Association of Red Cell Distribution Width with In-Hospital Outcomes in Patients with Acute Myocardial Infarction

Background: Red cell distribution width (RDW) is a routinely available hematological parameter that has been associated with adverse cardiovascular outcomes. However, evidence regarding its prognostic significance in Bangladeshi patients with acute myocardial infarction (AMI) is limited. Objective: To evaluate the association between admission RDW and in-hospital outcomes in patients with AMI. Methods: This prospective observational study included 70 consecutive adults with AMI admitted to the Department of Cardiology, Dhaka Medical College Hospital, Bangladesh, from January to December 2018. Demographic, clinical, laboratory, electrocardiographic and echocardiographic data were recorded. Patients were categorized into lower-RDW (n=38) and higher-RDW (n=32) groups. In-hospital mortality, heart failure, cardiogenic shock, arrhythmia, recurrent myocardial infarction, mechanical ventilation and prolonged hospitalization were assessed. Correlation and multivariable logistic regression analyses were performed. Results: The mean age was 58.7 ± 11.4 years, and 53 (75.7%) patients were male. STEMI occurred in 45 (64.3%) and NSTEMI in 25 (35.7%) patients. Mean admission RDW was 14.1 ± 1.7%. Compared with the lower-RDW group, patients with higher RDW were older (62.6 ± 11.4 vs. 55.4 ± 10.6 years; P=0.008), had lower hemoglobin (11.9 ± 1.9 vs. 13.5 ± 1.4 g/dL; P<0.001), higher creatinine (1.25 ± 0.46 vs. 1.03 ± 0.24 mg/dL; P=0.012), and lower LVEF (42.6 ± 10.5% vs. 49.2 ± 8.1%; P=0.004). Heart failure (37.5% vs. 15.8%; P=0.04) and prolonged hospitalization (43.8% vs. 18.4%; P=0.02) were significantly more frequent in the higher-RDW group. Non-survivors had higher RDW than survivors (16.1 ± 1.7% vs. 13.8 ± 1.4%; P<0.001). RDW correlated positively with age, creatinine and hospital stay and inversely with hemoglobin and LVEF. Higher RDW remained independently associated with adverse in-hospital outcome (adjusted OR 2.84; 95% CI, 1.16–6.95; P=0.022). Conclusion: Elevated admission RDW was associated with greater disease severity, impaired ventricular function, heart failure, prolonged hospitalization and adverse in-hospital outcomes in patients with AMI. RDW may serve as a simple and inexpensive supplementary prognostic marker, although larger multicenter studies are needed to validate its clinical utility and optimal cutoff.