- Category: Liver & Kidney Disease
- Published on Wednesday, 07 August 2013 00:00
- Written by Liz Highleyman
HIV positive people in the U.S. and Canada are nearly 4 times as likely to develop end-stage renal disease than HIV negative people in the general population, largely driven by a very high rate among blacks, researchers reported last month at the 7th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2013) in Kuala Lumpur.
Over the course of the epidemic numerous studies have reported higher rates of kidney problems among people with HIV, but it is not yet clear whether this is due to HIV infection itself, resulting metabolic or inflammatory changes, toxicities of antiretroviral drugs, or some combination of factors. Studies to date -- some done before the advent of effective antiretroviral therapy (ART) -- have produced widely varying kidney disease incidence rates.
Keri Althoff from Johns Hopkins and colleagues looked at the incidence of end-stage renal disease (ESRD) -- defined by the need for dialysis or kidney transplantation -- in the large North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) population.
The investigators identified HIV positive individuals in 12 NA-ACCORD cohorts -- together including 37,801 participants -- who had 2 or more estimated glomerular filtration rate (eGFR) measurements <30 mL/min taken at least 90 days apart or a diagnosis of kidney disease between January 2000 and December 2009.
Overall, about 80% of study participants were men, about 40% were white, about one-third were black, and about 25% were age 50 or older. Male sex, black race, and older age are known kidney disease risk factors. Approximately 20% had CD4 T-cell counts below 200 cells/mm3 and another 20% between 200-350 cells/mm3.
- Initial screening identified 822 patients with suspected ESRD; 616 were found to have medical evidence of ESRD, out of which there were 306 verified new or incident cases.
- The overall crude incidence rate in NA-ACCORD was 192 cases per 100,000 person-years (PY), which compares with 36 per 100,000 PY among the general U.S. population.
- However, rates varied substantially across demographic groups.
- Higher ESRD rates were seen with increasing age, from 146 cases per 100,000 PY in the 18-39 age group, to 189 cases in the 40-49 age group, to 259 cases among those age 50-59, and 298 cases among those age 60 or older.
- The ESRD rate among men was 171 cases per 100,000 PY, compared with 266 cases among women.
- Blacks had a much higher rate than other racial/ethnic groups at 445 cases per 100,000 PY, compared with 54 case for whites and 83 cases for Hispanics.
- Rates in NA-ACCORD for all racial/ethnic groups were higher than the corresponding general population rates (78, 31, and 30 cases per 100,000 PY, respectively), but the disparity was greatest for blacks.
- ESRD incidence rates were 110 cases per 100,000 PY among men who have sex with men, 267 cases among injection drug users, and 306 cases among people in the heterosexual transmission category.
- Compared with people age 40-49, those age 50-59 had an adjusted incidence rate ratio (IRR) of 1.39, rising to 2.02 for those age 60 or over.
- Compared with whites, adjusted IRRs were 6.37 for blacks and 1.51 for Hispanics.
- CD4 counts of 350-500 or >500 cells/mm3 were associated with lower ESRD rates compared with <350 cells/mm3 (adjusted IRRs 0.66 and 0.73, respectively), as was undetectable HIV viral load (adjusted IRR 0.58), while history of clinical AIDS was associated with a higher rate (adjusted IRR 1.45).
- Looking at standardized incidence ratios (SIRs) comparing people with HIV to the general population, HIV positive whites had nearly twice the ESRD incidence (SIR 1.89) and HIV positive Hispanics had a 1.6-fold higher rate (SIR 1.61, not a significant difference), while HIV positive blacks had more than a 4-fold higher rate (SIR 4.44).
"The overall estimated incidence of ESRD in the NA-ACCORD is higher than estimates from Europe [121 per 100,000 PY in EuroSIDA], and lower than estimates from the Veteran’s Aging Cohort Study [300 per 100,000 PY]," the researchers concluded. "These differences are likely attributed to the differences in age, race, sex, and risk factor composition of these populations."
While the finding that women had a higher rate of ESRD is contrary to what is usually seen in the general population, the investigators said this was likely attributable to the fact that a higher proportion of HIV positive women are black. After adjusting for demographics and HIV-related characteristics, there was no longer a difference by sex.
Having an undetectable HIV viral load lowered the risk of ESRD by 42%, underlining the importance of treatment.
They added that more research is needed looking at additional kidney disease risk factors such as smoking, hepatitis C infection, and diabetes.
K Althoff, A Abraham, M Estrella, et al. Incidence of end stage renal disease in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD). 7th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention. Kuala Lumpur, June 30-July 3, 2013. Abstract MOPE082.