Our study examined the prevalence of CKD and its associated factors among HIV infected individuals on HAART for at least one year and undetectable viral load (which is a quite clinically stable population). The prevalence of CKD was 8.4%, which is quite close, albeit higher, to the ones reported by other studies that vary from 4.7% to 7.6% 
. Although somehow expected, this finding was worrisome for us, as it is estimated that about 5% of the general Brazilian population older than 60 years is expected to have CKD, whereas our cohort had a greater prevalence with CKD with a mean age almost 15 years younger (mean age was 45.6 years) 
. Likewise, as we selected HIV “healthy” patients (undetectable viral load and CD4 > 200 cells/3) and without previous renal disease we were anticipating a lower prevalence of CKD.
The factors associated were: hypertension, time on HAART and TDF use. As expected, hypertension was found to be a major risk factor associated with CKD (RR
3.88, 95% CI 1.84–8.16)), which is in accordance to other studies 
. The risk was slightly higher than the other studies, which varied from 1.68% to 3.8% 
Another unique finding was that time on antiretroviral therapy was significantly associated with CKD. In our study, there was a 15% increased prevalence of CKD per year of additional exposure to ARVs (RR
1.15, 95% CI 1.03–1.27). This could be explained by the fact that prolonged use of HAART could be associated with greater long term renal toxicity, meaning the more exposition leading to higher toxicity.
Adverse effects of the exposure to individuals ARVs were demonstrated by other studies which described the cumulative association of TDF, ATV, indinavir and RTV to the development of CKD 
. In our study, the only antiretroviral that was independently associated to CKD, was TDF (RR
2.25, 95% CI 1.04–4.95). Our findings were somewhat higher than what have been found in other studies which varied from 1.5 to 2.18 higher chance of renal disease 
. We did not have enough patients on indinavir (only 2) to find any association. Perhaps with a larger sample we could come across major findings regarding ritonavir use and, consequently, atazanavir, as it is the antiretroviral used along with 100 mg of ritonavir daily.
An important finding was related to the body weight (RR
0.89, 95% CI 0.82–0.96, which was significantly associated as a protection factor. To our knowledge, this is the first study that found this association. Individuals with lower body weight were at greater risk of having CKD. Despite it is known that weight may play an important function in drug metabolism, once it can influence the bioavailability and pharmacokinetics of ARVs 
, there is still limited data about the effect of weight in HAART. Perhaps this should be a window of opportunity to individualize ARVs dosage and minimize toxicity.
The study has several limitations that should be considered when interpreting the results. Although all studies estimate the GFR in HIV individuals, this could be not accurate enough to allow a firm conclusion of kidney function. MDRD equation, generally more accurate and utilized 
, might not be fully applicable to specific populations. Limited data suggests that MDRD may underestimate GFR in individuals with normal renal function 
and therefore have led to an overestimation of renal impairment. We suggest that there is a need of an individualized equation to estimate the GFR in each population. Likely, due to constraints of MDRD, we excluded malnourished and obese patients, which could have better contributed to some of our findings. Secondly, our sample size might have limited our findings as it may have not been large enough to detect all CKD risk factors in this population, such as age and DM. Thirdly, this is a cross sectional study and therefore we can only draw association of events and not establish temporal sequence. Lastly, although we tried to minimize HIV infection and its co-morbidities, selecting individuals with CD4 counts greater than 200 cells/mm3
and at least one year with undetectable viral load, it is not possible to exclude any influence of HIV infection and related diseases or other nephrotoxic medications in the prevalence of renal impairment 
In summary, according to our findings, in HIV population which would most resemble the general population, hypertension, time on HAART, and exposure to tenofovir were associated with a higher prevalence of CKD. On the other hand, individuals with higher body weight appeared to be “protected” from chronic kidney disease. We suggest that an equation to eGFR should be routinely applied to better identify decrease in renal function, and should be performed at the moment of HIV diagnosis and later at regular intervals, depending on the associated risk factors. Further studies are necessary to confirm risks associated to renal disease in HIV-infected individuals.