Anorexia nervosa in adolescents: evolution of weight history and impact of excess premorbid weight

The purpose of our study is to establish if the proportion of patients diagnosed with anorexia nervosa that have a history of excess weight has increased over a 10-year period and to study how different premorbid weight groups vary in terms of clinical characteristics. We performed a single-center, retrospective cohort study of all new patients presenting with anorexia nervosa, restrictive and binge/purge subtypes, in 2004 and 2014 at the Adolescent Medicine Clinic of Sainte-Justine University Health Centre (n = 172). The prevalence of excess premorbid weight was similar in both cohorts (32% in 2004 versus 29.5% in 2014). The historically overweight subgroup had a lower heart rate at intake (64.77 versus 69.75, p = 0.03). Patients with excess premorbid weight lost an average of 1 kg more per month than their historically thinner counterparts (2.6 kg versus 1.6 kg/month, p = 0.0011). The total decrease in BMI was much greater in patients with a history of excess weight (7 BMI points versus 3.8, p = 0.0001).