Abstract
Objective: To study the association between red blood cell distribution width and poor outcome in patients suffering from seasonal influenza (H1N1).
Methodology: This cross-sectional study was carried out at Department of Medicine, Seasonal Flu Ward, Nishtar Hospital, Multan, Pakistan from November 2017 to January 2018. During hospitalization, 57 patients were divided into two groups on the basis of the red blood cell distribution width; above 14.5% were in Group-H and below 14.5% were in Group-L. Complicated hospitalization was the primary outcome and it was defined as septic shock, hospital stay longer than seven days, transfer to intensive care unit, requirement of mechanical ventilation, and thirty day mortality. Age, gender, hemoglobin and creatinine levels were documented and analyzed at admission. Fisher's Exact or chi-square and one way ANOVA tests were applied, as applicable. Data was analyzed using SPSS version 23. Results: In group-H and group-L, hemoglobin level was 11.33±1.25 mg/dl and 12.95±0.77 mg/dl (p=0.000); creatinine level was 2.15±.764 g/dl and 1.22±.355 g/dl (p=0.000). Average hospital stay was 7.88±3.86 days and 5.42±3.38 days (p=0.013); thirty day mortality was 23% and 3.2 % (p=0.023), respectively.
Conclusion: High red blood cell distribution width was associated with increased morbidity and mortality in the patients suffering from seasonal influenza (H1N1). Patients with high red blood cell distribution width stayed in the hospital for a longer period too.

Key words: Red blood cell distribution width, Influenza, H1N1, Mortality, Hospital complication.