By Liz Highleyman

Chronic hepatitis C virus (HCV) infection is an important cause of liver disease in people with end-stage renal disease (ESRD), which includes kidney dialysis patients and those who have received kidney transplants. Conversely, kidney failure may contribute to illness and death among people with hepatitis C.

Two recent journal reports reviewed the incidence, outcomes, and management of patients with co-existing chronic hepatitis C and kidney disease. Another recent article discussed the impact of HCV on HIV-related kidney disease in HIV-HCV coinfected patients.

Report 1

In the first report, published in the August 2008 American Journal of Gastroenterology, E.J. Okoh and colleagues discussed HCV infection in patients with ESRD.

"Nosocomial" transmission in healthcare settings is the second most common route of HCV transmission, after shared use of needles and other drug injection equipment. Thanks to improved awareness and implementation of infection-control measures, the prevalence of HCV infection in hemodialysis clinics has declined since 1995, according to the authors.

Given the severe shortage of donor kidneys, some experts have explored transplanting organs from HCV positive donors to recipients who also already have HCV. Use of HCV positive donor kidneys is associated with an increase in the prevalence of liver disease, the authors wrote, "but when compared with continued hemodialysis, transplantation using these kidneys is associated with improved survival." Overall, survival in patients with chronic hepatitis C appears to be better after kidney transplantation compared with continued dialysis.

Data support the use of interferon-based therapy -- and the higher efficacy of pegylated interferon compared with the older conventional formulation -- for treatment of chronic hepatitis C in ESRD patients, although "tolerability continues to be troublesome," they said.

The "newest and most promising data" are from treatment with pegylated or conventional interferon plus a reduced dose of ribavirin, but caution is advised since people with impaired kidney function may eliminate ribavirin more slowly and therefore should have their plasma levels carefully monitored.

Finally, the authors wrote that there currently is "no evidence to support treatment with interferon-based therapy" in HCV positive individuals after kidney transplantation, leading them to conclude that "pre-transplant treatment remains the best option whenever possible."

Report 2

In the second report, which appeared in the October 2008 Journal of Hepatology, P. Martin and F. Fabrizi presented a comprehensive overview of HCV diagnosis and management in ESRD patients.

In addition to nosocomial transmission of HCV within dialysis clinics, they wrote, HCV is also implicated in the pathogenesis of kidney dysfunction, often mediated by cryoglobulins, in both original and transplanted kidneys.

"The role of antiviral therapy for hepatitis C in patients with renal failure remains unclear," the authors explained. Monotherapy with conventional interferon appears to be more effective in dialysis patients than in those with normal kidney function -- likely due in part to reduced clearance of conventional interferon in patients on hemodialysis -- but drug tolerance is lower.

To date, there are only limited data from controlled studies of pegylated interferon, with or without ribavirin, in dialysis patients. However, they wrote, "Clinical experience with antiviral therapy for acute HCV in dialysis population is encouraging."

On the other hand, they stated that "interferon remains contraindicated" after kidney transplantation, due to concerns about graft dysfunction. However, transplant candidates who achieve sustained virological response with interferon-based antiviral therapy prior to transplantation usually maintain this response after the transplant, and such treatment may reduce HCV-related post-transplant complications such as diabetes, glomerulonephritis, and chronic allograft nephropathy.

9/23/08

References

Pl Martin and F Fabrizi. Hepatitis C virus and kidney disease. Journal of Hepatology 49(4): 613-624. October 2008. (Full text).

EJ Okoh, JR Bucci, JF Simon, and others. HCV in patients with end-stage renal disease. American Journal of Gastroenterology 103(8): 2123-2134. August 2008. (Abstract).