Red blood cell distribution width as a predictor of long-term mortality in patients with carbon monoxide poisoning
Hamza Sunman1, Tolga Çimen1, Mehmet Erat1, Kadriye Gayretli Yayla1, Tolga Han Efe1, Seda Özkan2, Engin Deniz Arslan2, Sadık Açıkel1
1Department of Cardiology, University of Health Sciences, Dışkapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey
2Department of Emergency Medicine, University of Health Sciences, Dışkapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey
Keywords: Carbon monoxide poisoning, Red blood cell distribution width, Long-term mortality
Objectives: Elevated red blood cell distribution width (RDW) is an independent prognostic factor for cardiovascular events that are major causes of mortality in patients with carbon monoxide (CO) poisoning. Due to the limited number of studies, we aimed to investigate the relationship between RDW levels and long-term mortality for these patients.
Method: This retrospective study included patients with CO poisoning, who presented to the emergency department. Baseline characteristics, laboratory results and survival status were retrieved from patients' hospital records. The severity of poisoning was determined according to COHb level and/or clinical signs and symptoms.
Results: The study included 571 patients (median age was 37.0 years) and less than half of these patients were male (n = 206, 36.1%). There were mild-moderate CO poisoning in 389 (68.1%) patients and severe poisoning in 182 (31.9%). At a median follow-up of 6.2 years, there were 33 deaths (5.8%). Univariate cox-regression analysis demonstrated that age, gender, presence of hypertension or diabetes mellitus, levels of hemoglobin, RDW, creatinine and alanine-aminotransferase, and white-blood-cell count were potential covariates of long-term all-cause mortality. In the multivariate analysis, the median age and RDW level remained independent predictors of mortality (age, Odds ratio [OR]: 1.070 95% confidence interval [CI]: 1.030–1.110, p = 0.001; RDW, OR: 1.221 95% CI: 1.042–1.431, p = 0.013). Patients with higher RDW levels had a significantly worse prognosis in terms of mortality than with lower RDW levels (log-rank test, p = 0.003).
Conclusion: This study demonstrated that RDW level is an independent predictor of long-term mortality in patients with CO poisoning.