Hepatitis C Positivity May Increase Risk for End-Stage Renal Disease

June 27, 2007 — Patients aged 18 to 70 years who have positive findings for hepatitis C virus are at an increased risk of developing end-stage renal disease, according to the results of a retrospective cohort study published in the June 25 issue of the Archives of Internal Medicine.
"Infection with chronic hepatitis C virus (HCV) has been linked to glomerulonephritis," write Judith I. Tsui, MD, from the University of California, San Francisco, and colleagues. "We undertook this study to determine whether having a positive HCV test result was associated with an increased risk for developing treated end-stage renal disease (ESRD)."
Using data from Medicare, the Department of Veterans Affairs (VA), and the US Renal Data System, the investigators performed a retrospective cohort study of 474,369 adult veterans with serum creatinine levels measurements between October 1, 2000, and September 30, 2001, and HCV antibody testing within 1 year of creatinine testing. Follow-up for the outcome of treated ESRD, defined as the onset of long-term dialysis or renal transplantation, continued through October 1, 2004. The relative risk for ESRD associated with HCV, after adjustment for other covariates (age, sex, race/ethnicity, and comorbidities), was determined with Cox proportional hazards models.
Findings from HCV antibody testing were positive in 52,874 (11.1%) of 474,369 patients. Patients with positive HCV test findings were more likely to develop ESRD, with a rate of 4.26 per 1000 person-years (95% confidence interval [CI], 3.97 - 4.57) for HCV-seropositive patients vs 3.05 (95% CI, 2.96 - 3.14) for HCV-seronegative patients.
For patients aged 18 to 70 years in whom estimated glomerular filtration rate was 30 mL/minute/1.73 m2 or greater, HCV seropositivity was associated with more than twice the risk of developing ESRD (adjusted hazard rate, 2.80; 95% CI, 2.43 - 3.23).
Study limitations include lack of generalizability to nonveteran populations; analysis being based on results of HCV antibody testing rather than HCV RNA testing; possibly reduced accuracy of the Modification of Diet in Renal Disease equation used to estimate glomerular filtration rate in patients with HCV; lack of data on proteinuria or albuminuria; use of International Classification of Diseases, Ninth Revision, codes for comorbidity diagnoses, when they are often insensitive and do not provide information on severity or control of the disease condition; possible unknown confounders; and short duration of follow-up.
"In this large national cohort of adult veterans, patients younger than 70 years with HCV seropositivity were at increased risk for developing ESRD treated with dialysis or transplantation," the authors write. "Our findings raise the question of whether current guidelines recommending that patients with ESRD and severe CKD [chronic kidney disease] be screened for HCV be expanded to include patients with moderate CKD and whether patients with HCV should routinely be screened for CKD. Future studies should investigate whether treatment eradicating HCV alters the risk for renal disease and whether existing treatments to delay the progression of CKD are effective in persons with chronic HCV."
The National Center for Research Resources of the National Institutes of Health and the National Institute on Aging supported this study. The authors have disclosed no relevant financial relationships.
Arch Intern Med. 2007;167:1271-1276.