Critical COVID-19 patients through first, second, and third wave: retrospective observational study comparing outcomes in intensive care unit.

With application of best practice as known by the time of the first three waves of the pandemic, our study failed to identify a significant improvement in mortality rate when comparing the different waves of the COVID-19 pandemic, notwithstanding, the sub-analyses showed a trend in mortality reduction in the third wave. Rather, our study identified a possible positive effect of dexamethasone on mortality rate reduction and the increased risk of death related to bacterial infections in the three waves.