Outcomes comparison between the first and the subsequent SARS-CoV-2 waves - a systematic review and meta-analysis

Area of Science:

• Infectious Diseases
• Critical Care Medicine
• Epidemiology

Background:

• Early COVID-19 pandemic response relied on supportive care due to unknown specific treatments.
• Subsequent pandemic waves benefited from advancements in diagnostics, antivirals, and vaccines.
• This study compares clinical outcomes between the initial and later phases of the SARS-CoV-2 pandemic.

Purpose of the Study:

• To conduct a meta-analysis and systematic review comparing clinical endpoints between the first and subsequent waves of the COVID-19 pandemic.
• To evaluate differences in mortality, resource utilization, and complications.
• To assess the impact of evolving medical knowledge and interventions over time.

Main Methods:

• Systematic review and meta-analysis of 25 studies involving 126,153 patients.
• Primary outcome: in-hospital mortality.
• Secondary outcomes included ICU mortality, ICU length of stay (LOS), acute renal failure, ECMO implantation, mechanical ventilation duration, hospital LOS, thromboembolism, myocarditis, and ventilator-associated pneumonia.

Main Results:

• No significant difference in in-hospital mortality (OR=0.94, p=0.35).
• Higher rates observed in the first wave group for ICU LOS (SMD=0.23, p<0.01), acute renal failure (OR=1.71, p<0.01), and ECMO implantation (OR=1.64, p=0.03).
• No significant differences in other secondary endpoints.

Conclusions:

• Patients during the first COVID-19 wave experienced increased ICU length of stay, acute renal failure, and ECMO use compared to subsequent waves.
• In-hospital and ICU mortality rates were not significantly different between the first and later waves.
• The findings highlight improvements in managing severe COVID-19 complications over time, despite similar overall mortality.