Treatment outcome in a specialized unit for adults with severe and extreme anorexia nervosa at one-year follow up

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Wuttke, Thorsten Koerner, Ulrich Cuntz, Ulrich Voderholzer This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5701532/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 25 Aug, 2025 Read the published version in Journal of Eating Disorders → Version 1 posted 8 You are reading this latest preprint version Abstract Background Inpatient treatment successfully increases body weight and decreases eating disorder and associated symptoms in patients with anorexia nervosa (AN). However, relapse rates are high, particularly within the first year after discharge. Methods We examined treatment outcome one year after discharge in adults with AN ( N = 80, 2 males; BMI at admission: M = 13.2 kg/m², SD = 1.79) who received treatment in a specialized inpatient unit for AN patients with severe underweight (body mass index < 15 kg/m²) and/or excessive purging or exercising. Results From admission to discharge, body weight and self-reported life satisfaction significantly increased and self-reported eating disorder symptoms, depressive symptoms, and compulsive exercise significantly decreased. From discharge to follow up, life satisfaction and body weight decreased, and eating disorder symptoms, depressive symptoms, and compulsive exercise increased, although 87% of patients indicated to have received some kind of eating disorder treatment in the past six months. At follow up, the majority of patients indicated that they regularly ate three meals per day in the past week, including consumption of high-calorie, formerly forbidden foods. However, only a minority of patients indicated that they adhered to the hospital’s guidelines on portion sizes. Patients’ self-reported desired body weight at follow up was significantly higher than their current body weight. Conclusions While inpatient treatment results in substantial improvements that are partially maintained after discharge, severe and extreme cases of AN require more long-lasting, alternating treatment approaches (e.g., interval treatment) to ensure long-term recovery. Inpatient treatment Severe and enduring anorexia nervosa Body mass index Eating disorders Psychotherapy Figures Figure 1 Figure 2 Figure 3 Plain English Summary This study examined outcomes of inpatient treatment for adults with anorexia nervosa one year after discharge. Initially, patients showed significant improvements in body weight, life satisfaction, and reductions in eating disorder symptoms, depression, and compulsive exercise. However, within a year after leaving the hospital, many patients experienced a decline in life satisfaction and body weight, along with a resurgence of eating disorder symptoms, depression, and compulsive exercise, despite most receiving some form of treatment during this period. While most patients reported eating three meals a day and consuming high-calorie foods, few followed the hospital's portion size guidelines. It is concluded that while inpatient treatment is effective, severe cases of anorexia nervosa need ongoing, innovative treatment approaches to support long-term recovery. Background Anorexia nervosa (AN) is an eating disorder that is characterized by significantly low body weight, which is maintained by behaviors such as restrictive eating, purging (e.g., self-induced vomiting, misuse of laxatives), and excessive exercise, and typically associated with a fear of weight gain (American Psychiatric Association, 2013 ). AN severity is assessed according to a person’s body mass index (BMI) in the current version of both the Diagnostic and Statistical Manual of Mental Disorders (DSM–5; American Psychiatric Association, 2013 ) and the International Classification of Diseases (ICD–11; World Health Organization, 2022 ). In the DSM–5, severity is categorized as mild (BMI ≥ 17.0 kg/m²), moderate (BMI ≥ 16.0 kg/m² and < 17.0 kg/m²), severe (BMI ≥ 15.0 kg/m² and < 16.0 kg/m²), and extreme (BMI < 15.0 kg/m²). In the ICD–11, severity is categorized as AN in recovery with normal body weight (BMI ≥ 18.5 kg/m²), AN with significantly low body weight (BMI < 18.5 kg/m² and ≥ 14 kg/m²), and AN with dangerously low body weight (BMI < 14 kg/m²). There have also been suggestions to alternatively consider overvaluation of weight and shape, illness duration, and previous treatments as indicators for AN severity (Dang et al., 2023 ; Wonderlich et al., 2020 ). For example, some studies defined so-called severe and enduring AN based on an illness duration of at least seven years (Broomfield et al., 2017 ). Hay and Touyz ( 2018 ) proposed to define severe and enduring AN as (1) a persistent state of dietary restriction, underweight, and overvaluation of weight and shape with functional impairment, (2) illness duration of longer than three years, and (3) exposure to at least two evidence-based treatments. Having severe and extreme AN is usually an indication for inpatient treatment, which often includes involuntary admission and enteral nutrition (Abry et al., 2024 ; Guinhut et al., 2021 ). However, voluntary inpatient treatment that includes a high-calorie refeeding schedule with supervised meals, individual psychotherapy sessions, group therapies, close medical monitoring, and micronutrient supplementation also successfully improves health status in persons with extreme AN (Cuntz et al., 2022 ; Koerner et al., 2020 ). Risk of relapse is high in persons with AN, particularly in the first year after inpatient treatment (Berends et al., 2018 ). Approximately 25–35% of AN patients need to be rehospitalized in that period (Danielsen et al., 2020 ; Golden et al., 2021 ; Meule et al., 2021 ). However, most studies report that body weight at discharge is—on average—largely maintained at one-year follow up in both adolescents and adults, the majority of which received psychotherapeutic aftercare (Dalle Grave et al., 2020 ; Danielsen et al., 2020 ; Golden et al., 2021 ; Meule et al., 2021 ; Pruccoli et al., 2023 ). Studies that examined outcome after inpatient treatment in persons with severe and extreme AN are rare. For example, Abry et al. ( 2024 ) recently reported on a study that compared involuntarily and voluntarily treated AN patients with an average BMI of 12 kg/m² at admission, in which BMI increased from discharge to follow up. However, these findings may be biased by small sample size and high attrition rates. The aim of the current study was to examine treatment outcome one year after discharge in a sample of persons with AN (94% being categorized as having severe or extreme AN according to DSM–5, see below) treated at a specialized inpatient unit. Specifically, we examined changes in BMI, eating disorder psychopathology, compulsive exercise, depressive symptoms, and life satisfaction across admission, discharge, and one-year follow up. We also tested whether BMI at admission, classifying patients as having severe and enduring AN, and illness duration would moderate changes over time of these variables. Finally, we also report on eating-, weight-, and treatment-related questions at follow up. Methods Sample characteristics The study was approved by the ethics committee of the University Hospital of the LMU Munich. One-hundred and thirty-nine adults with AN who received inpatient treatment at the Schoen Clinic Roseneck (Rosenheim, Germany) between 2018 and 2020 were contacted one year after discharge between 2019 and 2021 (Fig. 1 ). Of these, 80 persons participated in the study (98% female, n = 78; mean age: M = 27.3 years, SD = 10.2). Fifty-three persons (66%) had restrictive-type AN (ICD–10 code F50.00), 26 (33%) had binge/purge-type AN (ICD–10 code F50.01), and one (1%) had atypical AN (ICD–10 code F50.1). Forty persons (50%) had at least one comorbid mental disorder, the most common of which were anxiety disorders (ICD–10 code F4; n = 26, 33%) and affective disorders (ICD–10 code F3; n = 17, 21%). A subset of patients received antidepressant ( n / N = 13/53, 25%) or antipsychotic ( n / N = 15/53, 28%) medication during the stay (information not available for 27 patients). When using the severity classification according to ICD–11 (World Health Organization, 2022 ), 66.3% ( n = 53) had AN with dangerously low body weight (BMI < 14.0 kg/m²) and 33.8% ( n = 27) had AN with significantly low body weight (BMI ≥ 14.0 kg/m² and < 18.5 kg/m²). When using the severity classification according to DSM–5 (American Psychiatric Association, 2013 ), 85.0% ( n = 68) had extreme AN (BMI < 15.0 kg/m²), 8.8% ( n = 7) had severe AN (BMI ≥ 15.0 kg/m² and < 16.0 kg/m²), 3.8% ( n = 3) had moderate AN (BMI ≥ 16.0 kg/m² and < 17.0 kg/m²), and 2.5% ( n = 2) had mild AN (BMI ≥ 17.0 kg/m²). Mean illness duration was 10.1 years ( SD = 9.74, Range: 1–40) and 55.0% ( n = 44) had an illness duration of at least seven years and 45.0% ( n = 36) had an illness duration of less than seven years. Illness duration did not relate to BMI at admission ( r pb = 0.05, p = .680). The mean number of previous treatments was 3.4 ( SD = 3.7, Range 0–16). When using the criteria by Hay and Touyz ( 2018 ), 53.3% ( n = 41) had severe and enduring AN and 46.8% ( n = 36) did not meet the criteria for severe and enduring AN (information not available for three patients). All patients were treated in a specialized inpatient unit for AN patients with severe underweight (BMI < 15 kg/m²) and/or excessive purging or exercising (length of stay: M = 102.7 days, SD = 52.2). The treatment at the hospital adheres to the German S3-guidelines for the treatment of AN in terms of admission criteria, treatment elements, and therapy goals (AWMF, 2020 ). Thus, patients received a cognitive-behavioral therapy-oriented, multimodal AN treatment that included several treatment elements such as individual psychotherapy sessions, group therapy sessions, exercise therapy, meal preparation classes, body image exposure, nutrition counseling, and food intake protocols as well as clinical management of medical complications, including micronutrient supplementation. The treatment includes a high-calorie refeeding schedule (starting on the first day of treatment) that aims at a weight gain of 0.7–1.0 kg per week for all underweight AN patients. This schedule includes three meals per day, each having approximately 700 kcal and, thus, totaling to a daily caloric intake of approximately 2100 kcal. Meals are supervised by a staff member (nurse, psychotherapist, or physician) in earlier treatment stages. The schedule is individually tailored if patients do not finish their meals or do not show the expected weight gain by increasing portion size, adding snacks between meals, or offering sip feeds. As normalization of eating behavior is one of the therapeutic goals, patients do not receive nasogastric feeding. Patients can choose between vegetarian and non-vegetarian menus; vegan menus are not offered. Compared to other eating disorder units at the hospital, the treatment at the specialized unit is more intensive and structured, with enhanced medical monitoring, closer behavioral supervision (e.g., during meals and to ensure limiting physical activity and preventing purging behaviors), daily weighing, and more frequent therapeutic contact tailored to patients with severe AN. Measures BMI . Body weight and height were measured at the hospital at admission and discharge and participants self-reported their current height and weight at follow up. BMI was calculated as kg/m². Eating Disorder Examination–Questionnaire (EDE–Q) . Eating disorder symptomatology was assessed with the German version (Hilbert & Tuschen-Caffier, 2016 ) of the EDE–Q (Fairburn & Beglin, 1994 ). The EDE–Q has 28 items, six of which assess the frequency of binge and purge behaviors in the past 28 days and are not included in the total score. The other 22 items are answered on a seven-point