Disease burden of chronic hepatitis B and C patients in South Korea: a population-based 16-year cohort study

Abstract

Background

The prevalence of chronic hepatitis B (CHB) and C viruses (CHC) has been studied widely, but the burden of CHB and CHC coinfection (CHB/CHC) remains to be elucidated. This study investigated the 16-year trend in the disease burden in patients with CHB and/or CHC.

Methods

This analysis used a customized database from 2002 to 2020 obtained from the Korean National Health Insurance Service. Prevalence of CHB/CHC in patients with CHB and/or CHC was analyzed for each year, sex, and type of healthcare providers. Development of cirrhosis and hepatocellular carcinoma (HCC), and overall survival were evaluated.

Results

A total of 747,476 patients (male: 53.5%) were divided into three groups: CHB (593,962; 79.5%), CHC (129,049; 17.3%), and CHB/CHC (24,465; 3.3%). Regarding age distribution, most patients were in their 30s to 60s across all groups (76.5%). Compared to patients in CHB/CHC group, those in CHC had significantly lower incidence of cirrhosis (CHB/CHC vs. CHC, adjusted hazard ratio [aHR] = 0.893, 95% confidence interval [CI] = 0.864–0.922) and HCC (aHR = 0.847, 95% CI = 0.809–0.886). The CHB and CHC groups had a lower risk of mortality compared to the CHB/CHC group. (CHB/CHC vs. CHB and CHC, aHR = 0.878 and 0.892, 95% CI = 0.852–0.905 and 0.864–0.922, respectively). CHB/CHC groups showed the highest average direct medical costs ($21,311) to HCC diagnosis compared to CHB ($19,685) and CHC ($17,650).

Conclusions

CHB/CHC is burdensome in its disease progression risk and medical costs compared to monoinfection. An effective screening strategy for early management of CHB/CHC is warranted for public health in South Korea.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-025-11666-z.

Background

Hepatitis B virus (HBV) and C virus (HCV) infections are a major global health challenge, contributing to most liver-related events (LREs), cirrhosis, and hepatocellular carcinoma (HCC) [1, 2]. The World Health Organization estimated that in 2022 there were approximately 254 million people Living with chronic HBV and 50 million with chronic HCV worldwide, and viral hepatitis overall caused about 1.3 million deaths (of which the majority were attributable to HBV and ~ 0.24 million to HCV) [2]. CHB and CHC are also the leading causes of 70% of cirrhosis and 80% of HCC in South Korea, which is a major cause of death [3]. In South Korea, the prevalence of HBV infection has markedly declined following the implementation of the national immunization program (from 8.6% in 1982 to 2.2% in 2021) [4, 5]. Nevertheless, the number of patients receiving care annually has continued to rise, particularly among middle-aged and older adults (40–60 years and above), reflecting the aging of pre-vaccination cohorts and the prolonged survival of chronically infected individuals with antiviral therapy [3, 4]. The annual incidence rate of CHC in South Korea was estimated 11.9 per 100,000 population in 2021, increasing with age [3]. CHB and CHC contribute 60–80% and 10–20% of cirrhosis and HCC, respectively. The annual Liver-related mortality rates are 18.9 and 2.02 per 100,000 population in South Korea, indicating an ongoing public health threat [3, 6]. Coinfection of hepatitis B and C (HBV/HCV) can occur by simultaneous cotransmission and superinfection, with HCV superinfection being more common and often associated with complex clinical courses influenced by viral dominance, host immunity, and treatment strategies. The global prevalence of chronic HBV/HCV (CHB/CHC) has significant geographical variation, reported at 1–15% [7–9]. The global number of people coinfected with HBV and HCV has been estimated at around 2.5 million, based on modelling studies including the Polaris Observatory report [10].

