Rates of comorbid obsessive-compulsive disorder in eating disorders: A meta-analysis of the literature

Background: The high comorbidity between Eating Disorders (EDs) and Obsessive-Compulsive disorder (OCD) is well known, as well as its implications in terms of worse outcome and need to adapt treatment. Estimates of OCD comorbidities in EDs are variable in different studies and poorly informative for clinical purposes. In this study, we sought to derive more consistent estimates, taking into account potential methodological and sampling confounding factors. Methods: We searched published studies reporting lifetime and current rates of comorbid OCD in ED samples based on recent diagnostic criteria. Comorbidity rates were meta-analyzed using a binary random effects model. Heterogeneity among the studies and publication bias were systematically checked. Potential confounding factors were tested by meta-regression analysis and adjusted by sensitivity analysis. Results: Globally, respectively 18% and 15% of all patients with an ED had a lifetime and current comorbidity with OCD. Rates were slightly higher in anorexia (19% and 14%) than in bulimia nervosa (13% and 9%), although only the current comorbid OCD was significantly higher in anorexia than in bulimia. Prospective follow-up studies provided considerably higher lifetime estimates (EDs 38%, anorexia 44%, bulimia 19%). Limitations: Temporal/causal relationship between ED and OCD could not be defined. Conclusions: OCD comorbidity in EDs is a relevant phenomenon, affecting almost one fifth of the patients in cross-sectional observations and up to nearly 40% in prospective follow-up studies. These data indicate the need for focused attention to non-food or body-shape related OCD symptoms, for better diagnostic and prognostic accuracy, and targeted treatment.