Introduction To describe the incidence and risks factors of ART induced nephrotoxicity and chronic kidney disease (CKD) in HIV-1-infected adults with low body mass index (<18.5kg/m²).

Methods A retrospective cohort study at the Ambulatory Treatment Centre in Brazzaville, Congo. Patients with estimated glomerular filtration rate (eGFR) decrease by 25% compared to baseline or a 0.5 mg/dL increase in Serum creatinine (Scr) above baseline were classified as having nephrotoxicity, and CKD was defined as a value less than 60 ml/min per 1.73m².We used Cox proportional hazards regression models to determine factors associated with nephrotoxicity and CKD.

Results Of 325 patients, 73.23% were women. Median values was: age: 37.55 years (IQR: 33.51–44.96), weight: 45 kg (IQR: 41–49), CD4 count: 137.5 cells/µl (42 – 245). In the first 24 – months followup on ART incidence rate of nephrotoxicity and CKD was 27.95 and 7.44 per 100 person – years respectively. Multivariate analysis identified as a risk factor of nephrotoxicity, baseline haemoglobin below or equal 8 g/dL (aHR=2.25; 95% CI, 1.28–3.98; p=0.005), eGFR between 60–80 (aHR=0.33; 95% CI, 0.20–0.56; p=0.001) and below 60 ml/min/1.73m² (aHR=0.11; 95% CI, 0.03–0.46; p=0.003), and the use of tenofovir (aHR=1.51; 95% CI, 1.01–2.26; p=0.04). Each 10 year older age was associated with an increased risk of developing CKD (aHR=1.95; 95% CI, 1.2–3.17; p=0.007).

Conclusion Incidence of nephrotoxicity and CKD were high. HIV positive patient with low BMI at baseline need close monitoring of their renal function when treated with tenofovir.