COVID-19 in Adults with Sickle Cell Disease

Introduction

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy and is estimated to affect more than 100,000 Americans. The unique constellation of SCD manifestations complicates both the diagnosis and management of COVID-19, particularly related to anticoagulation and transfusion practices. A previous literature review of COVID-19 outcome and SCD noted the need for studies evaluating genotype and SCD-modifying therapies (Hoogenboom et al. 2022). We report on the outcomes for all hospitalized inpatients with SARS-CoV-2 and SCD at institutions using the Cerner Real World Database (RWDB).

Methods

The Cerner RWD is a large, cloud-based deidentified database that includes electronic health records (EHR) data from >100 United States health systems (Ehwerhemuepha et al. 2022). We obtained approval to access these data with an exempt status from IRB to conduct a retrospective study including patients records from February 27, 2020 to August 14, 2022. Those with sickle cell trait were excluded. Descriptive statistics were performed.

Results:

The final dataset included 1547 adult patients, 609 of whom were hospitalized, 25 of whom received invasive ventilation, and 51 of whom died. Hospitalized patients were more likely to be male, have Medicaid or Medicare, and have Hgb SS or Hgb SC genotype than the 938 ambulatory patients (Table 1). Of the hospitalized patients, the 51 who died and the 25 who received invasive ventilation were, older, and as expected, had longer length of stays. Labs and treatments for hospitalized patients are summarized in Tables 2 & 3. We were not able to find evidence of exchange transfusion; however, 14% of hospitalized patients received red blood cell transfusion. Those who were under invasive ventilation were more likely to have higher C-reactive protein (CRP), creatinine (CRT), erythrocyte sedimentation rate (ESR), and procalcitonin as well as lower white blood cell counts on initial labs. Hemoglobin, hematocrit, and ferritin levels were similar. A majority of patients under invasive ventilation received dexamethasone and heparin while as many as 24% of all hospitalized patients received dexamethasone and 57% received heparin or enoxaparin. Only 199 (33%) hospitalized patients received hydroxyurea while admitted and few patients who received invasive ventilation were transfused (<44%).

Discussion

This study describes one of the largest populations of patients with SCD and COVID-19 in the United States. Demographics of the overall cohort were consistent with known characteristics. More patients with Hgb SS or Hgb SC were hospitalized than expected. Although steroids are used with caution in patients with SCD, almost a quarter of hospitalized patients were treated with dexamethasone. The small number of hospitalized patients receiving hydroxyurea while admitted is surprising, although it is not known how this compares to ambulatory patients with COVID-19. The small number of patients being transfused is also concerning.

One of the notable limitations is that the dataset draws only from institutions using Cerner EHR, a 26% market share. Additionally, there is likely significant variability between institutions' treatment protocols, particularly in the early months of the pandemic. Finally, we were not able to compare these patients to a control population, an area which offers opportunity for future investigation.

TABLE 1- Demographics- hospitalized vs. ambulatory patients

TABLE 2- Hospitalized patients- all vs. mechanically ventilated vs. deaths

TABLE 3- Treatments- Invasively ventilated vs. all hospitalized patients