Hepatitis viruses can be transmitted through various routes, including vertical transmission during pregnancy. Maternal HBsAg screening and universal infant immunization are effective in preventing HBV mother-to-infant transmission; however, high maternal HBV DNA levels remain a significant risk factor for intrauterine infection [11]. Hepatitis infection in pregnancy has been associated with severe complications, such as intrahepatic cholestasis and fulminant hepatitis, which may progress to acute liver failure and increase maternal–fetal mortality [12–14]. Managing such cases requires early referral to tertiary centers and multidisciplinary care, including supportive and obstetric interventions [15]. The natural course of hepatitis virus infection differs by viral type. In hepatitis B virus (HBV) infection, some individuals may remain in an inactive carrier state, characterized by low viral replication and normal liver function, which requires separate clinical consideration. In contrast, hepatitis C virus (HCV) infection progresses to chronicity in approximately 75–85% of cases after acute infection [16]. Reliable markers are crucial for managing hepatitis B and C infections. In HBV, HBsAg, HBeAg, HBV DNA, and newer markers like HBcrAg and serum HBV RNA help assess disease activity and predict prognosis [17]. For HCV, HCV RNA and genotype aid diagnosis, while fibrosis scores such as APRI and FIB-4 guide treatment decisions [18]. Emerging public health concerns, including severe acute hepatitis of unknown origin in children [19], underscore the need for vigilant surveillance beyond classical viral hepatitis markers.

Considering that higher rates of advanced liver disease have been reported with HBV/HCV compared to the monoinfection [7, 9, 20], understanding the current status of CHB/CHC is essential for the public health policy in South Korea. The multicenter-based prevalence of CHB/CHC in South Korea was reported as 1.5% to 2.4% among patients with CHB or CHC [20–22]; however, nationwide cohort-based analysis and prognosis estimation have been lacking in South Korea. Therefore, we analyzed the baseline characteristics, long-term prognosis, and disease burden of patients with CHB/CHC in South Korea compared with those with CHB or CHC monoinfection using the Korean National Health Insurance Service (KNHIS) data.

Methods

Study design and data source

For this retrospective longitudinal cohort study, we used the customized health information data between 2002 and 2020 for patients with chronic hepatitis B and C provided by the Korean National Health Insurance Service (KNHIS), which covers approximately 97% of the Korean population and broadly represents it. The Korean National Health Insurance Service (KNHIS) database provides (1) “qualification database” containing age, sex, type of subscription (e.g., insured employees, insured self-employed individuals, or medical aid beneficiaries), income rank, and death; (2) medical check-up database containing general health examination data for the insured employees every 1 or 2 years, and data for insured self-employed and insured employees who receive Lifetime transition period medical check-ups at age 40 years and 66 years; (3) medical institution database containing the clinic type, number of beds, number of medical doctors, and location of each medical care institution; and (4) treatment database containing the diseases, the 10th Revision of the International Classification of Diseases (ICD-10) codes, and prescriptions of all subscribers [23]. Customized health information data includes the de-identified medical information and prognosis of 3.5 million Korean people, randomly distributed sociodemographic factors such as sex, age, economic status, and residential area. Patients with CHB and/or CHC were defined as those with one or more national health insurance claims listing CHB and/or CHC as the main or sub-diagnosis code: CHB was defined using ICD-10 codes B18.0 and B18.1, CHC with B18.2, cirrhosis with K74.3 to 74.6 and HCC with C22.0. The number of patients who made claims with CHB and/or CHC diagnoses from 2002 to 2020 was 5,737,000, but due to limited database capacity, only 2,858,500 patients were included following sex-/age-based 50% sampling. Inclusion criteria were (1) patients diagnosed with CHB or CHC at least once between 2004 and 2015 and (2) patients with data of a qualification database. Exclusion criteria were (1) patients already had records for cirrhosis, HCC, or death before diagnosis of CHB and/or CHC, and (2) patients with missed data on eligibility or insurance fees (Fig. 1).

Fig. 1.

