Dataset Information

Estimating GFR by Serum Creatinine, Cystatin C, and ?2-Microglobulin in Older Adults: Results From the Canadian Study of Longevity in Type 1 Diabetes.

ABSTRACT:

Introduction

Glomerular filtration rate (GFR) is routinely used for clinical assessment of kidney function. However, the accuracy of estimating equations in older adults is uncertain.

Methods

In 66 adults with ?50 years type 1 diabetes (T1D) duration and 73 nondiabetic controls from age/sex-matched subgroups (65 ± 8 years old and 77[55%] were women) we evaluated the performance of estimated GFR (eGFR) by creatinine (Modification of Diet and Renal Disease [MDRD], Chronic Kidney Disease-Epidemiology [CKD-EPI]_cr), cystatin C (CKD-EPI_cys, CKD-EPI_cr-cys), and ?₂-microglobulin (?2M) compared with measured GFR by inulin clearance (mGFR). Performance was evaluated using metrics of bias (mean difference), precision (SD), and accuracy (proportion of eGFR that differed by >20% of mGFR).

Results

Mean mGFR was 104 ± 18 ml/min per 1.73 m² (range: 70-154 ml/min per 1.73 m²) and was not different between T1D and controls (103 ± 17 vs. 105 ± 19 ml/min per 1.73 m², P = 0.39). All equations significantly underestimated mGFR (bias: -15 to -30 ml/min per 1.73 m², P < 0.001 for all comparisons) except for ?2M, which had bias of 1.9 ml/min per 1.73 m² (P = 0.61). Bias was greatest in cystatin C-based equations. Precision was lowest for ?2M (SD: 43.5 ml/min per 1.73 m², P < 0.001 for each comparison). Accuracy was lowest for CKD-EPI_cysC (69.1%, P < 0.001 for each comparison). Cystatin C-based equations demonstrated greater bias and lower accuracy in older age subgroups (<60, 60-69, ?70 years). All equations demonstrated greater bias across higher ranges of mGFR (60-89, 90-119, ?120 ml/min per 1.73 m²). Results were similar between T1D and controls except that ?2M had lower performance in T1D.

Conclusion

Better estimates of GFR in older adults are needed for research and clinical practice, as this subgroup of the population has an amplified risk for the development of chronic kidney disease (CKD) that requires accurate GFR estimation methods.

SUBMITTER: Scarr D

PROVIDER: S-EPMC6551543 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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Publications

Estimating GFR by Serum Creatinine, Cystatin C, and β2-Microglobulin in Older Adults: Results From the Canadian Study of Longevity in Type 1 Diabetes.

Scarr Daniel D Bjornstad Petter P Lovblom Leif E LE Lovshin Julie A JA Boulet Genevieve G Lytvyn Yuliya Y Farooqi Mohammed A MA Lai Vesta V Orszag Andrej A Weisman Alanna A Keenan Hillary A HA Brent Michael H MH Paul Narinder N Bril Vera V Cherney David Z I DZI Perkins Bruce A BA

Kidney international reports 20190221 6

<h4>Introduction</h4>Glomerular filtration rate (GFR) is routinely used for clinical assessment of kidney function. However, the accuracy of estimating equations in older adults is uncertain.<h4>Methods</h4>In 66 adults with ≥50 years type 1 diabetes (T1D) duration and 73 nondiabetic controls from age/sex-matched subgroups (65 ± 8 years old and 77[55%] were women) we evaluated the performance of estimated GFR (eGFR) by creatinine (Modification of Diet and Renal Disease [MDRD], Chronic Kidney Dis ...[more]

PMID: 31194091

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