Prolonged Oxygen Therapy Post COVID-19 Infection: Factors Leading to the Risk of Poor Outcome

Background: Coronavirus disease 2019 (COVID-19) infection is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a single-stranded ribonucleic acid (RNA) β-coronavirus. Prolonged duration of symptoms, ill health, disability, and need for hospitalisation are all well-known features of severe COVID-19 disease. Objective: To describe the epidemiological, clinical and imaging characteristics of hospitalised patients of COVID-19 who required prolonged oxygen therapy after testing negative for SARS-CoV-2 and attempt to determine the associated factors leading to delayed recovery, failure to wean, and mortality. Material and Method: Prospective observational study from 9th September to 6th November 2020 in a tertiary care COVID hospital of Jharkhand. Included COVID-19-infected patients requiring oxygen to maintain a saturation of ≥95% after testing reverse transcription polymerase chain reaction (RT-PCR) negative. Patients were classified as Group I, those who could be weaned off oxygen, and Group II, those who could not be weaned off oxygen during their stay in the isolation ward. A detailed assessment for outcome in these two groups related to age, gender, presence or absence of co-morbidities, nature of co-morbidities and findings of high-resolution CT (HRCT) thorax was done to ascertain risk factors for failure to wean and adverse outcomes. Results: During the study period, 93 patients suffering from moderate to severe COVID-19 infection, could not be discharged from the hospital and were admitted to the post-COVID isolation ward after testing RT-PCR negative, due to breathlessness and need for oxygen therapy, with a male predominance, M:F ratio of 2.2:1. Of these 93 patients, 51 could be weaned off oxygen in the isolation ward. The mean and median age of patients who could be successfully weaned was 58.5±14.3 years and 60 years respectively, compared to a mean age of 64±12.4 years and a median age of 67 years for patients who could not be weaned off oxygen during the isolation period. Patients aged ≥60 years were at risk for prolonged requirement of oxygen compared to those <50 years of age, relative risk (RR) 1.43 (95%CI 0.9-2, p=0.051). Failure to wean in <50 years was noted in presence of co-morbidities, RR 4 (95%CI 1.5-10.6, p=0.005). Multivariable logistic regression analysis calculated an odds ratio (OR) of 12.22 (95%CI 2.4-61.5, p<0.002) in patients of coronary artery disease (CAD), and 3.34 (95%CI 1.01-10.9, p<0.046) in patients of diabetes, for failure to wean with delayed recovery in patients aged 50 years and more, having multiple co-morbidities. Presence of ≥three co-morbid conditions was associated with increased risk of critical care unit (CCU) admissions (RR 2.1, p=0.02), failure to wean (RR 1.79, p<0.006), and death (p=0.02). Elderly male patients (mean age of 81.3±7.2years) with CAD and multiple comorbidities were at a high risk of mortality (p=0.01). Conclusion: Patients ≥50 years of age having ≥three co-morbidities are at increased risk of prolonged hospitalisation and oxygen therapy in moderate to severe COVID-19 infection, precluding their discharge even after they test negative for SARS-CoV-2. Elderly male patients of COVID-19 with CAD and multiple comorbidities are at a high risk of mortality.