Flow chart of patient selection. CHB chronic hepatitis B; CHC chronic hepatitis C; KNHIS Korean National Health Insurance System; CHB/CHC coinfection of CHB and CHC

Definitions and outcomes

Newly diagnosed patients were defined as those with CHB and/or CHC between 2004 and 2015, with no claim records for HBV, HCV, cirrhosis, or HCC during the preceding two years.

Patients were categorized into three groups: the CHB group (CHB monoinfection), the CHC group (CHC monoinfection), and the CHB/CHC group (patients with claims for both CHB and CHC). The index date was defined as the date of first diagnosis based on ICD codes (Fig. 1). Outcomes included the development of cirrhosis, hepatocellular carcinoma (HCC), and all-cause mortality. Medical costs were calculated by summing all reimbursed claims for each patient from the index date to the occurrence of HCC, and were expressed in United States dollars (USD) using the exchange rate of 1 USD = 1,461.41 Korean Won (KRW). Cost per patient-year to HCC was calculated by dividing each patient’s total medical cost from diagnosis to HCC by the duration from diagnosis to HCC, expressed in years.

Statistical analysis

Descriptive statistics, including frequencies and percentages, were used to summarize categorical variables. Differences in proportions between groups were assessed using the chi-square test. Age- and sex-adjusted Cox proportional hazards models were applied to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for each outcome. All analyses were conducted using SAS Enterprise Guide software, version 7.1 (SAS Institute Inc., Cary, NC, USA). A two-sided P-value of < 0.05 was considered statistically significant.

Ethics statement

The institutional review board of the Korea Disease Control and Prevention Agency (KDCA) provided ethical approval for this study (approval number: 2022-03-01-PE-A). The requirement of informed consent from patients was waived by the board owing to the observational nature of the study.

Results

Baseline qualification data

A total of 747,476 patients (53.5% male) were selected according to the inclusion and exclusion criteria and classified into three groups: CHB (n = 593,962, 79.5%), CHC (n = 129,049, 17.3%), and CHB/CHC (n = 24,465, 3.3%) (Fig. 1). Regarding age distribution, most patients were in their 30s to 60s across all groups (76.5%): 76.5% in the CHB group, 75.7% in the CHC group, and 79.9% in the CHB/CHC group. More than half of the patients in the CHB group were first diagnosed at primary clinics (48.5%), whereas those in the CHC group were more frequently diagnosed at secondary (31.8%) or tertiary (37.9%) medical centers. Patients in the CHB/CHC group were diagnosed at primary (46.5%), secondary (31.7%), and tertiary (21.8%) medical institutions (Table 1).

Table 1.

Summary of qualification database of patients diagnosed with chronic hepatitis B and C

Variables	Total (n = 747,476)	CHB (n = 593,962, 79.4%)	CHC (n = 129,049, 17.3%)	CHB/CHC (n = 24,465, 3.3%)	P-value
Male sex	400,258 (53.5)	319,556 (53.8)	66,827 (51.8)	13,875 (56.7)	< 0.001
Age, years	45 (34–55)	45 (34–55)	55 (34–65)	45 (34–55)
Age distribution*					< 0.001
<20	37,600 (5.1)	31,962 (5.4)	4,842 (3.7)	796 (3.2)
20–29	92,404 (12.4)	79,549 (13.4)	10,472 (8.1)	2,383 (9.7)
30–39	146,067 (19.5)	123,645 (20.8)	18,454 (14.3)	3,968 (16.2)
40–49	184,242 (24.6)	152,065 (25.6)	26,371 (20.4)	5,806 (23.7)
50–59	157,067 (21.0)	121,306 (20.4)	29,870 (23.1)	5,891 (24.1)
60–69	84,393 (11.3)	57,486 (9.7)	23,014 (17.8)	3,893 (15.9)
70≤	45,703 (6.1)	27,949 (4.7)	16,026 (12.4)	1,728 (7.1)
Healthcare Providers at Diagnosis**	747,311 (99.9)	593,825 (99.9)	129,043 (99.9)	24,463 (99.9)	< 0.001
Primary clinic	362,533 (48.5)	312,094 (52.6)	39,062 (30.3)	11,377 (46.5)
Secondary hospital	253,076 (33.9)	204,315 (34.4)	41,018 (31.8)	7,743 (31.7)
Tertiary medical center	131,722 (17.6)	77,416 (13.0)	48,963 (37.9)	5,343 (21.8)