scale (0–6) with different response labels. Higher mean total scores indicate higher eating disorder symptomatology. Internal reliability at admission, discharge, and follow up ranged between ω = .95 and .98. Commitment to Exercise Scale (CES). Compulsive exercise was assessed with the German version (Zeeck et al., 2017 ) of the CES (Davis et al., 1993 ). The CES has eight items and, in the original version, these were answered on a visual analogue scale with different anchors. In the current study, we applied a four-point scale (e.g., 1 = never to 4 = always ) response format, in line with other studies (Dittmer et al., 2020 ; Dittmer et al., 2018 ; Thome & Espelage, 2007 ). Higher mean total scores indicate higher compulsive exercising. Internal reliability at admission, discharge, and follow up ranged between ω = .95 and .97. Beck Depression Inventory–Revised (BDI–II) . Depressive symptoms were assessed with the German version (Hautzinger et al., 2009 ) of the BDI–II (Beck et al., 1996 ). The BDI–II has 21 items that are answered on a four-point scale (0–3) with different response labels. Higher total sum scores indicate higher depressive symptomatology. Internal reliability at admission, discharge, and follow up ranged between ω = .91 and .95. Satisfaction With Life Scale (SWLS) . Life satisfaction was assessed with the German version (Glaesmer et al., 2011 ) of the SWLS (Diener et al., 1985 ). The SWLS has five items that are answered on a seven-point scale (1 = strongly disagree to 7 = strongly agree ). Higher total sum scores indicate higher life satisfaction. Internal reliability at admission, discharge, and follow up ranged between ω = .88 and .92. Eating- and weight-related questions at follow up. Current meal frequency was assessed with three questions asking “On how many days in the past seven days have you had breakfast/lunch/dinner?”. Responses were recorded on an eight-point scale from 0 to 7 (ω = .77) and averaged to a mean score. Current meal portions were assessed with three questions asking “On how many days in the past seven days have you eaten according to the portion size guidelines by the hospital at breakfast/lunch/dinner?”. Responses were recorded on an eight-point scale from 0 to 7 (ω = .86) and averaged to a mean score. Current intake of high-calorie foods was assessed with one question asking “On how many days in the past seven days have you eaten high-caloric (previously “forbidden”) foods?”. Responses were recorded on an eight-point scale from 0 to 7. Current desired body weight was assessed with one item stating “My current desired body weight is … kg.”. Questions on current and past treatments at follow up . Eating disorder treatments were assessed with five questions asking “Have you received outpatient [physician]/outpatient [psychotherapist]/outpatient [group]/daypatient/inpatient eating disorder treatment in the past six months?” (yes/no). Current psychotherapeutic treatment was assessed with one question asking “Do you currently receive psychotherapeutic treatment?” (yes/no). Current psychopharmacological treatment was assessed with one question asking “Do you currently take medication to treat your mental disorder?” (yes/no, if yes enter name of drugs). Data analyses Statistical analyses were conducted with R version 4.5.0 ( https://www.r-project.org ) in RStudio version 2025.05.0 ( https://posit.co ). As assumptions of the general linear model are often violated when analyzing clinical psychology data, it has been suggested preferring nonparametric and robust analysis techniques (Field & Wilcox, 2017 ). Therefore, changes in BMI as well as EDE–Q, CES, BDI–II, and SWLS scores across admission, discharge, and follow up were examined with robust mixed models with the robustlmm package (Koller, 2016 ). Specifically, separate models were calculated with either BMI, EDE–Q, CES, BDI–II, or SWLS scores as dependent variable. Fixed effects of time were added by including first- and second-order orthogonal polynomials of the time term as independent variables, modeling linear and non-linear changes across the three measurements (Mirman, 2014 ). The models also included a random intercept (i.e., person-level random variability in scores at admission). As the robustlmm package does not produce parameter-specific p -values, we used the workaround described by Geniole et al. ( 2019 ). Specifically, non-robust models were fitted with the lme4 package (Bates et al., 2015 ) to obtain Satterthwaite-approximated degrees of freedom and two-sided p -values were then computed for the robust t -values using the approximated degrees of freedom. Pairwise comparisons (admission vs. discharge, discharge vs. follow up) were computed with the emmeans package (Lenth, 2023 ) and Cohen’s d was computed as effect size with the effectsize package (Ben-Shachar et al., 2020 ). Note that—although there were missing data for each dependent variable—these mixed models included all 80 cases because of the restricted maximum likelihood estimation. In another set of robust mixed models, we added the fixed effect of BMI at admission and its interaction with the two time terms to examine whether changes in BMI and questionnaire scores across admission, discharge, and follow up would be moderated by BMI at admission. Specifically, in contrast to the models described above that only included time and time² as independent variables, these models included time , time² , BMI at admission , time × BMI at admission , and time² × BMI at admission as independent variables. Note, however, that the only effect of interest here was the interaction effect time² × BMI at admission , testing whether the non-linear changes across time would differ as a function of BMI at admission but all “subordinate” effects have to be included in such a model as well. Similar models were run to examine whether changes would be moderated by severe and enduring AN groups and illness duration. Internal reliability coefficients (McDonald’s ω) for all questionnaires for which items were averaged or summed were obtained with the psych package (Revelle, 2023 ). Descriptive statistics for variables used for sample description, eating- and weight-related questions at follow up, and questions on current and past treatments at follow up were obtained with the summarytools package (Comtois, 2022 ). Meal frequency and meal portions as well as current and desired body weight at follow up were compared with Wilcoxon paired signed-rank tests with the rcompanion package (Mangiafico, 2019 ). The data and code with which all analyses can be reproduced are available at https://osf.io/3uypd . Results BMI BMI changed non-linearly across the three measurements (effect of time² : b = −2.27, SE = 0.18, p < .001). Specifically, BMI increased from admission to discharge ( b = 4.38, SE = 0.25, p < .001, d = 2.16) and decreased from discharge to follow up ( b = −1.17, SE = 0.26, p < .001, d = −0.37; Fig. 2 A). Changes in BMI differed as a function of BMI at admission (interaction effect of time² × BMI at admission : b = 0.23, SE = 0.09, p = .010): lower BMI at admission related to steeper increases in BMI across measurements (Fig. 3 A). Changes in BMI did not differ as a function of severe and enduring AN groups (interaction effect of time² × groups : b = 0.09, SE = 0.37, p = .817) or illness duration (interaction effect of time² × illness duration : b = 0.003, SE = 0.02, p = .861). EDE–Q Eating disorder symptomatology changed non-linearly across the three measurements (effect of time² : b = 0.93, SE = 0.16, p < .001). Specifically, EDE–Q scores decreased from admission to discharge ( b = −1.69, SE = 0.21, p < .001, d = −1.36) and increased from discharge to follow up ( b = 0.60, SE = 0.21, p = .004, d = 0.36; Fig. 2 B). Changes in EDE–Q scores did not differ as a function of BMI at admission (interaction effect of time² × BMI at admission : b = 0.05, SE = 0.09, p = .579) or severe and enduring AN groups (interaction effect of time² × groups : b = 0.01, SE = 0.32, p = .969) or illness duration (interaction effect of time² × illness duration : b = 0.02, SE = 0.02, p = .247). CES Compulsive exercise changed non-linearly across the three measurements (effect of time² : b = 0.30, SE = 0.08, p < .001). Specifically, CES scores decreased from admission to discharge ( b = −0.44, SE = 0.11, p < .001, d = −0.69) and increased from discharge to follow up ( b = 0.29, SE = 0.11, p = .007, d = 0.30; Fig. 2 C). Changes in CES scores did not differ as a function of BMI at admission (interaction effect of time² × BMI at admission : b = 0.03, SE = 0.05, p = .532) or severe and enduring AN groups (interaction effect of time² × groups : b = 0.02, SE = 0.16, p = .889) or illness duration (interaction effect of time² × illness duration : b = 0.003, SE = 0.01, p = .677). BDI–II Depressive symptomatology changed non-linearly across the three measurements (effect of time² : b = 10.8, SE = 1.58, p < .001). Specifically, BDI–II scores decreased from admission to discharge ( b = −17.1, SE = 2.13, p < .001, d = −1.27) and increased from discharge to follow up ( b = 9.41, SE = 2.12, p < .001, d = 0.64; Fig. 2 D). Changes in BDI–II scores did not differ as a function of BMI at admission (interaction effect of time² × BMI at admission : b = −0.62, SE = 0.92, p = .503) or severe and enduring AN groups (interaction effect of time² × groups : b = 3.17, SE = 3.33, p = .343). However, they differed as a function of illness duration (interaction effect of time² × illness duration : b = 0.35, SE = 0.16, p = .028): a longer illness duration related to steeper decreases in BDI–II scores from admission to discharge and steeper increases in BDI–II scores from discharge to follow up (Fig. 3 B). SWLS Life satisfaction changed non-linearly across the three measurements (effect of time² : b = −2.23, SE = 0.69, p = .002). Specifically, SWLS scores increased from admission to discharge ( b = 3.61, SE = 0.93, p < .001, d = 0.57) and decreased from discharge to follow up ( b = −1.86, SE = 0.94, p = .048, d = −0.16; Fig. 2 E). Changes in SWLS scores did not differ as a function of BMI at admission (interaction effect of time² × BMI at admission : b = 0.11, SE = 0.41, p = .785) or severe and enduring AN groups (interaction effect of time² × groups : b = −0.09, SE = 1.41, p = .952) or illness duration (interaction effect of time² × illness duration : b = −0.06, SE = 0.07, p = .392). Eating- and weight-related questions at follow up On average, participants reported to eat three meals per day on about six days in the past week ( M = 6.14 days, SD = 1.52) but reported adhering to portion size guidelines on significantly fewer days ( M = 3.77, SD = 2.59; V = 1649, p < .001, r rb = .995). The majority of participants (90%, n / N = 71/79, information not available for one participant) indicated that they ate high-caloric, formerly forbidden foods on at least one day in the past week. Current self-reported body weight ( M = 45.5 kg, SD = 9.16) was significantly lower than desired body weight ( M = 47.6, SD = 8.93; V = 471, p = .002, r rb = .468). In fact, 69% of participants ( n / N = 43/62, information not available for 18 participants) indicated that their desired weight was higher than their current weight, 26% ( n / N = 16/62) indicated that their desired weight was lower than their current weight, and 5% ( n / N = 3/62) indicated that their desired weight was equal to their current weight. When converting desired weight into BMI ( M = 17.5 kg/m², SD = 2.79), the majority of participants (61%, n / N = 39/62) indicated that their desired BMI was lower than 18.5 kg/m² (that is, in the underweight range according to the classification of the World Health Organization). Questions on current and past treatments at follow up The majority of participants (87%, n / N = 68/78, information not available for two participants) indicated they received any eating disorder treatment in the past six