The association between red cell distribution width and incident hypertension in Korean adults

Red cell distribution width (RDW), a measure of variation in red blood cell size, is routinely reported in the results of a complete blood count. Recent studies have found that RDW is a predictor of high cardiovascular morbidity and mortality. Furthermore, previous cross-sectional studies have shown a possible association between high RDW and hypertension. However, the longitudinal relationship between high RDW and incident hypertension is uncertain. The aim of this study was to investigate the association between RDW and the development of hypertension. In this retrospective cohort study, we analyzed 124,261 participants without hypertension at baseline who underwent two health checkups at 4-year intervals from 2005 to 2016. The subjects were divided into quartiles (Q1–Q4) according to their baseline RDW levels. Multivariate logistic regression was used to estimate the OR and 95% CI for the development of hypertension after 4 years. After 4 years, 6827 cases (5.5%) of incident hypertension were observed. The incidence rates of hypertension were 4.66%, 5.66%, 5.99%, and 5.46% for Q1, Q2, Q3 and Q4 of RDW, respectively. The ORs (95% CIs) for incident hypertension compared with Q1 were 1.19 (1.10–1.29), 1.28 (1.18–1.39), and 1.32 (1.22–1.44) for Q2, Q3, and Q4 of RDW, respectively. High RDW was significantly and independently associated with the development of hypertension in Korean adults. Further research is warranted to verify the mechanism underlying this relationship.