Abbreviation: CHB chronic hepatitis B monoinfection group, CHC chronic hepatitis C monoinfection group, CHB/CHC chronic hepatitis B and C coinfection group

Values are expressed as number (percentage)

* Data are presented as median (Q1–Q3) for continuous variables and number (%) for categorical variables

^**Missing value (n = 145)

Newly developed CHB, CHC, and CHB/CHC by year

The annual estimated numbers of CHB, CHC, and CHB/CHC diagnoses by year are summarized in Fig. 2. The number of individuals included in the study, representing the total population of hepatitis cases each year, was 84,377 in 2004, gradually decreasing to 39,727 in 2015. CHB infection was the most common; however, the number of newly diagnosed CHB cases gradually decreased from 69,083 in 2004 to 31,108 (45.0%) in 2015. A similar downward trend was observed in CHC (from 10,997 to 7,976) and CHB/CHC (from 4,297 to 643) over the same period. The proportion of CHB/CHC patients among all hepatitis cases decreased from 5.1% in 2004 to 1.6% in 2015. Additionally, the proportion of patients younger than 40 years declined from 43.9% in 2004 to 26.3% in 2015 (Supplementary Table 1).

Fig. 2.

Number of hepatitis B and C diagnoses by year. HBV hepatitis B virus; HCV hepatitis C virus

Comparison of outcomes between the groups

Based on event rates, cirrhosis occurred in 14.8% of CHB/CHC patients, 9.3% of CHB patients, and 8.8% of CHC patients, with mean durations of 49, 59, and 55 months, respectively. The incidence of HCC was 8.4% in the CHB/CHC group, 5.2% in the CHB group, and 4.3% in the CHC group, with corresponding mean durations of 61, 69, and 68 months. All-cause mortality was highest in the CHB/CHC group (17.4%), followed by the CHC (17.1%) and CHB (10.2%) groups, with respective mean times to death of 74, 79, and 80 months. All hazard ratios were adjusted for sex and age using Cox proportional hazards models. Table 2 presents the adjusted hazard ratios (aHRs) for cirrhosis, hepatocellular carcinoma (HCC), and all-cause mortality among the three patient groups. Compared to the CHB/CHC coinfection group, the CHC group had significantly lower risks of cirrhosis (aHR = 0.893; 95% CI, 0.864–0.922) and HCC (aHR = 0.847; 95% CI, 0.809–0.886). The CHB group showed comparable risks of cirrhosis (aHR = 1.006; 95% CI, 0.976–1.036) and HCC (aHR = 1.020; 95% CI, 0.980–1.061) relative to the CHB/CHC group. However, both the CHB (aHR = 0.787; 95% CI, 0.752–0.905) and CHC (aHR = 0.892; 95% CI, 0.864–0.922) groups had significantly lower all-cause mortality compared to the coinfected group.

Table 2.

Comparison of the development of cirrhosis, HCC, and all-cause death among the CHB, CHC, and CHB/CHC group

Group	Overall	Cirrhosis			HCC c)			Death
		n (%)	Mean of duration (months)	aHR† (95% CI)	n (%)	Mean of duration (months)	aHR† (95% CI)	n (%)	Mean of duration (months)	aHR† (95% CI)
CHB/CHC	24,465	3,621 (14.8)	49	Reference	2,062 (8.4)	61	Reference	4,250 (17.4)	74	Reference
CHB	593,962	55,439 (9.3)	59	1.006 (0.976, 1.036)	31,090 (5.2)	69	1.02 (0.98, 1.061)	60,542 (10.2)	80	0.878 (0.852, 0.905)
CHC	129,049	11,341 (8.8)	55	0.893(0.864, 0.922)	5,527 (4.3)	68	0.847 (0.809, 0.886)	21,998 (17.1)	79	0.892 (0.864, 0.922)