months (outpatient [physician]: 42%, n / N = 33/78; outpatient [psychotherapist]: 63%, n / N = 49/78; outpatient [group]: 9%, n / N = 7/78; daypatient: 5%, n / N = 4/78; inpatient: 35%, n / N = 27/78) and that they currently received psychotherapeutic treatment (63%, n / N = 49/78). The minority of participants (44%, n / N = 35/79, information not available for one participant) indicated that they currently received psychopharmacological treatment (antidepressants: 35%, n / N = 28/79; antipsychotics: 19%, n / N = 15/79). Discussion The current study examined treatment outcome in persons with AN treated at a specialized unit for severe and extreme AN across admission, discharge, and one-year follow up. Disorder-specific and related symptoms substantially improved during treatment but somewhat declined after treatment. For example, average BMI increased from 13.2 kg/m² at admission (with all patients being underweight [BMI < 18.5 kg/m²]) to 17.5 kg/m² at discharge (with 27 of 80 patients [33.8%] having a BMI ≥ 18.5 kg/m²) but decreased to 16.6 kg/m² after one year (with 18 of 73 patients [22.5%] having a BMI ≥ 18.5 kg/m²). These changes were moderated by BMI at admission such that a lower BMI at admission related to steeper weight gain from admission to discharge. This effect might be explained by several factors. Biologically, larger weight gain in those with lower BMI may be due to lower resting metabolic rate at the beginning of treatment. Psychologically, many patients accept that they have to gain weight during treatment but refuse to exceed certain self-imposed thresholds (e.g., 50 kg), which are reached faster by those who start with higher BMI at admission. Besides these explanations, however, it has been observed that—due to regression to the mean—there is always a correlation between baseline scores and change scores, regardless of any treatment effects (Clifton & Clifton, 2019 ). Thus, while it appears that AN patients with a lower BMI at admission achieve a higher weight gain during inpatient treatment, an incorrect interpretation would be to conclude that the treatment is more effective for these patients (Meule et al., 2025 ). Although most patients had severe and extreme AN according to their BMI at admission, only about half of the sample met the criteria for severe and enduring AN by Hay and Touyz ( 2018 ). Furthermore, changes in AN symptomatology during and after treatment did not differ between those classified as having severe and enduring AN and those not classified as having severe and enduring AN. Moreover, patients with a longer illness duration even showed stronger decreases in depressive symptoms from admission to discharge, which yet were not maintained at follow up. Thus, the current findings do not indicate that patients with severe and enduring AN have a less favorable treatment outcome or should be treated differently than patients without severe and enduring AN, as has been discussed in the literature (Wonderlich et al., 2020 ). Accompanying the pattern of changes in body weight, eating disorder psychopathology, compulsive exercise, and depressive symptoms decreased during inpatient treatment but increased afterwards. Similarly, life satisfaction increased during inpatient treatment but decreased afterwards. These changes were not moderated by BMI at admission, indicating that patients showed improvements in these aspects independent of their initial body weight. This finding dovetails with suggestions that the DSM–5 severity specifiers based on BMI may not reflect meaningful differences in terms of psychopathology, distress, and prognosis (Dang et al., 2022 ; Dang et al., 2023 ). Yet, the current results still suggest that persons with severe and extreme AN have a poorer prognosis than those with a higher body weight as studies that examined samples that also included (or were mainly composed of) persons with mild and moderate severity reported a more favorable treatment outcome at one-year follow up (Dalle Grave et al., 2020 ; Danielsen et al., 2020 ; Golden et al., 2021 ; Meule et al., 2021 ; Pruccoli et al., 2023 ). The finding that the treatment led to substantial symptom improvements but—despite that most patients received psychotherapeutic aftercare—there were still refractory symptoms after discharge is also reflected in the eating- and weight-related variables assessed at follow up. While the majority of participants indicated that they regularly ate three meals per day that also included high-caloric, formerly forbidden foods, most participants did not adhere to the portion size guidelines from the hospital. Furthermore, while participants’ desired body weight at follow up was higher than their current body weight—possibly indicating a high motivation to recover—this desired body weight was still in the underweight range for most participants. Interpretation of results is limited to inpatients with AN treated in Germany and, thus, may not translate to other countries with different healthcare systems (e.g., length of stay is usually shorter in the USA than in Europe; Kan et al., 2021 ). Furthermore, body weight at follow up was based on self-report, which may be biased. Yet, persons with AN are extremely accurate when self-reporting their own weight. For example, self-reported weight has been found to be more accurate in women with AN than in normal-weight and overweight women (Engstrom et al., 2003 ). Although it has been found that they slightly overestimate their weight, this overestimation is less than one kilogram on average (Ciarapica et al., 2010 ; McCabe et al., 2001 ; Meyer et al., 2009 ). Thus, it is unlikely that using self-report of current weight at follow up substantially affected results of the current study. Yet, other variables such as eating behaviors and compulsive exercise were also based on self-report and, thus, influences like recall bias or demand effects cannot be excluded. Therefore, including objective measures of these variables would be desirable in future studies. In conclusion, the current study shows that voluntary inpatient treatment that includes a high-calorie refeeding schedule with supervised meals, individual psychotherapy sessions, group therapies, close medical monitoring, and micronutrient supplementation in patients with severe and extreme AN leads to substantial improvements that are partially maintained after discharge. However, symptom improvements somewhat deteriorate after discharge despite psychotherapeutic aftercare, indicating that persons with severe and extreme AN require more long-lasting, alternating treatment approaches (e.g., interval treatment; Peters et al., 2021 ) to ensure long-term recovery. Declarations Availability of data and materials The data and code with which all results can be reproduced can be accessed at https://osf.io/3uypd. Funding No funding was received for this study. Competing interests All authors declare that they do not have any conflicts of interest. Ethics approval and consent to participate The study was approved by the ethics committee of the University Hospital of the LMU Munich. All participants signed informed consent before commencing the study. Consent for publication Signed informed consent was obtained from all participants. Acknowledgments The authors thank Richard Schreiber and Sofia Anders for collecting the data. Authors' contributions AM: Formal analysis, Visualization, Writing – original draft, Writing – review & editing. EPW: Data curation, Writing – review & editing. TK: Resources, Writing – review & editing. UC: Conceptualization, Writing – review & editing. UV: Conceptualization, Writing – review & editing. References Abry F, Gorwood P, Hanachi M, Di Lodovico L. Longitudinal investigation of patients receiving involuntary treatment for extremely severe anorexia nervosa. Eur Eat Disorders Rev. 2024;32(2):179–87. https://doi.org/10.1002/erv.3033 . American Psychiatric Association. 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Broomfield C, Stedal K, Touyz S, Rhodes P. Labeling and defining severe and enduring anorexia nervosa: A systematic review and critical analysis. Int J Eat Disord. 2017;50(6):611–23. https://doi.org/10.1002/eat.22715 . Ciarapica D, Mauro B, Zaccaria M, Cannella C, Polito A. Validity of self-reported body weight and height among women including patients with eating disorders. Eat Weight Disorders. 2010;15:e74–80. https://doi.org/10.1007/bf03325282 . Clifton L, Clifton DA. The correlation between baseline score and post-intervention score, and its implications for statistical analysis. Trials. 2019;20(1):43. https://doi.org/10.1186/s13063-018-3108-3 . Comtois D. (2022). Tools to Quickly and Neatly Summarize Data (R package version 1.0.1) . https://cran.r-project.org/package=summarytools Cuntz U, Körner T, Voderholzer U. Rapid renutrition improves health status in severely malnourished inpatients with AN - score-based evaluation of a high caloric refeeding protocol in severely malnourished inpatients with anorexia nervosa in an intermediate care unit. Eur Eat Disorders Rev. 2022;30(2):178–89. https://doi.org/10.1002/erv.2877 . Dalle Grave R, Conti M, Calugi S. Effectiveness of intensive cognitive behavioral therapy in adolescents and adults with anorexia nervosa. Int J Eat Disord. 2020;53:1428–38. https://doi.org/10.1002/eat.23337 . Dang AB, Giles S, Fuller-Tyszkiewicz M, Kiropoulos L, Krug I. A systematic review and meta-analysis on the DSM–5 severity ratings for eating disorders. Clin Psychol Sci Pract. 2022;29(4):325–44. https://doi.org/10.1037/cps0000078 . Dang AB, Kiropoulos L, Castle DJ, Jenkins Z, Phillipou A, Rossell SL, Krug I. Assessing severity in anorexia nervosa: Do the DSM-5 and an alternative severity rating based on overvaluation of weight and shape severity differ in psychological and biological correlates? Eur Eat Disorders Rev. 2023;31(4):447–61. https://doi.org/10.1002/erv.2969 . Danielsen M, Bjørnelv S, Weider S, Myklebust TÅ, Lundh H, Rø Ø. The outcome at follow-up after inpatient eating disorder treatment: a naturalistic study. J Eat Disorders. 2020;8(1):67. https://doi.org/10.1186/s40337-020-00349-6 . Davis C, Brewer H, Ratusny D. Behavioral frequency and psychological commitment: necessary concepts in the study of excessive exercising. J Behav Med. 1993;16:611–28. https://doi.org/10.1007/bf00844722 . Diener E, Emmons RA, Larsen RJ, Griffin S. The Satisfaction With Life Scale. J Pers Assess. 1985;49:71–5. https://doi.org/10.1207/s15327752jpa4901_13 . Dittmer N, Voderholzer U, Mönch C, Cuntz U, Jacobi C, Schlegl S. Efficacy of a specialized group intervention for compulsive exercise in inpatients with anorexia nervosa: a randomized controlled trial. Psychother Psychosom. 2020;89:161–73. https://doi.org/10.1159/000504583 . Dittmer N, Voderholzer U, von der Mühlen M, Marwitz M, Fumi M, Mönch C, Alexandridis K, Cuntz U, Jacobi C, Schlegl S. Specialized group intervention for compulsive exercise in inpatients with eating disorders: feasibility and preliminary outcomes. J Eat Disorders. 2018;6(27):1–11. https://doi.org/10.1186/s40337-018-0200-8 . Engstrom JL, Paterson SA, Doherty A, Trabulsi M, Speer KL. Accuracy of self-reported height and weight in women: an integrative review of the literature. J Midwifery Women's Health. 2003;48:338–45. https://doi.org/10.1016/s1526-9523(03)00281-2 . Fairburn CG, Beglin SJ. Assessment of eating disorders: Interview or self-report questionnaire? Int J Eat Disord. 1994;16:363–70. https://doi.org/10.1002/1098-108X(199412)16:43.0.CO;2-#. Field AP, Wilcox RR. Robust statistical methods: A primer for clinical psychology and experimental psychopathology researchers. Behav Res Ther. 2017;98:19–38. https://doi.org/10.1016/j.brat.2017.05.013 . Geniole SN, Proietti V, Bird BM, Ortiz TL, Bonin PL, Goldfarb B, Watson NV, Carré JM. (2019). Testosterone reduces the threat premium in competitive resource division. Proceedings of the Royal Society B , 286 (1903), 20190720. https://doi.org/10.1098/rspb.2019.0720 Glaesmer H, Grande G, Braehler E, Roth M. The German version of the Satisfaction With Life Scale (SWLS). Eur J Psychol Assess. 