Comparing severe COVID-19 outcomes of first and second/third waves: a prospective single-centre cohort study of health-related quality of life and pulmonary outcomes 6 months after infection

OBJECTIVE: We aimed to compare long-term outcomes in intensive care unit (ICU) survivors between the first and second/third waves of the COVID-19 pandemic. More specifically, to assess health-related quality of life (HRQL) and respiratory health 6 months post-ICU and to study potential associations between patient characteristic and treatment variables regarding 6-month outcomes. DESIGN: Prospective cohort study. SETTING: Single-centre study of adult COVID-19 patients with respiratory distress admitted to two Swedish ICUs during the first wave (1 March 2020–1 September 2020) and second/third waves (2 September 2020– 1 August 2021) with follow-up approximately 6 months after ICU discharge. PARTICIPANTS: Critically ill COVID-19 patients who survived for at least 90 days. MAIN OUTCOME MEASURES: HRQL, extent of residual changes on chest CT scan and pulmonary function were compared between the waves. General linear regression and multivariable logistic regression were used to present mean score differences (MSD) and ORs with 95% CIs. RESULTS: Of the 456 (67%) critically ill COVID-19 patients who survived at least 90 days, 278 (61%) were included in the study. Six months after ICU discharge, HRQL was similar between survivors in the pandemic waves, except that the second/third wave survivors had better role physical (MSD 20.2, 95% CI 7.3 to 33.1, p<0.01) and general health (MSD 7.2, 95% CI 0.7 to 13.6, p=0.03) and less bodily pain (MSD 12.2, 95% CI 3.6 to 20.8, p<0.01), while first wave survivors had better diffusing capacity of the lungs for carbon monoxide (OR 1.9, 95% CI 1.1 to 3.5, p=0.03). CONCLUSIONS: This study indicates that even though intensive care treatment strategies have changed with time, there are few differences in long-term HRQL and respiratory health seems to remain at 6 months for patients surviving critical COVID-19 in the first and second/third waves of the pandemic.