May 21 (HealthDay News) -- While survival rates have improved for liver transplant patients without hepatitis C (HCV), that's not the case for liver recipients infected with the virus, new research shows.

HCV-induced liver disease is the most common reason for liver transplantation in the United States.

The Johns Hopkins School of Medicine-led study looked at more than 5,700 HCV-infected patients and more than 16,100 non-HCV-infected patients who had undergone a liver transplant in the United States between January 1991 and October 2001.

During that time, there was a dramatic spike in the percentage of liver transplant patients with HCV -- from 16.4 percent in 1991 to 54.7 percent in 2001. But the study also found that liver recipients with HCV had a lower 3-year survival rate (78.5 percent) than non-HCV recipients (81.7 percent).

During the study period, survival rates for non-HCV patients improved, but there was no improvement among HCV patients.

"In summary, the survival of patients transplanted with HCV is significantly lower than those without HCV," the study authors wrote. "There has been a statistically significant improvement in patient and graft survival for non-HCV recipients between 1991 and 2001, but for HCV recipients, the survival rate has remained unchanged without any obvious explanations."

The findings are published in the May issue of the journal Liver Transplantation.