Evolving changes in mortality of 13,301 critically ill adult patients with COVID-19 over 8 months

• Published in: Intensive care medicine Vol. 47; no. 5; pp. 538 - 548
• Main Authors: Kurtz, Pedro, Bastos, Leonardo S. L., Dantas, Leila F., Zampieri, Fernando G., Soares, Marcio, Hamacher, Silvio, Salluh, Jorge I. F., Bozza, Fernando A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2021; Springer; Springer Nature B.V
• Subjects: Adult; Analysis; Anesthesiology; Brazil; Brazil - epidemiology; Confidence intervals; Coronavirus; Coronaviruses; COVID-19; Critical Care Medicine; Critical Illness; Emergency Medicine; Hospital Mortality; Hospitals; Humans; Intensive; Intensive Care Units; Mechanical ventilation; Medicine; Medicine & Public Health; Mortality; Original; Oxygen therapy; Pain Medicine; Pandemics; Patients; Pediatrics; Pneumology/Respiratory System; Polymerase chain reaction; Respiration, Artificial; SARS-CoV-2; Statistical analysis; Survival; Brazil; In-hospital mortality; Coronavirus; Non-invasive ventilation; Respiratory support
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-021-06388-0

Purpose
Clinical characteristics and management of COVID-19 patients have evolved during the pandemic, potentially changing their outcomes. We analyzed the associations of changes in mortality rates with clinical profiles and respiratory support strategies in COVID-19 critically ill patients.
Methods
A multicenter cohort of RT-PCR-confirmed COVID-19 patients admitted at 126 Brazilian intensive care units between February 27
th
and October 28
th
, 2020. Assessing temporal changes in deaths, we identified distinct time periods. We evaluated the association of characteristics and respiratory support strategies with 60-day in-hospital mortality using random-effects multivariable Cox regression with inverse probability weighting.
Results
Among the 13,301 confirmed-COVID-19 patients, 60-day in-hospital mortality was 13%. Across four time periods identified, younger patients were progressively more common, non-invasive respiratory support was increasingly used, and the 60-day in-hospital mortality decreased in the last two periods. 4188 patients received advanced respiratory support (non-invasive or invasive), from which 42% underwent only invasive mechanical ventilation, 37% only non-invasive respiratory support and 21% failed non-invasive support and were intubated. After adjusting for organ dysfunction scores and premorbid conditions, we found that younger age, absence of frailty and the use of non-invasive respiratory support (NIRS) as first support strategy were independently associated with improved survival (hazard ratio for NIRS first [95% confidence interval], 0.59 [0.54–0.65],
p
 < 0.001).
Conclusion
Age and mortality rates have declined over the first 8 months of the pandemic. The use of NIRS as the first respiratory support measure was associated with survival, but causal inference is limited by the observational nature of our data.