Risk of death related to psychotropic drug use in older people during the European 2003 heatwave: a population-based case-control study.

OBJECTIVE

The authors investigated the association between death of older people and use of psychotropic drugs before and during the Western European August 2003 heatwave.

METHOD

A retrospective population-based case-control study was conducted using the French social security insurance national database. Exposure to psychotropic drugs in cases aged 70-100 years who died before (N = 2,093) and during (N = 9,531) the August 2003 heatwave was compared with those of survivors matched for age, gender, and presence of chronic illness, by using conditional logistic regressions.

RESULTS

The association between death and psychotropic drug use was modified by level of external temperature (Wald chi(2) = 13.1, degree of freedom = 1, p <0.001). Use of any psychotropic drug was associated with a 30% increased risk of death during the heatwave, with a significant dose-response relationship between the number of psychotropic drugs and the risk of death (adjusted odds ratio [aOR] for linear trend 1.25, 95% confidence interval [95% CI]: 1.21-1.29). During the heatwave, therapeutic classes independently associated with an increased risk of death were antidepressants (aOR 1.71, 95% CI: 1.57-1.86) and antipsychotics (aOR 2.09, 95% CI: 1.89-2.35), whereas exposure to anxiolytics/hypnotics use (aOR 0.85, 0.79-0.91) was associated with a decreased risk. Findings remained unchanged after adjustment on cardiotropic, antidementia, or anti-parkinsonian drug use.

CONCLUSION

Our findings suggest that a causal relationship may exist between psychotropic drug use during a heatwave and increased risk of death in older people. The risk/benefit ratio of antidepressant and antipsychotic drugs should be carefully assessed in older people during a heatwave.