Objectives: Red blood cell distribution width (RDW), a measure of the variability in size of circulating erythrocytes, has recently been shown to be a strong predictor of adverse outcomes in patients with a great spectrum of cardiovascular disease. Recently, cholesterol content of erythrocytes membranes (CEM) has been associated with clinical instability in coronary artery disease whilst it has been linked with red blood cells (RBC) size and shape. Since the biological mechanisms underlying the association of higher RDW with cardiovascular mortality risk are currently unclear, we studied the association of CEM with RDW.
Methods: 296 consecutive angina patients (236 men, mean age 69 ± 2 years) were prospectively assessed; 160 had chronic stable angina (CSA) and 136 had an acute coronary syndrome (ACS).
Results: Patients presenting with ACS had increased CEM levels (121.6 μg/mg (40.1) vs 74.4 μg/mg (26.6), p < 0.001) as well as exhibited greater anisocytosis (13.9% (0.9) vs 13.3% (0.7), p < 0.001) compared to patients with CSA. Simple correlation analysis showed that CEM levels were positively associated with RDW values (r = 0.320, p < 0.001). Multivariable linear regression showed that CEM levels were associated with RDW values independently from possible confounders (inflammatory, nutritional renal or hematological).
Conclusions: Data from the present study showed an independent association between cholesterol content of erythrocyte membranes and anisocytosis. Increased CEM levels -a novel biomarker of clinical instability in CAD - may facilitate our understanding why RDW is associated with increased morbidity and mortality in cardiovascular disease.