Red cell distribution width/albumin ratio and 90-day mortality after burn surgery

Background Red cell distribution width (RDW) and serum albumin concentration are associated with postoperative outcomes. However, the usefulness of the RDW/albumin ratio in burn surgery remains unclear. Therefore, we evaluated the association between RDW/albumin ratio and 90-day mortality after burn surgery. Methods Between 2013 and 2020, a retrospective review of patients in a burn intensive care unit (ICU) was performed. Receiver operating characteristic curve, multivariate Cox logistic regression, multivariate logistic regression and Kaplan-Meier analyses were conducted to evaluate the association between RDW/albumin ratio and 90-day mortality after burn surgery. Additionally, prolonged ICU stay rate (>60 days) and ICU stay were assessed. Results Ninety-day mortality was 22.5% (210/934) in burn patients. Risk factors for 90-day mortality were RDW/albumin ratio at postoperative day 1, age, American Society of Anesthesiologists physical status, diabetes mellitus, inhalation injury, total body surface area burned, hypotensive event and red blood cell transfusion volume. The area under the curve of the RDW/albumin ratio at postoperative day 1 to predict 90-day mortality, after adjusting for age and total body surface area burned, was 0.875 (cut-off value, 6.8). The 90-day mortality was significantly higher in patients with RDW/albumin ratio >6.8 than in those with RDW/albumin ratio <= 6.8 (49.2% vs 12.3%, p < 0.001). Prolonged ICU stay rate and ICU stay were significantly higher and longer in patients with RDW/albumin ratio >6.8 than in those with RDW/albumin ratio <= 6.8 (34.5% vs 26.5%; 21 [11-38] vs 18 [7-32] days). Conclusion RDW/albumin ratio >6.8 on postoperative day 1 was associated with higher 90-day mortality, higher prolonged ICU stay rate and longer ICU stay after burn surgery.