OBJECTIVES: Drug-induced diabetes is an increasingly important cause of diabetes mellitus worldwide. Certain psychotropic drugs may cause weight gain, but the long-term effect of this on the incidence of type 2 diabetes (T2DM) is not clear. This study compared the 5-year incidence of diabetes in a cohort of chronic user of psychotropic drugs and a cohort of patients unexposed.

METHODS : A retrospective cohort study was made using an outpatient prescription database for approximately 6.5 million people insured by the NHSC. Two cohorts were selected from non-diabetic patients aged 18 to 64 years old; new chronic users (≥6 months) of psychotropic drugs (N=2,118) and a cohort of patients unexposed (N=1,877). Patients were followed between 2012 and 2016. The outcome of the study was the occurrence of a diabetic event (first prescription of drugs for the treatment of diabetes). Incidence rates were compared by cohorts. Data was processed and analyzed using R studio.

RESULTS : During 14,754 years of follow-up, the cumulative incidence of diabetic events was 5.1% (n=204); 3.6% (n=67) in unexposed and 6.5% (n=137) in exposed. The mean time until NOD was 28.7±17.3 months in unexposed and 31.7±16.0 months in exposed (p=0.238). The number needed to harm was 34. The incidence rate ratio (IRR) significantly higher for exposed in the first (IRR = 2.378, 95%CI 1.291 – 4.379) and second (IRR = 2.009, 95%CI 1.084 – 3.725) years of follow-up and for the entire follow up period (IRR = 1.661, 95%CI 1.240 – 2.225), but not in the third to fifth year of follow up.

CONCLUSIONS: Chronic users of psychiatric drugs had a higher incidence of diabetes than not exposed patients during the first and second year of treatment.