Chronic kidney disease prevalence and risk factors among HIV-infected patients.

To the Editors: Chronic kidney disease (CKD) in its different stages is independently related to higher risk of death, development of cardiovascular diseases, and higher hospitalization rates. It is currently considered a relevant and growing public health problem. Therefore, early diagnosis is crucial for the implementation of preventive measures. The regular use of combined antiretroviral therapy (CART) has had a substantial impact on the survival rate of human immunodeficiency virus (HIV)– infected patients, resulting in the aging of this population in which chronic pathologies can appear. The deterioration of renal function is clinically silent. Only through specific analyses it is possible to diagnose and evaluate the presence of CKD in the early stages. For all these, there is an increasing concern about renal dysfunction in HIV-infected patients. A cross-sectional study was carried out onHIV-infected patients at a university hospital in Barcelona, Spain. All patients were 20 years or older. Exclusion criteria included evidence of clinical signs of active acquired immunodeficiency syndrome or no related acquired immunodeficiency syndrome infections in the 3 months before inclusion due to their possible impact on the anthropometric and biochemical parameters. A control group, adjusted by age, was recruited during the same period from the outpatient clinic of the hospital. These patients should have had a minimum follow-up of 3 consecutive visits during 1 year. Estimated glomerular filtration rate (GFR) was ascertained according to the Modification of Diet in Renal Disease (MDRD-4) formula. CKD was defined as GFR <60 mL/min/1.73 m on at least 2 occasions separated by at least 3months. In the control group, only age, sex, and GFR were recorded. For each HIV-infected patient, cardiovascular risk factors were evaluated according to the recommendations of Panel III of the National Cholesterol Education Program. We also recorded HIV exposure (mutually exclusive in the following order: intravenous drug use, homosexual or heterosexual activity), length of time from diagnosis, nadir lymphocyte CD4 cell count and the viral load before starting CART, HIV disease status according to the 1993 Centers for Disease Control and Prevention classification, exposure to antiretroviral treatment, classified as ‘‘naive’’ or ‘‘currently in treatment,’’ and hepatitis C coinfection. For those receiving CART, duration of exposure was also considered. The physical examination included height and weight measurements and arterial pressure readings. Lipodystrophy was defined through the patient’s own perception of changes in distribution of body fat and an evaluation by a single investigator. We studied 854 patients. Seven hundred forty-seven (87.5%) received antiretroviral treatment, and of these, 156 (18.3%) were exposed to tenofovir (TDF). Average exposure to CART was 80 months. In the control group (2134 HIVnegative patients), a prevalence of CKD was 5.6% [95% confidence interval (CI): 4.7 to 6.7], whereas in the HIV infected was 7.6% (95% CI: 6.0 to 9.6). In naive patients, CKD prevalence was 4.7% and in CARTexposed was 8% (P: 0.3). Thus, in comparison to the control group, HIV-infected patients showed a greater prevalence of CKD (Odds ratio (OR): 1.40; 95% CI: 1.02 to 1.91; P: 0.04). Whenwe analyzed the factors potentially associated to CKD, TDF exposure was related to a high proportion of patients with CKD (9.3%); however, it did not reach statistical significance compared neither with naives nor patients exposed to other antiretroviral drugs (7.6%). In the univariate analysis, the factors associated with CKD were older age, female gender, hypertension, and diabetes mellitus. Other risk factors associated with CKD were being exposed to CART for more than 5 years, to have a symptomatic HIV infection (B+C category), and the presence of lipoatrophy. In the multivariate logistic regression model, classic risk factors, such as the presence of hypertension and diabetes mellitus, lost statistical significance. Only age (AOR: 3.19 per 10-year increment; 95% CI: 2.42 to 4.21), being female (AOR: 4.55; 95% CI: 2.46 to 8.40), the presence of lipoatrophy (AOR: 1.84; 95% CI: 1.03 to 3.27), and the symptomatic HIV infection (Adjusted odds ratio (AOR): 1.77; 95% CI: 1 to 3.14) appeared as factors independently associated with CKD (Table 1). The prevalence of CKD among HIV-infected patients was higher than in the HIV-negative patients. However, when datawere adjusted by age and gender, HIV infection did not result as an independent risk factor for CKD. The Third National Health and Nutrition Examination Survey III conducted in the United States included 15,626 adults from the general population estimating a prevalence of CKD of 4.6% for GFR <60 mL/min. In Spain, the prevalence of CKD defined as GFR <60 mL/min is 5.7% in a population whose average age is 49.5 years. It must be stated that the HIV-negative population of the present study does not constitute the general population but rather individuals seeking outpatient care at our hospital. Moreover, this population has an average age nearly 10 years older than the population sample discussed in other studies, and for this reason, it could be possible that they have an increased burden of CKD risk factors. However, our results were very similar to those reported in the above mentioned studies carried out in the general population. Data concerning the prevalence of CKD in the HIV-infected population are scarce. The study, which included the greatest number of patients, found a prevalence of 3.5% when using the Cockcroft–Gault equation or 4.7% using MDRD formula. A study that included a high proportion of black race patients found a prevalence of CKD of 15.5%. Our study group is representative of the Spanish population; the relatively low prevalence of CKD may be explained by the low proportion of black race patients. In the logistic regression analysis, factors such as hypertension and diabetes