Response to Letter: Antipsychotic Drugs, Fracture Risk, and Frailty in Older Patients

We are grateful for the opportunity to respond to comments raised by Tomoyuki Kawada. The studies1,2 referred to by Dr Kawada show a positive association between increasing frailty level and risk of fracture. Kawada highlights differences in the reported magnitude of the estimates of association in these studies (inter alia). These differences could be explained by (1) differences in the populations at risk, which are not identical in the 2 studies with systematic differences in sample selection; (2) analyses are not identical and adjustment for confounding variables differs between these studies; or (3) odds ratios are expected to provide more extreme estimates than relative risks.