exert a substantially greater influence on patient-reported quality of life. This highlights the importance of systematic psychological assessment in routine post-transplant care, even when global cognitive performance appears preserved. 5. Strengths and limitations Strengths : This study provides a pragmatic evaluation of cognitive function, depressive symptoms, and health-related quality of life in a well-defined cohort of clinically stable kidney transplant recipients. The inclusion of a homogeneous outpatient population minimizes confounding by acute illness or graft dysfunction, while the use of standardized instruments, including the Mini-Mental State Examination, ensures reproducibility and comparability with existing literature. By reflecting routine clinical screening practice, the findings offer clinically relevant insights into post-transplant cognitive and psychological status. In addition, the combined assessment of cognitive performance, depressive symptoms, and health-related quality of life within the same cohort allows a more comprehensive and clinically meaningful interpretation of post-transplant neuropsychological status. Limitations : Several limitations should be acknowledged. The cross-sectional design precludes causal inference, and cognitive function was assessed using a single global screening instrument with limited sensitivity for subtle deficits. The study population consisted of clinically stable recipients from a single center, which may limit generalizability to higher-risk or early post-transplant populations. Finally, the small number of participants meeting MMSE criteria for cognitive impairment restricts the robustness of subgroup analyses. 6. Future Research Directions Future studies should adopt longitudinal designs to better define cognitive and psychological trajectories after kidney transplantation. The use of more sensitive, domain-specific cognitive assessments alongside global screening tools may improve the detection of subtle cognitive impairment and clarify its clinical relevance. Further research is also needed to explore the interplay between cognitive function, depressive symptoms, and health-related quality of life, as well as to validate these findings in larger, multicenter, and more diverse transplant populations. 5. Conclusion In clinically stable kidney transplant recipients, MMSE-defined cognitive impairment and depressive symptoms were uncommon, and overall quality of life was generally preserved. However, depressive symptoms were consistently associated with poorer quality-of-life domains, underscoring their clinical relevance. The low prevalence of cognitive impairment may reflect the use of a brief screening tool, and more comprehensive assessments may be needed to detect subtle post-transplant cognitive deficits. Declarations Competing interests The authors declare that they have no competing interests. Ethics approval and consent to participate The study was conducted in accordance with the Declaration of Helsinki and was approved by the local Ethics Committee (approval no. 1796/27.02.2024). Data availability The data that support the findings of this study are not publicly available due to their containing information that could compromise the privacy of research participants. De-identified data may be made available from the corresponding author upon reasonable request, subject to institutional approval and applicable data protection regulations. Authors’ contributions Bogdan Agavriloaei, Luminita Voroneanu, and Adrian Covic contributed to the conceptualization and study design. Data collection was performed by Bogdan Agavriloaei, Baluță Cezar, Namolovan Călin, and Lucian Sirițeanu. Data analysis and interpretation were carried out by Bogdan Agavriloaei and Luminita Voroneanu. Bogdan Agavriloaei drafted the initial version of the manuscript. Luminita Voroneanu, Baluță Cezar, Namolovan Călin, Lucian Sirițeanu, and Adrian Covic critically revised the manuscript for important intellectual content. All authors read and approved the final manuscript. Funding Declaration: no References Murray, A. M., & Knopman, D. S. (2010). Cognitive impairment in CKD: no longer an occult burden. American Journal Of Kidney Diseases , 56 (4), 615–618. Murray, A. M., et al. (2006). Cognitive impairment in hemodialysis patients is common. Neurology , 67 (2), 216–223. Jurgensen, A., Qannus, A. A., & Gupta, A. (2020). Cognitive Function in Kidney Transplantation. Curr Transplant Rep , 7 , 145–153. Haugen, C. E., et al. (2019). Frailty and Access to Kidney Transplantation. Clinical Journal Of The American Society Of Nephrology , 14 (4), 576–582. Gupta, A., et al. (2017). Prevalence and correlates of cognitive impairment in kidney transplant recipients. Bmc Nephrology , 18 (1), 158. Harciarek, M., et al. (2009). Cognitive performance before and after kidney transplantation: a prospective controlled study of adequately dialyzed patients with end-stage renal disease. Journal Of The International Neuropsychological Society , 15 (5), 684–694. Mitchell, A. J. (2009). A meta-analysis of the accuracy of the mini-mental state