Race, Age, and Geography Impact Hepatitis C Genotype Distribution in the United States

Abstract

Goals: To determine the impact of geography and patient characteristics on hepatitis C virus (HCV) genotype and subtype distribution in a large sample of patients under routine clinical care BACKGROUND:: HCV genotype impacts disease course and response to treatment. Although several studies have reported genotype distribution within specific US populations, there are no comprehensive descriptions in large, geographically diverse cohorts.

Study: Using data from the Chronic Hepatitis Cohort Study, we present the distribution of HCV genotypes (GT) and subtypes (ST) among a racially diverse cohort of over 8000 HCV-infected patients from four large US health systems.

Results: Genotype distribution varied significantly by geographic and demographic factors. In age-adjusted analyses, African American patients had significantly higher prevalence of GT1 (85%) than other racial categories, largely driven by a markedly higher proportion of GT1 subtype b (∼34%) than in Asian/other (24%) and white (21%) patients. GT3 represented an increasing proportion of infections as birth decade progressed, from 4% in patients born before 1946 to 18% of those born after 1976. Within the cohort of "living/uncured" patients, highly elevated alanine aminotransferase (>2 times the upper limit of normal) was significantly more common in GT3 patients, whereas Fibrosis-4 Index scores indicative of cirrhosis were most common in the combined group of GT4&6 patients.

Conclusion: Distribution of HCV genotypes and subtypes in the United States is more variable than suggested by previous national-level estimates and single-center studies. "Real-world" prevalence data may improve targeting of prevention, screening, and treatment efforts for hepatitis C.

FIGURE 1

All genotyped patients (N = 8140). A, Unadjusted proportional distribution of HCV GT/ST by site and patient-level characteristics. B, Unadjusted proportional distribution of treatment and vital status by GT/ST. GHS indicates Geisinger Health System; GT, genotype; HCV, hepatitis C virus; HFHS, Henry Ford Health System; KPHI, Kaiser-Permanente Hawai’I; KPNW, Kaiser-Permanente Northwest; SVR, sustained virological response; ST, subtype.

FIGURE 2

All genotyped patients (N = 8140), adjusted probability of GT/ST by CHeCS site. Category (site) percentages sum to 100. GHS indicates Geisinger Health System; GT, genotype; HFHS, Henry Ford Health System; KPHI, Kaiser-Permanente Hawai’I; KPNW, Kaiser-Permanente Northwest; ST, subtype.

FIGURE 3

All genotyped patients (N = 8140), adjusted probability of GT/ST by race. Category (race) percentages sum to 100. GT indicates genotype; ST, subtype.

FIGURE 4

All genotyped patients (N = 8140), adjusted probability of GT/ST by birth decade. Category (birth decade) percentages sum to 100. GT indicates genotype; ST, subtype.

FIGURE 5

Living/uncured patients (N = 5138), unadjusted proportional distribution of select clinical factors across GT/ST. A, ALT category at most recent encounter, subset of living/uncured patients with available data (n = 3715). B, FIB4 category at most recent encounter, subset of living/uncured patients with available data (n = 3173). C, Charlson/Deyo comorbidity index as of most recent encounter, all living/uncured patients (N = 5138). ALT indicates alanine aminotransferase; FIB4, Fibrosis-4; GT, genotype; ST, subtype; ULN, upper limit of normal.

FIGURE 6

Living/uncured patients: adjusted probability of (N = 5138) ALT (A) and FIB4 (N = 3173) (B) by GT/ST. Genotype/subtype percentages sum to 100. ALT indicates alanine aminotransferase; FIB4, Fibrosis-4; GT, genotype; ST, subtype.