S1007 Epidemiology of Extrahepatic Manifestations of Chronic Hepatitis C Infection: A National, Population-Based Study

Abstract

INTRODUCTION: Although primarily an infection of the liver, chronic hepatitis C virus (HCV) infection has been associated with numerous extrahepatic manifestations (EHM). These include autoimmune, lymphoproliferative, dermatologic and renal disorders. Although a direct causal link has not been well established, experimental studies have shown that HCV can disrupt the body’s immune system and induce autoimmunity. Despite being a major cause of morbidity and mortality, large scale studies describing the epidemiologic characteristics of these EHM are limited. METHODS: We evaluated the prevalence of EHM among patients with chronic HCV infection using a large commercial database called Explorys, which is an aggregate of electronic health data from 26 US healthcare systems. We identified patients with chronic HCV infection between June 2015 and June 2020, based on Systematized Nomenclature of Medicine-Clinical Terms (SNOMED-CT). Within this cohort, we investigated the prevalence of several well documented EHM associated with chronic HCV (Table 1) and compared it with the control group (active patients without chronic HCV infection). RESULTS: Of the 39,212,680 individuals active in the database, we identified a total of 181,450 individuals with chronic HCV infection. Prevalence of chronic HCV infection was 0.46%, and was higher among African Americans in comparison to Caucasians (prevalence ratio (PR): 1.78, 95 CI 1.76–1.81), and higher among men than women (PR: 1.70; 95 CI 1.68–1.72). Compared to our control, patients with chronic HCV had significantly higher prevalence of various EHM including dermatologic, rheumatoid, hematologic, and autoimmune diseases that were described in our study (Table 1). Notably, relative to the patients without HCV, the prevalence ratio of cryoglobulinemia was the highest compared to other EHM (PR: 102.5; 95 CI 93.1–112.9). Interestingly, we also found no significant difference in prevalence of Hashimoto thyroiditis between the chronic HCV cohort and control group (OR: 0.953; 95 CI 0.88–1.03 P < 0.3). CONCLUSION: This is one of the largest studies to date describing the epidemiological characteristics of EHM among patients with chronic HCV infection. EHM are often the initial presenting complaint among patients with undiagnosed chronic HCV infection. Hence, understanding its prevalence is an integral factor in appropriate screening and treatment of chronic HCV infections.Table 1.: Prevalence ratio of EHM among patients with chronic HCV infection (compared to patients without chronic HCV infection)