HIV and the kidney: a spotlight on racial disparities.

In 1984, physicians at a New York City hospital described an aggressive form of kidney disease affecting 12% of their patients with AIDS [1]. Progression to endstage renal disease (ESRD) was nearly universal, and all affected patients were African American or Haitian immigrants. Subsequent studies have consistently demonstrated a strong association between black race and this unique form of kidney disease, now recognized as HIVassociated nephropathy (HIVAN) [2– 4]. In the United States, African Americans account for nearly 90% of the incident ESRD attributed to HIVAN [5], a racial predisposition rivaling that associated with sickle-cell nephropathy [6]. Because these data are based primarily on clinical diagnoses, it is likely that many cases of ESRD that are attributed to HIVAN actually reflect a broader spectrum of HIVrelated and comorbid kidney diseases [4, 7]. Until recently, the impact of race on these other forms of HIV-related kidney disease has not been well understood. Several recent publications have highlighted the significant influence of race on the epidemiology of chronic kidney disease (CKD) in HIV-infected patients, regardless of the underlying pathology [8–11]. Although decreased kidney function was identified in 5% of the largely white EuroSIDA cohort [8], cross-sectional data from a New York City HIV clinic demonstrated a high prevalence of kidney disease in minority patients, including ESRD in 4% and pre– end-stage CKD in 11% of patients [9]. In addition to this striking disparity in prevalence, investigators from the US Veterans Affairs Medical System have recently described racial differences in the incidence and progression of HIV-related kidney disease [10]. Although the baseline prevalence of decreased kidney function was similar in HIV-infected veterans regardless of their race, the incidence of ESRD was nearly 6-fold higher in HIV-infected African Americans. HIVAN was the most common presumed diagnosis, but more than half of the cases of ESRD were attributed to another etiology [10]. In a smaller cohort of veterans who had preexisting kidney disease the rate of progression in HIV-infected African Americans was similar to that observed in patients with diabetes [11]. In this issue of the Journal, Lucas et al. describe the impact of race on the epidemiology of CKD in the Johns Hopkins HIV Clinical Cohort [12]. The findings of their study are consistent with those arising from the study of the Veterans Affairs cohort [10] and suggest that the disproportionate burden of ESRD in HIVinfected African Americans is primarily attributable to more-rapid progression of kidney disease. Although the incidence of CKD was only slightly increased in African American participants compared with white participants, the risk of progression to ESRD was 18-fold higher. In a subgroup of patients, for whom kidneybiopsy data were available, African Americans were significantly more likely to progress to ESRD, regardless of the etiology of kidney disease, suggesting that the observed racial disparity is not unique to HIVAN. The incidence of ESRD in whites in the Johns Hopkins cohort was actually so low that Lucas et al. were unable to adjust for other demographic and clinical characteristics that could confound the relationship between race and the progression of kidney disease; however, it is reassuring that similar results were observed in the larger Veterans Affairs cohort after adjustment for age, sex, baseline kidney function, comorbid conditions, and socioeconomic status. Notably, fewer than one-tenth of HIV-infected veterans were women, compared with nearly one-third of the participants in the Johns Hopkins cohort. The impact of sex on the risk for progression of kidney disease should be the subject of further study in other patient cohorts, particularly because Lucas et al. have identified female sex as a risk factor for incident kidney disease but not for ESRD [12, 13]. Although the inclusion of data from a single institution or hospital network may limit the generalizability of these recent studies, singleand multicenter cohorts are increasingly important resources for Received 5 February 2008; accepted 6 February 2008; electronically published 18 April 2008. Potential conflicts of interest: The author is on the renal speakers bureau of Gilead Sciences. Reprints or correspondence: Christina M. Wyatt, Box 1243, One Gustave Levy Pl., New York, NY 10029 (christina.wyatt@mssm.edu). The Journal of Infectious Diseases 2008; 197:1490 –2 © 2008 by the Infectious Diseases Society of America. All rights reserved. 0022-1899/2008/19711-0002$15.00 DOI: 10.1086/587995 E D I T O R I A L C O M M E N T A R Y