Weight changes over time in adults treated with the oral or depot formulations of olanzapine: a pooled analysis of 86 clinical trials

Abstract

Several analytical approaches were used to characterize time progression of weight changes observed in adults treated with olanzapine from a 12,425-patient database of 86 studies of oral and depot formulations of olanzapine (mean modal dose 13.3 mg/day). Descriptive mean profile plots for completer and modified completer groups showed weight increasing throughout each observed period, with apparent slowing in rate of change after 3 or 4 months. Mixed-effects model repeated measures analyses also showed that weight increased most rapidly early in treatment and slowed within 2 to 4 months. The slowing in rate of change was greatest for patients obese at baseline and least for patients underweight at baseline. This pattern was also observed in a nonparametric regression-based profile. Based on visual inspection of profile plots, 2, 3, 4, and 5 months were postulated as potential ‘change points’ beyond which rate of increase might slow, and the proportions of patients whose slope after each change point was ≤90% of the slope before change point were calculated. Over 85% of patients who gained weight showed slowing rate of weight change after each postulated change point. Potential consequences of weight gain should be considered prior to starting olanzapine. Olanzapine-treated patients should receive regular weight monitoring.