Plasma Cystatin C based renal function assessment among adolescent and young adults failing antiretroviral treatment (ART) on a tenofovir based-ART in Harare, Zimbabwe

Abstract

Objective: To assess renal function using plasma CystatinC (CysC) among adolescent and young adult  PLWH failing a Tenofovir Disoproxil Fumarate (TDF)-containing Antiretroviral Therapy (ART) regimen with  no clinical signs of kidney disease. 

Design: Retrospective cohort laboratory analysis. 

Participants: Adolescents and young adults aged 10-24 years with VL>400 copies/ml enrolled in an adherence intervention cohort. 

Setting: Parirenyatwa Hospital Family Care Centre & Harare City Health Clinics.

Materials and Methods: The Human Cystatin-C Test CYSC2, (test ID 0‑ 139) kit was used for the  immunoturbidimetric quantification of CysC in human plasma on the COBAS INTEGRA400 system.

Main Outcome Measures: Renal function status at week 36.Mild impaired renal function was defined by 2 2 eGFR<90mL/min/1.73 m with moderate to severe renal dysfunction defined by eGFR<60mL/min/1.73 m . 

Results: We enrolled 139 participants; 86% completed follow-up of 36 weeks. Mean or Standard Deviation  (SD) age was 18.38 (2.99) years. Median duration on TDF-containing ART was 3.03 years (IQR 1.47-4.73).  Median or Interquartile Range (IQR) plasma CysC concentration was 0.78 (0.71-0.87) mg/L. There was no  significant correlation between plasma CysC with age (r=0.0785), weight (r=-0.1181), height (r=0.0310) and  2 BMI (r=-0.0977). About 67% had impaired renal function (eGFR<90 mL/min/1.73 m ) at endpoint, a  significant increase from 51% at enrolment (p=<0.0001).  

Conclusions: There is a high burden of impaired renal function in adolescent and young adult patients on  tenofovir containing ART in Harare Zimbabwe with asymptomatic renal disease. The decline in renal  function over 36 weeks reported in this cohort was significant and concerning. Enhanced renal monitoring is  recommended for these patients. CysC is a reliable marker of renal function independent of age and anthropometric measurements.