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Red cell distribution width (RDW), a numerical measure of the variability of the size of circulating erythrocytes, has been shown to be an independent predictor of mortality in patients undergoing PCI. Patients with renal impairment are known to have higher rates of death and myocardial infarction after PCI. The purpose of this study was to determine if RDW is a prognostic marker of death and MACE after PCI in patients with chronic kidney disease (CKD).
The study population included 3825 patients with coronary artery disease and chronic kidney disease (CKD) stage 2-5 who were subjected to PCI. The RDW was derived from a complete blood count (CBC) drawn before PCI. Stages of CKD were defined by a glomerular filtration rate of >90, 89-60, 59-30, 29-15, <15 ml/min/1.73m2 for stages 1-5 respectively. Only patients who were on hemodialysis were excluded. Multivariable logistic analysis of TVR MACE and mortality at 1 year was performed using a logistic regression model. Baseline characteristics of acute myocardial infarction, diabetes mellitus, peripheral vascular disease, and congestive heart failure were included in the model. Category free Net Reclassification Improvement (NRI) was used to determine if adding RDW to the model would improve the predictive ability of CKD for mortality and TVR MACE.
On multivariable analysis, after adjustment for known correlates, CKD stages 2-5 were a significant predictor of TVR MACE (OR 1.36, 95% CI 1.02-1.81, p=0.038) and mortality (OR 1.56, 95% CI 1.13- 2.16). When RDW was added to the model in a category free NRI in TVR Mace (46%, p<0.001) and in 1 year mortality (52%, p<0.001) indicating a strong improvement in predicting mortality and TVR MACE in this population.
RDW, an easily obtainable marker, has a strong independent relationship with TVR MACE and mortality in patients with CKD stages 2-5. This data suggests that there may be a link with worse outcomes in patients with CKD and elevated RDW values.
- 2013 American College of Cardiology Foundation