Tariq Shafi1, Xiaoqian Zhu2, Seth T Lirette2, Andrew D Rule3, Thomas Mosley4, Kenneth R Butler4, Michael E Hall5, Pradeep Vaitla6, James J Wynn7, Maria Clarissa Tio6, Neville R Dossabhoy8, Eliseo Guallar9, Javed Butler10. 1. Division of Nephrology, Department of Medicine, Department of Physiology, and Department of Population Health, Bower School of Population Health, The University of Mississippi Medical Center, Jackson, Mississippi (T.S.). 2. Department of Data Science, Bower School of Population Health, The University of Mississippi Medical Center, Jackson, Mississippi (X.Z., S.T.L.). 3. Division of Nephrology, Department of Medicine, Mayo Clinic, Rochester, Minnesota (A.D.R.). 4. The Mind Center, The University of Mississippi Medical Center, Jackson, Mississippi (T.M., K.R.B.). 5. Division of Cardiology, Department of Medicine, The University of Mississippi Medical Center, Jackson, Mississippi (M.E.H.). 6. Division of Nephrology, Department of Medicine, The University of Mississippi Medical Center, Jackson, Mississippi (P.V., M.C.T.). 7. Department of Surgery, The University of Mississippi Medical Center, Jackson, Mississippi (J.J.W.). 8. Division of Nephrology, Department of Medicine, and Department of Physiology, The University of Mississippi Medical Center, Jackson, Mississippi (N.R.D.). 9. Department of Epidemiology and Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland (E.G.). 10. Division of Cardiology, Department of Medicine, The University of Mississippi Medical Center, Jackson, Mississippi, and Baylor Scott & White Research Institute, Dallas, Texas (J.B.).
Abstract
BACKGROUND: Although the population-level differences between estimated glomerular filtration rate (eGFR) and measured glomerular filtration rate (mGFR) are well recognized, the magnitude and potential clinical implications of individual-level differences are unknown. OBJECTIVE: To quantify the magnitude and consequences of the individual-level differences between mGFRs and eGFRs. DESIGN: Cross-sectional study. SETTING: Four U.S. community-based epidemiologic cohort studies with mGFR. PATIENTS: 3223 participants in 4 studies. MEASUREMENTS: The GFRs were measured using urinary iothalamate and plasma iohexol clearance; the eGFR was calculated from serum creatinine concentration alone (eGFRCR) and with cystatin C. All GFR results are presented as mL/min/1.73 m2. RESULTS: The participants' mean age was 59 years; 32% were Black, 55% were women, and the mean mGFR was 68. The population-level differences between mGFR and eGFRCR were small; the median difference (mGFR - eGFR) was -0.6 (95% CI, -1.2 to -0.2); however, the individual-level differences were large. At an eGFRCR of 60, 50% of mGFRs ranged from 52 to 67, 80% from 45 to 76, and 95% from 36 to 87. At an eGFRCR of 30, 50% of mGFRs ranged from 27 to 38, 80% from 23 to 44, and 95% from 17 to 54. Substantial disagreement in chronic kidney disease staging by mGFR and eGFRCR was present. Among those with eGFRCR of 45 to 59, 36% had mGFR greater than 60 whereas 20% had mGFR less than 45; among those with eGFRCR of 15 to 29, 30% had mGFR greater than 30 and 5% had mGFR less than 15. The eGFR based on cystatin C did not provide substantial improvement. LIMITATION: Single measurement of mGFR and serum markers without short-term replicates. CONCLUSION: A substantial individual-level discrepancy exists between the mGFR and the eGFR. Laboratories reporting eGFR should consider including the extent of this uncertainty to avoid misinterpretation of eGFR as an mGFR replacement. PRIMARY FUNDING SOURCE: National Institutes of Health.
BACKGROUND: Although the population-level differences between estimated glomerular filtration rate (eGFR) and measured glomerular filtration rate (mGFR) are well recognized, the magnitude and potential clinical implications of individual-level differences are unknown. OBJECTIVE: To quantify the magnitude and consequences of the individual-level differences between mGFRs and eGFRs. DESIGN: Cross-sectional study. SETTING: Four U.S. community-based epidemiologic cohort studies with mGFR. PATIENTS: 3223 participants in 4 studies. MEASUREMENTS: The GFRs were measured using urinary iothalamate and plasma iohexol clearance; the eGFR was calculated from serum creatinine concentration alone (eGFRCR) and with cystatin C. All GFR results are presented as mL/min/1.73 m2. RESULTS: The participants' mean age was 59 years; 32% were Black, 55% were women, and the mean mGFR was 68. The population-level differences between mGFR and eGFRCR were small; the median difference (mGFR - eGFR) was -0.6 (95% CI, -1.2 to -0.2); however, the individual-level differences were large. At an eGFRCR of 60, 50% of mGFRs ranged from 52 to 67, 80% from 45 to 76, and 95% from 36 to 87. At an eGFRCR of 30, 50% of mGFRs ranged from 27 to 38, 80% from 23 to 44, and 95% from 17 to 54. Substantial disagreement in chronic kidney disease staging by mGFR and eGFRCR was present. Among those with eGFRCR of 45 to 59, 36% had mGFR greater than 60 whereas 20% had mGFR less than 45; among those with eGFRCR of 15 to 29, 30% had mGFR greater than 30 and 5% had mGFR less than 15. The eGFR based on cystatin C did not provide substantial improvement. LIMITATION: Single measurement of mGFR and serum markers without short-term replicates. CONCLUSION: A substantial individual-level discrepancy exists between the mGFR and the eGFR. Laboratories reporting eGFR should consider including the extent of this uncertainty to avoid misinterpretation of eGFR as an mGFR replacement. PRIMARY FUNDING SOURCE: National Institutes of Health.
Authors: Hiroshi Miyake; Takehiro Michikawa; Satsue Nagahama; Keiko Asakura; Yuji Nishiwaki Journal: Int J Environ Res Public Health Date: 2022-09-28 Impact factor: 4.614