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

Abstract

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.

Keywords: CKD-EPI; awareness; chronic kidney disease; estimated glomerular filtration rate.

Figure 1

Prevalence of CKD awareness by MDRD Study eGFR (n = 26,213) and CKD-EPI eGFR (n = 23,572) stages. Bars indicate 95% confidence intervals. CKD stages are defined as follows: Stage 1, eGFR ≥ 90 mL/min/1.73 m² with ACR ≥ 30 mg/g; Stage 2, eGFR 60-89 mL/min/1.73 m² with ≥ ACR 30 mg/g; Stage 3, eGFR 30-59 mL/min/1.73 m²; Stages 4-5, eGFR < 30 mL/min/1.73 m². ACR, albumin-creatinine ratio; CKD, chronic kidney disease; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFR, estimated glomerular filtration rate; MDRD, Modification of Diet in Renal Disease.