The Burden of Clostridioides difficile Infection in Korea

Clostridioides difficile infection (CDI) is the most commonly recognized cause of healthcare-associated infection.1 The clinical presentation of CDI varies from asymptomatic colonization to fulminant disease (e.g., toxic megacolon, bowel perforation, renal failure, sepsis and death). Established risk factors for CDI include antibiotic use, advanced age, hospitalization, and comorbidities.2, 3 In addition, since the emergence of hypervirulent strains of CDI led to an increase in the incidence of CDI,2 CDI has been perceived as a significant burden on the healthcare system.

The incidence of CDI varies according to countries and the surveillance programs in place. Using surveillance data from the CDC EIP in 10 U.S. sites, the estimated national burden of CDI declined from 2011 through 2017 (476,400 cases, 95% confidence interval [CI], 419,900~532,900 in 2011; 462,100 cases, 95% CI, 428,600~495,600 in 2017).1 Contrastingly, a study to identify the long-term trend of CDI in Korea using National Health Insurance Service-National Sample Cohort (NHIS-NSC) reported a steady increase in the rate of CDI from 0.030% in 2006 to 0.317% in 2015.4 However, studies on the recent incidence of CDI using big data are limited in Korea, which is entering a super-aged society.

In the current issue of Journal of Korean Medical Science, Kim et al.5 assessed the incidence of CDI in Korea using the Health Insurance Review and Assessment Service (HIRA) data and an active surveillance program in 18 hospitals. In this study, incidence of CDI was calculated from HIRA data between 2008 and 2020, and from an active surveillance program between 2020 and 2021. CDI was classified into healthcare-associated CDI (HA-CDI) and community-acquired CDI (CA-CDI). The results of Kim et al.5 showed that the incidence of CDI from 2008 to 2020 increased gradually (from 0.3 to 1.8 per 10,000 patient-days, 0.3 to 1.6 per 1,000 admissions, and 6.9 to 56.9 per 100,000 persons). Using the active surveillance program in 18 hospitals, the vast majority of CDI were HA-CDI (92.5%). In the latest reported EIP data,6 the crude overall incidence of CDI in 2021 was 110.2 cases per 100,000 persons. In contrast to the results of Kim et al.,5 CA-CDI (55.9 cases per 100,000 persons) showed a slightly higher incidence than HA-CDI (54.3 cases per 100,000 persons).6 As Kim et al. mentioned,5 the proportion of CA-CDI can be underestimated due to selection bias in the enrolled patients or the participating hospitals. In this study by Kim et al.,5 the incidence of CDI in 2020 using HIRA data was similar between tertiary and general hospitals (5.1 per 10,000 patient-days in tertiary hospitals vs. 5 per 10,000 patient-days in general hospitals), whereas the incidence using the active surveillance was higher in general hospitals than in tertiary hospitals (9.45 per 10,000 patient-days in 7 general hospitals vs. 6.38 per 10,000 patient-days in 11 tertiary hospitals). The probable reasons for the high incidence rate in general hospitals include lack of awareness of CDI among physician and lack of available CDI tests.

Many studies using big data, including the study by Kim et al.,5 have limitations such as heterogenous operational definition, under-reporting or insufficient data. Unlike HIRA data, data using the active surveillance program in 18 hospitals do not represent the incidence of CDI in Korea. Therefore, the results of Kim et al. should be interpreted while considering these limitations. A detailed analysis of risk factors for CDI occurrence in Korea was also not conducted in this study. Nevertheless, this study reflects the current status that the burden of CDI cases in Korea has been continually increasing. Based on the results of this study, it is essential that physicians’ efforts to reduce the risk of C. difficile transmission in hospitals. More detailed analyzed studies for the current status of CDI using big data in Korea are required in the future.