Contribution of Cystatin C to the Estimation of Glomerular Filtration Rate in Patients with End-Stage Renal Disease Undergoing Hemodialysis at the Souro Sanou Teaching Hospital in Bobo-Dioulasso (Burkina Faso)

Introduction: Glomerular filtration rate (GFR) is calculated to estimate renal function. Classically, the formulae used to calculate it include creatinine, which is a marker influenced physiologically by age, sex, muscle mass and race. Given these difficulties, cystatin C (cystC), a protein that is freely filtered by the glomerulus, has emerged as a promising biomarker of renal function. The main objective of this study was to investigate the contribution of cystatin C to GFR estimation in patients with end-stage renal disease (ESRD) undergoing hemodialysis at the SS-TH of Bobo-Dioulasso in Burkina Faso. Material and Methods: This was a prospective study of CKD hemodialysis patients recruited at the SS-TH from 1 January 2022 to 28 February 2022. Socio-demographic data were obtained after review of the medical records of hemodialysis patients with ESRD. All biochemical parameters were measured on the COBAS® 6000 automated system. Colorimetric methods were used to measure urea, creatinine and albumin. CRP, alpha-1-glycoprotein acid and transthyretin were determined by the immunoturbidimetric method. The GFRs were calculated using the calculator on the website of the Société Francophone de Néphrologie, Dialyse et Transplantation. Discussion: A total of 39 hemodialysis patients with CKD were included in the study. The mean age was 43.87 ± 11.75 years. There was a male predominance with a sex ratio (M/F) of 1.56. Mean serum cystC was 7.38 ± 1.66 g/L. A positive and significant correlation was observed between cystC and markers such as albuminemia (r = 0.574, p = 0.0001) and transthyretinemia (r = 0.572, p = 0.0001). The CKD-EPI-Creat-CystC formula was more accurate in identifying 100% of patients in stage 5 (GFR 2), unlike the other formulas (Cockcroft and Gault, MDRD, CKD-EPI-Creat, CKD-EPI-CystC). The mean GFR values of the CKD-EPI-Creat and CKD-EPI-Creat-CystC formulae were significantly higher in male patients. Hypertensive patients had mean GFR values obtained by the CKD-EPI-Creat-CystC formula that were significantly higher than those of patients without hypertension (5.72 ± 2.30 mL/min/1.73m2 vs 4.16 ± 0.75 mL/min/1.73m2, p-value = 0.004). Conclusion: Estimation of GFR using the CKD-EPI-Creat-CystC formula would contribute to accurate diagnosis of the clinical stage of chronic kidney disease and could predict cardiovascular risk in CKD patients undergoing hemodialysis.