Incident diabetes associated with antipsychotic use in the United Kingdom General Practice Research Database

Background: Recent reports suggest an association between antipsychotic use and development or exacerbation of diabetes. This study evaluated the risk of incident diabetes associated with the use of atypical and conventional antipsychotics. Method: This nested case-control study included all patients in the U.K. General Practice Research Database treated with antipsychotic drugs between January 1994 and December 1998. The main outcome measures were the odds ratios of current (within prior 6 months) or recent (7 to 12 months) antipsychotic exposure among those with (N = 424) compared with those without incident diabetes (N = 1522). Results: The adjusted odds ratio for current use of any antipsychotic drug compared with no use in the past year among those with diabetes was 1.7 (95% confidence interval [CI] = 1.3 to 2.3). The adjusted odds ratio for current use of atypical and conventional antipsychotic drugs compared with no use in the past year among those with diabetes was 4.7 (95% Cl = 1.5 to 14,9) and 1.7 (95% CI = 1.2 to 2.3), respectively. The adjusted odds ratio for recent use of conventional antipsychotic drugs compared with no use in the past year among those with diabetes was 1.0 (95% Cl = 0.6 to 1.6). The odds ratio for recent atypical antipsychotic drug use could not be calculated because no study subjects had this exposure. Conclusion: This study showed an increased risk of incident diabetes among current users of atypical and conventional antipsychotic medications. These results were independent of other established risk factors. The larger association observed for atypical antipsychotic users should be regarded as preliminary given the small number of incident diabetes cases in this group.