A prospective, community-based evaluation of liver enzymes in individuals with hepatitis C after drug use

Serum alanine transaminase (ALT) levels are used to select hepatitis C viru s (HCV)-infected patients for treatment and liver biopsy. However, the natu ral history of these measurements is poorly understood. To examine the hypo thesis that ALT levels vary over time in HCV-infected patients, serial seru m ALT levels were prospectively measured in a cohort of 1,235 persons with a history of prior illicit drug use, Over 25 months of follow-up, there was a median of four evaluations per patient. ALT values were higher in 1,164 (94%) HCV-infected individuals than in 71 (6%) HCV-uninfected individuals. The remainder of the analysis focused on these HCV-infected individuals, 64 7 (62%) of whom had normal ALT values at their initial visit. However, 323 (49%) of these had at least one elevated ALT over the next 25 months. Of th e 395 patients whose ALT was initially abnormal, 332 (84%) had at least one normal value over the next 25 months. Overall, among individuals with four or more visits, ALT values were persistently normal in 42%, persistently e levated in 15%, and intermittently elevated in 43%. Because serum ALT level s have high visit-to-visit variability, single assessments should not be us ed to manage HCV-infected individuals. Further investigation is needed to a scertain the correlation of serial ALT trends with important disease outcom es.