Risk of developing diabetes mellitus and hyperlipidemia among patients with bipolar disorder,major depressive disorder,and schizophrenia: A 10-year nationwide population-based prospective cohort study

Background

The high comorbidity of metabolic side effects with severe mental disorders (SMDs), including bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia, had gained much attention, because the excess mortality of these patients is mainly due to physical illness. However, most of these studies were with cross-sectional study design, the time course of metabolic side effects and SMD cannot be elucidated without a cohort study.

Method

Using a nationwide database with a large sample size and a matched control cohort study design, we enrolled patients with SMDs but without diagnoses of and medications for DM and hyperlipidemia from 1996 to 2000, and followed them to the end of 2010. We compared them with age and gender-matched controls (1:4) for the incidence of DM and hyperlipidemia.

Results

The identified cases were 367 patients with BD, 417 patients with MDD, and 1993 patients with schizophrenia, with average age of 45.3±14.0, 46.5±13.7, and 45.9±12.3, respectively. The patients with BD and schizophrenia had increased risk of initiation of anti-diabetic medications (10.1% vs. 6.3%, p=0.012; 13.3% vs. 7.2% p<0.001; respectively), and anti-hyperlipidemia medications (15.8% vs.10.5%, p=0.004; 14.2% vs.12.1%, p=0.005; respectively) than the controls. After controlling age, gender, urbanization, and income, the Cox regression model showed significantly increased risk of initiation of anti-diabetic medications among patients with BD (hazard ratio (HR) of 1.702, 95% confidence interval (CI): 1.155–2.507) and schizophrenia (HR of1.793, 95% CI: 1.532–2.098). Increased risk of initiation of anti-hyperlipidemia medications was also noted among patients with BD (HR of 1.506, 95% CI: 1.107–2.047) and schizophrenia (HR of 1.154, 95% CI: 1.002–1.329). The patients with MDD did not show increased risk of initiation of these medications than the controls.

Conclusions

This first 10-year nationwide population-based prospective matched control cohort study showed increased risks of initiation of anti-diabetic and anti-hyperlipidemia medications among patients with BD and schizophrenia. No significant increased risk was noted among the patients with MDD.