Aims: Some studies have reported that ALT determination is of little value in the study of chronic hepatitis C in hemodialysis (HD) patients. This could be due to the fact that ALT values are lower in HD patients than in healthy individuals; ALT in HCV infection follows a fluctuating pattern and the HCV viremia may be intermittent. The aim of this study was to establish the reference ALT values in a large group of hepatitis-free HD patients, and to determine their role in predicting viremia in anti-HCV-positive HD patients.
Methods: Four subject groups were studied: group I, patients with normal renal function (n = 88); group II, hepatitis-free HD patients (n = 218); group III, non-viremic anti-HCV+ HD patients (n = 9); and group IV, viremic anti-HCV+ HD patients (n = 24). The ALT used for calculation purposes was the mean value of the twelve previous months for each individual patient. PCR screening for HCV-RNA was performed at least twice for anti-HCV+ patients; these were deemed viremic (HCV-RNA+) if at least one screening was positive, and non-viremic (HCV-RNA) if all PCR results were negative.
Results: Mean ALT in group II was lower than in subjects with normal renal function (15.6 +/- 12 vs. 22.7 +/- 18 IU/l, p < 0.05). No significant differences were observed between group III and group II (17.7 +/- 6 vs. 15.6 +/- 6 IU/l, ns). ALT levels in group IV patients were higher than those of groups II and III (38.5 +/- 39 IU/l, p < 0.05). The upper limit (mean + 2 SD and 95th percentile) for ALT in hepatitis-free HD patients was 27 IU/l. Sensitivity of a mean ALT value > or = 27 IU/l in the diagnosis of HCV viremia was 50%, and specificity was 100%. The positive predictive value of this test in the diagnosis of hepatitis C viremia was 100%.
Conclusions: ALT values are lower in HD patients and a high ALT level can constitute an excellent tool in predicting viremia in anti-HCV-positive HD patients once other causes of liver disease have been excluded.