Comparison of CKD Awareness in a Screening Population Using the Modification of Diet in Renal Disease (MDRD) Study and CKD Epidemiology Collaboration (CKD-EPI) Equations

Background: Low awareness of chronic kidney disease (CKD) may reflect uncertainty about the accuracy or significance of a CKD diagnosis in individuals otherwise perceived to be low risk. Whether reclassification of CKD severity using the CKD Epidemiology Collaboration (CKD-EPI) equation to estimate glomerular filtration rate (GFR) modifies estimates of CKD awareness is unknown. Methods: In this cross-sectional study, we used data collected from 2000-2009 for 26,213 participants in the Kidney Early Evaluation Program (KEEP), a community-based screening program, with CKD based on GFR estimated using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation and measurement of albuminuria. We assessed CKD awareness after CKD stage was reclassified using the CKD-EPI equation. Results: Of 26,213 participants with CKD based on GFR estimated using the MRDR equation (eGFR MDRD), 23,572 (90%) also were classified with CKD based on eGFR CKD-EPI. Based on eGFR MDRD, 9.5 % of participants overall were aware of CKD, as were 4.9%, 6.3%, 9.2%, 41.9%, and 59.2 % with stages 1-5, respectively. Based on eGFR CKD-EPI, 10.0 % of participants overall were aware of CKD, as were 5.1%, 6.6%, 10.0%, 39.3%, and 59.4 % with stages 1-5, respectively. Reclassification to a less advanced CKD stage using eGFR CKD-EPI was associated with lower odds for awareness (OR, 0.58; 95 % CI, 0.50-0.67); reclassification to a more advanced stage was associated with higher odds for awareness (OR, 1.50; 95 % CI, 1.05-2.13) after adjustment for confounding factors. Of participants unaware of CKD, 10.6 % were reclassified as not having CKD using eGFR CKD-EPI. Conclusions: Using eGFR CKD-EPI led to a modest increase in overall awareness rates, primarily due to reclassification of low-risk unaware participants