[OP.5B.05] IMMUNE UNREACTIVE URINARY ALBUMIN AS A PREDICTOR OF CARDIOVASCULAR EVENTS: THE HORTEGA FOLLOWUP STUDY. (September 2017) - García, F. Martínez
Abstract : Objective: The clinical significance of albumin that cannot be detected by traditional immunoassays (Immune Unreactive Albumin Excretion [IURAE]) is not clear. We aimed to determine if IURAE that can be determined by HPLC is associated with CV events in a representative sample of a general population from Spain. Design and method: We included 1376 cardiovascular-free individuals who participated in Hortega Follow-Up Study. The primary endpoint was cardiovascular incidence, including both fatal and non fatal events. UAE was measured in spot voided urine frozen at -80°C both by HPLC and by immunonephelometry. IURAE was determined as the difference between HPLC and immunonephelometry values (IRAE). We estimated fully adjusted hazard ratios of cardiovascular incidence by Cox regression. C-statistic was used to compare predictive accuracy of IURAE and IRAE. Results: After an average at-risk follow-up was 13 years, we observed 167 cardiovascular incidence events. The correlation between the IURAE and IRAE was 0.54 (p < 0.001); 93 and 357 participants showed microalbuminuria defined by IRAE and IURAE concentrations > = 30 mg/g Cr, respectively. Among discordant pairs, there were 54 events in those classified as microalbuminurics by IURAE but IRAE-based normoalbuminurics by immunonephelometry vs 2 for the opposite case, being the threshold to detect these individuals by immunonephelometry of 10.1 mg/g Cr. After logarithmic transformation, UAE was a significant independent factor for cardiovascular incidence [fully adjusted HR 1.27 (1.02–1.58) and 1.13 (1.01–1.27), for IURAE and IRUAE]. Fully adjusted survival curves were significant reduced according to categories of UAE. Figure. No caption available. The C-statistic comparing fully adjusted models with IUAE and IRAE, respectively, were similar of around 0.85. Conclusions: IURAE could give similar or even better prognostic information as the commonly used IRAE. Our findings suggest the need for mechanistic studies to evaluate the biological implications of the observed differences in the evaluated markers.