Individual and Environmental Factors Associated with Proteinuria in Korean Children: A Multilevel Analysis

Diagnostic efficacy and influence factors of urinary protein/creatinine ratio replacing 24-h urine protein as an evaluator of proteinuria in children

PURPOSE

The aim was to investigate the diagnostic efficacy of urinary protein/creatinine ratio (UPCR) and factors influencing its substitutability of 24-h urine protein (24hUP) in children with proteinuria.

METHODS

A total of 356 children were recruited, including 149 with non-nephrotic-range proteinuria and 207 with nephrotic-range proteinuria which were further divided into Henoch-Schönlein purpura nephritis (HSPN), lupus nephritis (LN), and primary nephrotic syndrome (PNS). The urine protein and creatinine were measured by routine methods. Bland-Altman analysis was used to test the agreement. Spearman correlation was performed to evaluate the relevance. The receiver operating characteristic curve was used to analyze the diagnostic efficacy of UPCR.

RESULTS

Bland-Altman analysis showed there was an excellent agreement between UPCR and 24hUP in each group. Correlations between UPCR and 24hUP were strong in 356 children (r = 0.869) and in the non-nephrotic-range proteinuria group (r = 0.806), but moderate in nephrotic-range proteinuria group (r = 0.586). With the increase of nephrotic-range proteinuria, the correlations between UPCR and 24hUP were decreased further, however, after UPCR was adjusted by 24-h urine creatinine (24hUCr), the correlation coefficient was improved (r = 0.682). In three subgroups with nephrotic-range proteinuria, high correlation coefficient (r = 0.731) was observed in HSPN, but not in LN (r = 0.552) and PNS (r = 0.563). The sensitivity and specificity of UPCR for diagnosing nephrotic-range proteinuria were 89.9 % and 92.2%.

CONCLUSIONS

UPCR is competent in evaluating proteinuria. The degree of proteinuria, 24hUCr and the underlying pathological types of renal disease may be the important influencing factors in the correlation between UPCR and 24hUP in children with nephrotic-range proteinuria.

Short-term exposure to PM2.5 components and renal health: Findings from the Veterans Affairs Normative Aging Study

There is little evidence on the short-term impact of fine particulate matter (PM_2.5) on renal health, and the potential interactions and various influences of PM_2.5 components on renal health have not been examined. We investigated whether short-term (≤28 days) ambient PM_2.5 and 15 PM_2.5 components were associated with serum uric acid (SUA), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and odds of incident chronic kidney disease (CKD) using both mixed-effect and Bayesian kernel machine regression (BKMR) models in the Normative Aging Study. This analysis included 2466 study visits from 808 older males enrolled during 1998-2016 with available data. BKMR showed positive relationships of PM_2.5 mixture with SUA and odds of CKD, and an inverse relationship with eGFR. In the 28-day exposure window, an interquartile range (IQR) increase in vanadium was associated with a 0.244-mg/dL higher SUA. IQR increases in sulfur and lead were associated with a 1.281- and 1.008-mL/min/1.73 m² decrease in eGFR, respectively. The same change in sulfur was also associated with a 39% higher odds of CKD. Our findings provide solid evidence supporting short-term adverse effects of PM_2.5 on renal health and further highlight that components from oil combustion and regional pollution may be major contributors.