Three-year variability in plasma concentrations of the soluble receptor for advanced glycation end products (sRAGE)

Objectives: The soluble receptor for advanced glycation end products (sRAGE) has been implicated in the development of diabetes-related vascular complications, but the variability of concentrations of sRAGE in the blood is unknown. The objective of this study was to characterize within-person three-year variability of plasma levels of sRAGE. Design and methods: We measured sRAGE in plasma samples from 179 men and women in the community-based Atherosclerosis Risk in Communities (ARIC) Study at two time points, three years apart. We calculated correlation coefficients and the within-person coefficient of variation (CV_w) to characterize variability in sRAGE. We compared these estimates to total cholesterol and white blood cell count (WBC) in the same participants. Results: Mean sRAGE concentrations at the two time points (mean time between measurements=2.9years) were 1096.2pg/mL and 990.2pg/mL, respectively (mean difference=-106.0pg/mL, p-value<0.001). The Pearson's correlation was 0.78 (Spearman's, 0.73). The intra-class correlation coefficient was 0.76 and the CV_w was 26.6%. Compared to sRAGE, Pearson's and Spearman's correlations for total cholesterol (0.76 and 0.77) and white blood cell count (0.61 and 0.72) were similar, although CV_w for both was lower (8.7% for cholesterol, 15.6% for WBC). Less than 4% of participants' values changed substantially (50% or greater) over the three-year interval. Conclusions: We observed that sRAGE concentrations remained relatively stable over three years. Our findings suggest that a single measure of circulating sRAGE tracks well in a community-based population and could be a useful measure in clinical and epidemiologic studies of long-term risk.