examination in the detection of dementia and mild cognitive impairment. Journal Of Psychiatric Research , 43 (4), 411–431. Cho, S., et al. (2022). Incidence of depression in kidney transplant recipients in South Korea: a long-term population-based study. Scientific Reports , 12 (1), 17603. Bugnicourt, J. M., et al. (2013). Cognitive disorders and dementia in CKD: the neglected kidney-brain axis. Journal Of The American Society Of Nephrology , 24 (3), 353–363. van Sandwijk, M. S., et al. (2020). Cognitive Improvement After Kidney Transplantation Is Associated With Structural and Functional Changes on MRI. Transplant Direct , 6 (3), e531. Troen, A. M., et al. (2012). Cognitive dysfunction and depression in adult kidney transplant recipients: baseline findings from the FAVORIT Ancillary Cognitive Trial (FACT). Journal Of Renal Nutrition : The Official Journal Of The Council On Renal Nutrition Of The National Kidney Foundation , 22 (2), 268–276e3. Golenia, A., Malyszko, J. S., & Malyszko, J. (2022). Cognitive Impairment and Kidney Transplantation: Underestimated, Underrecognized but Clinically Relevant Problem. Kidney & Blood Pressure Research , 47 (7), 459–466. Tables Table 1 to 10 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files 2.tables.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 02 Apr, 2026 Reviewers agreed at journal 30 Mar, 2026 Reviewers agreed at journal 30 Mar, 2026 Reviewers invited by journal 16 Mar, 2026 Editor assigned by journal 16 Mar, 2026 Submission checks completed at journal 16 Mar, 2026 First submitted to journal 10 Mar, 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9084932","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":607199440,"identity":"b0ce6d1e-9371-4721-8a5e-ad0cc46635ec","order_by":0,"name":"Namolovan Călin","email":"","orcid":"","institution":"Grigore T. 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Introduction","content":"\u003cp\u003eCognitive impairment and depressive symptoms are common complications in patients with chronic kidney disease and are strongly associated with adverse clinical outcomes, reduced quality of life, and increased mortality [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. In patients receiving dialysis, cognitive dysfunction has been extensively documented and is attributed to a complex interplay of vascular disease, uremic toxins, inflammation, and metabolic disturbances [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Kidney transplantation improves survival and quality of life and is generally assumed to mitigate many of these risk factors; however, the extent to which cognitive function and mood fully recover after transplantation remains incompletely understood [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCognitive impairment is a key component of frailty in patients with end-stage kidney disease and kidney transplant candidates and has been consistently associated with adverse outcomes, including increased mortality, both before and after transplantation. These observations suggest that cognitive vulnerability may persist even in clinically stable kidney transplant recipients and warrant focused cognitive evaluation in this population [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Cognitive dysfunction reported prevalence rates vary widely across studies. This marked heterogeneity is largely attributable to differences in study populations, time elapsed since transplantation, and, critically, the cognitive assessment tools used, with more sensitive instruments consistently identifying a higher burden of cognitive impairment than brief global screening tests [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Generally, kidney transplantation has been associated with significant improvements in overall neurocognitive performance compared with the dialysis period [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], but the assessment of post-transplant cognitive function remains heterogeneous and insufficiently standardized, relying on a wide range of neuropsychological instruments with variable sensitivity across studies. A meta-analysis evaluating the diagnostic accuracy of the Mini-Mental State Examination demonstrated limited sensitivity for detecting mild to moderate cognitive impairment, with a substantial proportion of affected individuals remaining unidentified in the absence of overt dementia. These findings indicate that reliance on MMSE alone may underestimate clinically relevant cognitive dysfunction, particularly in populations with preserved global functioning [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDepression in kidney transplant recipients is associated with impaired quality of life and adverse clinical outcomes, while incident depression after transplantation remains an important determinant of increased mortality and graft failure despite an overall lower depression risk compared with patients with end-stage kidney disease [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite growing interest in cognitive outcomes after kidney transplantation, most studies rely on heterogeneous neuropsychological batteries or focus on early post-transplant periods. Data addressing cognitive performance, depressive symptoms, and quality of life simultaneously in clinically stable kidney transplant recipients, as assessed by tools commonly used in routine practice, remain limited. In this context, we aimed to evaluate global cognitive function using the MMSE, depressive symptoms, and health-related quality of life in a well-characterized cohort of stable kidney transplant recipients, and to explore their clinical correlates.