Background Kidney failure disproportionately affects older blacks versus whites. The reasons are unknown and may be related to lower measured glomerular filtration rate (GFR) and higher levels of albuminuria in community-based population samples. Study Design Cross-sectional analysis of a substudy of a prospective cohort. Setting & Participants Ancillary study following Multi-Ethnic Study of Atherosclerosis (MESA) visit 5. Predictor Age, sex, and race. Outcomes & Measurements Measured GFR using plasma clearance of iohexol and urine albumin-creatinine ratio (ACR). Results GFR was measured in 294 participants. Mean age was 71 ± 9 (SD) years, 47% were black, 48% were women, mean GFR was 73 ± 19 mL/min/1.73 m2, and median ACR was 10.0 (IQR, 5.8-20.9) mg/g. Measured GFR was on average 1.02 (95% CI, 0.79-1.24) mL/min/1.73 m2 lower per year older. Mean GFR indexed for body surface area was not different between blacks versus whites (mean difference, 2.94 [95% CI, −1.37 to 7.26] mL/min/1.73 m2), but was lower in women than men (mean difference, −9.34 [95% CI, −13.53 to −5.15] mL/min/1.73 m2); this difference persisted and remained significant after adjustment for demographics, clinical characteristics, and measures of body size. The difference between men and women, but not between blacks and whites, was substantially greater when GFR was not indexed for body surface area. ACR was higher in older versus younger participants (mean difference, 3.2% [95% CI, 1.5%-4.8%] per year), but geometric mean ratio of ACR did not differ between blacks versus whites (mean difference, 19.7%; 95% CI, −39.1% to 6.1%) or between men versus women (mean difference, −4.4%; 95% CI, −27.7% to 26.3%). Limitations This is a study of survivors. People who agreed to participate were younger than those who refused. Conclusions In this first community-based study that included blacks and whites, no differences in measured GFR between races were found, suggesting that other factors must account for the disproportionately higher burden of kidney failure in older blacks versus whites.
Bibliographical noteFunding Information:
Support: Research reported in this publication was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (NIH). This publication was made possible by the Johns Hopkins Institute for Clinical and Translational Research, which is funded in part by grant UL1 TR 001079 from the National Center for Advancing Translational Sciences , a component of the NIH, and NIH Roadmap for Medical Research. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the Johns Hopkins Institute for Clinical and Translational Research, National Center for Advancing Translational Sciences, or NIH. This research was also supported by grant R01DK087961 from the NIH ; contracts N01-HC-95159 , N01-HC-95160 , N01-HC-95161 , N01-HC-95162 , N01-HC-95163 , N01-HC-95164 , N01-HC-95165 , N01-HC-95166 , N01-HC-95167 , N01-HC-95168 , and N01-HC-95169 from the National Heart, Lung and Blood Institute ; and grants UL1-TR-000040 and UL1-TR-001079 from the National Center for Research Resources . The funders of this study had no role in the study design; collection, analysis, and interpretation of the data; writing of the report; or the decision to submit the report for publication.
© 2016 National Kidney Foundation, Inc.
Copyright 2017 Elsevier B.V., All rights reserved.
- GFR decline trajectory
- Glomerular filtration rate (GFR)
- albumin-creatinine ratio (ACR)
- body size
- chronic kidney disease (CKD)
- health disparities
- measured GFR
- racial differences
- renal function