Abbreviation: HCC hepatocellular carcinoma, CHB chronic hepatitis B monoinfection group, CHC chronic hepatitis C monoinfection group, CHB/CHC chronic hepatitis B and C coinfection group, aHR adjusted hazard ratio, CI confidence interval

^†Adjusted by sex and age

Cumulative medical costs from hepatitis diagnosis to HCC diagnosis

The mean total medical cost in the CHB group was USD 19,551 (Korean Won [KRW] 28,768,754) from initial CHB diagnosis to HCC diagnosis, with a mean copayment of USD 2,199 (KRW 3,234,479; 11.2%). The mean total medical cost in the CHC group was USD 17,537 (KRW 25,793,942), with a mean copayment of USD 1,980 (KRW 2,912,601; 11.3%). The CHB/CHC group had a mean total medical cost of USD 21,172 (KRW 31,144,252), with a mean copayment of USD 2,591 (KRW 3,812,792; 11.2%) (Table 3). To mitigate the potential bias from differences in time-to-HCC across groups, we also calculated the mean cost per patient until HCC diagnosis: USD 4,192 for CHB/CHC, USD 3,424 for CHB, and USD 3,115 for CHC.

Table 3.

Average direct medical cost by infection group, with mean cost relative to time-to-HCC (in parentheses)

Group	Number of patients	Direct medical cost
		Total	National Health Insurance Contribution	Individual	%
CHB/CHC	2,062	21,311.1 (4192.4)	18,655.9 (3670.0)	2,609.0 (513.2)	11.2 (14.0)
CHB a)	31,090	19,685.6 (3423.6)	17,453.5 (3035.4)	2,276.0 (395.8)	11.2 (13.0)
CHC b)	5,527	17,650.0 (3114.7)	15,626.0 (2757.5)	1,993.0 (351.7)	11.3 (12.8)
Abbreviation: HCC hepatocellular carcinoma, CHB chronic hepatitis B monoinfection group, CHC chronic hepatitis C monoinfection group, CHB/CHC chronic hepatitis B and C coinfection group, aHR adjusted hazard ratio, CI confidence interval

Values in parentheses represent the mean direct medical cost per patient until the time of HCC diagnosis (i.e., cost relative to time-to-HCC). All costs are presented in USD

Discussion

The present study demonstrated the comparison of long-term prognosis and disease burden of CHB and/or CHC in South Korea using 16-year longitudinal follow-up data of 747,476 patients diagnosed between 2004 and 2015 from Korean National Health Insurance Service (KNHIS) database. The period prevalence of CHB/CHC among patients with CHB or CHC between 2004 and 2015 was 4% and 16%, respectively. Patients with CHB/CHC were predominantly male (56.7%) and older than 40 years (77.1%), reflecting the epidemiological characteristics of each mono-infection: CHB being more common in men, and CHC being more prevalent among older individuals in South Korea. CHC and CHB/CHC diagnoses were more frequently made in secondary or tertiary care settings compared to CHB diagnoses. This may have been attributed to that CHB diagnosis, based on HBsAg positivity for more than six months, was straightforward in primary clinicians. In contrast, CHC diagnosis typically required HCV RNA testing and often involved interferon-based treatment during the study period (2004–2015), which may have been less accessible in primary care settings. Patients with CHB/CHC have a higher risk of cirrhosis, HCC, and all-cause mortality. Moreover, medical costs from CHB and/or CHC diagnosis to HCC diagnosis were highest in patients with CHB/CHC. Since only direct medical costs were considered in this study, inclusion of indirect costs such as productivity loss and caregiver burden would likely have led to a significantly higher total cost.

