Evaluation of Vaso-occlusive Crises in United States Sickle Cell Disease Patients: A Retrospective Claims-based Study

Sickle cell disease (SCD) is a life-threatening vascular disease that burdens affected persons physically. SCD-related vaso-occlusive crises (VOCs) are one of the primary causes of morbidity and mortality. Our objective was to examine the epidemiology of pain crises and the relationship between pain crises and major acute complications among SCD patients. Using the Medicaid Analytic Extracts from 2009-2013, patients with SCD were selected and the first clinical claim indicating SCD during the identification period was defined as the index date. Patients were required to have continuous Medicaid enrollment for ≥6 months pre- and 12 months post-index period. Clinical outcomes included mortality, inpatient pain crises, and complications. Cox regressions were applied to examine the relationship between pain crises and deaths or acute complications, respectively. A total of 20 909 patients were included with a mean age of 17.9 years. The rate of VOC events in 100 person-years was 142.20 for adults and 53.91 for pediatric patients. Patients with VOCs were associated with a higher risk for death (hazard ratio=1.56; 95% confidence interval: [1.19-2.05]) or acute complications including acute chest syndrome, stroke, pulmonary embolism, splenic sequestration, and pulmonary hypertension. SCD patients have a substantial burden of disease-related complications. This study suggests that inpatient vaso-occlusive crisis is a key risk factor for acute complications.