Healthcare Utilization and Costs in Patients With Somatic Symptom and Related Disorders Compared With Those With Depression and Healthy Controls: A Nationwide Cohort Study

Introduction: Patients with somatic symptom and related disorders (SSRDs) often face diagnostic delays, leading to frustration, unnecessary medical procedures, and excessive costs. This study examines healthcare utilization and costs in the 3 years before diagnosing SSRDs, comparing them to patients with depressive disorders and individuals with no mental disorder using data from the Korean National Health Insurance claims database. The analysis also addresses the influence of medical comorbidities by focusing on patients without them.

Methods: Utilizing Korean nationwide medical claims database covering all South Koreans, we identified individuals aged 15–64 diagnosed with SSRDs between 2015 and 2019. A corresponding group diagnosed with depression served as controls for nonpsychotic mental disorders. We analyzed medical costs and healthcare utilization comparing the SSRDs group to the depression group and the group with no mental disorder using nonparametric tests, including a specific analysis for those with a Charlson Comorbidity Index (CCI) of zero.

Results: The study encompassed 84,223 SSRD patients, 336,919 with depressive disorders, and 269,444 individuals with no mental disorder. Patients with SSRDs had significantly higher healthcare costs and made more frequent use of outpatient and emergency services than both control groups, a pattern consistent even in patients without medical comorbidities.

Conclusion: This large nationwide cohort study confirmed that patients with SSRDs frequently used the healthcare system and incurred considerable costs before their diagnosis. The findings suggest that plans for early recognition and intervention, along with mental health support for this population, are urgently needed to assist them and improve the efficiency of the healthcare system.