Dataset Information

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients.

ABSTRACT:

Background

Agreement between spot and 24-hour urine protein measurements is poor in kidney transplant recipients. We investigated whether using formulae to estimate creatinine excretion rate (eCER), rather than assuming a standard creatinine excretion rate, would improve the estimation of proteinuria from spot urine samples in kidney transplant recipients.

Methods

We measured 24 hour urine protein and albumin and spot albumin:creatinine (ACR) and spot protein:creatinine (PCR) in 181 Kidney transplant recipients." We utilized 6 different published formulae (Fotheringham, CKD-EPI, Cockcroft-Gault, Walser, Goldwasser and Rule) to estimate eCER and from it calculated estimated albumin and protein excretion rate (eAER and ePER). Bias, precision and accuracy (within 15%, 30% and 50%) of ACR, PCR, eAER, ePER were compared to 24-hour urine protein and albumin.

Results

ACR and PCR significantly underestimated 24-hour albumin and protein excretion (ACR Bias (IQR), -5.9 mg/day; p< 0.01; PCR Bias, (IQR), -35.2 mg/day; p<0.01). None of the formulae used to calculate eAER or ePER had a bias that was significantly different from the 24-hour collection (eAER and ePER bias: Fotheringham -0.3 and 7.2, CKD-EPI 0.3 and 13.5, Cockcroft-Gault -3.2 and -13.9, Walser -1.7 and 3.1, Goldwasser -1.3 and -0.5, Rule -0.6 and 4.2 mg/day respectively. The accuracy for ACR and PCR were lower (within 30% being 38% and 43% respectively) than the corresponding values estimated by utilizing eCER (for eAER 46% to 49% and ePER 46-54%).

Conclusion

Utilizing estimated creatinine excretion to calculate eAER and ePER improves the estimation of 24-hour albuminuria/proteinuria with spot urine samples in kidney transplant recipients.

SUBMITTER: Wang MK

PROVIDER: S-EPMC5135043 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Publications

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients.

Wang Michael Ke MK White Christine C Akbari Ayub A Brown Pierre P Hussain Naser N Hiremath Swapnil S Knoll Greg G

PloS one 20161202 12

<h4>Background</h4>Agreement between spot and 24-hour urine protein measurements is poor in kidney transplant recipients. We investigated whether using formulae to estimate creatinine excretion rate (eCER), rather than assuming a standard creatinine excretion rate, would improve the estimation of proteinuria from spot urine samples in kidney transplant recipients.<h4>Methods</h4>We measured 24 hour urine protein and albumin and spot albumin:creatinine (ACR) and spot protein:creatinine (PCR) in 1 ...[more]

PMID: 27911917

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Project description:BackgroundMuscle wasting may explain the paradoxical mortality of patients with high estimated glomerular filtration rates (eGFRs) derived from equation methods. However, empirical evidence and solutions remain insufficient.MethodsIn this retrospective cohort study, we compared the performance of equation methods for predicting all-cause mortality; we used 24-h creatinine clearance (24-h CrCl), equation-based eGFRs, and a new eGFR estimating equation weighting for population 24-h urine creatinine excretion rate (U-CER). From 2003 to 2018, we identified 4986 patients whose data constituted the first 24-h CrCl measurement data in the Clinical Research Data Repository of China Medical University Hospital and were followed up for at least 5 years after careful exclusion. Three GFR estimation equations [the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Modification of Diet in Renal Disease (MDRD) Study, and Taiwanese MDRD], 24-h CrCl, and 24-h U-CER-adjusted eGFR were used.ResultsA high correlation was observed among the eGFR levels derived from the equation methods (0.995-1.000); however, the correlation decreased to 0.895-0.914 when equation methods were compared with the 24-h CrCl or 24-h U-CER-adjusted equation-based eGFR. In the Bland-Altman plots, the average discrepancy between the equation methods and the 24-h CrCl method was close to zero (maximal bias range: 5.12 for the Taiwanese MDRD equation vs. 24-h CrCl), but the range in limit of agreement was wide, from ±43.7 mL/min/1.73 m2 for the CKD-EPI equation to ±54.3 mL/min/1.73 m2 for the Taiwanese MDRD equation. A J-shaped dose-response relationship was observed between all equation-based eGFRs and all-cause mortality. Only 24-h CrCl exhibited a non-linear negative dose-response relationship with all-cause mortality. After adjustment for 24-h U-CER in the statistical model, the paradoxical increase in mortality risk for an eGFR of >90 mL/min/1.73 m2 returned to null. When 24-h U-CER was used directly to correct eGFR, the monotonic non-linear negative relationship with all-cause mortality was almost identical to that of 24-h CrCl.ConclusionsThe 24-h U-CER-adjusted eGFR and 24-h CrCl are viable options for informing mortality risk. The 24-h U-CER adjustment method can be practically implemented to eGFR-based care and effectively mitigate the inherent confounding biases from individual's muscle mass amount due to both sex and racial differences.

Project description:BackgroundThe 24-h urine protein (24-hUP) excretion is the gold standard for evaluating proteinuria. This study aimed to evaluate the diagnostic efficacy of protein/creatinine ratio (PCR) for estimating 24-hUP at various levels of renal function and proteinuria levels.MethodsA cross-sectional study was conducted between December 2021 and December 2023 in Salvador, Bahia-Brazil, as an extension of previously published data from the TUNARI study. The study included 217 samples from 152 patients with various levels of renal function and proteinuria. PCR in isolated samples and 24-hUP were determined conventionally within a 24-h timeframe. Patients were classified into three groups according to the level of renal function (Group 1 = 10 to < 30 mL/min, Group 2 = 30-60 mL/min, and Group 3 = > 60 mL/min) and level of proteinuria (< 0.3 g/day, 0.3-3.5 g/day, and > 3.5 g/day). The data were analyzed using the Spearman correlation (rs), coefficient of determination (r2), Bland-Altman plots and receiver operating characteristic (ROC) curve. Likelihood ratios, positive (LR +), and negative (LR-) were derived from the sensitivity and specificity of PCR.ResultsMean age was 41.5 ± 15.7 years, 61.8% were women, 36.8% Black and 52% Mixed-race. Glomerulopathies constituted 80.3%; 46.1% with lupus nephritis. Of the total urine samples, we observed a high correlation between PCR in the total sample of 24-hUP sample (rs = 0.86, p < 0.001) across different levels of renal function. However, agreement between PCR and 24-hUP was reduced at higher levels of proteinuria. The ROC analysis showed an AUC of 0.95 (95% CI = 0.92, 0.98), sensitivity of 91% and specificity of 86.5% (LR + 6.7; LR- 0.1), with an optimal cut-off of 0.77. These results were similar across renal function levels. Proteinuria ≤ 0.3 g/day showed a high sensitivity of 83.3% and specificity of 90%, with an area under (AUC) of 0.85 (95% CI = 0.71; 0.94). In the 24-hUP range > 0.3-3.5 g/day, the sensitivity was 64.1%, the specificity was 84.6%, and the AUC was 0.76 (95% CI = 0.67; 0.84), PCR detected all cases > 3.5 g/day.ConclusionsPCR is a suitable measure to be used as an indicator of 24-hUP at different levels of renal function, but may have limitations at higher levels of proteinuria. Analysis of PCR by proteinuria level found that agreement as well as sensitivity decreases at higher levels, but it maintains good specificity and is able to identify nephrotic range proteinuria.

Dataset Information

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients.

Background

Methods

Results

Conclusion

Publications

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients.

Similar Datasets

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