2011;27:127–32. https://doi.org/10.1027/1015-5759/a000058 . Golden NH, Cheng J, Kapphahn CJ, Buckelew SM, Machen VI, Kreiter A, Accurso EC, Adams SH, Le Grange D, Moscicki A-B, Sy AF, Wilson L, Garber AK. Higher-calorie refeeding in anorexia nervosa: 1-year outcomes from a randomized controlled trial. Pediatrics. 2021;147(4):e2020037135. https://doi.org/10.1542/peds.2020-037135 . Guinhut M, Melchior J-C, Godart N, Hanachi M. Extremely severe anorexia nervosa: Hospital course of 354 adult patients in a clinical nutrition-eating disorders-unit. Clin Nutr. 2021;40(4):1954–65. https://doi.org/10.1016/j.clnu.2020.09.011 . Hautzinger M, Keller F, Kühner C. BDI-II - Beck Depressions-Inventar Revision. 2nd ed. Hogrefe; 2009. Hay P, Touyz S. Classification challenges in the field of eating disorders: can severe and enduring anorexia nervosa be better defined? J Eat Disorders. 2018;6(1):41. https://doi.org/10.1186/s40337-018-0229-8 . Hilbert A, Tuschen-Caffier B. Eating Disorder Examination–Questionnaire. dgvt; 2016. https://www.dgvt-verlag.de/e-books/2_Hilbert_Tuschen-Caffier_EDE-Q_2016.pdf . Kan C, Hawkings Y-R, Cribben H, Treasure J. Length of stay for anorexia nervosa: systematic review and meta-analysis. Eur Eat Disorders Rev. 2021;29:371–92. https://doi.org/10.1002/erv.2820 . Koerner T, Haas V, Heese J, Karacic M, Ngo E, Correll CU, Voderholzer U, Cuntz U. Outcomes of an accelerated inpatient refeeding protocol in 103 extremely underweight adults with anorexia nervosa at a specialized clinic in Prien, Germany. J Clin Med. 2020;9(5):1535. https://doi.org/10.3390/jcm9051535 . Koller M. robustlmm: an R package for robust estimation of linear mixed-effects models. J Stat Softw. 2016;75(6):1–24. https://doi.org/10.18637/jss.v075.i06 . Lenth RV. (2023). Estimated Marginal Means, aka Least-Squares Means (R package version 1.8.6) . https://CRAN.R-project.org/package=emmeans Mangiafico S. (2019). Functions to Support Extension Education Program Evaluation (R package version 2.0.10) . https://cran.r-project.org/package=rcompanion McCabe RE, McFarlane T, Polivy J, Olmsted MP. Eating disorders, dieting, and the accuracy of self-reported weight. Int J Eat Disord. 2001;29:59–64. https://doi.org/10.1002/1098-108x(200101)29:13.0.Co;2-#. Meule A, Kolar DR, Voderholzer U. Predictors of treatment outcome in persons with anorexia nervosa: on the practice of regressing body mass index at the end of treatment on body mass index at baseline. Int J Eat Disord. 2025;58(1):254–8. https://doi.org/10.1002/eat.24324 . Meule A, Schrambke D, Furst Loredo A, Schlegl S, Naab S, Voderholzer U. Inpatient treatment of anorexia nervosa in adolescents: a one-year follow up study. Eur Eat Disorders Rev. 2021;29:165–77. https://doi.org/10.1002/erv.2808 . Meyer C, Arcelus J, Wright S. Accuracy of self-reported weight and height among women with eating disorders: a replication and extension study. Eur Eat Disorders Rev. 2009;17:366–70. https://doi.org/10.1002/erv.950 . Mirman D. Growth Curve Analysis and Visualization Using R. Chapman & Hall/CRC; 2014. Peters K, Meule A, Voderholzer U, Rauh E. Effects of interval-based inpatient treatment for anorexia nervosa: An observational study. Brain Behav. 2021;11(11):e2362. https://doi.org/10.1002/brb3.2362 . Pruccoli J, Pugliano R, Pranzetti B, Parmeggiani A. Premenarchal anorexia nervosa: clinical features, psychopharmacological interventions, and rehospitalization analysis in a 1-year follow-up, controlled study. Eur J Pediatrics. 2023;182(6):2855–64. https://doi.org/10.1007/s00431-023-04960-y . Revelle W. (2023). psych: Procedures for Psychological, Psychometric, and Personality Research (R package version 2.3.3) . https://CRAN.R-project.org/package=psych Thome JL, Espelage DL. Obligatory exercise and eating pathology in college females: replication and development of a structural model. Eat Behav. 2007;8:334–49. https://doi.org/10.1016/j.eatbeh.2006.11.009 . Wonderlich SA, Bulik CM, Schmidt U, Steiger H, Hoek HW. Severe and enduring anorexia nervosa: Update and observations about the current clinical reality. Int J Eat Disord. 2020;53:1303–12. https://doi.org/10.1002/eat.23283 . World Health Organization. (2022). International Classification of Diseases (11th ed.). World Health Organization. https://icd.who.int/browse11 Zeeck A, Schlegel S, Giel KE, Junne F, Kopp C, Joos A, Davis C, Hartmann A. Validation of the German version of the Commitment to Exercise Scale. Psychopathology. 2017;50:146–56. https://doi.org/10.1159/000455929 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 25 Aug, 2025 Read the published version in Journal of Eating Disorders → Version 1 posted Editorial decision: Accepted 08 Aug, 2025 Reviews received at journal 04 Aug, 2025 Reviewers agreed at journal 12 Jul, 2025 Reviews received at journal 09 Jul, 2025 Reviewers agreed at journal 09 Jul, 2025 Reviewers invited by journal 07 Jul, 2025 Submission checks completed at journal 02 Jul, 2025 First submitted to journal 28 Jun, 2025 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-5701532","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":481809165,"identity":"f9a01d8a-f464-4755-9132-7b9a1e2d0ece","order_by":0,"name":"Adrian Meule","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA10lEQVRIiWNgGAWjYFCCBIYDEAZzA8MHEH2AeC2MDYwziNXCANPCzEOMFv723IcHfu5giOaXSGx8bNt2j4HveAN+LRJnnhsc7D3DkDtzRmKzcW5bMYPkGULW3EhjOMDbxpC74UZim3RuWwKDwY0E/DrkgVoO/gVq2X8jsf23JUjL/Qf4tRgAtRwG2yKR2MbMCLaFgLsMzzxjOCzbJpE748zDZsmecwk8kmcIOEzueBrzx7dtNrn97ckHP/woS5DjO36AgDUQIAFn8RClfhSMglEwCkYBfgAA/DhJ9FtZIU0AAAAASUVORK5CYII=","orcid":"","institution":"University of Regensburg","correspondingAuthor":true,"prefix":"","firstName":"Adrian","middleName":"","lastName":"Meule","suffix":""},{"id":481809166,"identity":"12210d2c-509a-4089-a35d-054cd86c833b","order_by":1,"name":"Eva P. Wuttke","email":"","orcid":"","institution":"LMU University Hospital, LMU Munich","correspondingAuthor":false,"prefix":"","firstName":"Eva","middleName":"P.","lastName":"Wuttke","suffix":""},{"id":481809167,"identity":"788c022b-55fe-4d2f-897a-0b38646b4618","order_by":2,"name":"Thorsten Koerner","email":"","orcid":"","institution":"Schoen Clinic Roseneck","correspondingAuthor":false,"prefix":"","firstName":"Thorsten","middleName":"","lastName":"Koerner","suffix":""},{"id":481809168,"identity":"b5067e4d-a3ca-4a30-80ee-e6fa54982bd6","order_by":3,"name":"Ulrich Cuntz","email":"","orcid":"","institution":"Schoen Clinic Roseneck","correspondingAuthor":false,"prefix":"","firstName":"Ulrich","middleName":"","lastName":"Cuntz","suffix":""},{"id":481809169,"identity":"b7cb4527-6c9c-4771-9ed4-0163cecaa44e","order_by":4,"name":"Ulrich Voderholzer","email":"","orcid":"","institution":"LMU University Hospital, LMU Munich","correspondingAuthor":false,"prefix":"","firstName":"Ulrich","middleName":"","lastName":"Voderholzer","suffix":""}],"badges":[],"createdAt":"2024-12-23 18:08:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5701532/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5701532/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s40337-025-01374-z","type":"published","date":"2025-08-25T15:58:07+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":86298373,"identity":"0c7af4a3-0c81-4ae1-8e72-455b7b37f396","added_by":"auto","created_at":"2025-07-09 05:54:06","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":5531751,"visible":true,"origin":"","legend":"\u003cp\u003eParticipant flow.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-5701532/v1/2934a549db5ddfad06c99a44.png"},{"id":86298378,"identity":"9beb43e9-98a2-4864-bbce-08dade495959","added_by":"auto","created_at":"2025-07-09 05:54:09","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2115278,"visible":true,"origin":"","legend":"\u003cp\u003eMean (A) body mass index and scores on the (B) Eating Disorder Examination–Questionnaire, (C) Commitment to Exercise Scale, (D) Beck Depression Inventory–Revised, and (E) Satisfaction With Life Scale at admission, discharge, and follow up. Error bars indicate standard error of the mean. The black lines are second-order polynomial fit lines indicating non-linear change over time and the grey-shaded areas represent 95% confidence intervals. Note that numbers in the different panels are not comparable because of different scaling and scoring of variables.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-5701532/v1/58dcd188ea55742a382a92bb.png"},{"id":86298375,"identity":"ac55ac21-f4ba-4c16-8af1-c322093c891f","added_by":"auto","created_at":"2025-07-09 05:54:07","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":807558,"visible":true,"origin":"","legend":"\u003cp\u003eChanges across admission, discharge, and follow up in (A) body mass index (BMI) as a function of BMI at admission and (B) scores on the Beck Depression Inventory–Revised as a function of illness duration. The lines are second-order polynomial fit lines indicating non-linear change over time and the grey-shaded areas represent 95% confidence intervals. Note that \u003cem\u003ehigh\u003c/em\u003e and \u003cem\u003elow\u003c/em\u003e refer to ±1 \u003cem\u003eSD\u003c/em\u003e from the sample’s mean BMI at admission and illness duration, respectively. These values are arbitrarily chosen for visualizing the interaction effect time² × BMI at admission and time² × illness duration in the robust mixed models. That is, BMI at admission and illness duration were used as continuous variables in these analyses and not categorized into groups.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-5701532/v1/508c1ffd5740ec5f666f672f.png"},{"id":90344948,"identity":"918cc2d8-406c-421c-90ed-762ddd1cf61a","added_by":"auto","created_at":"2025-09-01 16:08:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":9075593,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5701532/v1/d1ab9016-ed03-495d-b274-5e7e87f2501c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Treatment outcome in a specialized unit for adults with severe and extreme anorexia nervosa at one-year follow up","fulltext":[{"header":"Plain English Summary","content":"\u003cp\u003eThis study examined outcomes of inpatient treatment for adults with anorexia nervosa one year after discharge. Initially, patients showed significant improvements in body weight, life satisfaction, and reductions in eating disorder symptoms, depression, and compulsive exercise. However, within a year after leaving the hospital, many patients experienced a decline in life satisfaction and body weight, along with a resurgence of eating disorder symptoms, depression, and compulsive exercise, despite most receiving some form of treatment during this period. While most patients reported eating three meals a day and consuming high-calorie foods, few followed the hospital\u0026apos;s portion size guidelines. It is concluded that while inpatient treatment is effective, severe cases of anorexia nervosa need ongoing, innovative treatment approaches to support long-term recovery.