Epidemiology, Clinical Characteristics, and Outcomes of a Large Cohort of COVID-19 Outpatients in Michigan

Background: Most outpatients with coronavirus disease 2019 (COVID-19) do not initially demonstrate severe features requiring hospitalization. Understanding this population's epidemiological and clinical characteristics to allow outcome anticipation is crucial in healthcare resource allocation.

Methods: Retrospective, multicenter (8 hospitals) study reporting on 821 patients diagnosed with COVID-19 by real-time reverse transcriptase-polymerase chain reaction assay of nasopharyngeal swabs and discharged home to self-isolate after evaluation in emergency departments (EDs) within Beaumont Health System in March, 2020. Outcomes were collected through April 14, 2020, with a minimum of 12 day follow-up and included subsequent ED visit, admission status, and mortality.

Results: Of the 821 patients, mean age was 49.3 years (SD 15.7), 46.8% were male and 55.1% were African-American. Cough was the most frequent symptom in 78.2% of patients with a median duration of 3 days (IQR 2-7), and other symptoms included fever 62.1%, rhinorrhea or nasal congestion 35.1% and dyspnea 31.2%. ACEI/ARBs usage was reported in 28.7% patients and 34.0% had diabetes mellitus. Return to the ED for re-evaluation was reported in 19.2% of patients from whom 54.4% were admitted. The patients eventually admitted to the hospital were older (mean age 54.4 vs 48.7 years, p=0.002), had higher BMI (35.4 kg/m² vs 31.9 kg/m², p=0.004), were more likely male (58.1% vs 45.4%, p=0.026), and more likely to have hypertension (52.3% vs 29.4%, p<0.001), diabetes mellitus (74.4% vs 29.3%, p<0.001) or prediabetes (25.6% vs 8.4%, p<0.001), COPD (39.5% vs 5.4%, p<0.001), and OSA (36% vs 19%, p<0.001). The overall mortality rate was 1.3%.

Conclusion: We found that 80.8% of patients did not return to the ED for re-evaluation. Sending patients with COVID-19 home if they experience mild symptoms is a safe approach for most patients and might mitigate some of the financial and staffing pressures on healthcare systems.