Mortality of intubated patients with COVID-19 during first and subsequent waves: a meta-analysis involving 363,660 patients from 43 countries.

Background: We attempted to investigate the change in mortality of intubated patients with coronavirus disease (COVID-19) from first to subsequent waves across several countries.

Methods: We pre-registered our meta-analysis with PROSPERO [Anonymized]. We searched PubMed, Scopus, and gray literature for observational studies reporting data on all-cause mortality of intubated patients with COVID-19 recruited both during first and subsequent waves of the pandemic. We considered studies published after 31 August 2020 up to 12 July 2021. The primary outcome of the meta-analysis was all-cause mortality. We used a random effects model to calculate pooled risk ratio (RR) and 95% confidence intervals (CI).

Results: By incorporating data of 363,660 patients from 43 countries included in 28 studies, we found that all-cause mortality of intubated patients with COVID-19 increased from first to subsequent waves (from 62.2% to 72.6%; RR 0.90, 95% CI 0.85-0.94, p < 0.00001). This finding was independent of the geo-economic variation of the included studies and persisted in several pre-specified subgroup and sensitivity analyses.

Conclusions: The robust finding of this meta-analysis suggests that mortality of intubated patients with COVID-19 did not improve over time. Future research should target this group of patients to further optimize their management.