\u003c/p\u003e"},{"header":"Background","content":"\u003cp\u003eAnorexia nervosa (AN) is an eating disorder that is characterized by significantly low body weight, which is maintained by behaviors such as restrictive eating, purging (e.g., self-induced vomiting, misuse of laxatives), and excessive exercise, and typically associated with a fear of weight gain (American Psychiatric Association, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). AN severity is assessed according to a person\u0026rsquo;s body mass index (BMI) in the current version of both the Diagnostic and Statistical Manual of Mental Disorders (DSM\u0026ndash;5; American Psychiatric Association, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) and the International Classification of Diseases (ICD\u0026ndash;11; World Health Organization, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In the DSM\u0026ndash;5, severity is categorized as mild (BMI\u0026thinsp;\u0026ge;\u0026thinsp;17.0 kg/m\u0026sup2;), moderate (BMI\u0026thinsp;\u0026ge;\u0026thinsp;16.0 kg/m\u0026sup2; and \u0026lt;\u0026thinsp;17.0 kg/m\u0026sup2;), severe (BMI\u0026thinsp;\u0026ge;\u0026thinsp;15.0 kg/m\u0026sup2; and \u0026lt;\u0026thinsp;16.0 kg/m\u0026sup2;), and extreme (BMI\u0026thinsp;\u0026lt;\u0026thinsp;15.0 kg/m\u0026sup2;). In the ICD\u0026ndash;11, severity is categorized as AN in recovery with normal body weight (BMI\u0026thinsp;\u0026ge;\u0026thinsp;18.5 kg/m\u0026sup2;), AN with significantly low body weight (BMI\u0026thinsp;\u0026lt;\u0026thinsp;18.5 kg/m\u0026sup2; and \u0026ge;\u0026thinsp;14 kg/m\u0026sup2;), and AN with dangerously low body weight (BMI\u0026thinsp;\u0026lt;\u0026thinsp;14 kg/m\u0026sup2;).\u003c/p\u003e\u003cp\u003eThere have also been suggestions to alternatively consider overvaluation of weight and shape, illness duration, and previous treatments as indicators for AN severity (Dang et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Wonderlich et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). For example, some studies defined so-called severe and enduring AN based on an illness duration of at least seven years (Broomfield et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Hay and Touyz (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) proposed to define severe and enduring AN as (1) a persistent state of dietary restriction, underweight, and overvaluation of weight and shape with functional impairment, (2) illness duration of longer than three years, and (3) exposure to at least two evidence-based treatments.\u003c/p\u003e\u003cp\u003eHaving severe and extreme AN is usually an indication for inpatient treatment, which often includes involuntary admission and enteral nutrition (Abry et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Guinhut et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, voluntary inpatient treatment that includes a high-calorie refeeding schedule with supervised meals, individual psychotherapy sessions, group therapies, close medical monitoring, and micronutrient supplementation also successfully improves health status in persons with extreme AN (Cuntz et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Koerner et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eRisk of relapse is high in persons with AN, particularly in the first year after inpatient treatment (Berends et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Approximately 25\u0026ndash;35% of AN patients need to be rehospitalized in that period (Danielsen et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Golden et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Meule et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, most studies report that body weight at discharge is\u0026mdash;on average\u0026mdash;largely maintained at one-year follow up in both adolescents and adults, the majority of which received psychotherapeutic aftercare (Dalle Grave et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Danielsen et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Golden et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Meule et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Pruccoli et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Studies that examined outcome after inpatient treatment in persons with severe and extreme AN are rare. For example, Abry et al. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) recently reported on a study that compared involuntarily and voluntarily treated AN patients with an average BMI of 12 kg/m\u0026sup2; at admission, in which BMI increased from discharge to follow up. However, these findings may be biased by small sample size and high attrition rates.\u003c/p\u003e\u003cp\u003eThe aim of the current study was to examine treatment outcome one year after discharge in a sample of persons with AN (94% being categorized as having severe or extreme AN according to DSM\u0026ndash;5, see below) treated at a specialized inpatient unit. Specifically, we examined changes in BMI, eating disorder psychopathology, compulsive exercise, depressive symptoms, and life satisfaction across admission, discharge, and one-year follow up. We also tested whether BMI at admission, classifying patients as having severe and enduring AN, and illness duration would moderate changes over time of these variables. Finally, we also report on eating-, weight-, and treatment-related questions at follow up.\u003c/p\u003e"},{"header":"Methods","content":"\n\u003ch3\u003eSample characteristics\u003c/h3\u003e\n\u003cp\u003e The study was approved by the ethics committee of the University Hospital of the LMU Munich. One-hundred and thirty-nine adults with AN who received inpatient treatment at the Schoen Clinic Roseneck (Rosenheim, Germany) between 2018 and 2020 were contacted one year after discharge between 2019 and 2021 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Of these, 80 persons participated in the study (98% female, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;78; mean age: \u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;27.3 years, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;10.2). Fifty-three persons (66%) had restrictive-type AN (ICD\u0026ndash;10 code F50.00), 26 (33%) had binge/purge-type AN (ICD\u0026ndash;10 code F50.01), and one (1%) had atypical AN (ICD\u0026ndash;10 code F50.1). Forty persons (50%) had at least one comorbid mental disorder, the most common of which were anxiety disorders (ICD\u0026ndash;10 code F4; \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;26, 33%) and affective disorders (ICD\u0026ndash;10 code F3; \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;17, 21%). A subset of patients received antidepressant (\u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;13/53, 25%) or antipsychotic (\u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;15/53, 28%) medication during the stay (information not available for 27 patients).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eWhen using the severity classification according to ICD\u0026ndash;11 (World Health Organization, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), 66.3% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;53) had AN with dangerously low body weight (BMI\u0026thinsp;\u0026lt;\u0026thinsp;14.0 kg/m\u0026sup2;) and 33.8% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;27) had AN with significantly low body weight (BMI\u0026thinsp;\u0026ge;\u0026thinsp;14.0 kg/m\u0026sup2; and \u0026lt;\u0026thinsp;18.5 kg/m\u0026sup2;). When using the severity classification according to DSM\u0026ndash;5 (American Psychiatric Association, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), 85.0% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;68) had extreme AN (BMI\u0026thinsp;\u0026lt;\u0026thinsp;15.0 kg/m\u0026sup2;), 8.8% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;7) had severe AN (BMI\u0026thinsp;\u0026ge;\u0026thinsp;15.0 kg/m\u0026sup2; and \u0026lt;\u0026thinsp;16.0 kg/m\u0026sup2;), 3.8% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3) had moderate AN (BMI\u0026thinsp;\u0026ge;\u0026thinsp;16.0 kg/m\u0026sup2; and \u0026lt;\u0026thinsp;17.0 kg/m\u0026sup2;), and 2.5% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2) had mild AN (BMI\u0026thinsp;\u0026ge;\u0026thinsp;17.0 kg/m\u0026sup2;). Mean illness duration was 10.1 years (\u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;9.74, Range: 1\u0026ndash;40) and 55.0% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;44) had an illness duration of at least seven years and 45.0% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;36) had an illness duration of less than seven years. Illness duration did not relate to BMI at admission (\u003cem\u003er\u003c/em\u003e\u003csub\u003epb\u003c/sub\u003e = 0.05, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.680). The mean number of previous treatments was 3.4 (\u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3.7, Range 0\u0026ndash;16). When using the criteria by Hay and Touyz (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), 53.3% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;41) had severe and enduring AN and 46.8% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;36) did not meet the criteria for severe and enduring AN (information not available for three patients).\u003c/p\u003e\u003cp\u003eAll patients were treated in a specialized inpatient unit for AN patients with severe underweight (BMI\u0026thinsp;\u0026lt;\u0026thinsp;15 kg/m\u0026sup2;) and/or excessive purging or exercising (length of stay: \u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;102.7 days, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;52.2). The treatment at the hospital adheres to the German S3-guidelines for the treatment of AN in terms of admission criteria, treatment elements, and therapy goals (AWMF, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Thus, patients received a cognitive-behavioral therapy-oriented, multimodal AN treatment that included several treatment elements such as individual psychotherapy sessions, group therapy sessions, exercise therapy, meal preparation classes, body image exposure, nutrition counseling, and food intake protocols as well as clinical management of medical complications, including micronutrient supplementation. The treatment includes a high-calorie refeeding schedule (starting on the first day of treatment) that aims at a weight gain of 0.7\u0026ndash;1.0 kg per week for all underweight AN patients. This schedule includes three meals per day, each having approximately 700 kcal and, thus, totaling to a daily caloric intake of approximately 2100 kcal. Meals are supervised by a staff member (nurse, psychotherapist, or physician) in earlier treatment stages. The schedule is individually tailored if patients do not finish their meals or do not show the expected weight gain by increasing portion size, adding snacks between meals, or offering sip feeds. As normalization of eating behavior is one of the therapeutic goals, patients do not receive nasogastric feeding. Patients can choose between vegetarian and non-vegetarian menus; vegan menus are not offered. Compared to other eating disorder units at the hospital, the treatment at the specialized unit is more intensive and structured, with enhanced medical monitoring, closer behavioral supervision (e.g., during meals and to ensure limiting physical activity and preventing purging behaviors), daily weighing, and more frequent therapeutic contact tailored to patients with severe AN.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eMeasures\u003c/h2\u003e\u003cp\u003e\u003cem\u003eBMI\u003c/em\u003e. Body weight and height were measured at the hospital at admission and discharge and participants self-reported their current height and weight at follow up. BMI was calculated as kg/m\u0026sup2;.\u003c/p\u003e\u003cp\u003e\u003cem\u003eEating Disorder Examination\u0026ndash;Questionnaire (EDE\u0026ndash;Q)\u003c/em\u003e. Eating disorder symptomatology was assessed with the German version (Hilbert \u0026amp; Tuschen-Caffier, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) of the EDE\u0026ndash;Q (Fairburn \u0026amp; Beglin, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1994\u003c/span\u003e). The EDE\u0026ndash;Q has 28 items, six of which assess the frequency of binge and purge behaviors in the past 28 days and are not included in the total score. The other 22 items are answered on a seven-point scale (0\u0026ndash;6) with different response labels. Higher mean total scores indicate higher eating disorder symptomatology. Internal reliability at admission, discharge, and follow up ranged between ω\u0026thinsp;=\u0026thinsp;.95 and .98.