OBJECTIVES: Sickle cell disease (SCD) is one of the most prevalent inherited diseases, with approximately 300,000 affected children born each year worldwide. A major cause of morbidity among patients with SCD is the occurrence of severely painful episodes, known as vaso-occlusive crisis (VOCs), which can impact quality of life and cause organ damage or even death. This study assessed the impact of VOC events on health-related quality of life (HRQoL) and associated utility of patients with SCD.

METHODS: The LEGACY registry (CICL670AUS38) is a prospective, multicenter, observational study that documented the outcomes of 498 SCD patients living in the United States. For the cohort of 181 adult patients (≥18 years), Short Form-36 (SF-36) Health Survey scores and VOCs were evaluated every 6 months for 3 years or until patient discontinuation. SF-36 scores were mapped to the EuroQoL five-dimension (EQ-5D) questionnaire. For each patient, the annualized rate of VOC events was calculated from first visit to each visit with HRQoL measures reported, and annualized VOC rates were subsequently grouped (<1, ≥1 to <3, ≥3 VOCs/year). Mean EQ-5D scores were compared between annualized VOC groups using generalized estimating equations to account for within-patient correlation across visits. Differences between the groups on the SF-36 component scores and SF-36 domains were also assessed.

RESULTS: Patients with ≥3 VOCs/year reported, on average, a mapped EQ-5D score 0.0697 lower (p = 0.014) than patients with <1 VOCs/year (0.6213 vs. 0.6910). Furthermore, patients who had ≥3 VOCs/year also showed, on average, a SF-36 Physical Component Score 2.480 lower (p = 0.025) compared to patients with <1 VOCs/year (48.684 vs. 51.164).

CONCLUSIONS: This analysis demonstrates the long-term impact of VOC frequency on HRQoL. SCD patients who had a higher number of annual VOCs were shown to have a worse HRQoL compared to patients with <1 VOCs/year.