Characteristics of Comorbid Physical Disease in Patients with Severe Mental Illness in South Korea: A Nationwide Population-Based Study (2014-2019)

Abstract

Abstract Purpose: The purpose of this study was to identify the associations of chronic physical disease between patients with severe mental illness and the general population of South Korea. Methods: This study was conducted with National Health Insurance Corporation (NHIC) data from 2014 to 2019. A total of 842,459 people were diagnosed with severe mental illness (SMI) in this period, and the same number of controls were established by matching by sex and age. A descriptive analysis was conducted on the sociodemographic characteristics of patients with SMI. Conditional logistic regression analysis was performed to identify the associations between comorbid physical disease in patients with SMI and those of the general population. SAS Enterprise Guide 7.1 (SAS, Inc, Cary, NC) were used to perform all statistical tests. Result: The analysis revealed significant differences in medical insurance, income level, and Charlson Comorbidity Index (CCI) weighted by chronic physical disease, between patients with severe mental illness and the general population. Conditional logistic regression analysis between the two groups also revealed significant differences in all nine chronic physical diseases. Conclusions: The study found that people with severe mental illness had more chronic comorbid physical diseases than the general population. Therefore, people with severe mental illness have a reduced quality of life and a higher risk of excess mortality.