\u003c/p\u003e\u003cp\u003e\u003cem\u003eCommitment to Exercise Scale (CES).\u003c/em\u003e Compulsive exercise was assessed with the German version (Zeeck et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) of the CES (Davis et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). The CES has eight items and, in the original version, these were answered on a visual analogue scale with different anchors. In the current study, we applied a four-point scale (e.g., 1\u0026thinsp;=\u0026thinsp;\u003cem\u003enever\u003c/em\u003e to 4\u0026thinsp;=\u0026thinsp;\u003cem\u003ealways\u003c/em\u003e) response format, in line with other studies (Dittmer et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Dittmer et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Thome \u0026amp; Espelage, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Higher mean total scores indicate higher compulsive exercising. Internal reliability at admission, discharge, and follow up ranged between ω\u0026thinsp;=\u0026thinsp;.95 and .97.\u003c/p\u003e\u003cp\u003e\u003cem\u003eBeck Depression Inventory\u0026ndash;Revised (BDI\u0026ndash;II)\u003c/em\u003e. Depressive symptoms were assessed with the German version (Hautzinger et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2009\u003c/span\u003e) of the BDI\u0026ndash;II (Beck et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). The BDI\u0026ndash;II has 21 items that are answered on a four-point scale (0\u0026ndash;3) with different response labels. Higher total sum scores indicate higher depressive symptomatology. Internal reliability at admission, discharge, and follow up ranged between ω\u0026thinsp;=\u0026thinsp;.91 and .95.\u003c/p\u003e\u003cp\u003e\u003cem\u003eSatisfaction With Life Scale (SWLS)\u003c/em\u003e. Life satisfaction was assessed with the German version (Glaesmer et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) of the SWLS (Diener et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e1985\u003c/span\u003e). The SWLS has five items that are answered on a seven-point scale (1\u0026thinsp;=\u0026thinsp;\u003cem\u003estrongly disagree\u003c/em\u003e to 7\u0026thinsp;=\u0026thinsp;\u003cem\u003estrongly agree\u003c/em\u003e). Higher total sum scores indicate higher life satisfaction. Internal reliability at admission, discharge, and follow up ranged between ω\u0026thinsp;=\u0026thinsp;.88 and .92.\u003c/p\u003e\u003cp\u003e\u003cem\u003eEating- and weight-related questions at follow up.\u003c/em\u003e Current meal frequency was assessed with three questions asking \u0026ldquo;On how many days in the past seven days have you had breakfast/lunch/dinner?\u0026rdquo;. Responses were recorded on an eight-point scale from 0 to 7 (ω\u0026thinsp;=\u0026thinsp;.77) and averaged to a mean score. Current meal portions were assessed with three questions asking \u0026ldquo;On how many days in the past seven days have you eaten according to the portion size guidelines by the hospital at breakfast/lunch/dinner?\u0026rdquo;. Responses were recorded on an eight-point scale from 0 to 7 (ω\u0026thinsp;=\u0026thinsp;.86) and averaged to a mean score. Current intake of high-calorie foods was assessed with one question asking \u0026ldquo;On how many days in the past seven days have you eaten high-caloric (previously \u0026ldquo;forbidden\u0026rdquo;) foods?\u0026rdquo;. Responses were recorded on an eight-point scale from 0 to 7. Current desired body weight was assessed with one item stating \u0026ldquo;My current desired body weight is \u0026hellip; kg.\u0026rdquo;.\u003c/p\u003e\u003cp\u003e\u003cem\u003eQuestions on current and past treatments at follow up\u003c/em\u003e. Eating disorder treatments were assessed with five questions asking \u0026ldquo;Have you received outpatient [physician]/outpatient [psychotherapist]/outpatient [group]/daypatient/inpatient eating disorder treatment in the past six months?\u0026rdquo; (yes/no). Current psychotherapeutic treatment was assessed with one question asking \u0026ldquo;Do you currently receive psychotherapeutic treatment?\u0026rdquo; (yes/no). Current psychopharmacological treatment was assessed with one question asking \u0026ldquo;Do you currently take medication to treat your mental disorder?\u0026rdquo; (yes/no, if yes enter name of drugs).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eData analyses\u003c/h3\u003e\n\u003cp\u003eStatistical analyses were conducted with R version 4.5.0 (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.r-project.org\u003c/span\u003e\u003cspan address=\"https://www.r-project.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) in RStudio version 2025.05.0 (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://posit.co\u003c/span\u003e\u003cspan address=\"https://posit.co\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e). As assumptions of the general linear model are often violated when analyzing clinical psychology data, it has been suggested preferring nonparametric and robust analysis techniques (Field \u0026amp; Wilcox, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Therefore, changes in BMI as well as EDE\u0026ndash;Q, CES, BDI\u0026ndash;II, and SWLS scores across admission, discharge, and follow up were examined with robust mixed models with the \u003cem\u003erobustlmm\u003c/em\u003e package (Koller, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Specifically, separate models were calculated with either BMI, EDE\u0026ndash;Q, CES, BDI\u0026ndash;II, or SWLS scores as dependent variable. Fixed effects of time were added by including first- and second-order orthogonal polynomials of the time term as independent variables, modeling linear and non-linear changes across the three measurements (Mirman, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). The models also included a random intercept (i.e., person-level random variability in scores at admission). As the \u003cem\u003erobustlmm\u003c/em\u003e package does not produce parameter-specific \u003cem\u003ep\u003c/em\u003e-values, we used the workaround described by Geniole et al. (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Specifically, non-robust models were fitted with the \u003cem\u003elme4\u003c/em\u003e package (Bates et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) to obtain Satterthwaite-approximated degrees of freedom and two-sided \u003cem\u003ep\u003c/em\u003e-values were then computed for the robust \u003cem\u003et\u003c/em\u003e-values using the approximated degrees of freedom. Pairwise comparisons (admission vs. discharge, discharge vs. follow up) were computed with the \u003cem\u003eemmeans\u003c/em\u003e package (Lenth, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) and Cohen\u0026rsquo;s \u003cem\u003ed\u003c/em\u003e was computed as effect size with the \u003cem\u003eeffectsize\u003c/em\u003e package (Ben-Shachar et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Note that\u0026mdash;although there were missing data for each dependent variable\u0026mdash;these mixed models included all 80 cases because of the restricted maximum likelihood estimation.\u003c/p\u003e\u003cp\u003eIn another set of robust mixed models, we added the fixed effect of BMI at admission and its interaction with the two time terms to examine whether changes in BMI and questionnaire scores across admission, discharge, and follow up would be moderated by BMI at admission. Specifically, in contrast to the models described above that only included \u003cem\u003etime\u003c/em\u003e and \u003cem\u003etime\u0026sup2;\u003c/em\u003e as independent variables, these models included \u003cem\u003etime\u003c/em\u003e, \u003cem\u003etime\u0026sup2;\u003c/em\u003e, \u003cem\u003eBMI at admission\u003c/em\u003e, \u003cem\u003etime\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e, and \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e as independent variables. Note, however, that the only effect of interest here was the interaction effect \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e, testing whether the non-linear changes across time would differ as a function of BMI at admission but all \u0026ldquo;subordinate\u0026rdquo; effects have to be included in such a model as well. Similar models were run to examine whether changes would be moderated by severe and enduring AN groups and illness duration.\u003c/p\u003e\u003cp\u003eInternal reliability coefficients (McDonald\u0026rsquo;s ω) for all questionnaires for which items were averaged or summed were obtained with the \u003cem\u003epsych\u003c/em\u003e package (Revelle, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Descriptive statistics for variables used for sample description, eating- and weight-related questions at follow up, and questions on current and past treatments at follow up were obtained with the \u003cem\u003esummarytools\u003c/em\u003e package (Comtois, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Meal frequency and meal portions as well as current and desired body weight at follow up were compared with Wilcoxon paired signed-rank tests with the \u003cem\u003ercompanion\u003c/em\u003e package (Mangiafico, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The data and code with which all analyses can be reproduced are available at \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://osf.io/3uypd\u003c/span\u003e\u003cspan address=\"https://osf.io/3uypd\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003eBMI\u003c/h2\u003e\u003cp\u003eBMI changed non-linearly across the three measurements (effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;2.27, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.18, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). Specifically, BMI increased from admission to discharge (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;4.38, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.25, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.16) and decreased from discharge to follow up (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;1.17, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.26, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;0.37; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA). Changes in BMI differed as a function of BMI at admission (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.23, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.09, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.010): lower BMI at admission related to steeper increases in BMI across measurements (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). Changes in BMI did not differ as a function of severe and enduring AN groups (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003egroups\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.09, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.37, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.817) or illness duration (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eillness duration\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.003, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.02, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.861).