Incidence, Outcomes, and Risk Factors for Mortality in Patients With Sepsis in South Korea: A Nationwide Cohort Study

OBJECTIVES: To examine contemporary nationwide trends in sepsis incidence and mortality in South Korea and the associated clinical and socioeconomic factors. DESIGN: Retrospective, population-based cohort study. SETTING: Korea's healthcare system from 2011 to 2022, utilizing the National Health Insurance Service database. PATIENTS: Adult patients 18 years old or older hospitalized for sepsis and identified using the International Classification of Diseases, 10th Revision codes. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Incidence and mortality were analyzed annually over the study period. Poisson and linear regression models were used to analyze temporal trends in sepsis incidence and mortality. Multivariable logistic regression was performed to evaluate risk factors for in-hospital mortality. In all, 1,149,379 sepsis cases were identified. The crude incidence of sepsis increased from 141.8 to 337.3 per 100,000 person-years from 2011 to 2022, whereas the age-standardized incidence increased by 53.1%. In-hospital mortality decreased from 27.0% to 17.0%. Poisson regression analysis showed significant increases in crude and age-standardized incidence (incidence rate ratio [IRR], 1.09; 95% CI, 1.08-1.09; p < 0.001 and IRR, 1.04; 95% CI, 1.04-1.04; p < 0.001, respectively). In-hospital mortality consistently declined from 27.0% in 2011 to 17.0% in 2022 (β = -1.1%; p < 0.001; R2 = 0.91). However, the total number of deaths increased from 15,605 in 2011 to 25,326 in 2022 (β = 779; p < 0.001; R2 = 0.98). Multivariable analysis identified that older age, male sex, higher comorbidity burden, and greater disease severity were independent risk factors for mortality. Socioeconomic disparities were evident: medical aid beneficiaries and rural residents had higher mortality, whereas treatment at tertiary hospitals was associated with improved outcomes. CONCLUSIONS: In this nationwide claims-based study, recorded sepsis incidence increased and in-hospital mortality declined over time, although these trends warrant cautious interpretation given potential shifts in case identification practices. Socioeconomic disparities in mortality persisted throughout the study period.