No differences in olanzapine- and risperidone-related weight gain between women and men: a meta-analysis of short- and middle-term treatment.

OBJECTIVE: A plethora of data deriving from single studies as well as meta-analyses demonstrates that weight gain is associated with the exposure to the majority of antipsychotics (AP). However, potential sex differences have widely evaded the attention of AP treatment trials. It is hypothesised that female patients gain more weight compared with male patients due to their enhanced susceptibility to adverse drug reactions.

METHOD: A meta-analysis was conducted using clinical trials of AP that reported weight change separately for female and male patients. Duration of AP use was stratified in four categories: <6 weeks, 6-16 weeks, 16-38 weeks and >38 weeks. Forest plots were generated for men and women separately, stratified by AP as well as by duration of use. Sex differences were tested by performing meta-regression.

RESULTS: Data of 26 studies were used in the present analysis because sufficient data were available only for olanzapine, risperidone and the no-medication group. Both female and male patients showed considerable weight gain after switch or initiate of olanzapine or risperidone, but meta-regression analyses did not show significant sex differences.

CONCLUSION: The present meta-analysis revealed that sex differences in AP-related weight gain have been under investigated hampering the detection of sex-specific patterns. In chronic patients switching to olanzapine or risperidone receiving short-or middle-term treatment, AP were associated with weight gain in both sex subgroups and no significant differences were reported.