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cp\u003e\u003cstrong\u003e2.1 Study design and participants\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis was a single-center, cross-sectional observational study conducted in a tertiary nephrology and kidney transplantation unit between October 2024 and November 2025. Patients were evaluated during routine outpatient follow-up consultations and were enrolled consecutively from the daily outpatient visit schedule.\u003c/p\u003e\n\u003cp\u003eInclusion criteria\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eAge \u0026ge;18 years;\u003c/li\u003e\n \u003cli\u003eA functional kidney transplant for a minimum of 3 months (first or subsequent graft);\u003c/li\u003e\n \u003cli\u003eClinical stability at the time of evaluation, defined as the absence of acute rejection episodes or ongoing graft dysfunction;\u003c/li\u003e\n \u003cli\u003eAbsence of severe visual or hearing impairment;\u003c/li\u003e\n \u003cli\u003eAbility to independently complete cognitive and psychometric questionnaires.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eExclusion criteria\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003ePre-existing major neuropsychiatric disorders (e.g., severe dementia, active psychosis);\u003c/li\u003e\n \u003cli\u003eOngoing acute illness;\u003c/li\u003e\n \u003cli\u003eCommunication barriers that precluded reliable cognitive or psychometric testing.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e2.2.Clinical and Demographic Variables Collected\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe following variables were recorded:\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eAge, sex, and level of education;\u003c/li\u003e\n \u003cli\u003eTime since kidney transplantation (in months);\u003c/li\u003e\n \u003cli\u003eDialysis history (modality and duration) prior to transplant;\u003c/li\u003e\n \u003cli\u003eComorbidities including hypertension, diabetes mellitus, and ischemic heart disease;\u003c/li\u003e\n \u003cli\u003eCurrent immunosuppressive regimen.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003ePsychometric Instruments (MMSE, BDI-II, SF-36)\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eMini-Mental State Examination (MMSE): Screening tool for global cognitive function (score range: 0\u0026ndash;30). Although a cutoff of \u0026lt;24 is widely used in clinical practice to indicate possible cognitive impairment, it is recognized that this threshold has limited sensitivity for detecting mild cognitive deficits, particularly in populations with preserved global cognitive functioning.\u003c/li\u003e\n \u003cli\u003eBeck Depression Inventory-II (BDI-II): 21-item self-report scale assessing depressive symptoms over the past two weeks (score range: 0\u0026ndash;63).\u003c/li\u003e\n \u003cli\u003eShort Form-36 Health Survey (SF-36): Assesses eight domains of health-related quality of life, with two composite scores for physical and mental components. Each domain is scored from 0 to 100.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eData Collection Process\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEach participant underwent a single standardized evaluation session. Clinical and demographic data were collected via medical chart review and patient interview. Psychometric tests were administered in a quiet, standardized setting, and responses were self-reported, with assistance provided by trained personnel, when necessary, without influencing participant responses.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;The study was conducted in accordance with the Declaration of Helsinki and was approved by the local Ethics Committee (approval no. 1796/27.02.2024).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Statistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStatistical analyses were performed to describe the study population and explore associations between cognitive function, depressive symptoms, and health-related quality of life. Continuous variables were expressed as mean \u0026plusmn; standard deviation (SD), and categorical variables as absolute numbers and percentages. Normality of distribution was assessed by visual inspection of histograms and Q\u0026ndash;Q plots.\u003c/p\u003e\n\u003cp\u003eBetween-group comparisons were conducted using independent samples t-tests or one-way ANOVA for normally distributed variables, with Welch corrections applied when appropriate. For non-normally distributed variables, the Mann\u0026ndash;Whitney U or Kruskal\u0026ndash;Wallis test was used. Associations between categorical variables were examined using the Chi-square test or Fisher\u0026rsquo;s exact test when necessary. Correlations between continuous variables were evaluated using Pearson\u0026rsquo;s correlation coefficient.