Using data from 27,313 HIV-infected adults on ART over a median follow up of 2.3 years (76,168 PYFU), the estimated incidence rate of CKD was 3.2 per 1,000 PYFU. Factors independently associated with CKD diagnosis were older age, type 2 diabetes, gout and urolithiasis, which are known risk factors in the general population12–15, receipt of TDF-containing regimens and absolute CD4 cell count <200 cells/mm3, both factors related to HIV infection.
The Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study in Europe, the USA, and Australia reported a CKD incidence rate of 1.8 per 1,000 PYFU (95% CI 1.6–2.0) in HIV-positive adults16, lower than in our study. However, in our study, data on atazanavir and abacavir were too scarce to be analyzed and compared to D:A:D study Two studies in Asia reported higher CKD incidence rates than in our study. The HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT) reported an overall CKD incidence rate of 10.4 per 1,000 PYFU but no breakdown by ART regimen was provided, limiting the possibility to compare17. The AIDS Clinical Center of National Center for Global Health and Medicine (NCGM) in Japan reported an overall CKD incidence rate of 20.6 per 1000 PYFU (95% CI 17.6–24.2), probably due to a high percentage of patients (83%) on ritonavir-boosted protease inhibitors18.
In our population, older age, T2DM, hypertension were associated with the risk of CKD like in the general population18–21. HBV and HCV co-infections were not associated with the risk of CKD in our study although an association with HBV was found in other studies22,23 and HCV8.
Two studies in Africa reported that the risk of CKD preferably occurred during the first 3 years following HIV diagnosis and in case of low CD4 cell counts24,25. In the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial, ART-naïve patients with CD4 cell counts ≤ 500 cells/µL had a higher prevalence of CKD than those with higher CD4 cell counts19. We also found an association with lower CD4 cell counts. Increased HIV-1 RNA load has also been reported as a significant risk factor17 but we could not analyze this association due to insufficient baseline HIV-1 RNA load data.
We found that TDF exposure increased the risk of CKD like in the EuroSIDA Study Group26, the U.S. veterans study27, a prospective cohort from France28, the Canadian HIV Observational Cohort study8 and the D:A:D study16. However, the NCGM study found no increase in incidence of CKD among patients on TDF (despite a median observation duration of 5.1 years) but a higher drop in eGFR with longer exposure to TDF18. Interestingly, a retrospective study in Kenya29 raised the question of a potential risk of CKD associated with NVP when in combination with TDF. To our knowledge only one other study, also in Thailand, showed that patients on TDF+3TC+NVP had a higher risk of renal impairment compared to patients on TDF+3TC+EFV30. It is unclear whether this could be explained by confounding factors that were not taken into account.
As for the use of protease inhibitor, the Canadian HIV Observational Cohort study8 and the D:A:D study16 reported that the exposure to LPV/r was significantly associated with an increased risk of CKD, as in our study. In HIV-positive adults with kidney dysfunction, plasma TDF concentration in peripheral blood mononuclear cells has been shown significantly higher among patients receiving LPV/r compared with those receiving an NNRTI (NVP or EFV)31. A recent study from the USA National Historical Cohort of HIV-infected Veterans, reported that a incidence rate of CKD in patients on EFV+FTC+TDF of 39.3 per 1,000 PYFU (95% CI 34.0-45.3), significantly lower when compared to ritonavir-boosted PI (atazanavir, LPV or darunavir) +FTC+TDF (66.1 per 1,000 PYFU, 95% CI 55.7-77.9) (HR 0.6, 95% CI 0.5-0.7)32.
There were several limitations in our study. The NAP database was primarily designed to facilitate the reimbursement of costs incurred by hospitals for the delivery of HIV related medical services, and risk factors for CKD were not systematically recorded. Another limitation is that some variables such as laboratory results at ART initiation were not recorded in the database (cholesterol, triglycerides, HIV-1 RNA load) and could not be fully assessed in our analysis. Nevertheless, this national database provides a unique source of information reflecting the actual CKD burden in people living with HIV.
In conclusion, based on the analysis of a large national dataset from HIV-infected patients treated in the real world, the risk of CKD was relatively low overall and mostly concentrated in patients receiving TDF with a higher incidence in those also on NVP or LPV/r.