Performance of Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration Equations Versus 99Tc-DTPA-Renogram in Assessing Kidney Function.

ABSTRACT

Objectives: To evaluate the performance of measurement of glomerular filtration rate (GFR) using Modification of Diet in Renal Disease equations (MDRD186, MDRD175) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, in comparison with technetium-99m diethylenetriaminepentaacetic acid (99Tc-DTPA) renogram method, the gold standard. A related aim was to correlate the three equations to estimate GFR and their impact on reclassifying the stages of CKD in adult Omani patients. Methods: This cross-sectional study recruited two groups of patients diagnosed with CKD during a 10-month period from January to October 2021. The first group comprised 48 patients who underwent a 99Tc-DTPA renogram procedure for GFR measurement, and the second group comprised 30 348 adult patients who did not undergo the same procedure; estimated GFR was calculated using the three equations. Results: The median of the reference GFR was 106.0 mL/min/1.73 m2, whereas the median estimated GFR for the MDRD175, MDRD186, and CKD-EPI equations were 92.5, 98.3, and 102.1, respectively. All three equations correlated moderately with the reference GFR (0.428, 0.428, 0.523, respectively; p < 0.010). The CKD-EPI showed lesser bias (3.7 vs. 12.9 and 7.5 for MDRD175 and MDRD186, respectively) and more accuracy (95.8% vs. 91.7% and 93.8%); however, it was the least precise (25.1 vs. 22.3 and 23.8). The MDRD186 performed similarly to the CKD-EPI equation at CKD stages 3a-5 and differed significantly at stages 1-2. Whereas the MDRD175 differed significantly with both equations at stages 1-3b and was similar to them at stages 4-5. Conclusions: The CKD-EPI equation had the highest accuracy and the least bias and precision in the general population. The MDRD186 CKD classification differed significantly from the CKD-EPI equation at CKD-stages 1-2 only. The CKD-EPI equation is preferred to MDRD for the detection and classification of early CKD stages.