\u003c/p\u003e\n\u003cp\u003eMultivariate analysis of variance (MANOVA) was performed to assess the overall effect of educational level on SF-36 domains, using Pillai\u0026rsquo;s Trace as the multivariate test statistic. Multivariable linear regression analyses were conducted to identify independent determinants of SF-36 domains. All tests were two-tailed, and a p-value \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e\u003cstrong\u003e3.1. Baseline characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.1. General patient characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe cohort included 201 kidney transplant recipients, with a mean age of 48.2 \u0026plusmn; 11.2 years, and a predominance of male participants (58.7%). Most patients resided in urban areas (62.2%). Deceased-donor transplantation was more frequent than living-donor transplantation. The mean graft vintage was 78.8 \u0026plusmn; 73.3 months. Educational attainment and monthly income showed a heterogeneous distribution, with lower educational levels and income more frequently observed among patients from rural areas (Table 1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.2. Pre-transplant CKD stage and etiology of kidney disease\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRenal replacement therapy prior to transplantation was required in 68.2% of patients. Most patients required renal replacement therapy prior to transplantation, predominantly hemodialysis, with a mean dialysis duration of 35.9 \u0026plusmn; 41.7 months. A minority (16.4%) of patients received immunosuppressive therapy before transplantation, most commonly corticosteroid-based regimens. (\u003cstrong\u003eTable 2\u003c/strong\u003e). The mean duration of dialysis before transplantation was 35.9 \u0026plusmn; 41.7 months (range 1\u0026ndash;312).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.3. Cardiovascular and metabolic comorbidities\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHypertension was present in 78.6% of patients. Diabetes mellitus was observed in 15.4% of recipients, including both pre-transplant and post-transplant diabetes. Vascular disease, defined as coronary artery disease, peripheral arterial disease, or prior stroke, was documented in 5.0% of the cohort. Atrial fibrillation was present in 2.0% of patients. Comorbidity data are presented in \u003cstrong\u003eTable 3\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1.4. Laboratory Parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMean hemoglobin was 13.3 \u0026plusmn; 2.2 g/dL (range 6.8\u0026ndash;19.2). Anemia (hemoglobin \u0026lt;12 g/dL) was present in 24% of patients, while moderate to severe anemia (hemoglobin \u0026lt;10 g/dL) occurred in 7%. Laboratory data are summarized in \u003cstrong\u003eTable 4\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2. Mini-Mental State Examination (MMSE)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe median MMSE score in the cohort fell within the normal range. MMSE-defined cognitive impairment was identified in 3 patients (1.5%), all classified as having mild impairment (MMSE 18\u0026ndash;23). No cases of moderate or severe cognitive impairment were observed. The distribution of MMSE categories is shown in \u003cstrong\u003eTable 5\u003c/strong\u003e. Given the very small number of participants classified as cognitively impaired by MMSE criteria, further subgroup analyses were not pursued.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2.1. Clinical and Sociodemographic Correlates of MMSE Scores\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGiven the markedly unbalanced distribution of MMSE categories, with only three patients classified as cognitively impaired, statistical power for group comparisons was limited. Associations between MMSE categories and clinical or sociodemographic variables are detailed in Table S1 (Supplementary Table S1)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3. Beck\u0026apos;s depression index\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMost participants (84.1%) reported minimal or no depressive symptoms. Mild depression was observed in 9.0% of patients, moderate depression in 3.5%, and severe depression in 1.5%. Beck Depression Inventory categories are presented in \u003cstrong\u003eTable 6\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eNo statistically significant associations were identified between Beck categories and demographic, clinical, transplant-related, or biochemical variables. Beck categories were not associated with MMSE categories (\u0026chi;\u0026sup2; = 0.502, p = 0.919).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;3.4. Health-Related Quality of Life Assessed by the SF-36\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMean scores for SF-36 domains are presented in \u003cstrong\u003eTable 7\u003c/strong\u003e. Higher mean scores were observed for Social Functioning and Mental Health domains, while lower scores were recorded for Role\u0026ndash;Physical and Role\u0026ndash;Emotional domains.