Proteinuria/creatininuria index and its correlation with the 24-hour proteinuria in renal transplanted patients

Background: Proteinuria (P) is a early sign of inflammation and renal damage. It has an important role in the detection, diagnosis, and monitoring of renal disease in transplanted patients. The aim of this study was to examine the correlation between random urinary proteinuria/creatininuria index (P/CI) and 24-hour total protein excretion among stable renal transplant patients.

Materials and methods: We obtained 1511 samples of 24-hour protein excretion (24-hr P) with corresponding P/CI were obtained from 197 adult patients beyond 6 months post-transplantation between 2009 and 2011. The population was divided into 2 groups: One to obtain a population of justification (755) and another, of validation (755). A scatter graft yielded was obtained by Pearson's coefficient of correlation. A "receiver operater characteristic curve" analysis was carried out to evaluate the sensitivity and specifity of PCI and 24hr-P, showing a cutoff of 0.15 for PCI.

Results: The PCI and 24 hr P Pearson's correlation was significant (r = 0.89; P = .0001). The sensitivities of the P/CI for the justification and the validation samples were 97% and 94%, respectively; the a cutoff was 0.15. Their negative predictive values for P/CI were 92% and 84% respectively (cutoff, 0.15). The specificity was below 50% in both groups.

Conclusions: We observed a significant correlation between P/CI and 24 hr P. The sensitivity was slightly higher than the specificity (50%) but the negative predictive value was >92%. The use of P/CI seemed to be adequate for screening of protein excretion during renal transplant recipient follow-up.