Prevalence of proximal tubular dysfunction in ambulatory HIV infected clients on 1st line HAART attending the Mater comprehensive care clinic

Abstract

BACKGROUND Tenofovir disoproxil fumarate (TDF), is now a widely used component of antiretroviral regimens owing to its high potency and acceptable safety profile. Multiple randomized clinical trials have shown low incidence of nephrotoxicity with use of TDF, though case reports and case series to the contrary abound. Apart from the costs involved in management of renal impairment, the risk of cardiovascular disease is increased significantly. OBJECTIVE To determine prevalence of proximal tubular dysfunction (PTD) in clients on 1st line highly active antiretroviral therapy (HAART) attending comprehensive care clinic at The Mater Misericordiae Hospital in Kenya. METHODOLOGY This was a cross sectional observational study conducted between August and November 2018 that enrolled clients who were 18 years and above and on HAART for at least two years. We used a structured questionnaire for both clinical and demographic data. Random blood and urine samples were analyzed for markers of proximal tubular dysfunction specifically fractional excretion of uric acid, fractional excretion of phosphate, proteinuria and normogylcemic glycosuria. Significant proximal tubular renal dysfunction was defined by the presence of at least two of the following; normoglycemic glycosuria, hyperphosphaturia, tubular proteinuria and hyperuricosuria with at least one cardinal feature of Fanconi syndrome (normoglycemic glycosuria,or hyperphophaturia). RESULTS 284 out of 2780 clients on 1st line regimens were sampled consecutively. 237 were on TDF and 47 were on non TDF regimen. Average age was 43 and 44 years and mean CD4 level was 365 and 309 cells/ml for the TDF and non TDF groups respectively. Median duration since diagnosis of HIV infection was 7 (IQR 4-9) years for TDF group and 9 (IQR 7-11) years for non TDF group. Proximal tubular dysfunction as defined by occurrence of FEP > 20% with concomitant FEU > 15% was found in 17% of participants in the TDF group compared to 10% in the non TDF group. No preselected risk factors were found to have significant association with the presence of proximal tubular dysfunction on univariate analysis. CONCLUSION There was a high prevalence of PTD in patients on the two first line regimens suggesting a significant contribution from HIV virus rather than the regimen used. Prevalence of proximal tubular dysfunction in ambulatory HIV infected clients on 1st line HAART attending the Mater Comprehensive care clinic.