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eEDE–Q\u003c/h3\u003e\n\u003cp\u003eEating disorder symptomatology changed non-linearly across the three measurements (effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.93, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.16, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). Specifically, EDE\u0026ndash;Q scores decreased from admission to discharge (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;1.69, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.21, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;1.36) and increased from discharge to follow up (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.60, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.21, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.004, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.36; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB). Changes in EDE\u0026ndash;Q scores did not differ as a function of BMI at admission (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.05, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.09, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.579) or severe and enduring AN groups (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003egroups\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.01, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.32, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.969) or illness duration (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eillness duration\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.02, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.02, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.247).\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eCES\u003c/h2\u003e\u003cp\u003eCompulsive exercise changed non-linearly across the three measurements (effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.30, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.08, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). Specifically, CES scores decreased from admission to discharge (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;0.44, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.11, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;0.69) and increased from discharge to follow up (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.29, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.11, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.007, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.30; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC). Changes in CES scores did not differ as a function of BMI at admission (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.03, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.05, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.532) or severe and enduring AN groups (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003egroups\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.02, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.16, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.889) or illness duration (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eillness duration\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.003, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.01, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.677).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eBDI–II\u003c/h3\u003e\n\u003cp\u003eDepressive symptomatology changed non-linearly across the three measurements (effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;10.8, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.58, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). Specifically, BDI\u0026ndash;II scores decreased from admission to discharge (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;17.1, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.13, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;1.27) and increased from discharge to follow up (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;9.41, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.12, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.64; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD). Changes in BDI\u0026ndash;II scores did not differ as a function of BMI at admission (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;0.62, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.92, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.503) or severe and enduring AN groups (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003egroups\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3.17, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3.33, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.343). However, they differed as a function of illness duration (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eillness duration\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.35, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.16, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.028): a longer illness duration related to steeper decreases in BDI\u0026ndash;II scores from admission to discharge and steeper increases in BDI\u0026ndash;II scores from discharge to follow up (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB).\u003c/p\u003e\n\u003ch3\u003eSWLS\u003c/h3\u003e\n\u003cp\u003eLife satisfaction changed non-linearly across the three measurements (effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;2.23, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.69, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.002). Specifically, SWLS scores increased from admission to discharge (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3.61, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.93, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.57) and decreased from discharge to follow up (\u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;1.86, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.94, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.048, \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;0.16; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eE). Changes in SWLS scores did not differ as a function of BMI at admission (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eBMI at admission\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.11, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.41, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.785) or severe and enduring AN groups (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003egroups\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;0.09, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.41, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.952) or illness duration (interaction effect of \u003cem\u003etime\u0026sup2;\u003c/em\u003e \u0026times; \u003cem\u003eillness duration\u003c/em\u003e: \u003cem\u003eb\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;0.06, \u003cem\u003eSE\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.07, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.392).\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eEating- and weight-related questions at follow up\u003c/h2\u003e\u003cp\u003eOn average, participants reported to eat three meals per day on about six days in the past week (\u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;6.14 days, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.52) but reported adhering to portion size guidelines on significantly fewer days (\u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3.77, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.59; \u003cem\u003eV\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1649, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001, \u003cem\u003er\u003c/em\u003e\u003csub\u003erb\u003c/sub\u003e = .995). The majority of participants (90%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;71/79, information not available for one participant) indicated that they ate high-caloric, formerly forbidden foods on at least one day in the past week. Current self-reported body weight (\u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;45.5 kg, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;9.16) was significantly lower than desired body weight (\u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;47.6, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;8.93; \u003cem\u003eV\u003c/em\u003e\u0026thinsp;=\u0026thinsp;471, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.002, \u003cem\u003er\u003c/em\u003e\u003csub\u003erb\u003c/sub\u003e = .468). In fact, 69% of participants (\u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;43/62, information not available for 18 participants) indicated that their desired weight was higher than their current weight, 26% (\u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;16/62) indicated that their desired weight was lower than their current weight, and 5% (\u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3/62) indicated that their desired weight was equal to their current weight. When converting desired weight into BMI (\u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;17.5 kg/m\u0026sup2;, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.79), the majority of participants (61%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;39/62) indicated that their desired BMI was lower than 18.5 kg/m\u0026sup2; (that is, in the underweight range according to the classification of the World Health Organization).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eQuestions on current and past treatments at follow up\u003c/h2\u003e\u003cp\u003eThe majority of participants (87%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;68/78, information not available for two participants) indicated they received any eating disorder treatment in the past six months (outpatient [physician]: 42%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;33/78; outpatient [psychotherapist]: 63%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;49/78; outpatient [group]: 9%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;7/78; daypatient: 5%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;4/78; inpatient: 35%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;27/78) and that they currently received psychotherapeutic treatment (63%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;49/78). The minority of participants (44%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;35/79, information not available for one participant) indicated that they currently received psychopharmacological treatment (antidepressants: 35%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;28/79; antipsychotics: 19%, \u003cem\u003en\u003c/em\u003e/\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;15/79).\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe current study examined treatment outcome in persons with AN treated at a specialized unit for severe and extreme AN across admission, discharge, and one-year follow up. Disorder-specific and related symptoms substantially improved during treatment but somewhat declined after treatment. For example, average BMI increased from 13.2 kg/m\u0026sup2; at admission (with all patients being underweight [BMI\u0026thinsp;\u0026lt;\u0026thinsp;18.5 kg/m\u0026sup2;]) to 17.5 kg/m\u0026sup2; at discharge (with 27 of 80 patients [33.8%] having a BMI\u0026thinsp;\u0026ge;\u0026thinsp;18.5 kg/m\u0026sup2;) but decreased to 16.6 kg/m\u0026sup2; after one year (with 18 of 73 patients [22.5%] having a BMI\u0026thinsp;\u0026ge;\u0026thinsp;18.5 kg/m\u0026sup2;). These changes were moderated by BMI at admission such that a lower BMI at admission related to steeper weight gain from admission to discharge. This effect might be explained by several factors. Biologically, larger weight gain in those with lower BMI may be due to lower resting metabolic rate at the beginning of treatment. Psychologically, many patients accept that they have to gain weight during treatment but refuse to exceed certain self-imposed thresholds (e.g., 50 kg), which are reached faster by those who start with higher BMI at admission. Besides these explanations, however, it has been observed that\u0026mdash;due to regression to the mean\u0026mdash;there is always a correlation between baseline scores and change scores, regardless of any treatment effects (Clifton \u0026amp; Clifton, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Thus, while it appears that AN patients with a lower BMI at admission achieve a higher weight gain during inpatient treatment, an incorrect