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Kidney Week

Abstract: SA-PO838

The Protein/Creatinine Ratio Is a Reliable Indicator of 24-Hour Urine Protein, Regardless of the Level of Renal Function in Patients with Glomerulopathies

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Gutierrez Peredo, Gabriel Brayan, Professor Edgard Santos University Hospital, Federal University of Bahia, Salvador, Bahia, Brazil
  • Montaño-Castellon, Iris, Professor Edgard Santos University Hospital, Federal University of Bahia, Salvador, Bahia, Brazil
  • Gutierrez-Peredo, Andrea Jimena, Professor Edgard Santos University Hospital, Federal University of Bahia, Salvador, Bahia, Brazil
  • Lopes, Antonio Alberto, Professor Edgard Santos University Hospital, Federal University of Bahia, Salvador, Bahia, Brazil

Group or Team Name

  • TUNARI Study.
Background

We aimed to determine the accuracy of the urine isolated protein/creatinine ratio (PCR) test, against the gold standard 24-hour urine protein (24hUP) measurement in patients with glomerulopathies, and according to the levels of renal function.

Methods

This prospective study of patients with glomerulopathies was developed at Professor Edgard Santos University Hospital in Salvador, Bahia-Brazil. The PCR and 24hUP measurements were performed using conventional methods within a maximum interval of 24 hours between the measurements. The patients were classified into three groups according to their renal function, group 1= <30 ml/min/1.73m2, group 2= 30-60 ml/min/1.73m2 and group 3= >60 ml/min/1.73m2. Spearman correlation coefficient (rs) and ROC curves were employed to compare PCR with 24hUP.

Results

The total was 167 urinary samples from 134 patients. The mean age was 42 ± 16 yrs, 68% were female and 91% non-white. A good correlation was observed between PCR and 24hUP total sample (rs= 0.7, p= <0.000), as well as in comparison with the different levels of renal function (rs= 0.8 for group 1, rs= 0.9 for group 2 and rs= 0.8 for group 3). The ROC between PCR and 24hUP total sample yield an AUC of 0.94 (CI= 0.89, 0.97), high sensitivity of 91% and specificity of 83%, at the optimal cut-off point was 0.7. The groups representing three levels of renal function showed high sensitivity and specificity in comparisons of both methods (group 1= 82%, 100%, group 2= 97%, 89% and group 3= 88%, 92%) with an AUC of 0.92, 0.96 and 0.96, respectively.

Conclusion

PCR shows high sensitivity and specificity for monitoring patients with glomerulopathies compared to 24hUP. Our findings suggest that PCR is a useful parameter to evaluate and monitor patients with different glomerulopathies regardless of the level of renal function.

Results in the total sample and by degree of renal function comparing protein/creatinine ratio with 24-hour urine protein
VariablesTotal N=167Spearman CorrelationCut-off by Youden IndexSensitivity (%)Specificity (%)Area under ROC curve (95%CI)
PCR vs 24hUP total sample1670.80.791830.94 (0.8;0.9)
Degree of kidney function      
<30 ml/min/1,73 m2350.70.8821000.92 (0.8;0.9)
30-60 ml/min/1,73 m2420.80.997890.96 (0.9;1.0)
>60 ml/min/1,73 m2900.80.888920.96 (0.9;1.0)