More than 8,000 Americans die of hepatitis C virus infection annually, and between 35,000 and 180,000 develop the infection. Given these figures, hepatitis C can be considered a principal cause of liver-related disease for which there is currently no definitive cure. Treatment with interferon-alfa has shown promise, with up to 76 percent of patients with hepatitis C virus infection showing an initial biochemical response after six months of treatment. However, only about 10 percent achieve a sustained response in which all biochemical, histologic and virologic evidence of chronic hepatitis C disappears. When treatment is extended to 12 months, an additional 5 to 7 percent of patients achieve a sustained response. Kim and associates analyzed the cost effectiveness of six-and 12-month courses of interferon-alfa therapy using a computer model that incorporated data about the progression of liver disease and response to interferon-alfa.
A randomized trial was simulated comparing three study groups (no treatment, six months of treatment and 12 months of treatment). Patients in the two treatment groups were given 3 million U of interferon-alfa three times a week. Those who achieved sustained remission were then assumed to follow the mortality pattern of the general population. Those who did not achieve remission followed the clinical course prescribed by a natural history model. Costs analyzed included those associated with treating decompensated cirrhosis, hepatocellular carcinoma and liver transplant, all of which were based on published information. The costs of interferon-alfa were based on wholesale prices plus 20 percent. Outcome measures included the number of deaths from liver disease, the total cost and the effect on the quality of life over time (quality-adjusted life years [QALYs]).
The computer model estimated that the effect of interferon-alfa therapy on hepatitis C was small. The lifetime risk of decompensated cirrhosis decreased from 34.5 percent in patients with no treatment to 31.5 percent in patients with 12 months of treatment. The proportion of patients who died of liver disease decreased from 26.5 to 24.3 percent in the same patients. Analysis of cost effectiveness showed that interferon-alfa therapy ($4,000 per QALY for six months of therapy and $5,000 per QALY for 12 months of therapy) compares favorably with other medical interventions, such as screening mammography ($20,000 per year of life) or cholesterol reduction for secondary cardiac prevention ($45,000 per year of life). However, under certain conditions (such as among older patients, who have poorer results with interferon-alfa therapy), the costs may exceed the amount acceptable to society for other medical interventions. Obviously, if the cost of interferon-alfa were reduced or if treatment were discontinued in patients who did not respond to treatment, cost effectiveness figures would improve markedly.
The authors conclude that although therapy with interferon-alfa is not necessarily ideal in patients with hepatitis C virus, its cost effectiveness after 12 months compares favorably with other widely used medical interventions. Cost effectiveness may improve if drug costs decrease and if treatment failures are identified early. Continuing treatment for 12 months in patients who achieve an initial response after one month, particularly in those with aggressive disease, appears to be appropriate.
In a related article, Bennett and associates also concluded that a six-month course of interferon-alfa in patients with mild chronic hepatitis C is cost effective, particularly in younger patients.