The CKD-EPI equation more accurately estimates glomerular filtration rate (eGFR) than the MDRD Study equation using the same variables, especially at higher GFR, but definitive evidence of its risk implications in diverse settings is lacking.
To evaluate risk implications of eGFRCKD-EPI compared to eGFRMDRD in populations with a broad range of demographic and clinical characteristics.
Design, Setting, and Participants
Meta-analyses based on data from 1,130,472 adults (aged 18 years or older) from 25 general population, 7 high-risk (of vascular disease), and 13 chronic kidney disease (CKD) cohorts. Data transfer and analyses were conducted between March 2011 and March 2012.
Main Outcome Measures
All-cause mortality (84,482 deaths from 40 cohorts), cardiovascular mortality (22,176 events from 28 cohorts), and end-stage renal disease (ESRD) (7,644 events from 21 cohorts) during 9.4 million person-years of follow-up (median of mean follow-up time across cohorts was 7.4 years).
eGFR was classified into six categories (≥90, 60-89, 45-59, 30-44, 15-29, and <15 ml/min/1.73m2) by both equations. Compared to eGFRMDRD, 24.4% and 0.6% of participants from general population cohorts were reclassified to a higher and lower eGFR category by the CKD-EPI equation, respectively, and the prevalence of CKD stage 3-5 (eGFR <60 ml/min/1.73m2) was reduced from 8.7% to 6.3%. 34.7% of participants with eGFRMDRD 45-59 were reclassified to eGFRCKD-EPI 60-89 and had lower incidence rates (per 1,000 person-years) of outcomes compared to those not reclassified (9.9 vs. 34.5 for all-cause mortality, 2.7 vs. 13.0 for cardiovascular mortality, and 0.5 vs. 0.8 for ESRD). The corresponding adjusted hazard ratios were 0.80 (95% confidence interval, 0.74 to 0.86) for all-cause mortality, 0.73 (0.65 to 0.82) for cardiovascular mortality, and 0.49 (0.27 to 0.88) for ESRD. Similar findings were observed in other eGFRMDRD categories. Net reclassification improvement (NRI) based on eGFR categories was significantly positive for all outcomes (range from 0.06 to 0.13, all P<0.001). NRI was similarly positive in most subgroups defined by age (< and ≥65 years), sex, race/ethnicity (white, Asian, and black), and presence or absence of diabetes and hypertension. The results in high-risk and CKD cohorts were largely consistent with the general population cohorts.
The CKD-EPI equation classified fewer individuals as CKD and more accurately categorized the risk for mortality and ESRD than did the MDRD Study equation across a broad range of populations.