Interrelation of RDW and coronary flow reserve in patient with idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDC) impairs and reduces coronary flow reserve (CFR). High level of red cell distribution width (RDW) is an independent risk factor for cardiovascular diseases. Therefore, in this observational case-control study we have aimed to determine whether RDW level is associated with CFR impairment in patients with IDC.

We examined 36 patients with IDC and 35 healthy subjects formed as a control group. In addition to this, patients with IDC were divided into two subgroups according to their CFR levels [normal CFR group (CFR value ≥2) and lower CFR group (CFR value<2)]. Control and patients groups were compared using the student t-test for multiple comparisons. The subgroups were compared using the Mann-Whitney U test for continuous variables and chi-square for categorical variables. The Pearson's and Spearman correlation analysis was used to test the possible associations between CFR and the study variables as appropriate. The receiver-operating characteristic (ROC) curve was determined to evaluate the predictive performance of RDW to detect low CFR.

There were no significantly differences between the lower and higher CFR groups' clinical data, baseline hemodynamic, medication and biochemical data except RDW and high-sensitivity C-reactive protein levels. We found that RDW level was a good predictor of low CFR at the receiver-operating characteristic curve. The area under the curve (AUC) was 73% (95% confidence interval between 0.56-0.90 is 95%, p: 0.018) After adjusting potential confounders include age, body-mass index, blood pressure, lipid and glucose, RDW independently associated with CFR level (Beta:-0.374; p=0.015) and hsCRP value (Beta:-0.520; p=0.001) were the independent predictors of lower CFR.

Results showed that there was an independent correlation between RDW level and CFR level in patients with IDC.