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.1. Correlations with SF-36 Domains\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAge showed modest negative correlations with Physical Functioning, Role\u0026ndash;Physical, Social Functioning, Bodily Pain, and Vitality. Graft vintage correlated positively with Role\u0026ndash;Emotional scores. Beck Depression Inventory scores demonstrated consistent negative correlations across all SF-36 domains (all p \u0026lt; 0.001). Hemoglobin levels correlated positively with Social Functioning, while serum phosphate showed weak correlations with Role\u0026ndash;Emotional and General Health domains. All statistically significant correlations are detailed in \u003cstrong\u003eTable 8\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5.Multivariate analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn multivariate linear regression analyses examining determinants of SF-36 domains, Beck Depression Inventory score emerged as the most consistent independent predictor across all domains. Higher Beck scores were independently associated with poorer Physical Functioning, Role\u0026ndash;Physical, Bodily Pain, and General Health scores, with adjusted R\u0026sup2; values ranging from 0.10 to 0.17.\u003c/p\u003e\n\u003cp\u003eFor the Vitality domain, the multivariate model explained a larger proportion of variance. Both Beck score and hemoglobin level were identified as significant independent predictors, indicating that lower depressive symptom burden and higher hemoglobin levels were associated with better perceived vitality.\u003c/p\u003e\n\u003cp\u003eSimilarly, Beck score remained an independent predictor of Social Functioning, Role\u0026ndash;Emotional, and Mental Health domains.\u003c/p\u003e\n\u003cp\u003eHemoglobin levels and immunosuppression status were not independently associated with most SF-36 domains, although hemoglobin showed a non-significant trend in the General Health domain and immunosuppression demonstrated a weak trend in the Mental Health domain. Independent determinants of SF-36 health-related quality-of-life domains: multivariate linear regression analysis were found in \u003cstrong\u003eTable 9\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5.1. Effects of Pre-Transplant Renal Replacement Therapy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients with pre-transplant renal replacement therapy had higher scores in Role\u0026ndash;Physical, Role\u0026ndash;Emotional, and Social Functioning domains compared with patients transplanted preemptively. No significant differences were observed in other SF-36 domains. Group comparisons are presented in \u003cstrong\u003eTable 10\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;3.5.2. Influence of Educational Level\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEducational level showed a significant overall effect on SF-36 domain scores. In univariate analyses, significant associations were observed with Mental Health, Role\u0026ndash;Emotional, General Health, and Social Functioning domains (Supplementary Table S2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5.4. Association Between Cognitive Status and SF-36 Scores\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eComparisons between patients with normal MMSE scores and those with mild MMSE-defined cognitive impairment showed no significant differences across most SF-36 domains. A significant difference was observed for the Vitality domain, with higher scores in patients with normal MMSE performance.\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003e\u003cstrong\u003e4.1. Cognitive Function Assessed by MMSE\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this cross-sectional study of clinically stable kidney transplant recipients, we observed a low prevalence of MMSE-defined cognitive impairment and depressive symptoms, alongside generally preserved health-related quality of life. These findings reflect the characteristics of a carefully selected, stable transplant cohort and the use of a brief global cognitive screening instrument, rather than the absence of cognitive vulnerability after transplantation.\u003c/p\u003e\n\u003cp\u003eCognitive impairment is highly prevalent in patients with advanced chronic kidney disease and those receiving dialysis, driven by vascular disease, metabolic disturbances, and chronic inflammation [9]. Although kidney transplantation has been associated with measurable improvements in cognitive function, particularly in attention, executive function, and processing speed, post-transplant cognitive performance has been assessed using a heterogeneous range of instruments, from global screening tools such as the Mini-Mental State Examination and Montreal Cognitive Assessment to comprehensive neuropsychological batteries. Despite overall improvement, residual or domain-specific deficits are frequently reported, highlighting the lack of standardized cognitive assessment and the persistence of subtle cognitive impairment after transplantation[10].