The authors of this research note that the two groups (those receiving a new prescription for an atypical antipsychotic and those not) were well matched at baseline, with no meaningful differences in 91 measured characteristics; additional characteristics relating to fracture risk (e.g. age; sex; history of previous fracture) were also well balanced. They say that their results complement those of other articles and confirm that the risk may exist with atypical antipsychotics as well as the typical agents. The increase in risk of hospital visits with falls was similar to the observed increase in risk for osteoporotic fractures; it could therefore be that falls (possibly due to side-effects such as hypotension and sedation) could be the mechanism by which these drugs increase fracture risk.
The study is however observational and therefore a causal association cannot be demonstrated. It is possible that there may have been confounding by indication (e.g. antipsychotics prescribed due to behavioural disturbances, which in turn may predispose patients to falls and fractures). The authors conclude however that their findings “call into question the widespread off-label use of atypical antipsychotic medications and support increasing evidence of safety concerns regarding their use in older adults”.