Does specialization of treatment influence mortality in eating disorders?--A comparison of two retrospective cohorts.

Eating disorders (EDs) are psychiatric disorders associated with high morbidity and mortality. It is well established that patients with anorexia nervosa (AN) have an increased risk of premature death, whereas mortality data are lacking for the other EDs. This study aimed to establish mortality rates in a sample of ED patients (n=998) with a mean follow-up of 12 years. This was compared to previous data from the same catchment area before a multidisciplinary centre was established. The standardized mortality ratio (SMR) was calculated. To compare the two cohorts, adjusted crude ratios were calculated with the confounding variables: body mass index (BMI), age at referral and diagnosis. In the latest cohort the SMR for AN was 2.89 vs 11.16 in the time before our specialization. SMR for bulimia nervosa (BN) and for eating disorder not otherwise specified (EDNOS) in the latest cohort were 2.37 and 1.14 respectively. When comparing two retrospective cohorts it is not possible to draw a definite conclusion, however the present study supports that integrating a somatic unit in a multidisciplinary centre may have a favourable influence on mortality in AN.