\u003c/p\u003e\n\u003cp\u003eA study published in 2011 demonstrated that the Mini-Mental State Examination has limited sensitivity for detecting mild cognitive impairment, as it inadequately captures deficits in executive function, attention, and processing speed, leading to an underestimation of clinically relevant cognitive dysfunction despite preserved global scores [11]. Consistent with this, transplant-focused studies indicate that cognitive impairment in kidney transplant recipients is frequently underrecognized, with subtle deficits persisting and being identified only through more sensitive or domain-specific assessments [12]. Our results should therefore not be interpreted as contradicting these findings, but rather as illustrating how MMSE-based screening may underestimate mild cognitive impairment in clinically stable recipients. The low prevalence observed in our cohort likely reflects both patient selection and the intrinsic characteristics of the screening instrument.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Age and educational level were associated with MMSE performance, in line with established determinants of cognitive test results in both transplant and non-transplant populations. In contrast, transplant-related variables showed no strong association with MMSE scores, suggesting that global cognitive performance may remain preserved once clinical stability is achieved. However, given the very small number of patients classified as cognitively impaired by MMSE criteria, these associations should be interpreted cautiously and considered exploratory.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.2. Depressive Symptoms and Health-Related Quality of Life\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDepressive symptoms were uncommon in this cohort and were predominantly mild, yet they showed consistent and clinically meaningful associations with multiple domains of health-related quality of life. This finding underscores the central role of psychological well-being in shaping patient-reported outcomes after transplantation, even in the absence of overt cognitive impairment. The lack of a strong association between depressive symptoms and MMSE scores further suggests that mood and global cognitive performance may represent partially independent dimensions of post-transplant recovery.\u003c/p\u003e\n\u003cp\u003eOur findings suggest that in clinically stable kidney transplant recipients, global cognitive screening using the MMSE identifies few cases of overt impairment, whereas depressive symptoms exert a substantially greater influence on patient-reported quality of life. This highlights the importance of systematic psychological assessment in routine post-transplant care, even when global cognitive performance appears preserved.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5. Strengths and limitations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStrengths\u003c/strong\u003e: This study provides a pragmatic evaluation of cognitive function, depressive symptoms, and health-related quality of life in a well-defined cohort of clinically stable kidney transplant recipients. The inclusion of a homogeneous outpatient population minimizes confounding by acute illness or graft dysfunction, while the use of standardized instruments, including the Mini-Mental State Examination, ensures reproducibility and comparability with existing literature. By reflecting routine clinical screening practice, the findings offer clinically relevant insights into post-transplant cognitive and psychological status. In addition, the combined assessment of cognitive performance, depressive symptoms, and health-related quality of life within the same cohort allows a more comprehensive and clinically meaningful interpretation of post-transplant neuropsychological status.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLimitations\u003c/strong\u003e: Several limitations should be acknowledged. The cross-sectional design precludes causal inference, and cognitive function was assessed using a single global screening instrument with limited sensitivity for subtle deficits. The study population consisted of clinically stable recipients from a single center, which may limit generalizability to higher-risk or early post-transplant populations. Finally, the small number of participants meeting MMSE criteria for cognitive impairment restricts the robustness of subgroup analyses.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e6. Future Research Directions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFuture studies should adopt longitudinal designs to better define cognitive and psychological trajectories after kidney transplantation. The use of more sensitive, domain-specific cognitive assessments alongside global screening tools may improve the detection of subtle cognitive impairment and clarify its clinical relevance. Further research is also needed to explore the interplay between cognitive function, depressive symptoms, and health-related quality of life, as well as to validate these findings in larger, multicenter, and more diverse transplant populations.