The urine albumin-to-creatinine ratio is a reliable indicator for evaluating complications of chronic kidney disease and progression in IgA nephropathy in China

Abstract

OBJECTIVE:This study investigated the correlation between the albumin-to-creatinine ratio in the urine and 24-hour urine proteinuria and whether the ratio can predict chronic kidney disease progression even more reliably than 24-hour proteinuria can, particularly in primary IgA nephropathy.METHODS:A total of 182 patients with primary IgA nephropathy were evaluated. Their mean urine albumin-to-creatinine ratio and 24-hour proteinuria were determined during hospitalization. Blood samples were also analyzed. Follow-up data were recorded for 44 patients. A cross-sectional study was then conducted to test the correlation between these parameters and their associations with chronic kidney disease complications. Subsequently, a canonical correlation analysis was employed to assess the correlation between baseline proteinuria and parameters of the Oxford classification. Finally, a prospective observational study was performed to evaluate the association between proteinuria and clinical outcomes. Our study is registered in the Chinese Clinical Trial Registry, and the registration number is ChiCTR-OCH-14005137.RESULTS:A strong correlation (r=0.81, p<0.001) was found between the ratio and 24-hour proteinuria except in chronic kidney disease stage 5. First-morning urine albumin-to-creatinine ratios of ≥125.15, 154.44 and 760.31 mg/g reliably predicted equivalent 24-hour proteinuria ‘thresholds’ of ≥0.15, 0.3 and 1.0 g/24 h, respectively. In continuous analyses, the albumin-to-creatinine ratio was significantly associated with anemia, acidosis, hypoalbuminemia, hyperphosphatemia, hyperkalemia, hypercholesterolemia and higher serum cystatin C. However, higher 24-hour proteinuria was only associated with hypoalbuminemia and hypercholesterolemia. Higher tubular atrophy and interstitial fibrosis scores were also associated with a greater albumin-to-creatinine ratio, as observed in the canonical correlation analysis. Finally, the albumin-to-creatinine ratio and 24-hour proteinuria were associated with renal outcomes in univariate analyses.CONCLUSION:This study supports the recommendation of using the albumin-to-creatinine ratio, rather than 24-hour proteinuria, to monitor proteinuria and prognosis in primary IgA nephropathy.

Diagnostic and prognostic value of galectin-3, serum creatinine, and cystatin C in chronic kidney diseases

“…27 In addition, creatinine level in saliva can also be used to diagnose CKD. Ratio of albumin-to-creatinine in urine was reported as a reliable predicator of CKD.…”

“…Ratio of albumin-to-creatinine in urine was reported as a reliable predicator of CKD. 27 In addition, creatinine level in saliva can also be used to diagnose CKD. 28 Moreover, Silva et al 29 reported that creatinine in dry blood sample is a convenient marker for CKD screening.…”

Spot urine protein/creatinine ratio as a reliable estimate of 24-hour proteinuria in patients with immunoglobulin A nephropathy, but not membranous nephropathy

“…Several previous studies showed this correlation in patients with CKD or normal kidney function [6, 11, 21, 22]. However, only a few studies focused on IgAN to investigate the association [23, 24]. Among patients with glomerulonephritis in this cross-sectional study, high correlation coefficients (r = 0.91, 95% CI: 0.95–0.98) were observed [23].…”

“…Among patients with glomerulonephritis in this cross-sectional study, high correlation coefficients (r = 0.91, 95% CI: 0.95–0.98) were observed [23]. In addition, in a cohort study of 182 selected patients with primary IgAN, a good correlation was found between urine albumin-to-creatinine ratio and 24HP, except those pertaining to CKD stage 5, in patients with IgAN [24]. In the current study, similar results were observed.…”

Monitoring Immune Responses in IgA Nephropathy: Biomarkers to Guide Management

“…Microalbuminuria has been shown to co-present with hematuria more often in those with IgAN; however, its sensitivity and specificity are too low to be of any value in clinical practice ( 96 ). Furthermore, the albumin-to-creatine ratio (ACR) yields little benefit over UPCR in IgAN ( 97 , 98 ).…”