Determining the optimal method for proteinuria detection in chronic spinal cord injury

Abstract

Study design: A retrospective analysis. Objectives: The objective of this study is to determine whether dipstick protein analysis (DSP) or random urine protein:creatinine ratios (UPC) are accurate in predicting clinical proteinuria in the chronic spinal cord injury (SCI) population. Methods: A retrospective analysis was performed in 219 veterans with SCI, comparing DSP and 24-h urine protein excretion. Sensitivity, specificity, predictive values (PV) and receiver-operator characteristic (ROC) curves of DSP in predicting clinical proteinuria were calculated with and without correction for specific gravity (SG). A prospective study was also performed in 62 SCI patients, comparing the UPC and 24-h urines. Sensitivity, specificity, PV and ROC curves of UPC in predicting clinical proteinuria were calculated. Results: Any level of positive DSP had high specificity, but low sensitivity, for detecting the presence of clinical proteinuria. ROC curves of DSP for identifying clinical proteinuria yielded area under the curve of 0.749 (95% confidence interval 0.699-0.794), and adjustment for SG did not significantly improve accuracy. A UPC of o0.3 was sensitive with a high negative PV for ruling out clinical proteinuria, whereas a ratio 40.8 was specific with a high positive PV. A UPC between 0.3-0.8 had an intermediate sensitivity and specificity. Conclusion: Urine collections of 24-h are still needed in the chronic SCI population for accurate detection of clinically significant proteinuria. DSP may not reliably detect low-grade clinical proteinuria, whereas a UPC below 0.3 may be used to rule out clinical range proteinuria.

Screening for proteinuria in ‘at-risk’ patients with spinal cord injuries: lessons learnt from failure

“…Alshayeb and associates [8] carried out a retrospective analysis in 219 veterans with spinal cord injury, comparing Dipstick protein analysis and 24-h urine protein excretion. These researchers concluded that urine collections of 24-hour are still needed in the chronic spinal cord injury population for accurate detection of clinically significant proteinuria.…”

“…National Institute for Health and Clinical Excellence [8] in England recommends ACE inhibitors/ARBs in patients with diabetes mellitus irrespective of whether they have hypertension or not, if albumin:creatinine ratio is > 2.5 mg/mmol (men) or > 3.5 mg/mmol (women).…”

Prevalence of Chronic Kidney Disease in Patients with Spinal Cord Injuries/Disorders

“…24-hour urine samples) is an essential aspect of care in SCI/D patients given the unreliability of qualitative measures of urine protein (e.g. urine dipstick) [37] and the importance of proteinuria as a powerful risk factor for CKD progression and death [5,8]. We were not able to identify these Veterans with elevated urine protein because neither 24-hour nor urine protein/creatinine ratio data are available in the national VA data sources used for this study, and while urine microalbumin/creatinine data are available in these VA data sources, it was found in <7% of the study cohort.…”