DENVER – The risk of death for patients with hepatitis C is higher than that of patients with chronic kidney disease, but when both conditions are present, chronic kidney disease does not significantly increase mortality beyond the risk associated with hepatitis C alone.
"Both patients with hepatitis C and [those with] chronic kidney disease die of similar causes," Dr. Rajiv J. Gandhi said in an interview during a poster session at the annual meeting of the American Society of Nephrology. "Overall, many of them die from heart disease. Albuminuria has been linked to cardiovascular risk and cardiovascular disease. Hepatitis C patients have more albuminuria than those without hepatitis. This might be a target for intervention to decrease cardiovascular risk."
Dr. Gandhi of the University of Minnesota, Minneapolis, and his associate Dr. Robert N. Foley studied 15,540 people aged 20 years and older in the National Health and Nutrition Examination Survey 1988-1994 who completed examination and laboratory testing for HCV antibody and serum creatinine, and were included in the mortality file linking them to the National Death Index.
The researchers performed descriptive analysis comparing participants on demographic, examination, laboratory, and questionnaire variables grouped by HCV antibody status and went on to compare mortality based on HCV and chronic kidney disease status, with follow-up through 2006.
The mean age of study participants was 43 years, and 57% were white. Overall, 388 of the study participants (2.5%) were HCV positive. Compared with HCV-negative patients, those who were HCV positive tended to have higher albumin-to-creatinine ratios, lower blood urea nitrogen levels, and higher estimated glomerular filtration rates.
At the end of follow-up, a higher proportion of HCV-positive individuals had died, compared with HCV-negative individuals (22.2% vs. 17.2%, respectively), but this difference did not reach statistical significance.
An analysis adjusted for age, sex, and race revealed that the hazard ratio for all-cause mortality was 2.5 for participants with chronic kidney disease alone, 3.9 for those with HCV alone and 4.2 when both conditions were present.
The researchers also found that albuminuria was associated with similarly increased mortality in HCV-negative and HCV-positive study participants (hazard ratio, 5.6 and 5.1, respectively). In addition, a glomerular filtration rate of less than 60 mL/min per1.73 m2 was associated with increased mortality in HCV-negative individuals (HR, 10.3), and mortality was markedly higher in HCV-positive individuals (HR, 54.3).
"Overall, HCV-positive participants have higher mean estimated glomerular filtration rates and albumin to creatinine ratios, which likely indicates early stages of kidney disease characterized by hyperfiltration and increased albuminuria," the researchers wrote in their poster. "Screening for early markers of kidney disease such as albuminuria among HCV-positive individuals may allow early intervention and could potentially decrease the mortality observed in this group."
Dr. Gandhi acknowledged certain limitations of the study, including its cross-sectional design and the fact that lab measurements were taken at one point in time.
Dr. Gandhi said that he had no relevant financial disclosures to make.