Cheaper test sufficient for microalbuminuria in diabetes
medwireNews: Measuring urinary albumin concentration is as accurate as the albumin-to-creatinine ratio (ACR) for detecting microalbuminuria in patients with diabetes, say the authors of a meta-analysis.
Study author Yu-Kang Tu (National Taiwan University, Taipei) and co-workers say that an ACR test can cost nearly 50% more than simply measuring the albumin concentration.
Given their findings, they suggest that measuring albumin concentration in random urine samples “may become the screening tool of choice for the population with [diabetes mellitus], considering the rising incidence of [diabetes mellitus] and the constrained health care resources in many countries.”
Twelve of the 14 studies in the team’s analysis assessed ACR, nine measured albumin concentration and all used a urinary albumin excretion rate of 30 to 300 mg/day in 24-hour urine samples as the gold standard for microalbuminuria. The studies involved a total of 2078 patients with diabetes, about a third of whom had microalbuminuria.
Across all the studies, measuring the albumin concentration in random urine samples was 85% sensitive and the ACR was 87% sensitive, relative to the gold standard, for detecting microalbuminuria. The difference between the sensitivities was not statistically significant, and the specificity was 88% for both tests. The overall accuracy for distinguishing between patients with and without microalbuminuria was 91% for albumin concentration and 94% for the ACR.
Previous research has suggested that the ACR in urine samples collected in the morning is the best reflection of values in 24-hour samples.
However, Tu et al found that the timing of sample collection did not contribute to heterogeneity among the studies. Also, the diagnostic accuracy of albumin concentration versus ACR did not differ between studies that collected urine samples in the morning and those that collected them at any time of day.
“Therefore, whether or not urine samples were collected in the morning did not seem to significantly influence our study results”, write the researchers in JAMA Internal Medicine. But they stress that “the results of meta-regression or subgroup analyses should be interpreted with caution because of limited statistical power.”
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2014
By Eleanor McDermid, Senior medwireNews Reporter