Dataset Information

Performance of Glomerular Filtration Rate Estimating Equations Before and After Bariatric Surgery.

ABSTRACT:

Rationale & objective

Evaluation of glomerular filtration rate (GFR) is challenging in adults undergoing bariatric surgery because creatinine and cystatin C levels are influenced by changes in muscle and fat mass. Additionally, indexing of GFR by body surface area (BSA) may by affected by decreases in BSA.

Study design

Prospective observational study.

Setting & participants

27 adults with body mass index (BMI) ? 35 kg/m² who underwent measurement of GFR before and after bariatric surgery.

Outcomes

Indexed and nonindexed GFRs measured (mGFRs) using plasma iohexol clearance, indexed and nonindexed estimated GFR (eGFR) based on levels of creatinine, cystatin C, or both from Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations.

Analytic approach

Bias and percent of estimates within 20% and 30% of mGFR (P₂₀ and P₃₀) for estimating equations were examined.

Results

Mean presurgery BMI was 49.5 (SD, 9.4) kg/m², BSA was 2.42 (SD, 0.27) m², nonindexed mGFR was 117.3 (SD, 34.1) mL/min, and indexed mGFR was 84.1 (SD, 22.0) mL/min/1.73 m². After 6 months, mean BMI changed by -13.8 (95% CI, -15.9 to -11.8) kg/m², BSA by -0.30 (95% CI, -0.33 to -0.27) m², and nonindexed mGFR by -9.2 (95% CI, -17.2 to -1.1) mL/min, while indexed mGFR was unchanged at 5.1 (95% CI, -0.1 to 10.4) mL/min/1.73 m². Nonindexed eGFR_cr was unbiased (median bias, 5.0 [95% CI, -4.3 to 11.6] mL/min) before surgery, but overestimated mGFR (8.8 [95% CI, 1.8 to 16.9] mL/min) after surgery. Nonindexed eGFR_cys underestimated mGFR before (median bias, -12.1 [95% CI, -21.4 to -1.2] mL/min) and after surgery (-11.2 [95% CI, -21.8 to -7.3] mL/min). Nonindexed eGFR_cr-cys was unbiased before (median bias, -6.0 [95% CI, -11.0 to 1.0] mL/min) and after surgery (-2.0 [95% CI, -8.8 to 4.9] mL/min). Findings were similar for indexed eGFR compared with indexed mGFR.

Limitations

Small, mostly white sample.

Conclusions

Changes in indexed and nonindexed GFRs may be discordant after bariatric surgery in adults because of decreases in BSA. Indexed and nonindexed eGFR_cr-cys may be less biased than indexed or nonindexed eGFR_cr or eGFR_cys because of opposite biases in estimating mGFR.

SUBMITTER: Chang AR

PROVIDER: S-EPMC7729215 | biostudies-literature | 2020 Nov-Dec

REPOSITORIES: biostudies-literature

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Publications

Performance of Glomerular Filtration Rate Estimating Equations Before and After Bariatric Surgery.

Chang Alex R AR George Jason J Levey Andrew S AS Coresh Josef J Grams Morgan E ME Inker Lesley A LA

Kidney medicine 20201017 6

<h4>Rationale & objective</h4>Evaluation of glomerular filtration rate (GFR) is challenging in adults undergoing bariatric surgery because creatinine and cystatin C levels are influenced by changes in muscle and fat mass. Additionally, indexing of GFR by body surface area (BSA) may by affected by decreases in BSA.<h4>Study design</h4>Prospective observational study.<h4>Setting & participants</h4>27 adults with body mass index (BMI) ≥ 35 kg/m<sup>2</sup> who underwent measurement of GFR before an ...[more]

