Bamlanivimab Reduces ED Returns and Hospitalizations and May Reduce COVID-19 Burden on Low-r esource Border Hospitals

Introduction: To evaluate the effectiveness of bamlanivimab at reducing return emergency department (ED) visits in primarily Latinx/Hispanic patients with mild or moderate coronavirus disease 2019 (COVID-19). Secondary aims were to evaluate the prevention of subsequent hospitalizations and deaths in a resource-limited United States (U.S.)-Mexico border hospital. Methods: We conducted a retrospective, open-label interventional study on 270 eligible adult patients diagnosed with mild-moderate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection who met criteria for receiving bamlanivimab from November 1, 2020 to January 31, 2021. The main outcomes of 14-day return visits to the ED and hospitalizations due to COVID-19 were compared between two groups - those who received bamlanivimab (exposed group) and those who did not receive bamlanivimab (unexposed group). Outcomes were analyzed through chi-square tests followed by multivariate regression modeling to adjust for patient demographics, characteristics, and comorbidities. Results: There were 136 COVID-19 patients who received bamlanivimab in the ED prior to discharge and an unexposed group of 134 COVID-19 patients who were evaluated and discharged from the ED without receiving bamlanivimab. Overall, mean age was 61.7 (S.D. +/-13.9) years, mean body mass index (BMI) 31.0 (S.D. +/-6.6) kg/m2, 91.5% identified as Latinx/Hispanic, 51.9% male, and 80.7% reported at least one comorbidity. Most commonly reported comorbidities were obesity (22.6%), hypertension (59.6%), and diabetes (41.1%). The bamlanivimab group had a 22.8% (mean estimate = 0.7717, 95% CI [0.6482, 0.8611]) risk reduction or 84.4% (0.3030, 95% CI = 0.166, 0.554, p=.0001) absolute reduction of ED return visits within 14 days compared to controls after adjusting for chronic kidney disease. The bamlanivimab group had 19.0% (mean estimate=0.8097, 95% CI [0.6451, 0.9087]) risk reduction or 96.2% (0.235, 95% CI 0.100, 0.550, p=0.0008) absolute reduction of subsequent hospitalizations compared to unexposed patients after adjusting for diabetes status. Conclusion: Bamlanivimab infusions for high-risk COVID-19 patients in the ED substantially reduced the risk of return visits to the ED and hospitalizations in our primarily Latinx/Hispanic population. Monoclonal antibody infusions may help reduce hospital utilization during COVID-19 surges at U.S.- Mexico border hospitals.