Decreased serum aminotransferase activity in patients with chronic renal failure: Impact on the detection of viral hepatitis

Hepatitis C virus (HCV) infection is common in the dialysis population and patients with chronic renal failure (CRF) not requiring dialysis. HCV is th e most important cause of chronic liver disease in dialysis patients; howev er, its role has been underestimated by the lower aminotransferase activity in the dialysis population. Aminotransferase activity in patients with CRF not requiring dialysis has not been adequately addressed to date. The aim of this study is to investigate whether serum aminotransferase levels in pr edialysis patients with CRF are less than those obtained in healthy individ uals and dialysis patients. We also analyzed the potential association betw een serum aminotransferase activity and demographic, clinical, and biochemi cal parameters. Aspartate (AST) and alanine aminotransferase (ALT) activity was greater in antibody to hepatitis C (anti-HCV)-positive than anti-HCV-n egative patients with CRF not requiring dialysis (AST, 32.3 +/- 19 versus 1 8.1 +/- 8 IU/L [P = 0.0001]; ALT, 32.9 +/- 28 versus 17.7 +/- 11 IU/L [P = 0.00001], respectively). Predialysis patients with CRF had lower AST and AL T activity in comparison to healthy individuals (AST, 19.7 +/- 11.2 versus 20.4 +/- 6.8 IU/L [P = 0.00001]; ALT, 19.5 +/- 15.1 versus 21.7 +/- 11.3 IU /L [P = 0.00001], respectively). The difference was much greater after corr ection for viral markers: AST and ALT levels in hepatitis B surface antigen (HBsAg)-negative anti-HCV-negative predialysis patients with CRF were less than those in the healthy population (AST, 17.9 +/- 8 versus 20.4 +/- 6.8 IU/L [P = 0.00001]; ALT, 17.5 +/- 10 versus 21.7 +/- 11.3 IU/L [P = 0.00001 ], respectively). Comparison of AST and ALT activity between age-matched he althy and predialysis seronegative CRF groups showed lower AST and ALT valu es in the study population. HBsAg-negative anti-HCV-negative dialysis patie nts had lower AST and ALT activity than seronegative predialysis patients w ith CRF (AST, 16.6 +/- 11.6 versus 17.9 +/- 8 IU/L [P = 0.01]; ALT, 16.3 +/ - 9.4 versus 17.5 10 [P = 0.041], respectively). Multivariate analysis in t he predialysis CRF population showed an independent association between AST (P = 0.00001) and ALT (P = 0.00001) activity and anti-HCV positivity, and age was negatively linked to AST (P = 0.011) and ALT levels (P = 0.001). AS T level was negatively related to serum creatinine level (P = 0.0001). In c onclusion, HCV infection causes significant liver injury in predialysis pat ients with CRF. These patients have decreased aminotransferase activity com pared with the general population. Dialysis patients show lower aminotransf erase activity than predialysis patients with CRF. Because serum aminotrans ferase levels are commonly used to screen for liver disease in the dialysis and predialysis CRF population, recognition of liver damage may be hampere d by the reduction in aminotransferase values in these patients. Studies ai med to clarify the pathogenesis of this phenomenon are in progress. (C) 200 1 by the National Kidney Foundation, Inc.