Red cell distribution width predicts incident dipstick albuminuria in Korean adults without chronic kidney disease

Background: Red cell distribution width (RDW) is an emerging marker of inflammation and a predictor of high cardiovascular morbidity and mortality as well as all-cause mortality. A previous cross-sectional study showed that RDW was associated with microalbuminuria, an indicator of target organ damage. However, the longitudinal association of RDW and development of albuminuria is not known. Methods: We analyzed 83,040 participants without chronic kidney disease (CKD) at baseline who underwent two health check-ups at a 4-year interval during 2005 to 2014. Urine albumin was determined by single urine dipstick semi-quantitative analysis, and incident albuminuria was defined as ≥ 1+ dipstick albumin at the second check-up. We used logistic regression analysis to determine the relationship between RDW and incident albuminuria. Results: Participants were divided into quartiles according to baseline RDW. After 4 years, 982 cases of incident albuminuria were observed. The cumulative incidences of albuminuria were 0.94, 1.05, 1.18, and 1.62% for the 1st through 4th quartiles of RDW, respectively. Multivariate logistic analysis showed that the odds ratios (95% confidence interval) for incident albuminuria compared to those in the 1st quartile were 1.11 (0.92-1.34), 1.26 (1.04-1.52), and 1.88 (1.58-2.24) for the 2nd, 3rd and 4th quartiles, respectively. Conclusion: RDW was associated with development of albuminuria in relatively healthy Korean adults without CKD. Further research is needed to verify the role of RDW in the development of albuminuria and renal injury.