PMID: 33319195

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Project description:IntroductionGlomerular filtration rate (GFR) is typically estimated with equations that use biomarkers such as serum creatinine and/or cystatin-C. The impact of these different biomarkers on GFR estimates in glomerular disease patients is unclear. In this study, we compared the different GFR estimating equations in the Cure Glomerulonephropathy (CureGN) cohort of children and adults with glomerular disease.MethodsAll available cystatin-C measurements from CureGN study participants were matched to same-day serum creatinine measurements to estimate GFR. To explore the strength of agreement between eGFR values obtained from the "Under 25" (U25) and Chronic Kidney Disease Epidemiology Collaboration (CKD-Epi) equations, we used intraclass correlation coefficients. Multivariable linear mixed effects models were used to determine which factors were independently associated with differences in eGFR values.ResultsA total of 928 cystatin-C measurements were matched to same-day serum creatinine measurements from N = 332 CureGN study participants (58% male, 69% White/Caucasian, 20% Black/African American). Among 628 measurements collected while study participants were under 25 years old, there was moderate agreement (0.731) in serum creatinine versus cystatin-C U25 equations. Models showed that higher eGFR values were associated with larger differences between the two equations (p < 0.001). Among 253 measurements collected while study participants were at least 18 years old, there was excellent agreement (0.891-0.978) among CKD-Epi equations using serum creatinine alone, cystatin-C alone, or the combination of both. Younger age was associated with larger differences between CKD-Epi equations (p = 0.06 to p = 0.016).ConclusionExcellent agreement between CKD-Epi equations indicates continued use of serum creatinine alone for GFR estimation could be appropriate for adults. In contrast, only moderate agreement between U25 equations indicates a need for more frequent measurement of cystatin-C among children and young adults, especially as eGFR increases.

Project description:ImportanceEstimating glomerular filtration rate (GFR) is useful in many clinical conditions. However, very few studies have evaluated the performance of GFR-estimating equations in older adults at various degrees of kidney impairment.ObjectiveTo determine the performance of plasma-creatinine-based equations Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI), Lund-Malmö Revised, (LMR), full age spectrum (FAS), and Berlin Initiative Study (BIS) 1 in older adults across a broad spectrum of GFRs.Design, setting, and participantsSingle-center cross-sectional study performed in France including 2247 participants aged 65 to 90 years who underwent inulin GFR measurements from July 1, 2003, to July 30, 2017, for suspected or established renal dysfunction, for renal risk, before kidney donation, or after kidney transplant.Main outcomes and measuresThe main outcome measure was GRF measured by inulin clearance. Equation performance criteria considered bias (difference between estimated and measured GFR), precision (interquartile range of the median difference), and accuracy P30 (percentage of estimated GFRs lying between [measured GFR - 30% of measured GFR] and [measured GFR + 30% of measured GFR]).ResultsThe mean (SD) age of the 2247 participants was 71.5 (5) years and 1192 (53.0%) were male. The difference in median (95% CI) bias was significant between CKD-EPI vs LMR (-4.0 [-4.0 to -3.5 mL/min/1.73 m2; P?<?.001]) and CKD-EPI vs FAS (-2.0 [-3.5 to -2.5] mL/min/1.73 m2, P?<?.001) but not significant between CKD-EPI vs BIS 1 (0.0 [-1.5 to 0.5], P?=?.07, Mood test). In patients aged 65 to 74 years with measured GFR<45 mL/min/1.73 m2, the difference in median P30 (95% CI) was not significant between CKD-EPI vs LMR (P?=?.08) and CKD-EPI vs FAS (P?=?.48) but significant vs BIS 1 (P?=?.004, McNemar test). In subjects 75 years and older, with measured GFR less than 45 mL/min/1.73 m2, LMR and BIS 1 were more accurate than CKD-EPI and FAS (P30?=?74.5 [70.0-79.5] and 73.0 [68.0-78.0] vs 69.0 [64.5-74.0] and 69.0 [65.5-72.0]). In all patients, despite small statistical differences, the performance of CKD-EPI equation was not clinically different from that of LMR, FAS, or BIS 1.Conclusions and relevanceIn a referral group of patients 65 years and older who had GFR estimated using CDK-EPI, LMR, BIS 1, and FAS equations, a comparison with renal inulin clearance found that none of the equations had a superior diagnostic performance. Each had limitations regarding accuracy.

Dataset Information

Performance of Glomerular Filtration Rate Estimating Equations Before and After Bariatric Surgery.

Rationale & objective

Study design

Setting & participants

Outcomes

Analytic approach

Results

Limitations

Conclusions

Publications

Performance of Glomerular Filtration Rate Estimating Equations Before and After Bariatric Surgery.

Similar Datasets

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