Assessment of Renal Function in A Rural Population by Different GFR Estimation Methods

Background: Accurate measurement of renal function is critical for diagnosing and stratifying kidney disease. Various methods to estimate glomerular filtration rate (GFR) have shown variable results depending on the studied population. Objective: This study aimed to evaluate the effectiveness of different GFR estimation methods in assessing renal function in a selected rural adult population. Method: A cross-sectional study was conducted from July 2019 to June 2020, including 222 participants based on specific inclusion and exclusion criteria. Detailed histories and relevant investigations were obtained from each participant. Estimated GFR (eGFR) was calculated using serum creatinine, cystatin C, and combined formulas. Data were recorded in separate case record forms and analyzed using SPSS 26.0 and MedCalc 13.0. Results: The mean (±SD) age of the study population was 41.12±12.72 years, with a majority aged 31-50 years (59.5%). There was a male predominance (53.6%). Mean eGFRs were as follows: MDRD 117.31±25.54 mL/min/1.73 m², Cockcroft-Gault 102.87±30.50 mL/min/1.73 m², CKD-EPI 119.52±20.48 mL/min/1.73 m², cystatin C-based 107.17±16.34 mL/min/1.73 m², and combined creatinine-cystatin C 105.48±20.87 mL/min/1.73 m². Renal function assessment by MDRD, Cockcroft-Gault, CKD-EPI, cystatin C, and combined equations showed significant agreement with each other. Conclusions: Different GFR estimation methods showed no clear superiority over each other. However, eGFR CKD-EPICr demonstrated perfect agreement with the MDRD equation, and eGFR CKD-EPICys showed substantial agreement with eGFR CKD-EPICr-Cys.