Screening for proteinuria in kidney transplant recipients

Proteinuria is a predictor of graft loss and death in kidney transplant recipients. This study examines the clinical significance of albumin-to-creatinine (ACR) and protein-to-creatinine (PCR) ratios compared with conventional dipstick measures of proteinuria.

At this single centre, 500 adult patients with a functioning kidney transplant > 4 months provided a urine sample for dipstick, ACR and PCR. The primary end point was defined as death-censored graft loss. Associations between proteinuria and graft loss were examined by concordance statistics and multivariate Cox models.

There were 32 graft losses over a mean 2.98 years follow-up. PCR (c = 0.82, P < 0.001) and ACR (c = 0.83, P < 0.001) demonstrated similar concordance with events, and both scored higher than dipstick (c = 0.76, P < 0.001). ACR cut points of 30 and 300 mg/g for grading albuminuria were equivalent to 130 and 490 mg/g for PCR. Moderate grades of proteinuria by ACR and PCR were predicted of adverse events in a multivariate analysis.

ACR and PCR are probably equivalent in predicting adverse events. Conventional dipstick is also predictive but does not appear to be as sensitive.