Assessing renal function with the use of cystatin C in a rural cohort of people living with HIV on highly active antiretroviral therapy within the Limpopo Province, South Africa

The kidneys in people living with HIV (PLWH) are constantly exposed to highly antiretroviral therapy (HAART) which may cause renal dysfunction. Cystatin C (CystC), a biomarker of renal function, is well associated with renal impairment in various populations, however, it is underexplored in the South African population of PLWH, as compared to creatinine-based measurements. Creatinine-based measurements for assessing kidney function in people with HIV can be limited due to the influence of muscle wasting, altered creatinine metabolism, and the potential for certain antiretroviral medications to impact creatinine secretion. Therefore, the current study aimed to explore the effect of HAART on renal function among PLWH with the use of Cyst C-based measures. We conducted a cross-sectional study of 111 adults PLWH, 84 on HAART, and 27 on HAART-naïve. The cluster of differentiation 4 (CD4 +) count, plasma CystC, as well as the estimated glomerular filtration rate (eGFR) using the chronic kidney disease-epidemiology collaboration (CKD-EPI) formula, were determined. In the present study, no significant differences were observed between HAART-treated and HAART-naïve groups in terms of plasma CystC and eGFRCystC. Participants who were on HAART for > 5 years were significantly associated with eGFRCystC < 90 mL/min/1.73 m2, as indicated by substantial odds ratio of 4.39 (confidence interval: 1.60–12.02, p = 0.004) in the unadjusted analysis and even after adjustment for age, sex and smoking status, with odds ratio of 4.10 (confidence interval: 1.41–11.86, p = 0.009). Advanced World Health Organization (WHO) clinical stage significantly associated with eGFRCystC < 90 mL/min/1.73 m2 as indicated by odds ratio of 11.73 (confidence interval: 2.27–60.75, p = 0.003) in the unadjusted analysis. Even after adjusting for confounders which included age, sex, and smoking status, the association persisted, with an odds ratio of 16.71 (confidence interval: 2.57–108.75, p = 0.003). In conclusion, CystC and eGFRCystC levels were not different between PLWH on HAART and not on HAART but prolonged HAART use for over five years and advanced HIV disease were associated with reduced renal function in this population of PLWH on HAART, as assessed using CystC-based measures. These findings may suggest that HAART had initial beneficial effects and long-term adverse effects. The future risk of progressive eGFR decline may be increased in this HIV population on HAART due to the cumulative effect of prolonged tenofovir disoproxil fumarate (TDF) use. These findings remain important to guide future research with larger populations on the management of conditions related to renal function decline in PLWH. Highlights.