Sickle cell disease in the emergency department Predictors of adverse outcomes: A prospective cohort study

Abstract

Introduction. Current evidence does not provide a clear risk stratification strategy for sickle cell disease patients in the emergency department (ED). The goal of this study was to develop a better understanding of the clinical features among patients with sickle cell disease and to determine the risk factors for short term adverse events. Methods. We conducted a prospective cohort study of sickle cell disease patients presenting to a tertiary care ED over six consecutive months. All patients were assessed by emergency physicians during the ED visit. All the patients had a 2 week structured telephone follow-up or a chart review if they had a repeat ED visit within 2 weeks or admitted. The adverse outcomes were classified as a clinically significant outcome (death, cerebrovascular accidents, acute chest syndrome, sepsis, hyper-hemolytic crisis and exchange blood transfusion) or not. We also classified patients as having acute chest syndrome or not. We analyzed the predictors of adverse outcomes using descriptive statistics and multiple logistic regression. Results. Over six consecutive months, we enrolled 732 patients. Seventy-five patients had a clinically significant outcome and 42 had acute chest syndrome. Using multivariate analysis, we found nine statistically significant predictors of a clinically significant adverse outcome: a prolonged painful episode (OR 10.1; 95%CI 5.3-19.3), age less than 8 years (OR 2.4; 95%CI 1.001 -5.9), oxygen saturation less than 96% (OR 3.9; 95%CI 1.6-10.9), patient appearing toxic (OR 7.8; 95%CI 2.2-27.2), presence of chest crackles (OR 6.5; 95%CI 2.3-18.6), splenomegaly (OR 2.6; 95%CI 1.2-5.5), local limb tenderness (OR 0.2; 95%CI 0.08-0.7), hemoglobin less than 7 g/dL (OR 3.6; 95%CI 1.1-11.6), reticulocyte count more than 15% (OR 4.0; 95%CI 1.4-11.5). Using multivariate analysis, we found seven statistically significant predictors of acute chest syndrome: a prolonged painful episode (OR 22.0; 95%CI 8.7-55.3), oxygen saturation less than 92% (OR 17.7; 95%CI 1.7-184.9), history of cough (OR 4.5; 95%CI 1.7-12.0), history of pneumococcal vaccine (OR 0.33; 95%CI 0.11-0.98), presence of chest crackles (OR 9.5; 95%CI 2.6-34.7), local limb tenderness (OR 0.20; 95%CI 0.05-0.80), and reticulocyte count more than 15% (OR 4.9; 95%CI 1.2-19.7). Conclusion. Our study of a tertiary hospital emergency department found nine identifiable variables which can help to predict the possibility of developing a clinically significant outcome. We also found seven identifiable variables which can help to predict the possibility of developing acute chest syndrome. This might be used in the future to risk stratify the sickle cell disease patients who presents to the emergency department and develop strategies to prevent those adverse outcomes.