Jorge Medina-Rosas1, Jiandong Su, Richard J Cook, Arthy Sabapathy, Zahi Touma. 1. From the *University of Toronto Lupus Clinic, Toronto Western Hospital, Centre for Prognosis Studies in the Rheumatic Diseases, Toronto; and †Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada.
Abstract
OBJECTIVES: The aim of this study was to determine whether spot urine protein-to-creatinine ratio (PCR) accurately measures the change in proteinuria compared with 24-hour proteinuria (24H-P). METHODS: This was a retrospective analysis on patients' paired visits and paired urine samples for PCR and 24H-P. Patients with both abnormal 24H-P (>0.5 g/d) and PCR (>0.05 g/mmol) or both normal 24H-P (≤0.5 g/d) and PCR (≤0.05 g/mmol) at baseline visit were identified.The first follow-up visit with partial recovery (50% decrease in proteinuria) or complete recovery (≤0.5 g/d) was identified for those with abnormal baseline 24H-P, and new proteinuria (>0.5 g/d) was identified for those with normal 24H-P. Twenty-four-hour urine collection and PCR end-point frequencies were compared. Twenty-four-hour urine collection results were converted to 24H-PCR. Twenty-four-hour PCR and PCR were utilized to measure the magnitude of change (by standardized response mean [SRM]) in patients who achieved the end points. RESULTS: Of 230 patients, at baseline, 95 patients had abnormal and 109 had normal 24H-P and PCR. On follow-up, 57 achieved partial recovery, and 53 achieved complete recovery by 24H-P. Standardized response mean was -1.03 and -1.10 for 24H-PCR and PCR, respectively. By PCR, 53 patients had partial recovery, and 27 had complete recovery. Standardized response mean was -1.25 and -0.86 by 24H-PCR and PCR, respectively.For new proteinuria, 28 patients were identified by 24H-P and 21 by PCR. Twenty-four-hour PCR SRM was 0.80, and PCR SRM was 0.68. CONCLUSIONS: Protein-to-creatinine ratio does not have sufficient accuracy compared with 24H-P for improvement and worsening to be used in lieu of 24H-P.
OBJECTIVES: The aim of this study was to determine whether spot urine protein-to-creatinine ratio (PCR) accurately measures the change in proteinuria compared with 24-hour proteinuria (24H-P). METHODS: This was a retrospective analysis on patients' paired visits and paired urine samples for PCR and 24H-P. Patients with both abnormal 24H-P (>0.5 g/d) and PCR (>0.05 g/mmol) or both normal 24H-P (≤0.5 g/d) and PCR (≤0.05 g/mmol) at baseline visit were identified.The first follow-up visit with partial recovery (50% decrease in proteinuria) or complete recovery (≤0.5 g/d) was identified for those with abnormal baseline 24H-P, and new proteinuria (>0.5 g/d) was identified for those with normal 24H-P. Twenty-four-hour urine collection and PCR end-point frequencies were compared. Twenty-four-hour urine collection results were converted to 24H-PCR. Twenty-four-hour PCR and PCR were utilized to measure the magnitude of change (by standardized response mean [SRM]) in patients who achieved the end points. RESULTS: Of 230 patients, at baseline, 95 patients had abnormal and 109 had normal 24H-P and PCR. On follow-up, 57 achieved partial recovery, and 53 achieved complete recovery by 24H-P. Standardized response mean was -1.03 and -1.10 for 24H-PCR and PCR, respectively. By PCR, 53 patients had partial recovery, and 27 had complete recovery. Standardized response mean was -1.25 and -0.86 by 24H-PCR and PCR, respectively.For new proteinuria, 28 patients were identified by 24H-P and 21 by PCR. Twenty-four-hour PCR SRM was 0.80, and PCR SRM was 0.68. CONCLUSIONS: Protein-to-creatinine ratio does not have sufficient accuracy compared with 24H-P for improvement and worsening to be used in lieu of 24H-P.
Authors: Vinicius Domingues; Benjamin A Levinson; Nicole Bornkamp; Judith D Goldberg; Jill Buyon; H Michael Belmont Journal: Lupus Sci Med Date: 2018-09-04