Risk factors associated with mortality among patients with COVID-19 in the intensive care unit: prospective cohort study from the early pandemic phase in Brazil.

OBJECTIVE

This prospective cohort study describes clinical, laboratory factors and virological factors associated with in-hospital mortality among 227 Intensive Care Unit (ICU) patients with SARS-CoV-2 infection admitted in Brazil during the pre-vaccination, pre-Omicron phase of the pandemic (September 2020 to March 2021).

METHODS

Clinical and laboratory data were extracted from medical records, and viral load was quantified by RT-qPCR Cycle threshold (Ct) values. Independent predictors of mortality were evaluated using multivariable Cox proportional hazards regression, and survival was analyzed with Kaplan-Meier curves.

RESULTS

Non-survivors were significantly older (p < 0.001) and more likely to have hypertension (p = 0.014) and chronic respiratory disease (p = 0.042). At admission, they exhibited higher leukocyte counts (p = 0.001), D-dimer (p = 0.028), and creatinine levels (p = 0.001), as well as more frequent tracheal intubation (p < 0.001). During hospitalization, non-survivors showed persistently elevated leukocyte counts and developed more complications, including acute kidney injury, septic shock, and cardiac arrest (p < 0.001). Viral load was higher in non-survivors (p = 0.026) and among those requiring intubation (p = 0.042) or with cardiovascular disease (p = 0.016). In the multivariable Cox model, only creatinine at admission remained independently associated with mortality (HR = 1.18; 95% CI: 1.00-1.39; p = 0.049). Survival analysis showed reduced survival among patients aged ≥ 65-years (p = 0.004) and those with chronic respiratory disease (p = 0.029).

CONCLUSIONS

This study integrates clinical, laboratory, and viral load data to detail the early COVID-19 severity and mortality patterns in a Brazilian ICU.