Relationship between Red Cell Distribution Width and Microalbuminuria: A Population-Based Study of Multiethnic Representative US Adults

Abstract

Introduction: Microalbuminuria (MA), a renal marker of vascular injury, is an independent predictor of cardiovascular (CV) events. Red cell distribution width (RDW), an emerging CV risk predictor, has not been evaluated for its association with MA. Methods: We evaluated 8,499 participants of the National Health and Nutrition Examination Survey (NHANES) 1999–2006, where RDW was evaluated as a continuous variable and in quartiles (Q₁ ≤12.1, Q₂ 12.2–12.5, Q₃ 12.6–13 and Q₄ >13). Multivariate adjusted logistic regression analysis was performed to estimate the odds of having MA (n = 1,736; adjusted for traditional CV risk factors, race, BMI, estimated glomerular filtration rate, hemoglobin, mean corpuscular volume, high-sensitivity C-reactive protein and nutritional factors deficiencies of iron, folate and vitamin B₁₂). Results: The prevalence of MA increased with increasing RDW (13.52% in Q₁ vs. 30.02% in Q₄, p < 0.001). The odds of having MA for those in Q₄ was 2.49 (95% CI: 1.95–3.18, p < 0.001) compared to those in Q₁ after the adjustments. No effect modification was observed by covariates on the association between RDW and MA. Conclusion: Elevated RDW is independently associated with a higher risk of MA. An interaction between chronic inflammation, oxidative stress, neurohumoral overactivity and endothelial dysfunction may explain this association and the attendant elevated CV/renal risk.