Assessing the Impact of the Covid-19 Pandemic on Outcomes of Patient Admitted with Sickle Cell Disease

Introduction:

Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy which affects millions of people worldwide. It is caused by a substitution of the glutamic acid (Glu) amino acid with valine (Val) at the sixth position of the β-globin gene, resulting in a mutated hemoglobin tetramer, HbS, in the erythrocytes of affected individuals. This morphology results in sickle-shaped red blood cells and hemolysis when deoxygenated and leads to vaso-occlusion with associated ischemia. SCD is characterized by repeated severe acute pain episodes, acute chest syndrome, and can be complicated by stroke, nephropathy, avascular necrosis, and more. Many studies have shown disparities in outcomes in racial/ethnic minorities as well as in those with lower socioeconomic status. These factors have also been linked to increased risk of COVID-19 infection and infection related mortality. In this study, we aim to explore the baseline characteristics of patients with SCD, prevalence of hospitalizations, and compare inpatient outcomes during the COVID-19 pandemic with those prior to the pandemic.

Methods:

Nationwide Inpatient Sample (NIS) was queried to determine adult hospitalized patients with a primary diagnosis of SCD using ICD-10 codes. They were stratified into two cohort groups based on year of admission, comparing admissions during 2016-2019 with admission during the year 2020. Primary outcomes assessed were inpatient mortality, length of stay (LOS), and total hospitalization charges. Secondary outcomes included respiratory failure, need for mechanical ventilation, cerebrovascular accident (CVA), myocardial infarction (MI), acute kidney injury (AKI), pulmonary embolism (PE), and need for blood transfusions. Multivariate linear and logistic regression analysis was performed to adjust for confounding variables.

Results:

A total of 456, 750 patients were hospitalized with SCD. 377, 285 were admitted between 2016-2019 and 79, 465 were admitted during 2020. Age distribution and sex were similar between the two groups. Patients admitted in the year 2020 were older and had more comorbidities when compared to patients admitted during prior years. Distribution of race, insurance type, hospital type, hospital size, hospital locations, and household income was not significantly different between the two groups.

In 2020 patients admitted with SCD had greater odds of developing acute respiratory failure and PE, though the overall prevalence of these secondary outcomes were very low (3.6% and 0.80% respectively). Despite these outcomes, there was no significant difference in inpatient mortality (0.31% vs. 0.23%) for SCD patients admitted during 2020 when compared to prior years. In addition, the length of hospital stay was not significantly different in these two groups as well (5.1 vs. 4.9 days). Finally, patients admitted in 2020 incurred significantly higher hospital costs than SCD during pre-pandemic years ($42, 307 vs. $36, 087).

Conclusion:

SCD is the most common hemoglobinopathy in the United States. The African American population is most commonly affected by this disease. In addition, it is well known that this racial minority suffers inequities in accessing and receiving health care, which is associated with worse overall outcomes. During the COVID-19 pandemic, reduced access to hospital services combined with fear of exposure to the virus, led to a significant drop in overall access to healthcare and treatment. In this study, we found that those with SCD admitted during the COVID-19 pandemic overall had more comorbidities and more commonly had respiratory failure and pulmonary embolism, yet there was no change in inpatient mortality and LOS for these patients. Although disparities existed during the pandemic, it is fortunate that SCD itself did not serve as an additional risk factor for inpatient mortality and hospitalization duration.