Hepatitis C infection in Alaska Natives with persistently normal, persistently elevated or fluctuating alanine aminotransferase levels


Michael G. Bruce, MD, MPH, Arctic Investigations Program, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 4055 Tudor Centre Drive, Anchorage, Alaska 99508.
Tel.: +907 729 3416
Fax: +907 729 3429
e-mail: zwa8@cdc.gov


Abstract: Background/Aims: An estimated one-third of patients with chronic hepatitis C virus (HCV) infection have persistently normal alanine transaminase (PNALT); however, in many previous studies alanine aminotransferase (ALT) levels were followed for ≤12 months.

Methods: We analyzed data from a population-based cohort of 935 Alaska Natives with HCV, recruited from 1994 to 2005, to determine the proportion of persons with PNALT, persistently elevated ALT (PEALT), and fluctuating ALT (FLUXALT) to determine factors for each ALT state. We selected persons with two positive HCV RNA results ≥1 year apart and ≥6 ALT levels measured over the subsequent 3 years with at least 1 month between ALT measurements (n=265). We defined a person as having PNALT, PEALT, or FLUXALT when all six ALT levels were normal, elevated, or did not fit either of the above two categories, respectively, during the 3-year follow-up period.

Results: Among 208 persistently HCV RNA-positive persons, 13 had PNALT, 121 PEALT, 74 FLUXALT. Among 77 persons who underwent liver biopsy, those with PEALT were more likely to have Ishak fibrosis scores >2 compared with persons with FLUXALT (44% vs. 10%, OR 7.0, 95% CI: 1.5–33.2). No statistically significant differences were found in ALT classification by age, gender, infection duration, median body mass index, alcohol consumption, residence, risk behavior, RNA level, or genotype.

Conclusions: Only 6% of persons with chronic HCV had PNALT. Persons with PEALT were significantly more likely to have higher fibrosis scores on liver biopsy than those with FLUXALT. Previous studies with short follow-up periods may have overestimated the proportion of persons with normal ALT levels.