Using Standardized Serum Creatinine Values in the Modification of Diet in Renal Disease Study Equation for Estimating Glomerular Filtration Rate

  1. Andrew S. Levey, MD;
  2. Josef Coresh, MD, PhD, MHS;
  3. Tom Greene, PhD;
  4. Lesley A. Stevens, MD, MS;
  5. Yaping (Lucy) Zhang, MS;
  6. Stephen Hendriksen, BA;
  7. John W. Kusek, PhD;
  8. Frederick Van Lente, PhD; and
  9. for the Chronic Kidney Disease Epidemiology Collaboration*
  1. From Tufts-New England Medical Center, Boston, Massachusetts; Johns Hopkins Medical Institution, Baltimore, Maryland; Cleveland Clinic Foundation, Cleveland, Ohio; and National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland.

    Abstract

    Background: Glomerular filtration rate (GFR) estimates facilitate detection of chronic kidney disease but require calibration of the serum creatinine assay to the laboratory that developed the equation. The 4-variable equation from the Modification of Diet in Renal Disease (MDRD) Study has been reexpressed for use with a standardized assay.

    Objective: To describe the performance of the revised 4-variable MDRD Study equation and compare it with the performance of the 6-variable MDRD Study and Cockcroft–Gault equations.

    Design: Comparison of estimated and measured GFR.

    Setting: 15 clinical centers participating in a randomized, controlled trial.

    Patients: 1628 patients with chronic kidney disease participating in the MDRD Study.

    Measurements: Serum creatinine levels were calibrated to an assay traceable to isotope-dilution mass spectrometry. Glomerular filtration rate was measured as urinary clearance of 125I-iothalamate.

    Results: Mean measured GFR was 39.8 mL/min per 1.73 m2 (SD, 21.2). Accuracy and precision of the revised 4-variable equation were similar to those of the original 6-variable equation and better than in the Cockcroft–Gault equation, even when the latter was corrected for bias, with 90%, 91%, 60%, and 83% of estimates within 30% of measured GFR, respectively. Differences between measured and estimated GFR were greater for all equations when the estimated GFR was 60 mL/min per 1.73 m2 or greater.

    Limitations: The MDRD Study included few patients with a GFR greater than 90 mL/min per 1.73 m2. Equations were not compared in a separate study sample.

    Conclusions: The 4-variable MDRD Study equation provides reasonably accurate GFR estimates in patients with chronic kidney disease and a measured GFR of less than 90 mL/min per 1.73 m2. By using the reexpressed MDRD Study equation with the standardized serum creatinine assay, clinical laboratories can report more accurate GFR estimates.

    *For a list of investigators of the Chronic Kidney Disease Epidemiology Collaboration, see the Appendix.

    Article and Author Information

    • Acknowledgments: The authors thank John Eckfeldt, PhD, and Amy Deysher for assistance.

    • Grant Support: By grants UO1 DK 053869, UO1 DK 067651, and UO1 DK 35073.

    • Potential Financial Conflicts of Interest:Grants received: A.S. Levey (National Institutes of Health, Amgen, National Kidney Foundation).

    • Requests for Single Reprints: Andrew S. Levey, MD, Division of Nephrology, Tufts-New England Medical Center, 750 Washington Street, Box 391, Boston, MA 02111.

    • Current Author Addresses: Drs. Levey and Stevens, Ms. Zhang, and Mr. Hendriksen: Division of Nephrology, Tufts-New England Medical Center, 750 Washington Street, Box 391, Boston, MA 02111.

    • Dr. Coresh: Johns Hopkins Medical Institution, 2024 East Monument Street, 2-645, Baltimore, MD 21205.

    • Drs. Greene and Van Lente: Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195.

    • Dr. Kusek: National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, 6707 Democracy Boulevard, Room 617, Bethesda, MD 20817.

    • Author Contributions: Conception and design: A.S. Levey, J. Coresh, T. Greene, L.A. Stevens, Y. Zhang, S. Hendriksen, J.W. Kusek, F. Van Lente.

    • Analysis and interpretation of the data: A.S. Levey, J. Coresh, T. Greene, L.A. Stevens, J.W. Kusek, F. Van Lente.

    • Drafting of the article: A.S. Levey, L.A. Stevens.

    • Critical revision of the article for important intellectual content: A.S. Levey, J. Coresh, T. Greene, L.A. Stevens, Y. Zhang, S. Hendriksen, J.W. Kusek, F. Van Lente.

    • Final approval of the article: A.S. Levey, J. Coresh, T. Greene, L.A. Stevens, Y. Zhang, S. Hendriksen, J.W. Kusek, F. Van Lente.

    • Provision of study materials or patients: A.S. Levey, T. Greene, J.W. Kusek, F. Van Lente.

    • Statistical expertise: J. Coresh, T. Greene, Y. Zhang.

    • Obtaining of funding: A.S. Levey, J. Coresh, T. Greene, F. Van Lente.

    • Administrative, technical, or logistic support: A.S. Levey, J. Coresh, T. Greene, L.A. Stevens, Y. Zhang, S. Hendriksen, J.W. Kusek, F. Van Lente.

    • Collection and assembly of data: A.S. Levey, J. Coresh, T. Greene, Y. Zhang, S. Hendriksen, F. Van Lente.

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