Prevalence of Vaso-Occlusive Crises in Patients with Sickle Cell Disease: A Retrospective US Claims Database Analysis

Introduction: Sickle cell disease (SCD) is an inherited blood disorder affecting ~100,000 individuals in the US. SCD is considered a chronic, lifelong condition that requires comprehensive management. Vaso-occlusive crises (VOCs) are the most common complications of SCD, resulting in intense pain and potential irreversible organ damage. The objective of this study was to characterize the demographic and clinical characteristics of patients with SCD.

Methods: A retrospective database analysis was conducted using data from the IBM MarketScan Commercial Claims and Medicare-Supplemental Claims database (July 1, 2013 to June 30, 2018). Patients were included if they met the following criteria: ≥2 diagnoses of SCD on different claims between July 1, 2013 and January 1, 2017, ≥6 years of age on January 1, 2017, and continuous enrollment throughout the 1-year study period (January 1, 2017 to December 31, 2017). Descriptive statistics were used to assess patient demographics (age and sex) and clinical characteristics (Charlson Comorbidity Index [CCI] and other selected comorbidities). In addition, the following outcomes were assessed: the proportion of patients who experienced ≥1 VOC, the frequency of VOCs by care setting, the duration of inpatient VOCs, the monthly VOC risk, and the time between subsequent VOCs.

Results: A total of 8174 patients met the inclusion criteria. The mean (± standard deviation [SD]) age was 40.8 (±19.5) years and 63.5% of the patients were female. The mean (±SD) CCI was 0.6 (±1.3), with chronic pulmonary disease, diabetes, renal disease, cerebrovascular disease, and stroke identified as the most common comorbidities. Approximately 20% (n=1659) of patients experienced ≥1 VOC and the mean monthly VOC risk was 0.07 (±0.19). Among patients with ≥1 VOC, the mean (±SD) number of VOCs was 5.2 (±7.7) and the median (interquartile range) time from first to second VOC was 2.4 (0.5-8.2) months. Approximately 18% (n=1461) of patients experienced ≥1 VOC managed in an outpatient setting and 10% (n=844) of patients experienced ≥1 VOC managed in an inpatient setting. Approximately 8% (n=646) of patients experienced ≥1 inpatient and ≥1 outpatient VOC during the study period. Among patients with ≥1 outpatient VOC, the mean (±SD) number of outpatient VOCs was 4.6 (±6.9); among patients with ≥1 inpatient VOC, the mean (±SD) number of inpatient VOCs was 2.2 (±2.3) and the mean (±SD) inpatient VOC duration was 6.6 (±6.4) days.

Conclusions: VOCs are common complications of SCD, affecting a subset of patients who often experience recurrent VOC episodes requiring professional health care. VOCs are associated with a significant disease burden on the patient and, potentially, the health care system.