Retrospective Study Evaluating Effect of Voxelotor Treatment on Acute Care Utilization during the Peak of COVID-19

Introduction

In sickle cell disease (SCD), the polymerization of deoxygenated HbS fundamentally alters the structure of the erythrocyte, producing the sickle cell that is characteristic of the disease. Clinical manifestations often perceived in patients suffering from SCD include vaso-occlusion, anemia, and hemolysis. Due to these sequelae, patients frequent the emergency room (ER), urgent care clinic, and hospital. Voxelotor, an oral medication approved by the Food and Drug Administration (FDA) in 2019 for the treatment of SCD, directly targets the pathophysiology of SCD by inhibiting deoxygenated HbS polymerization. Results of the Phase III HOPE trial indicate that the drug can increase hemoglobin levels and reduce markers of hemolysis as well as the incidence of worsening anemia in patients with SCD (Vichinsky et al. N Engl J Med 2019).

The COVID-19 pandemic has posed several challenges for patients with SCD in 2020. Amid the pandemic, patients continued to seek out acute medical care, including care in the ER, urgent care clinics, and hospital. The aim of this study was to determine whether utilization of acute medical care differed for patients who received voxelotor before and after therapy in 2020. We also evaluated the utilization of healthcare through telemedicine platforms to facilitate access to novel therapies such as voxelotor for patients with SCD.

Methods

13 patients (≥18 years of age as of January 1, 2020) with SCD who had begun treatment with voxelotor between January 1, 2020 and December 31, 2020 were included in the initial analysis. Six patients were excluded from final analysis: three discontinued treatment due to side effects, one was noncompliant with treatment, and two were lost to follow-up. Acute care utilization, measured by the number of times each patient visited the ER, urgent care clinic, and hospital was compared for each patient in the period six months prior to their first dose of voxelotor and in the period six months after their last dose of the drug in 2020 using paired t-tests and Wilcoxon matched-pairs signed rank tests. Demographic information and the type of visit at which patients agreed to proceed with voxeletor was recorded for each patient. Simple linear regressions and multiple regressions controlled for covariates, defined as sex, BMI, age, type of insurance coverage, and duration of treatment.

Results

All seven (100%) patients discussed voxelotor treatment with their provider during a telehealth video visit. In the period before initiating treatment, patients frequented the ER an average of 2.71 (SD=6.75) times. In the six months after their last dose, patients visited the ER less than they had in the period prior to treatment, on average 0.57 (SD=0.79) times. This difference did not achieve statistical significance (p>0.9999). The mean number of visits to the urgent care clinic in the six months before treatment was 2.71 (SD=6.75) compared to 2 (SD=4) in the period after patients' last dose in 2020. This finding was not statistically significant (p>0.9999). Hospitalizations, on average, decreased significantly from 5.14 (SD=2.34) in the six months before starting treatment to 1.57 (SD=0.98) after ending therapy for 2020 (p=0.0015). Covariates did not have an effect on the differences in acute care utilization before treatment and after last treatment in 2020.

Conclusions

The findings of this study imply that treatment with voxelotor was associated with a decrease in the frequency of hospitalizations for the seven patients analyzed. This finding can potentially be attributed to the efficacy of voxelotor in improving anemia and reducing complications associated with SCD. While the difference between ER visits and urgent care visits before treatment and after the last dose in 2020 did not achieve statistical significance, likely due to small sample size, the data does suggest a reduction in both outcomes. In addition, the observation that all visits in which patient and provider discussed and initiated treatment were virtual support the use of telemedicine technology to improve access to multidisciplinary care and novel therapies for SCD patients. The impact of voxelotor treatment will continue to be assessed in SCD patients at our institution, and more data from clinical encounters will lead to a greater understanding of the efficacy of voxelotor.

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