A case series investigation of association between co-morbid psychiatric disorder and the improvement in body mass index among patients with anorexia nervosa and eating disorder not otherwise specified of the anorexia nervosa type

BACKGROUND Anorexia nervosa and eating disorder not otherwise specified* (not fulfilling Anorexia Nervosa DSM IV criteria) are increasing in Singapore. Patients with eating disorders may also present with other psychiatric disorders such as depression and anxiety. The paper aims to investigate the association of co-morbid psychiatric disorders with the improvement of body mass index (BMI) in these patients. METHODS A retrospective cohort analysis of 182 patients with anorexia and eating disorder not otherwise specified at a tertiary hospital was done. The clinical course of co-morbid psychiatric disorders was correlated with the improvement of body mass index. RESULTS 109 patients were included in the analysis and the mean BMI on resolution of co-morbid psychiatric disorders was BMI 16.9. There is a significant association between the BMI groups and the resolution of co-morbid psychiatric disorders, χ2 = 10.2, p = .03. Patients in BMI group 5 (BMI 16.6 - 18.5) were noted to be significantly less likely to resolve their psychiatric co-morbidity compared to the other 4 groups. (OR = 0.323). CONCLUSION Patients with anorexia nervosa and eating disorders not otherwise specified were at increased risk of having co-morbid psychiatric disorders and the clinical course of co-morbid psychiatric disorders appeared to correlate with improved BMI. Specifically patients with BMI < 16.5 with co-morbid psychiatric disorders were more likely to recover from their co-morbid psychiatric disorder with nutritional rehabilitation than patients with a higher BMI.