Weekend Effect and Predictors of Mortality for Patients Presenting to Emergency Department with COVID-19 Infection.

Background: Weekend presentation to the emergency department (ED) has been associated with increased morbidity and mortality in various clinical settings. However, the literature is scant whether such an effect exists for patients presenting with COVID-19 infection. Additionally, comparative analyses of mortality predictors in COVID-19 patients evaluated at the emergency department need further exploration. Methods: This retrospective cohort study examined factors associated with mortality among adult patients (aged ≥ 18 years) who presented with COVID-19 to the emergency departments of five hospitals within the Johns Hopkins Health System (combined capacity: 2513 beds) between March 1 and 4 May 2020. Data were extracted from electronic health records. Multivariable logistic regression was utilized to assess the relationship between mortality and a range of variables, including sociodemographic characteristics, clinical presentation, laboratory parameters, pre-existing comorbidities, and weekend versus weekday presentation. Results: Of the 2767 patients, 685 (25%) presented to the emergency department on weekends. Compared to weekday presenters, weekend patients were more likely to be hospitalized (64%), and these patients had a mean symptom duration of 5 days (SD ± 6). Weekend presenters also exhibited higher rates of clinical frailty, dehydration, hypoxia, and respiratory distress upon arrival. In multivariable logistic regression analysis adjusting for sociodemographic characteristics, clinical risk factors, and laboratory findings, independent predictors of increased mortality included absence of a primary care provider (OR 3.47; 95% CI: 2.37-5.07), peripheral oxygen saturation (SpO₂) < 95% at presentation (OR 1.46; 95% CI: 1.001-2.12), and hyperglycemia (OR 2.13; 95% CI: 1.25-3.65). Notably, the presence of crackles on physical examination demonstrated a trend toward reduced mortality (OR 0.47; 95% CI: 0.24-0.92). Conclusions: While weekend presentation was associated with higher hospitalization rates among patients with COVID-19, it did not independently predict increased mortality. Absence of a primary care provider, hypoxia, and hyperglycemia at presentation emerged as strong, independent predictors of mortality in the ED setting. Race, gender, and obesity were not significantly associated with mortality in this cohort, warranting further investigation. These findings may support more effective triage and risk stratification strategies in current and future public health emergencies.