Epidemiology of sepsis in Korea: a population-based study of incidence, mortality, cost and risk factors for death in sepsis

Abstract

Objective: To investigate the epidemiology of sepsis in Korea and identify risk factors for death in sepsis.

Methods: We conducted a longitudinal, population-based epidemiological study of sepsis in Korea from 2005 to 2012 using the National Health Insurance Service-National Sample Cohort, a population-based cohort representing 2.2% of the Korean population. The primary objective was to assess the incidence, mortality and cost of sepsis. The secondary objective was to identify the risk factors for death in sepsis. Claim records of admitted adult patients (aged ≥15 years) were analyzed. Sepsis was defined as 1) bacterial or fungal infection or the conditions they often complicate, 2) prescription of intravenous antibiotics, and 3) presence of any organ dysfunction. Comorbidities were defined using the Charlson/Deyo method. Risk factors for 6-month mortality were assessed using multivariable logistic regression.

Results: A total of 22,882 cases were identified. Both incidence and 6-month mortality increased from 265.7 (95% confidence interval [CI], 254.7 to 277.1) to 453.1 (95% CI, 439.0 to 467.5) per 100,000 person-years (P-trend <0.001) and from 26.5% (95% CI, 24.4% to 28.8%) to 30.1% (95% CI, 28.4% to 31.9%), respectively. After standardization, the increasing trend of incidence was slower but still significant (P-trend <0.001), while that for mortality was not (P-trend 0.883). The average cost increased by 75.5% (P-trend <0.001). Multivariable logistic regression identified various risk factors for mortality.

Conclusion: The burden of sepsis in Korea was high and is expected to increase considering the aging population. Proactive measures to curtail this increase should be sought and implemented.

Keywords: Epidemiology; Incidence; Mortality; Risk factors; Sepsis.

Fig. 1.

An illustration of the case identification and the assessment of variables. IV, intravenous; ICU, intensive care unit.

Fig. 2.

Eight-year trend of sepsis incidence and mortality. (A) Crude and adjusted incidence rate of sepsis. (B) Relative change of incidence of sepsis according to the age group. (C) Relative change of incidence of sepsis according to the comorbidity. (D) Crude and adjusted 6-month mortality of sepsis. CCI, Charlson comorbidity index.

Fig. 3.

Eight-year trend of national expenditure on sepsis. (A) Mean cost per case of sepsis. (B) Total national cost of sepsis. KRW, Korean won.

Fig. 4.

Differential survival probability by age, comorbidity burden, organ dysfunction, and the site of infection. (A) Survival according to the age group. (B) Survival according to the comorbidity. (C) Survival according to the number of organ dysfunction. (D) Survival according to the site of infection. CCI, Charlson comorbidity index; MS, musculoskeletal.

Fig. 5.

Predictors of the 6-month mortality model of sepsis. CCI, Charlson comorbidity index; CNS, central nervous system; MS, musculoskeletal.

Fig. 6.

Predictive performance of the 6-month mortality model of sepsis. AUC, area under the receiver operating characteristic curve; CI, confidence interval.