Serum creatinine-based estimates of glomerular filtration rates (GFR) may misjudge the true GFR in patients with HIV disease and thereby miscalculate the frequency of kidney disease in these patients.
As reported in the June issue of the American Journal of Kidney Diseases, Dr. Clara Y. Jones of Tufts University in Boston and colleagues considered 250 HIV-infected subjects on highly active antiretroviral therapy (HAART) participating in the Nutrition for Healthy Living (NFHL) study and 2,628 subjects enrolled in the National Health and Nutrition Examination Survey (NHANES) of 2000-2001.
The investigators compared serum creatinine levels, serum cystatin C levels and estimates of GFR based on each of the actions in the two groups.
Creatinine levels were lower in HIV-positive subjects in the NFHL cohort than in NHANES subjects, even though hepatitis, diabetes and drug use were more widespread in the former group.
Estimates of GFR based on cystatin C levels showed a higher prevalence of kidney disease than estimates based on serum creatinine, Dr. Jones and colleagues report. "Of NFHL subjects, only 2.4% had a creatinine-based estimated GFR less than 60 mL/min/1.73 m, but 15.2% had a cystatin-based estimated GFR less than 60 mL/min/1.73 m."
They advise, "Cystatin C levels may be a better marker of abnormal kidney function in the HIV population, predominantly those with chronic viral hepatitis coinfection... Studies using gold-standard exogenous clearance methods for measuring GFR are required for more definitive answers." |
