JMIR Publications

ABSTRACT

Background:

Since early 2021, monoclonal antibody (mAb) therapy has emerged as an efficacious intervention for patients with mild-to-moderate COVID-19 infections, particularly those at high risk of progressing to more severe infections. With favorable results from clinical trials, the U.S. Food and Drug Administration (FDA) issued Emergency Use Authorizations for a series of mAb treatments. As these therapeutic agents became readily available, clinicians and researchers embarked on comprehensive investigations into their impact on hospitalization rates and mortality outcomes.

Objective:

This study delves deeper into the effectiveness of accessible mAb therapies and their synergistic interactions with COVID-19 vaccinations in mitigating rehospitalization and mortality over a span of 19 months, within the encompassing landscape of greater Seattle in western Washington.

Methods:

We conducted an IRB-approved retrospective chart review of non-hospitalized adult patients who presented to emergency departments (ED) in the greater Seattle area from March 2021 through October 2022, exhibiting with mild-to-moderate COVID-19 infections and met eligibility criteria for monoclonal antibody therapy, having at least one of the following active comorbidities: arrythmia, cancer, cardiovascular dysfunction, diabetes, immunosuppression, obesity, renal dysfunction, a respiratory disorder, and/or tobacco use. We compared outcomes of patients who were treated with monoclonal antibodies to eligible patients who were not treated. Primary outcomes were rates of 28-day rehospitalization and all-cause hospital mortality. Secondary outcomes were rates of hospital inpatient admission, intensive care unit admission, and necessity for mechanical ventilation. We used propensity score matching and logistic regression models to isolate the effect of monoclonal antibody treatment on the outcome variables controlling for demographic characteristics and comorbidities. All statistical analyses were done in R Studio, and the MatchIt package was used for propensity score matching.

Results:

A total of 21,139 patients were included in the analysis. In the matched cohorts (mAb treated: N = 1,349; untreated: N = 1,349), mAb treatment was associated with reduced significantly odds of 28-day rehospitalization (adjusted odds ratio [aOR] 0.66, [95% confidence interval (CI)] 0.49-0.87), P = 0.004), mortality (adjusted odds ratio [aOR] 0.32, [95% confidence interval (CI)] 0.19-0.51), P < 0.001), and inpatient admissions (adjusted odds ratio [aOR] 0.43, [95% confidence interval (CI)] 0.31-0.61), P < 0.001).

Conclusions:

From March 2021 through October 2022, monoclonal antibodies emerged as a pivotal factor in significantly reducing the incidence of rehospitalization, mortality, and inpatient admission amongst patients with mild-to-moderate COVID-19 infections in western Washington. Our study contributes real-world evidence to the medical literature, reaffirming the efficacy of monoclonal antibodies as a therapeutic option for outpatients with mild-to-moderate COVID-19 who are at an increased risk of developing severe infection. In light of the evolving landscape of the COVID-19 pandemic, marked by changing variants, the efficacy of individual mAb agents should continue to be vigilantly evaluated.