Performance of four creatinine-based equations in assessing glomerular filtration rate in adults with diabetes.

Aims To evaluate diagnostic performance of glomerular filtration rate (GFR) estimated by modification of diet in renal disease (MDRD), chronic kidney disease epidemiology collaboration (CKD-EPI), full age spectrum (FAS), and revised Lund-Malmo (r-LM) equations in adults with diabetes. Methods Individuals were included in this cross-sectional study if they had at least one measurement of technetium-99m diethylenetriamine-pentaacetic acid ( 99mTc-DTPA) GFR (mGFR) and serum creatinine (1487 patients with 2703 measures). GFR calculated by estimation equations was compared with mGFR. Diagnostic performance was assessed using concordance correlation coefficient (CCC), bias, precision, accuracy, reduced major axis regression (RMAR), and Bland-Altman plot. Analysis was repeated in subgroups based on sex, diabetes type, HbA1c, and GFR level. Results Of all patients, 1189 (86%) had type2 diabetes. Mean mGFR, MDRD, CKD-EPI, FAS and revised Lund-Malmo eGFR were 66, 72, 74, 71, and 67 ml/min/1.73m 2, respectively. Overall, the r-LM had the highest CCC (=0.83), lowest bias (-1.4ml/min/1.73m 2), highest precision (16.2 ml/min/1.73m 2), and highest accuracy (P10=39%). The RMAR (slope, intercept) in r-LM, FAS, MDRD and CKD-EPI was 1.18, -13.35; 0.97, -2.9; 1, -6.4, and 1.04, -11.3, respectively. The Bland-Altman plot showed that r-LM had the lowest mean difference and the narrowest 95% limit of agreement (-1.0, 54.1 ml/min/1.73m 2), while mean difference was more than 5-folds higher in FAS, MDRD, and CKD-EPI (-5.2, -6.3, and -8.2, respectively). Conclusions In adults with diabetes the revised Lund-Malmo performs better than MDRD, CKD-EPI and FAS in calculating point estimates of GFR.