Predictors and outcomes of different growth curve trajectories of weight gain in hospital-based treatment for anorexia nervosa
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Date
2016-01-01
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Psychology
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Psychology
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This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. For permission to publish or reproduce, please see http://aok.lib.umbc.edu/specoll/repro.php or contact Special Collections at speccoll(at)umbc.edu
Distribution Rights granted to UMBC by the author.
Distribution Rights granted to UMBC by the author.
Abstract
Anorexia Nervosa (AN) is primarily characterized by extremely low body weight and can result in medical, psychological, and social complications. Weight restoration, or returning to a medically normal weight, is a primary goal of treatment and is associated with positive outcomes. Though treatment programs strive for fast and consistent weight gain to increase the likelihood of achieving weight restoration prior to discharge, research using growth curve trajectories indicates there is variation in weight gain during inpatient treatment. Further, trajectories of weight gain may be predictive of long-term outcomes. However, research on the heterogeneity of weight gain during treatment as well as precursors and outcomes of differing trajectories is limited, and distinct patterns of weight gain are not clear. This study aimed to identify subgroups of patients with differing patterns of weight gain during hospital-based treatment of AN using mixture modeling, and identify predictors and treatment outcomes of estimated trajectory groups. Participants were female inpatients with AN or subthreshold AN (N = 219) who were admitted to the Johns Hopkins Eating Disorders Program between 2003 and 2012. Participants completed self-report measures, including eating disorder behaviors and psychosocial constructs, at admission and a subset (n = 123) were measured again six-months after treatment discharge. Clinical outcome variables were assessed via chart review following discharge. Three distinct patterns of weight gain were found; a negative quadratic trajectory (Optimal group), a negative quadratic trajectory with a faster initial rate of weight gain (Accelerated group), and a positive linear trajectory with slower rate of weight gain (Sub-optimal group). Previous hospitalization, highest lifetime BMI, behavioral subtype, regularly restricting, bingeing, vomiting, and using laxatives at admission, and extraversion were predictors of group membership. Group membership predicted BMI and weight restoration at both discharge and follow-up, and regularly bingeing, and drive for thinness at follow-up. The Accelerated group emerged as the most distinct relative to the Optimal and Sub-optimal groups at admission, discharge, and follow-up whereas the Optimal and Sub-optimal groups appeared relatively similar. The Accelerated group was associated with increased disorder severity at admission and was primarily composed of women with bingeing and purging behaviors. Further, following treatment, the Accelerated group was associated with more positive weight outcomes; however they were also more likely to return to pre-treatment behaviors and had the least amount of improvement on psychological aspects of AN. Results suggest variation in weight gain with certain patterns associated with increased illness severity and risk of relapse. Further, results highlight the importance of psychological factors when defining recovery in addition to weight markers.