The Road to Recovery: Impact of COVID-19 on Healthcare Utilization in South Korea Using an Interrupted Time-Series Analysis

Background: The COVID-19 pandemic substantially disrupted the normal patterns of healthcare utilization globally. South Korea had been praised widely in its efforts to contain the spread of the pandemic, which possibly contributed to a significantly smaller reduction in healthcare utilization compared to neighboring countries. However, it remains unknown how the COVID-19 pandemic impacted on utilization pattern across population sub-groups, particularly vulnerable patient groups in South Korea. This paper quantifies the changes in healthcare utilization attributable to COVID-19 and COVID-19 vaccination by subpopulations.Methods: An interrupted time series analysis was conducted to examine the impact of COVID-19 on healthcare utilization in South Korea from 2016-2022 using aggregated patient-level data from the national health insurance system that accounts for 99% of all healthcare services in South Korea. We applied population averaged negative binomial models adjusting for seasonality and serial correlation. Stratified analyses by type of healthcare services, age, sex, income level, health facility type, and avoidable/non-avoidable hospitalizations, we assessed differences in utilization trends between population groups across three phases of the pandemic.Findings: In early 2020, the COVID-19 pandemic led to overall reductions in both monthly volume of outpatient and inpatient utilization with reductions of 19.1% and 14.5% respectively. Most utilization recovered but failed to return to pre-COVID-19 levels as of January 2022. We observed heterogeneity in the magnitude of relative changes in utilization across subpopulations. The youngest age groups experienced a 58.3% utilization decrease compared to pre-COVID, while a 10.6% increase in utilization of inpatient services was observed for those aged 65-74. The magnitude of changes across types of services varied from a 58.5% decrease for pediatrics, 50.6% in public health centers, avoidable hospitalizations fell by 33%, while non-avoidable hospitalizations fell by 9% compared to the pre-pandemic. The post-recovery (i.e. post Sept 2021) outpatient utilization rates were between 20% and 30% higher for children 0 to 18 compared to pre-pandemic levels and no statistical difference in post-recovery utilization was detected for groups aged 19 years or compared with pre-pandemic utilization.Interpretation: The impact of the COVID-19 pandemic on reducing healthcare utilization in South Korea was lesser compared to its neighboring countries. Utilizations of vulnerable population including adults over 65 years old and lowest-income group suffered less than other groups. No significant difference was found between women and men’s use of healthcare services.Funding: No funding.Declaration of Interest: None to declare. Ethical Approval: This study was exempt from the approval by the Institutional Review Board (IRB) at Seoul National University (IRB No. E2203/003-001).