Weight change by baseline BMI from three-year observational data: findings from the Worldwide Schizophrenia Outpatient Health Outcomes Database

The aim was to explore weight and body mass index (BMI) changes by baseline BMI in patients completing three years of monotherapy with various first- and second-generation antipsychotics in a large cohort in a post hoc analysis of three-year observational data.

Data were analyzed by antipsychotic and three baseline BMI bands: underweight/normal weight (BMI <25 kg/m²), overweight (25–30 kg/m²) and obese (>30 kg/m²).

Baseline BMI was associated with subsequent weight change irrespective of the antipsychotic given. Specifically, a smaller proportion of patients gained ≥7% baseline bodyweight, and a greater proportion of patients lost ≥7% baseline bodyweight with increasing baseline BMI. For olanzapine (the antipsychotic associated with highest mean weight gain in the total drug cohort), the percentage of patients gaining ≥7% baseline weight was 45% (95% CI: 43–48) in the underweight/normal weight BMI cohort and 20% (95% CI: 15–27) in the obese BMI cohort; 7% (95% CI: 6–8) of the underweight/normal cohort and 19% (95% CI: 13–27) of the obese cohort lost ≥7% baseline weight.

BMI has an association with the likelihood of weight gain or loss and should be considered in analyses of antipsychotic weight change.