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eIn clinically stable kidney transplant recipients, MMSE-defined cognitive impairment and depressive symptoms were uncommon, and overall quality of life was generally preserved. However, depressive symptoms were consistently associated with poorer quality-of-life domains, underscoring their clinical relevance.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;The low prevalence of cognitive impairment may reflect the use of a brief screening tool, and more comprehensive assessments may be needed to detect subtle post-transplant cognitive deficits.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCompeting interests\u003cbr\u003e\u003c/strong\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003cbr\u003e\u003c/strong\u003eThe study was conducted in accordance with the Declaration of Helsinki and was approved by the local Ethics Committee (approval no. 1796/27.02.2024).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003cbr\u003e\u003c/strong\u003eThe data that support the findings of this study are not publicly available due to their containing information that could compromise the privacy of research participants. De-identified data may be made available from the corresponding author upon reasonable request, subject to institutional approval and applicable data protection regulations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003cbr\u003e\u003c/strong\u003eBogdan Agavriloaei, Luminita Voroneanu, and Adrian Covic contributed to the conceptualization and study design. Data collection was performed by Bogdan Agavriloaei, Baluță Cezar, Namolovan Călin, and Lucian Sirițeanu. Data analysis and interpretation were carried out by Bogdan Agavriloaei and Luminita Voroneanu. Bogdan Agavriloaei drafted the initial version of the manuscript. Luminita Voroneanu, Baluță Cezar, Namolovan Călin, Lucian Sirițeanu, and Adrian Covic critically revised the manuscript for important intellectual content. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Declaration:\u0026nbsp;\u003c/strong\u003e no\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMurray, A. M., \u0026amp; Knopman, D. S. (2010). Cognitive impairment in CKD: no longer an occult burden. \u003cem\u003eAmerican Journal Of Kidney Diseases\u003c/em\u003e, \u003cem\u003e56\u003c/em\u003e(4), 615\u0026ndash;618.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMurray, A. M., et al. (2006). Cognitive impairment in hemodialysis patients is common. \u003cem\u003eNeurology\u003c/em\u003e, \u003cem\u003e67\u003c/em\u003e(2), 216\u0026ndash;223.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJurgensen, A., Qannus, A. A., \u0026amp; Gupta, A. (2020). Cognitive Function in Kidney Transplantation. \u003cem\u003eCurr Transplant Rep\u003c/em\u003e, \u003cem\u003e7\u003c/em\u003e, 145\u0026ndash;153.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaugen, C. E., et al. (2019). Frailty and Access to Kidney Transplantation. \u003cem\u003eClinical Journal Of The American Society Of Nephrology\u003c/em\u003e, \u003cem\u003e14\u003c/em\u003e(4), 576\u0026ndash;582.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGupta, A., et al. (2017). Prevalence and correlates of cognitive impairment in kidney transplant recipients. \u003cem\u003eBmc Nephrology\u003c/em\u003e, \u003cem\u003e18\u003c/em\u003e(1), 158.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarciarek, M., et al. (2009). Cognitive performance before and after kidney transplantation: a prospective controlled study of adequately dialyzed patients with end-stage renal disease. \u003cem\u003eJournal Of The International Neuropsychological Society\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e(5), 684\u0026ndash;694.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMitchell, A. J. (2009). A meta-analysis of the accuracy of the mini-mental state examination in the detection of dementia and mild cognitive impairment. \u003cem\u003eJournal Of Psychiatric Research\u003c/em\u003e, \u003cem\u003e43\u003c/em\u003e(4), 411\u0026ndash;431.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCho, S., et al. (2022). Incidence of depression in kidney transplant recipients in South Korea: a long-term population-based study. \u003cem\u003eScientific Reports\u003c/em\u003e, \u003cem\u003e12\u003c/em\u003e(1), 17603.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBugnicourt, J. M., et al. (2013). Cognitive disorders and dementia in CKD: the neglected kidney-brain axis. \u003cem\u003eJournal Of The American Society Of Nephrology\u003c/em\u003e, \u003cem\u003e24\u003c/em\u003e(3), 353\u0026ndash;363.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan Sandwijk, M. S., et al. (2020). Cognitive Improvement After Kidney Transplantation Is Associated With Structural and Functional Changes on MRI. \u003cem\u003eTransplant Direct\u003c/em\u003e, \u003cem\u003e6\u003c/em\u003e(3), e531.