Intensive care unit hospitalizations and outcomes in patients with severe COVID-19 during summer and fall surges in Georgia.

Background: There is limited data on the difference in the clinical characteristics and outcomes of patients with severe coronavirus disease 2019 (COVID-19) infection in the summer compared to the fall surge.

Aim: To compare the sociodemographic, clinical characteristics, and outcomes among mechanically ventilated patients with severe COVID-19 infection admitted to the intensive care unit (ICU) during the summer and fall surges in the year 2020.

Methods: We included patients admitted to the ICU and treated with invasive mechanical ventilation for COVID-19 associated respiratory failure between April 1 and December 31, 2020. Patients were categorized into summer surge for ICU admissions between June 15, 2020, and August 15, 2020, and fall surge between October 15, 2020, and December 31, 2020. We compared patients' characteristics and outcomes using descriptive and inferential statistics.

Results: A total of 220 patients were admitted to the Grady Memorial Hospital ICU and mechanically ventilated for COVID-19 associated hypoxemic respiratory failure during the period considered (125 during the summer surge and 95 during the fall surge). More women were admitted in the fall compared to summer (41.1% vs 36.8%, difference, 4.3%; 95%CI: 1.2, 7.5). Patients admitted in the fall had fewer comorbidities (chronic obstructive pulmonary disease, stroke, diabetes mellitus, obstructive sleep apnea and body mass index ≥ 35 kg/m²). Overall, patients in the fall had a lower ICU mortality rate (27.4% vs 38.4%, difference, -11.0; 95%CI: -6.4, -18.2), shorter length of stay on the mechanical ventilator (7 d vs 11 d, difference, 4 d; 95%CI: 2.1, 6.6) and shorter ICU length of stay (9 d vs 14 d, difference, 5 d; 95%CI: 2.7, 9.4).

Conclusion: Patients admitted with severe COVID-19 infection requiring mechanical ventilation had better outcomes in the fall than summer. This difference observed is likely attributable to a better understanding of the condition and advances in treatment strategies.