Our study has several important implications. First, it provides reliable epidemiologic data on CHB/CHC based on a nationwide database. Previous studies in South Korea were limited to multicenter healthcare data or regional cohort data. For example, Choi et al. reported that anti-HCV antibody was positive in 22 (1.5%) of 1,501 patients with CHB in a prospective survey conducted across 46 referral and 129 local hospitals [23]. Similarly, Kim et al. found that 18 (2.4%) of 758 patients with CHC who underwent peg-interferon alfa and ribavirin treatment in Gyeonggi Province had CHB/CHC coinfection [22]. Although our analysis was restricted to only half of the customized health information data, the observed 11-year period prevalence of coinfection, which captured a broader and more representative population, was higher than that reported in previous studies (4% in CHB and 16% in CHC). These findings highlight that coinfection may be underestimated in South Korea and should not be overlooked. Second, our study demonstrates that patients with CHB/CHC coinfection had a higher risk of cirrhosis, HCC, and all-cause mortality compared to those with monoinfection. This finding is consistent with previous literature, which has shown that coinfection has been associated with greater liver disease severity and fibrosis than monoinfection, leading to an increased risk of cirrhosis and HCC development [24–27]. Meanwhile, patients with CHB in our study exhibited a comparable risk of cirrhosis and HCC development, whereas a French cohort study reported that the matched CHB/CHC group had a higher risk compared to the matched CHB group, rather than the CHC group [27]. Although the exact reason is unclear, this may be related to South Korea being an HBV-endemic area involving a homogenous genotype C strain with a poor prognosis, which may have contributed to a higher risk of cirrhosis and HCC development among CHB group in our study compared to those in the French cohort [28]. Third, our study provides medical cost data for CHB/CHC coinfection, a topic that has been lacking in the literature. The healthcare cost incurred between the diagnosis of CHB and/or CHC and the development of HCC was higher in the CHB/CHC group compared to the monoinfection groups. Although the CHB/CHC group had a higher risk of HCC development, resulting in a shorter time to HCC occurrence, the overall cost burden was still greater in this group. This remained considerably high even when taking into account that the primary management strategy for HBV during the study period was antiviral therapy, and for HCV was interferon-based therapy. Therefore, cost-effectiveness strategies specifically targeting CHB/CHC coinfection should be prioritized. In South Korea, the presence of HBV has been screened as part of the national health checkup at the age of 40, whereas screening for anti-HCV antibodies has been conducted through individual center-based health checkups. However, since 2025, anti-HCV antibody testing has also been incorporated into the national health checkup program at the age of 56. Early detection through this expanded screening strategy is expected to contribute to improved cost-effectiveness.

