More than 28% of patients with chronic hepatitis C (CHC) virus infection met at least one criterion for cirrhosis, while only 7% had biopsy confirmation of the condition, investigators reported in the August issue of the American Journal of Gastroenterology.

Furthermore, only half of the patients with a positive biopsy had been given an associated ICD-9-CM code , said Dr. Stuart Gordon at Henry Ford Health System in Detroit and his associates. Cirrhosis in CHC therefore might often go unreported, leading to “overly conservative” estimates of its prevalence, associated health care costs, and the cost-effectiveness of the newer HCV treatments, they said.

The researchers analyzed data for 9,783 patients with CHC from the Chronic Hepatitis Cohort Study who were treated between 2006 and 2010. They compared the prevalence of biopsy-confirmed cirrhosis (Metavir stage 4 or pathologist’s report) with the proportion of patients who met at least one of four criteria: positive biopsy; Fibrosis-4 score of at least 5.88, or the presence of a diagnosis or procedural code for cirrhosis or hepatic decompensation. Patients averaged 55 years of age, and most were white males with health insurance, the researchers said ( Am. J. Gastroenterol. 2015;110:1169-77 ).

In all, 28.5% of CHC patients met at least one of the four criteria, including 22% who met the Fibrosis-4 threshold, 6.8% who were biopsy positive, and 5.7% and 4.9% who had a diagnostic or procedural code for cirrhosis or hepatic decompensation, respectively, said the investigators. Patients had significantly greater odds of cirrhosis (P less than .05) if they were older, male, Asian, Hispanic, had genotype 3 HCV infection, HIV coinfection, or a history of antiviral treatment, alcohol abuse, or diabetes, they added. “Our findings are the first in the United States to attempt an accurate estimate of the prevalence of cirrhosis in the CHC patient population at large,” the researchers concluded. “Use of additional parameters suggests a fourfold higher prevalence of cirrhosis than is revealed by biopsy alone. These findings suggest that cirrhosis in CHC patients may be significantly underdocumented and underdiagnosed.”

The CDC Foundation funds the Chronic Hepatitis Cohort Study. Dr. Gordon reported financial relationships with numerous makers of anti-HCV therapies. The other investigators reported having no conflicts of interest.