interpretation would be to conclude that the treatment is more effective for these patients (Meule et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAlthough most patients had severe and extreme AN according to their BMI at admission, only about half of the sample met the criteria for severe and enduring AN by Hay and Touyz (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Furthermore, changes in AN symptomatology during and after treatment did not differ between those classified as having severe and enduring AN and those not classified as having severe and enduring AN. Moreover, patients with a longer illness duration even showed stronger decreases in depressive symptoms from admission to discharge, which yet were not maintained at follow up. Thus, the current findings do not indicate that patients with severe and enduring AN have a less favorable treatment outcome or should be treated differently than patients without severe and enduring AN, as has been discussed in the literature (Wonderlich et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAccompanying the pattern of changes in body weight, eating disorder psychopathology, compulsive exercise, and depressive symptoms decreased during inpatient treatment but increased afterwards. Similarly, life satisfaction increased during inpatient treatment but decreased afterwards. These changes were not moderated by BMI at admission, indicating that patients showed improvements in these aspects independent of their initial body weight. This finding dovetails with suggestions that the DSM\u0026ndash;5 severity specifiers based on BMI may not reflect meaningful differences in terms of psychopathology, distress, and prognosis (Dang et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Dang et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Yet, the current results still suggest that persons with severe and extreme AN have a poorer prognosis than those with a higher body weight as studies that examined samples that also included (or were mainly composed of) persons with mild and moderate severity reported a more favorable treatment outcome at one-year follow up (Dalle Grave et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Danielsen et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Golden et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Meule et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Pruccoli et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe finding that the treatment led to substantial symptom improvements but\u0026mdash;despite that most patients received psychotherapeutic aftercare\u0026mdash;there were still refractory symptoms after discharge is also reflected in the eating- and weight-related variables assessed at follow up. While the majority of participants indicated that they regularly ate three meals per day that also included high-caloric, formerly forbidden foods, most participants did not adhere to the portion size guidelines from the hospital. Furthermore, while participants\u0026rsquo; desired body weight at follow up was higher than their current body weight\u0026mdash;possibly indicating a high motivation to recover\u0026mdash;this desired body weight was still in the underweight range for most participants.\u003c/p\u003e\u003cp\u003eInterpretation of results is limited to inpatients with AN treated in Germany and, thus, may not translate to other countries with different healthcare systems (e.g., length of stay is usually shorter in the USA than in Europe; Kan et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Furthermore, body weight at follow up was based on self-report, which may be biased. Yet, persons with AN are extremely accurate when self-reporting their own weight. For example, self-reported weight has been found to be more accurate in women with AN than in normal-weight and overweight women (Engstrom et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Although it has been found that they slightly overestimate their weight, this overestimation is less than one kilogram on average (Ciarapica et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; McCabe et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Meyer et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Thus, it is unlikely that using self-report of current weight at follow up substantially affected results of the current study. Yet, other variables such as eating behaviors and compulsive exercise were also based on self-report and, thus, influences like recall bias or demand effects cannot be excluded. Therefore, including objective measures of these variables would be desirable in future studies.\u003c/p\u003e\u003cp\u003eIn conclusion, the current study shows that voluntary inpatient treatment that includes a high-calorie refeeding schedule with supervised meals, individual psychotherapy sessions, group therapies, close medical monitoring, and micronutrient supplementation in patients with severe and extreme AN leads to substantial improvements that are partially maintained after discharge. However, symptom improvements somewhat deteriorate after discharge despite psychotherapeutic aftercare, indicating that persons with severe and extreme AN require more long-lasting, alternating treatment approaches (e.g., interval treatment; Peters et al., \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) to ensure long-term recovery.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eThe data and code with which all results can be reproduced can be accessed at https://osf.io/3uypd.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eNo funding was received for this study.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eAll authors declare that they do not have any conflicts of interest.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eThe study was approved by the ethics committee of the University Hospital of the LMU Munich. All participants signed informed consent before commencing the study.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eSigned informed consent was obtained from all participants.\u003c/p\u003e\n\u003cp\u003eAcknowledgments\u003c/p\u003e\n\u003cp\u003eThe authors thank Richard Schreiber and Sofia Anders for collecting the data.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eAM: Formal analysis, Visualization, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing. EPW: Data curation, Writing \u0026ndash; review \u0026amp; editing. TK: Resources, Writing \u0026ndash; review \u0026amp; editing. UC: Conceptualization, Writing \u0026ndash; review \u0026amp; editing. UV: Conceptualization, Writing \u0026ndash; review \u0026amp; editing.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbry F, Gorwood P, Hanachi M, Di Lodovico L. 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Psychopathology. 2017;50:146\u0026ndash;56. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1159/000455929\u003c/span\u003e\u003cspan address=\"10.1159/000455929\" 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":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-eating-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"joed","sideBox":"Learn more about [Journal of Eating Disorders](http://jeatdisord.biomedcentral.com)","snPcode":"40337","submissionUrl":"https://submission.nature.com/new-submission/40337/3","title":"Journal of Eating Disorders","twitterHandle":"@JEatDisord","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Inpatient treatment, Severe and enduring anorexia nervosa, Body mass index, Eating disorders, Psychotherapy","lastPublishedDoi":"10.21203/rs.3.rs-5701532/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5701532/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eInpatient treatment successfully increases body weight and decreases eating disorder and associated symptoms in patients with anorexia nervosa (AN). However, relapse rates are high, particularly within the first year after discharge.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eWe examined treatment outcome one year after discharge in adults with AN (\u003cem\u003eN\u003c/em\u003e\u0026thinsp;=\u0026thinsp;80, 2 males; BMI at admission: \u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;13.2 kg/m\u0026sup2;, \u003cem\u003eSD\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.79) who received treatment in a specialized inpatient unit for AN patients with severe underweight (body mass index\u0026thinsp;\u0026lt;\u0026thinsp;15 kg/m\u0026sup2;) and/or excessive purging or exercising.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eFrom admission to discharge, body weight and self-reported life satisfaction significantly increased and self-reported eating disorder symptoms, depressive symptoms, and compulsive exercise significantly decreased. From discharge to follow up, life satisfaction and body weight decreased, and eating disorder symptoms, depressive symptoms, and compulsive exercise increased, although 87% of patients indicated to have received some kind of eating disorder treatment in the past six months. At follow up, the majority of patients indicated that they regularly ate three meals per day in the past week, including consumption of high-calorie, formerly forbidden foods. However, only a minority of patients indicated that they adhered to the hospital\u0026rsquo;s guidelines on portion sizes. Patients\u0026rsquo; self-reported desired body weight at follow up was significantly higher than their current body weight.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eWhile inpatient treatment results in substantial improvements that are partially maintained after discharge, severe and extreme cases of AN require more long-lasting, alternating treatment approaches (e.g., interval treatment) to ensure long-term recovery.\u003c/p\u003e","manuscriptTitle":"Treatment outcome in a specialized unit for adults with severe and extreme anorexia nervosa at one-year follow up","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-09 05:53:12","doi":"10.21203/rs.3.rs-5701532/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Accepted","date":"2025-08-08T14:27:49+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-04T16:33:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"236325278763323634021729929730875467047","date":"2025-07-12T14:31:20+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-09T13:58:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"186118099398051035580983171160185727711","date":"2025-07-09T13:50:47+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-07T13:32:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-02T23:13:10+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Eating Disorders","date":"2025-06-28T16:08:45+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-eating-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"joed","sideBox":"Learn more about [Journal of Eating Disorders](http://jeatdisord.biomedcentral.com)","snPcode":"40337","submissionUrl":"https://submission.nature.com/new-submission/40337/3","title":"Journal of Eating Disorders","twitterHandle":"@JEatDisord","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c3647442-a5fa-4eaf-812a-570abb54ce54","owner":[],"postedDate":"July 9th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-09-01T16:03:21+00:00","versionOfRecord":{"articleIdentity":"rs-5701532","link":"https://doi.org/10.1186/s40337-025-01374-z","journal":{"identity":"journal-of-eating-disorders","isVorOnly":false,"title":"Journal of Eating Disorders"},"publishedOn":"2025-08-25 15:58:07","publishedOnDateReadable":"August 25th, 2025"},"versionCreatedAt":"2025-07-09 05:53:12","video":"","vorDoi":"10.1186/s40337-025-01374-z","vorDoiUrl":"https://doi.org/10.1186/s40337-025-01374-z","workflowStages":[]},"version":"v1","identity":"rs-5701532","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5701532","identity":"rs-5701532","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}