Original Investigation
Pathogenesis and Treatment of Kidney Disease
Risk Implications of the New CKD Epidemiology Collaboration (CKD-EPI) Equation Compared With the MDRD Study Equation for Estimated GFR: The Atherosclerosis Risk in Communities (ARIC) Study

https://doi.org/10.1053/j.ajkd.2009.12.016Get rights and content

Background

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) recently published an equation for estimated glomerular filtration rate (eGFR) using the same variables (serum creatinine level, age, sex, and race) as the Modification of Diet in Renal Disease (MDRD) Study equation. Although the CKD-EPI equation estimates GFR more precisely compared with the MDRD Study equation, whether this equation improves risk prediction is unknown.

Study Design

Prospective cohort study, the Atherosclerosis Risk in Communities (ARIC) Study.

Setting & Participants

13,905 middle-aged participants without a history of cardiovascular disease with median follow-up of 16.9 years.

Predictor

eGFR.

Outcomes & Measurements

We compared the association of eGFR in categories (≥120, 90-119, 60-89, 30-59, and <30 mL/min/1.73 m2) using the CKD-EPI and MDRD Study equations with risk of incident end-stage renal disease, all-cause mortality, coronary heart disease, and stroke.

Results

The median value for eGFRCKD-EPI was higher than that for eGFRMDRD (97.6 vs 88.8 mL/min/1.73 m2; P < 0.001). The CKD-EPI equation reclassified 44.9% (n = 3,079) and 43.5% (n = 151) of participants with eGFRMDRD of 60-89 and 30-59 mL/min/1.73 m2, respectively, upward to a higher eGFR category, but reclassified no one with eGFRMDRD of 90-119 or <30 mL/min/1.73 m2, decreasing the prevalence of CKD stages 3-5 from 2.7% to 1.6%. Participants with eGFRMDRD of 30-59 mL/min/1.73 m2 who were reclassified upward had lower risk compared with those who were not reclassified (end-stage renal disease incidence rate ratio, 0.10 [95% CI, 0.03-0.33]; all-cause mortality, 0.30 [95% CI, 0.19-0.48]; coronary heart disease, 0.36 [95% CI, 0.21-0.61]; and stroke, 0.50 [95% CI, 0.24-1.02]). Similar results were observed for participants with eGFRMDRD of 60-89 mL/min/1.73 m2. More frequent reclassification of younger, female, and white participants explained some of these trends. Net reclassification improvement in participants with eGFR < 120 mL/min/1.73 m2 was positive for all outcomes (P < 0.001).

Limitations

Limited number of cases with eGFR < 60 mL/min/1.73 m2 and no measurement of albuminuria.

Conclusions

The CKD-EPI equation more appropriately categorized individuals with respect to long-term clinical risk compared with the MDRD Study equation, suggesting improved clinical usefulness in this middle-aged population.

Section snippets

Study Population

We analyzed data from participants in the Atherosclerosis Risk in Communities (ARIC) Study, a population-based cohort study of middle-aged individuals from 4 US communities: Forsyth County, NC; suburban Minneapolis, MN; Washington County, MD; and Jackson, MS. Details of the ARIC Study are described elsewhere.13 In brief, 15,792 men and women aged 45-64 years were enrolled from 1987 through 1989. In the present study, we excluded participants self-reporting race other than white or black (n =

Characteristics of Study Participants

Participants with CKD stage 3 (eGFRCKD-EPI of 30-59 mL/min/1.73 m2) or stage 4/5 (eGFRCKD-EPI < 30 mL/min/1.73 m2) were more likely to be older, women, and black and have more comorbid conditions, including diabetes, compared with individuals with eGFRCKD-EPI of 90-119 mL/min/1.73 m2 (Table 1). The category of eGFRCKD-EPI ≥ 120 mL/min/1.73 m2 mainly consisted of black women who also tended to have a higher prevalence of diabetes and left ventricular hypertrophy, more often reported using

Discussion

Overall, our results suggest that categorization of kidney function using the CKD-EPI equation more appropriately stratifies middle-aged individuals according to risk of important clinical outcomes compared with the conventional MDRD Study equation. The prevalence of CKD stage 3 (eGFR, 30-59 mL/min/1.73 m2) at baseline was decreased from 2.5% (n = 347) to 1.4% (n = 196) comparing the CKD-EPI and MDRD Study equations in a large community-based middle-aged population. Importantly, participants

Acknowledgements

The authors thank the staff and participants of the ARIC Study for their important contributions.

Support: The ARIC Study is carried out as a collaborative study supported by National Institutes of Health (NIH) National Heart, Lung, and Blood Institute (NHLBI) contracts N01-HC-55015, N01-HC-55016, N01-HC-55018, N01-HC-55019, N01-HC-55020, N01-HC-55021, and N01-HC-55022. Dr Matsushita was supported by a grant from the Japan Society for the Promotion of Science. Dr Selvin was supported by the NIH

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    Originally published online as doi:10.1053/j.ajkd.2009.12.016 on March 2, 2010.

    Because the Editor-in-Chief recused himself from consideration of this manuscript, the Deputy Editor (Daniel E. Weiner, MD, MS) served as Acting Editor-in-Chief. Details of the journal's procedures for potential editor conflicts are given in the Editorial Policies section of the AJKD website.

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