Performance of Estimated Glomerular Filtration Rate Prediction Equations in Preeclamptic Patients Arnold B. Alper, M.D., M.P.H., 1 Yeonjoo Yi, Ph.D., 2,3 Mahfuz Rahman, M.D., 1 Larry S. Webber, Ph.D., 3 Laura Magee, M.D., 4 Peter von Dadelszen, M.B.Ch.B., D.Phil., 4 Gabriella Pridjian, M.D., 5 Abimbola Aina-Mumuney, M.D., 6 George Saade, M.D., 7 Jamie Morgan, M.D., 7 Bahij Nuwayhid, M.D., Ph.D., 8 Michael Belfort, M.D., 9 and Jules Puschett, M.D. 1 ABSTRACT Accurate estimation of the glomerular filtration rate (GFR) in patients with preeclampsia requires the collection of a 24-hour urine and can have important therapeutic and diagnostic implications. This procedure is often difficult or impossible to accomplish in this patient group. In this study, the Cockcroft-Gault, the Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas were evaluated for their accuracy in determining GFR in the setting of preeclampsia. The estimated GFRs calculated from the above formulas were compared with the creatinine clearance values obtained from a 24-hour urine collections in 543 preeclamptic patients recruited from several large hospitals. Additionally, a set of new equations, preeclampsia GFR (PGFR), based on ethnicity, was created. The Cockcroft- Gault, MDRD, and CKD-EPI formulas were inaccurate in predicting GFR and both were significantly less accurate than PGFR. The latter formula provided an estimated GFR that was much closer to the creatinine clearance. Current GFR estimation equations based on serum creatinine values in nonpregnant patients are not reliable measures of renal function in patients with preeclampsia. The use of a new formula (PGFR) is recommended. KEYWORDS: Glomerular filtration rate, preeclampsia, pregnancy Renal hemodynamics, including renal plasma flow and glomerular filtration rate (GFR), change sig- nificantly during pregnancy. 1 Many of these changes can be altered or attenuated in patients with preeclampsia, making the importance of a noninvasive and accurate measurement of GFR in these patients an important 1 Department of Medicine (Section of Nephrology), Tulane University School of Medicine, New Orleans, Louisiana; 2 Social Science Research Institute, Duke University, Durham, North Carolina; 3 Department of Biostatistics, Tulane University School of Public Health, New Orleans, Louisiana; 4 Population, Policy, and Aging Center, University of British Columbia, Vancouver, British Columbia, Canada; 5 Depart- ment Obstetrics and Gynecology, Tulane University School of Med- icine, New Orleans, Louisiana; 6 Department of Obstetrics and Gynecology, Johns Hopkins School of Medicine, Baltimore, Maryland; 7 Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas; 8 Department of Obstetrics and Gynecology, Texas Tech-El Paso School of Medicine, El Paso, Texas; 9 Department of Obstetrics and Gynecology, University of Utah School of Medicine, Salt Lake City, Utah. Address for correspondence and reprint requests: Jules Puschett, M.D., Texas A&M Health Science Center, College of Medicine/Scott & White, 2401 S. 31st Street, Medical Education Building, 407 L, Temple, TX 76508 (e-mail: jpuschett@swmail.sw.org). Am J Perinatol 2011;28:425–430. Copyright # 2011 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662. Received: July 14, 2010. Accepted after revision: September 27, 2010. Published online: November 18, 2010. DOI: http://dx.doi.org/10.1055/s-0030-1268712. ISSN 0735-1631. 425 Downloaded by: University of British Columbia. Copyrighted material.