Clinical outcomes and healthcare utilization in patients with sickle cell disease: a nationwide cohort study of Medicaid beneficiaries

Abstract

To add to the limited existing evidence on clinical outcomes and healthcare use in sickle cell disease (SCD) among beneficiaries of the US Medicaid program, we conducted a cohort study using nationwide Medicaid claims data (2000-2013). Patients were included based on HbSS SCD diagnosis and followed until Medicaid disenrollment, death, bone marrow transplant, or end of data availability to assess vasoocclusive crises (VOC), emergency room (ER) visits, hospitalizations, outpatient visits, and blood transfusions. Annualized event rates (with 95% confidence intervals [CI]) were reported. The impact of VOCs on the risk of mortality was analyzed using a multivariable Cox model with VOC modeled as time-varying and updated annually. In a total of 44,033 SCD patients included with a mean (SD) age of 15.7 (13.6) years, the VOC rate (95% CI) was 3.71 (3.70-3.72) per person-year, with highest rate among patients 19-35 years who had ≥ 5 VOCs at baseline (13.20 [13.15-13.26]). Event rates (95% CI) per person per year for other outcomes were 2.97 (2.97-2.98) ER visits, 2.39 (2.38-2.40) hospitalizations, 5.80 (5.79-5.81) outpatient visits, and 0.91 (0.90-0.91) blood transfusions. A higher VOC burden in the preceding year was associated with an increased risk of mortality, with a hazard ratio (95% CI) of 1.26 (1.14-1.40) for 2-4 VOC vs. < 2 and 1.57 (1.41-1.74) for ≥ 5 VOC vs < 2. In conclusion, we documented a substantial burden of SCD in US Medicaid enrollees, especially during early adulthood and noted that ongoing burden of VOC is associated with mortality in these patients.

Keywords: Epidemiology; Medicaid; Sickle cell disease; Vasoocclusive crises.