Factors associated with oxygen requirement and persistent symptoms 1 year after severe COVID-19 infection

Objective: We aimed to describe the prevalence and factors associated with the need for supplemental oxygen and persistent symptoms 1 year after severe SARS-CoV-2 infection. Methods: In this historical cohort and nested case–control study, we included adults with severe COVID-19 (requiring admission to the intensive care unit or invasive mechanical ventilation). We evaluated factors associated with a need for supplemental oxygen and persistent symptoms 1 year after severe infection. Results: We included 135 patients (median age 62 years, 30% women). At 1-year follow-up, the main symptoms were dyspnea (32%), myalgia (9%), cough (7%), anxiety (4%), and depression (5%); 12.59% of patients had prolonged requirement for supplemental oxygen. Factors associated with a persistent requirement for supplemental oxygen were female sex (odds ratio 3.15, 95% confidence interval 1.11–8.90) and Charlson Comorbidity Index > 4 (odds ratio 1.60, 95% confidence interval 1.20–2.12). Conclusions: We found that a high prevalence of supplemental oxygen requirement 1 year after severe COVID infection was associated with female sex and a baseline high rate of comorbidities. It is unknown whether this prevalence was related to other factors, such as the altitude at which patients lived. More than half of patients had prolonged post-COVID syndrome.