Incidence of Type 2 Diabetes Mellitus and Its Association with Antipsychotics in Mental Disorder Inpatients in Beijing, China: A Retrospective Cohort Study

Abstract

Background: Previous studies in developed countries have found that antipsychotics is associated with type 2 diabetes mellitus, and the antipsychotic exposure time are risk factors for type 2 diabetes in antipsychotic exposed population. However, large cohort study in Chinese mental disorder inpatients reporting incidence of type 2 diabetes and examining the association between antipsychotics and the risk of type 2 diabetes is scarce. We designed a retrospective cohort study using electronic health record (EHR) data from 2005 to 2018 in all 19 specialized psychiatric hospitals in Beijing, China, to estimate the incidence of type 2 diabetes and investigate its association with antipsychotics in mental disorder inpatients. Methods: In this retrospective cohort study, we enrolled 115157 adult mental disorder inpatients between Jan 1, 2005, and Dec 31, 2018 from all 19 specialized psychiatric hospitals in Beijing, China. 24524 eligible inpatients were identified and were divided into exposed group with antipsychotics prescription, and control group without antipsychotics prescription. Incident type 2 diabetes was identified from discharge diagnoses during follow-up. We calculated the incidence rate for type 2 diabetes by follow years, and used Cox regression models to estimate the hazard ratio (HR) for the risk of type 2 diabetes in antipsychotics exposed inpatients. Findings: In this cohort study, 24524 inpatients were eligible to participate. 18344 (74.80%) exposed inpatients were identified with antipsychotics prescription, 6180 (25.20%) were controls without antipsychotics prescription. This cohort had 85207.49 person-years of follow-up, during which there were 1584 incident type 2 diabetes cases, with an incidence rate of 18.59 per 1000 person-years. There were 1100 and 484 incident type 2 diabetes in exposed group and control group, the incidence rate was 21.76 and 13.97 per 1000 person-years. The antipsychotics exposed inpatients had a 1.65 fold (95%CI: 1.47-1.85) increased risk for type 2 diabetes, which was highest in the 18-29 years group (HR=2.34, 95%CI: 1.51-3.60). The increased risk was apparent within the first year of exposure (HR=2.47, 95%CI: 1.88-3.25). After 5 years exposure, the risk was also elevated and increased with increasing exposure years (HR=1.72-3.16). Interpretation: Incidence of type 2 diabetes was high in Chinese adult mental disorder inpatients. Antipsychotics exposed inpatients had a 1.65 fold increased risk for type 2 diabetes, which was highest in the 18-29 years group. Prevention and control programmes for diabetes should be utmost important in mental disorder inpatients’ care, treatment, and management. Funding Statement: This study was supported by the grant from National Natural Science Foundation of China (No. 71874003 and No. 81703240). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The study used information that is available in database of the Beijing Municipal Commission of Health and Family Planning Information Center, and all identifiable information was removed. Patients and the public were not involved in the design and conduct of the study.