Although our study utilized a large, nationally representative cohort to investigate the long-term outcomes of chronic hepatitis B and/or C infection, several limitations should be acknowledged. First, infection status was determined using diagnostic codes from the KNHIS database, which may have resulted in misclassification. In particular, coinfection was defined as the presence of both HBV and HCV codes during the observation period; however, due to the inherent limitations of claims-based data, we could not determine whether these infections occurred concurrently or sequentially. As such, our operational definition may include both simultaneous coinfection and superinfection. Such heterogeneity in infection timing may have influenced the clinical course and prognosis, and should be taken into account when interpreting our results. Second, due to limited access to clinical details such as laboratory values, treatment history, and comorbidities, we could not fully adjust for potential confounders. In particular, the absence of imaging findings or histologic confirmation may have led to misclassification of outcomes such as cirrhosis or HCC, which in turn may have biased risk estimates. Given these limitations, the observed differences in cirrhosis, HCC, and all-cause mortality may have been influenced by unmeasured factors and should therefore be interpreted with caution. These limitations suggest that our findings should be interpreted with caution and not regarded as definitive evidence of causality. Third, given the period (2004–2020), the development of antiviral strategies, especially for CHC, may not be reflected in the incidence of cirrhosis, HCC, and death, considering that the direct-acting antivirals have been introduced and applied to the treatment of HCV since 2016. Fourth, details of a participant’s specific medical treatment, such as insurance claims for other comorbidities, and non-insurance benefits data, such as nucleos(t)ide analog and direct-acting antiviral uses without coverage, are challenging to obtain. Fifth, cause-specific mortality could not be assessed due to the unavailability of validated cause-of-death information in the claims data. This limitation should be considered when interpreting mortality-related outcomes. Another limitation is that we could not include other potential confounding factors such as comorbidities (e.g., diabetes, alcohol use, or HIV), which may influence clinical outcomes. These variables were not available in the current dataset. Therefore, residual confounding cannot be excluded, and future studies incorporating detailed clinical covariates are warranted. Nonetheless, the strength of our study is that we obtained a sufficient sample size through the nationwide data to obtain representative results, which was meaningful in that it provided fundamental data to investigate the status of these infections in South Korea and compare the results to those of other countries. CHB/CHC coinfection imposes higher clinical and economic burdens than monoinfection. Early screening and management strategies are essential to strengthen public health efforts in South Korea. In South Korea, HBsAg screening has been included in the national health examination at age 40 since 1998, and nationwide anti-HCV antibody testing will be introduced at age 56 starting in 2025. Building on these programs, further strategies such as additional screening of older cohorts not covered by the NIP, reflex confirmatory testing with automatic referral systems, and targeted outreach to high-risk groups including people who inject drugs (PWID) should be considered to maximize the impact of diagnostic expansion and linkage-to-care.

Conclusions

In conclusion, patients with chronic hepatitis B and C coinfection exhibited higher risks of cirrhosis, hepatocellular carcinoma, and all-cause mortality, along with increased medical costs, compared to those with monoinfection. From a public health perspective, these results underscore the need for targeted screening strategies and early identification of coinfected individuals. Expanding access to diagnostic testing and linking high-risk patients to timely antiviral therapy should be prioritized as part of national hepatitis elimination efforts. Further research incorporating richer clinical data is needed to validate and expand upon these results.

Abbreviations

HBV

Hepatitis B virus

HCC

Hepatocellular carcinoma

HCV

Hepatitis C virus

ICD-10

International Statistical Classification of Diseases and Related Health Problems

KCD-8

Korean Classification of Disease 8th revision

KNHIS

Korean National Health Insurance Service

CI

Confidence interval

Authors’ contributions

Oeuk Jeong: Methodology, Validation, Formal analysis, Investigation, Data Curation, Writing - Original Draft, Writing - Review & Editing, Visualization. Changhee Chu: Methodology, Validation, Formal analysis, Investigation, Data Curation, Visualization. Jungyeon Kim: Writing - Review & Editing, Supervision, Jae Seung Lee: Methodology, Writing - Original Draft, Writing - Review & Editing. Jun Yong Park: Writing - Review & Editing. Kyung Eun Lee: Writing - Review & Editing. Jaehyun Seong: Conceptualization, Methodology, Investigation, Writing - Original Draft, Writing - Review & Editing, Supervision, Project administration. Min Jin Go: Conceptualization, Methodology, Writing - Review & Editing.

Funding

This research was supported by the National Institute of Health (NIH) research project (2022-NI-037-00) and the Chronic Infectious Disease Cohort Study (2025-E1901-00).

Data availability

The data that support the fundings of this study are available from [National Health Insurance Service] but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available.

Declarations

Ethics approval and consent to participate

This study was performed in line with the principles of the Declaration of Helsinki. Ethical approval was obtained from the Institutional Review Board of the Korea Disease Control and Prevention Agency (KDCA; approval number: 2022-03-01-PE-A) and the National Health Insurance Service (NHIS; approval number: NHIS-2022-1-430). The requirement for informed consent was waived by the IRB of the KDCA, as the data analyses were conducted retrospectively using anonymized health records derived from the South Korean NHIS database. Data were extracted by an independent medical record technician at the NHIS center who was unaffiliated with this study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.