Diabetes mellitus onset in geriatric patients: does long-term atypical antipsychotic exposure increase risk?

Abstract

Background: Diabetes mellitus (DM) in common in adults using psychotropic medications. However, it remains largely unknown whether there is an additional risk of diabetes mellitus (DM) in elderly psychiatric outpatients, particularly those with long-term exposure to atypical antipsychotics (AP).

Methods: In this retrospective longitudinal study, 61 atypical AP-exposed and 64 atypical AP-unexposed geriatric psychiatric patients were compared to a group of 200 psychotropic-naïve controls. Our main composite outcome was diabetes incidence over a 4-year period, defined by fasting blood glucose ≥ 7.0 mmol/L or a new-onset oral hypoglycaemic or insulin prescription during the 4-year period.

Results: The 4-year incidence of DM did not differ significantly between groups: 12.3%, 6.7%, and 11.9% in the atypical AP-exposed, atypical AP-unexposed, and control groups, respectively (χ(2) = 1.40, P = 0.50). Depression and antidepressant, cholinesterase inhibitor, and valproate use were independently associated with increases in fasting glucose. However, hyperglycaemia and hypoglycaemic prescriptions were not more common in geriatric psychiatric patients.

Conclusions: DM does not appear to be more common in geriatric psychiatric patients than similarly aged controls and is not more common in atypical AP users. However, depression and antidepressant, cholinesterase inhibitor, and valproate use may increase fasting glucose levels, and the clinical significance of this warrants further investigation. Nonetheless, given the rates of untreated and undertreated fasting hyperglycaemia in both our geriatric psychiatric and control samples (>10% of all patients), we recommend regular screening for DM in these populations.

Keywords: antidepressants; atypical antipsychotic; depression; diabetes mellitus; hyperglycaemia; valproate.