Comparison of the Urine Protein to Creatinine Ratio with 24-Hour Urinary Protein Amounts in Patients with Kidney Transplants

Kim, Su Jin; Choi, An Sook; Lee, Jin Ho; Yu, Seong Min; Oh, Joon Seok; Kim, Sung Min; Sin, Yong Hun; Kim, Joong Kyung

Abstract

BACKGROUND/AIMS
Many studies have reported the correlation between the spot urine protein to creatinine (P/C) ratio and 24-hour urinary protein amounts in patients with glomerulonephritis. This correlation has also been reported in Western patients with kidney transplants, but no prior study has reported on this association in Eastern populations. We compare the correlation between the spot urine P/C ratio and 24-hour urinary protein amounts and the associating factors in Korean patients with kidney transplants.
METHODS
The study included 66 patients with kidney transplants from our hospital. The subjects had urine samples evaluated between January 2005 and July 2010. We compared 24-hour urinary protein amounts with a spot urine P/C ratio collected in the morning and analyzed the factors affecting the correlation in each group.
RESULTS
The 24-hour urinary protein amounts were 1.31 +/- 1.69 g/day and the spot urine P/C ratio was 1.29 +/- 1.70 in all subjects. A strong positive linear correlation was observed between the 24-hour urinary protein amounts and the spot urine P/C ratio (r = 0.95). The primary factor affecting accurate quantitation of proteinuria using the spot urine P/C ratio was gender (p = 0.003). The spot urine P/C ratio and the 24-hour urinary protein levels were 1.05 +/- 1.51 and 1.26 +/- 1.68 g/day in males (p = 0.005) and 1.57 +/- 1.88 and 1.36 +/- 1.72 g/day in females (p = 0.047), respectively.
CONCLUSIONS
We determined that the spot urine P/C ratio provides an accurate estimate of 24-hour urinary protein levels in Korean patients with kidney transplants.