Overall, 7.9% (5/63) of patients receiving bamlanivimab had a subsequent ED/hospital visit, hospitalization, or death compared with 19.2% (46/239) in the control group (P = .03) (Table 2).
While the primary outcome of overall improvement was significantly different between the 2 groups, comparison of the individual components, including subsequent ED visits, hospitalizations, or death, were not significant. No treatment patients were hospitalized, compared with 5.4% (13/239) in the control group (P = .05). In the treatment group, 6.3% (4/63) returned to the ED compared with 12.6% (30/239) of the control group (P = .17). Finally, 1.6% (1/63) of the treatment group had a subsequent death that was due to COVID-19 compared with 1.3% (3/239) in the control group (P = .84) (Figure 2).
Discussion
In this retrospective cohort study, we observed a significant difference in rates of COVID-19 patients requiring repeat ED visits, hospitalizations, and deaths among those who received bamlanivimab compared with those who did not. Our study focused on high-risk patients with mild or moderate COVID-19, a unique subset of individuals who would normally be followed and treated via outpatient monitoring. We propose that treating high-risk patients earlier in their disease process with mAb therapy can have a major impact on overall outcomes, as defined by decreased subsequent hospitalizations, ED visits, and death.
Compared to clinical trials such as BLAZE-1 or REGN-COV2, every patient in this trial had at least 1 high-risk characteristic.9,11 This may explain why a greater proportion of our patients in both the control and treatment groups had subsequent hospitalization, ED visits, and deaths. COVID-19 patients seen in the ED may be a uniquely self-selected population of individuals likely to benefit from mAb therapy since they may be more likely to be sicker, have more comorbidities, or have less readily available primary care access for testing and treatment.14
Despite conducting a thorough literature review, we were unable to find any similar studies describing the ED as an appropriate setting for mAb treatment in patients with COVID-19. Multiple studies have used outpatient clinics as a setting for mAb treatment, and 1 retrospective analysis found that neutralizing mAb treatment in COVID-19 patients in an outpatient setting reduced hospital utilization.15 However, many Americans do not have access to primary care, with 1 study finding that only 75% of Americans had an identified source of primary care in 2015.16 Obstacles to primary care access include disabilities, lack of health insurance, language-related barriers, race/ethnicity, and homelessness.17 Barriers to access for primary care services and timely care make these populations more likely to frequent the ED.17 This makes the ED a unique location for early and targeted treatment of COVID-19 patients with a high risk for progression to severe COVID-19.