There is a high rate of kidney problems in HIV-positive patients, according to a French study reported at the fourth IAS Conference on HIV Pathogenesis, Treatment and Prevention, in Sydney. Older age, advanced HIV disease, and being on a tenofovir-containing drug regimen for longer than a year were among the factors associated with an increased risk of renal impairment.
While renal failure—a decrease in kidney function—is believed to be common in HIV-positive patients, there have been few detailed studies looking at its prevalence and risk factors.
To explore this, Philippe Morlat, MD, and his colleagues analyzed data involving 2,588 patients enrolled in the French Aquitaine Cohort between January 2004 and August 2006.
Renal failure was defined using creatinine clearance (CRCL) rate testing. Found in the blood, creatinine is a waste product generated by the normal breakdown of muscle cells. If kidney function is impaired, creatinine removal from the blood slows down. The rate of creatinine clearance therefore helps determine how well the kidneys are functioning.
Mild renal impairment was defined as a CRCL rate between 60 and 80 mL/min. A rate of 30 to 60 mL/min defined moderate renal impairment. A rate between 10 and 30 mL/min meant severe renal impairment. End-stage impairment—complete kidney failure—was defined as a rate below 10 mL/min.
Approximately 33 percent of the study participants were male; the average age upon entering the cohort was 42 years. Approximately 92 percent were on antiretroviral (ARV) therapy—25 percent were on a tenofovir (the active ingredient in Viread and a component of Truvada and Atripla)—and the average viral load and CD4 count were 90 copies and 430 cells, respectively.
Almost 23 percent of the cohort participants had some degree of renal impairment. Approximately 18 percent of the cases were mild, 4 percent were moderate, 0.3 percent were severe, and 0.2 percent were end-stage.
Multivariate analysis of the data, a statistical technique that considers multiple variables simultaneously, indicated that being over the age of 50 was the greatest risk factor, leading to a 13.32-fold increase. A low body mass index, defined as a BMI below 22, was associated with a 3.84-fold risk increased. Being female meant a 3.22-fold increased risk. Having an AIDS diagnosis meant an increased risk of 1.32 fold.
As for ARV-treatment-related factors, only prolonged tenofovir use, defined as being on the drug for longer than a year, was associated with kidney problems—a 1.62-fold increased risk. Having an undetectable viral load translated into a 1.57-fold increased risk.
In conclusion, Dr. Morlat’s team said the prevalence of renal failure is high in HIV-positive patients. “Although advanced stages of renal impairment seem uncommon,” they write, “renal function should be carefully monitored in those HIV-positive patients with older age, low BMI, female gender, tenofovir exposure, undetectable viral load and AIDS (diagnoses).”
Source:
Morlat PJM, Deti E, Lawson-Ayayi S, et al. Prevalence and factors associated with renal failure in HIV-infected patients, ANRS Aquitaine Cohort, France [Abstract MOPEB066]. Fourth IAS Conference on HIV Pathogenesis, Treatment and Prevention, Sydney, 2007.