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTroen, A. M., et al. (2012). Cognitive dysfunction and depression in adult kidney transplant recipients: baseline findings from the FAVORIT Ancillary Cognitive Trial (FACT). \u003cem\u003eJournal Of Renal Nutrition : The Official Journal Of The Council On Renal Nutrition Of The National Kidney Foundation\u003c/em\u003e, \u003cem\u003e22\u003c/em\u003e(2), 268\u0026ndash;276e3.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGolenia, A., Malyszko, J. S., \u0026amp; Malyszko, J. (2022). Cognitive Impairment and Kidney Transplantation: Underestimated, Underrecognized but Clinically Relevant Problem. \u003cem\u003eKidney \u0026amp; Blood Pressure Research\u003c/em\u003e, \u003cem\u003e47\u003c/em\u003e(7), 459\u0026ndash;466.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 to 10 are available in the Supplementary Files section.\u003c/p\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":"cognitive-therapy-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cotr","sideBox":"Learn more about [Cognitive Therapy and Research](http://link.springer.com/journal/10608)","snPcode":"10608","submissionUrl":"https://www.editorialmanager.com/cotr/default.aspx","title":"Cognitive Therapy and Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Kidney transplantation, Cognitive function, Depression, Mini-Mental State Examination, Quality of life, Clinically stable recipients","lastPublishedDoi":"10.21203/rs.3.rs-9084932/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9084932/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eKidney transplantation improves survival in patients with end-stage kidney disease; however, cognitive and psychological outcomes after transplantation remain incompletely characterized. This study aimed to assess cognitive performance, depressive symptoms, and health-related quality of life in clinically stable kidney transplant recipients.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eIn this cross-sectional study, 201 adult kidney transplant recipients with stable graft function were evaluated. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), depressive symptoms using the Beck Depression Inventory (BDI), and quality of life using the Short Form-36 (SF-36). Associations between clinical variables and psychological outcomes were analyzed using correlation and multivariable regression analyses.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eGlobal cognitive performance was largely preserved, with MMSE scores within the normal range in the majority of participants. Minimal or no depressive symptoms were observed in 84.1% of patients, while mild, moderate, and severe depressive symptoms were present in 9.0%, 3.5%, and 1.5%, respectively. Quality-of-life domains showed variability across physical and mental components. Depressive symptom severity was significantly associated with reduced quality-of-life scores (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), whereas MMSE scores showed limited correlation with depressive symptoms. Clinical variables demonstrated selective associations with psychological and quality-of-life measures.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eIn clinically stable kidney transplant recipients, overall cognitive performance appears preserved, although a subset of patients continues to experience depressive symptoms and impaired quality of life. These findings underscore the importance of routine psychological evaluation alongside standard clinical follow-up in transplant care.\u003c/p\u003e","manuscriptTitle":"Cognitive Function, Depressive Symptoms and Quality of Life in Clinically Stable Kidney Transplant Recipients","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-18 03:05:52","doi":"10.21203/rs.3.rs-9084932/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-02T17:49:07+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"9156024534209844688201258760092985116","date":"2026-03-30T15:48:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"321527266792880049959826994710915141747","date":"2026-03-30T13:57:55+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-16T21:58:07+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-16T05:30:17+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-16T05:29:23+00:00","index":"","fulltext":""},{"type":"submitted","content":"Cognitive Therapy and Research","date":"2026-03-10T13:51:06+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"cognitive-therapy-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cotr","sideBox":"Learn more about [Cognitive Therapy and Research](http://link.springer.com/journal/10608)","snPcode":"10608","submissionUrl":"https://www.editorialmanager.com/cotr/default.aspx","title":"Cognitive Therapy and Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"adc6e5b3-eda4-4438-afed-2fea243c3088","owner":[],"postedDate":"March 18th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-18T03:05:53+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-18 03:05:52","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9084932","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9084932","identity":"rs-9084932","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}