Modification of the CKD epidemiology collaboration (CKD-EPI) equation for Japanese: accuracy and use for population estimates

Am J Kidney Dis. 2010 Jul;56(1):32-8. doi: 10.1053/j.ajkd.2010.02.344. Epub 2010 Apr 22.

Abstract

Introduction: We previously reported a modification to the Modification of Diet in Renal Disease (MDRD) Study equation for use in Japan. Recently, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) developed a new equation that is more accurate and yields a lower CKD prevalence estimate in the United States than the MDRD Study equation. We modified the CKD-EPI equation for use in Japan, compared its accuracy with the Japanese modification of the MDRD Study equation, and compared the prevalence of CKD in Japan using both equations.

Design: A diagnostic test study comparing the Japanese coefficient-modified CKD-EPI equation and Japanese coefficient-modified MDRD Study equation and a cross-sectional study comparing distribution of estimated glomerular filtration rate and prevalence of CKD in participants in a Japanese annual health check program.

Setting & participants: 763 Japanese patients (413 for development and 350 for validation) were included. Prevalence estimates were based on 574,024 participants from the annual health check program.

Index test: Japanese modification of the MDRD Study and CKD-EPI equations.

Reference test: Inulin clearance.

Results: The Japanese coefficient of the modified CKD-EPI equation was 0.813 (95% CI, 0.794-0.833). In the validation data set, the modified CKD-EPI equation performed better than the modified MDRD Study equation. Bias (measured GFR [mGFR] - eGFR) was 0.4 +/- 17.8 (SD) versus 1.3 +/- 19.8 mL/min/1.73 m(2) overall, respectively (P = 0.02); 7.3 +/- 20.6 versus 7.8 +/- 22.2 mL/min/1.73 m(2) for participants with mGFR >or=60 mL/min/1.73 m(2), respectively (P < 0.001); and -4.4 +/- 13.8 versus -3.3 +/- 15.6 mL/min/1.73 m(2) for participants with mGFR <60 mL/min/1.73 m(2), respectively (P = 0.5). The modified CKD-EPI equation yields a lower estimated prevalence of CKD than the modified MDRD Study equation (7.9% vs 10.0%), primarily because of a lower estimated prevalence of stage 3 (5.2% vs 7.5%).

Limitation: Most study participants had CKD. The study population contained a limited number of participants with mGFR >or=90 mL/min/1.73 m(2).

Conclusion: The Japanese coefficient-modified CKD-EPI equation is more accurate than the Japanese coefficient-modified MDRD Study equation and leads to a lower estimated prevalence of CKD in Japan.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Asian Continental Ancestry Group / ethnology*
  • Cooperative Behavior*
  • Cross-Sectional Studies
  • Female
  • Glomerular Filtration Rate / physiology
  • Humans
  • Kidney Failure, Chronic / diagnosis
  • Kidney Failure, Chronic / ethnology*
  • Kidney Function Tests / methods
  • Male
  • Middle Aged
  • Population Groups / ethnology*