Predictors of Outcome in Inpatients with Anorexia Nervosa: A Prospective Multi-Center Study

to study inclusion. The local research ethics committees (the Medical Associations of Hamburg and Schleswig-Holstein and the University Medical Centre of Munich) approved the study. At admission (t0) and discharge (t1), the participants completed a battery of standardized questionnaires (ED pathology: EDI-2 [5] ; depressive symptoms: PHQ-9; anxiety symptoms: GAD-7; somatic symptoms: PHQ-15 [6] , and therapy motivation: FEVER [7] ). Patient weight was measured at t0 and t1 and weekly during treatment by a staff member. Patients with missing data for all BMI measurements after t0 or missing t0 BMI were excluded from the analysis. We tested for baseline differences between the therapy completers and noncompleters using twotailed t tests and χ 2 tests. For t0 and t1 BMIs, paired sample t tests and effect sizes (Cohen’s d) were conducted. Inpatient BMI gain was predicted using stepwise linear regression analysis with the following predictors: therapy duration; median split age; age of onset; living alone; partnership; education; previous hospitalizations; AN subtype; BMI t0 ; centers; PHQ-9 t0 ; PHQ-15 t0 ; GAD-7 t0 ; median split FEVER t0 , and all EDI-2 t0 subscales. All analyses were calculated for the therapy completers and the intention-totreat (ITT) sample. We recruited 233 patients (April 2010–July 2012). Twenty-five patients were removed from the analysis because of implausible or missing BMI measurements. In 3 cases, BMI t1 was imputed using the last observation carried forward (the BMI 1 week earlier). Of the 208 patients analyzed, 176 completed the therapy (noncompletion rate: 15.4%). The regression analyses included the patients who had complete data for all predictor variables. The ITT study sample consisted of patients with a mean age of 26.9 years (SD = 8.6, range: 17–58) and an average age of illness onset of 17.8 years (SD = 5.9). The majority had a restrictive AN subtype (n = 103, 53.7 %) and at least one previous psychiatric or psychosomatic inpatient stay (n = 120, 57.7 %). Only about one third of the patients (n = 67, 32.2 %) were currently in a partnership. Therapy completers stayed longer in the hospital compared to noncompleters (t = 7.01, p < 0.001, mean Completers = 11.8 weeks, SD Completers = 5.2; mean Noncompleters = 5.1, SD Noncompleters = 3.1). We found no baseline differences between therapy completers and therapy noncompleters with respect to clinical or demographic variables. As expected, the BMI significantly improved from t0 to t1 with an effect size of 1.16 within the ITT sample (t = –19.7, p < 0.001; mean t0 = 15.0, SD t0 = 1.6, range t0 : 10.8–18.0; mean t1 = 16.9, SD t1 = 1.7, range t1 = 11.8–20.7) and an effect size of 1.35 for completers (t = –20.1, p < 0.001; mean t0 = 15.0, SD t0 = 1.6, range t0 = 10.8–18.0; mean t1 = 17.1, SD t1 = 1.5, range t1 = 12.8–20.7). Inpatient treatments for anorexia nervosa (AN) are highly effective with respect to rapid weight gain. Nevertheless, the proportion of patients with poor responses in recent naturalistic studies appears to be critically high: more than half of the patients remain underweight (BMI <17.5) at discharge [1, 2] , and there is a strong need for more effective treatments for inpatients with AN [3] . An important starting point for evidence-based improvements and tailored recommendations is knowledge of the factors associated with poor responses. However, only one study predicted adult inpatient BMI gain using a comprehensive set of potential predictors [4] . This study found that BMI gain depended solely on the therapy duration. Thus, the predictive value of the remaining variables was judged to be insufficient, and the need for future research was highlighted. Other studies focused on the influence of one specific factor on BMI gain, potentially ignoring yet unidentified but important control variables. Consequently, we aimed to analyze predictors of BMI gain in a large sample of adult inpatients with AN. We conducted a prospective multi-center study with a prepost design. Three participating hospitals offering adult eating disorder (ED) specialist treatment (Schön clinics Bad Bramstedt, Prien, and Hamburg-Eilbek) recruited patients who met the following inclusion criteria: primary DSM-IV diagnosis of AN; female gender; a minimum age of 16 years, and sufficient German language skills. The exclusion criteria were acute drug or alcohol abuse, acute suicidality, psychotic or bipolar disorders, or severe somatic disorders. Written informed consent was obtained prior Received: October 14, 2014 Accepted after revision: March 3, 2015 Published online: May 23, 2015