Under-management of diabetes can lead to a hyperglycaemic episode (HCE), which could be further strengthened in the presence of schizophrenia and the use of antipsychotics. This study aims to investigate the risk of HCE in diabetic patients with schizophrenia. Additionally, the duration of antipsychotic use on the risk of HCE is examined.

A total of 13858 diabetic patients with schizophrenia and 55407 controls (without schizophrenia) matched by gender, age, index year, and Charlson Comorbidity Index score were included between 1999 and 2010 and followed to the end of 2013 using from the Taiwan National Health Insurance Research Database. During the follow-up period, participants who developed HCE were identified. Cox regression analysis was used to calculate the hazard ratio (HR) with 95% confidence interval (95% CI) of the HCE incidence rate between the two groups studied.

Diabetic patients with schizophrenia were associated with an increased risk of HCE compared with unaffected controls after adjusted for baseline demographics and duration of antipsychotic use (4.73 versus 2.43 per 1,000 person-years, HR: 2.16, 95% CI: 1.85-2.51). Also, in diabetic patients with schizophrenia, a longer duration of antipsychotic use was associated with a lower risk of HCE after adjustment for the above-mentioned variables, suggesting a protective effect of antipsychotics against HCE during prolonged use.

This study highlights the need to pay more attention to the risk of HCE in diabetic patients with schizophrenia and the importance of proper use of antipsychotics may reduce the risk of HCE.