High red blood cell distribution width is associated with the metabolic syndrome

OBJECTIVES: High values of Red Blood Cell Distribution Width (RDW) have been associated with adverse outcome in various clinical settings. The mechanism behind this association is not clear. The Metabolic Syndrome (MetS) is a chronic inflammatory disorder that increases the risk for cardiovascular disease and death. The aim of our study was to evaluate the association between high RDW and the MetS in a relatively large cohort of patients. METHODS: A cohort of 3,529 consecutive patients undergoing coronary angiography was used to evaluate the association between RDW and the MetS. The association was assessed by using a logistic regression. Cox's regression analysis was used to evaluate the impact of RDW on long term mortality. RESULTS: The mean age was 65 years (range 24-97), with 27% women. Overall, 30% were diagnosed with metabolic syndrome. The prevalence of MetS was 29% in patients with RDW < 14% and 34% in patients with RDW >= 14% (P = 0.003). Using multivariate analysis, RDW values above 14% were independently associated with MetS (odds ratio 1.2 [95% CI 1.0-1.4], P = 0.043). Among all the criteria of the metabolic syndrome, hypertension, elevated glucose levels and abdominal obesity were associated with high RDW, with hypertension being the strongest criteria, with an increased risk of 1.8 fold ([95% CI 1.5-2.1]; P = 0.001). During follow up (1614 +/- 709 days, 2-2763 days), long term mortality was 8% in the low RDW group and 28% in the high RDW group (p < 0.001). CONCLUSION: RDW >= 14% is independently associated with higher rates of metabolic syndrome and long-term all-cause mortality.