SAN FRANCISCO – The prevalence of cirrhosis among patients in the United States infected with hepatitis C virus (HCV) is rising steeply, according to data presented at the annual meeting of the American Association for the Study of Liver Diseases (AASLD).

“While the overall prevalence of HCV in the United States has declined, the number of HCV patients with cirrhosis has risen significantly. As many patients with HCV are asymptomatic and unaware of their infection, the data underline the need for systematic HCV surveillance,” reported Dr. Prowpanga Udompop, a postdoctoral research fellow in gastroenterology at Stanford (Calif.) University.

In this study, the rates of cirrhosis were calculated from National Health and Nutrition Examination Survey (NHANES) data by using two surrogate indicators, the aspartate amino transferase to platelet ratio index (APRI) and the FIB-4 score. The rates of HCV and cirrhosis among those with HCV were compared for three eras, 1988-1994, 1999-2006, and 2007-2012.

A steady decline in HCV prevalence among the NHANES survey participants was observed over these three eras, falling from 1.5% in the first era to 1.2% in the second era and 1.0% in the third.

In contrast, the prevalence of cirrhosis among patients infected with HCV, according to estimates based on conventional APRI and FIB-4 thresholds for a high probability of cirrhosis, climbed steadily over this same period. By APRI score, the estimated prevalence of cirrhosis climbed from 6.6% in the first era to 7.6% and 17% in the next two eras, respectively. By FIB-4, the estimated rates, showing a very similar pattern and proportionality, rose sequentially from 8.6% to 10% and then to 16%.

In a logistic regression analysis, increasing age and increasing rates of diabetes mellitus among the HCV patients correlated with a rising prevalence of cirrhosis. For example, by odds ratio (OR), the risk of cirrhosis in those with diabetes was more than doubled as calculated with APRI score (OR, 2.33; 95% CI, 1.01-5.04) and more than tripled as calculated with FIB-4 (3.37; 95% CI, 1.24-9.5). Obesity was also strongly correlated with cirrhosis by APRI score (OR, 2.95; 95% CI, 1.15-7.57).

Neither race nor drinking status was significantly correlated with the increasing rates of cirrhosis as observed across the three eras using APRI score or the FIB-4 index.

The rapid and ongoing increase in the prevalence of cirrhosis in patients with HCV has important clinical implications, according to Dr. Udompap. By her estimates, 15% of HCV-infected patients aware of their diagnosis have cirrhosis, but the prevalence may be as high as 20% in those who are asymptomatic and undiagnosed.

Moreover, these rates are likely to continue to increase because of the increasing age and rising rates of obesity and diabetes among both the general population and patients infected with HCV. All three factors appear to contribute to the risk of HCV-associated cirrhosis. This suggests that although the national burden of HCV is declining, the rates of end-stage liver complications may increase without efforts to screen and initiate therapies that provide high rates of sustained virologic response.

“These data reinforce current guidelines for screening asymptomatic individuals and for systematic assessment for liver fibrosis in those diagnosed with HCV,” Dr. Udompap reported.