Source Division of Nephrology and Dialysis, Maggiore Hospital, IRCCS Foundation, Milano, Italy.
Hepatitis C virus (HCV) remains the most common cause of liver damage in patients with chronic kidney disease including patients on long-term dialysis. The natural history of HCV infection in patients with chronic kidney disease is not fully elucidated despite the adverse effect of HCV infection on survival in patients receiving long-term dialysis. A recent meta-analysis of seven observational studies (11,589 patients on dialysis) reported that the summary estimate for adjusted relative risk (all-cause mortality) with anti-HCV antibody was 1.34 with a 95% confidence interval of 1.13-1.59. As a cause of death, hepatocellular carcinoma and liver cirrhosis were significantly more frequent among anti-HCV-positive than -seronegative dialysis patients; the summary estimate for unadjusted liver-related mortality risk was 5.89 (95% confidence interval 1.93-17.99). Impairment of quality of life due to HCV has also been suggested to explain the diminished survival in this setting. Recent data also suggest an excess risk of cardiovascular disease in HCV-infected dialysis patients. Recent evidence supports the notion that the progression of HCV-related liver disease is probably slower in the dialysis population than in non-uremic patients despite the immune compromise conferred from chronic uremia; numerous mechanisms have been mentioned to explain it. It appears that the hemodialysis procedure per se reduces the HCV viral load, and the mechanisms by which this phenomenon occurs remain largely speculative - the intradialytic production of interferon-α, hepatocyte growth factor, or other cytokines provided with antiviral activities have been implicated. This is an area of intense investigation, and further studies are indicated.