Mortality and Associated Factors in Critically Ill COVID-19 Patients: A Retrospective Cohort Study

Abstract Structured AbstractBackgroundThe COVID-19 pandemic has led to a substantial increase in intensive care unit (ICU) admissions worldwide, with high mortality rates among critically ill patients. Identifying mortality rates and associated factors is crucial for guiding clinical management and resource allocation.Methods This retrospective, single-center study included 410 adult patients with confirmed COVID-19 admitted to the ICU between March 2020 and March 2021 at a tertiary care hospital in Antalya, Türkiye. Demographic characteristics, comorbidities, clinical interventions, laboratory parameters, and outcomes were recorded. Survivors and non-survivors were compared using the Mann–Whitney U, Chi-square, and Fisher’s exact tests. Cox regression analysis was performed to identify independent predictors of mortality.ResultsThe overall ICU mortality rate was 48.3%. Non-survivors were older (median age: 70 vs. 66 years, p < 0.001), had higher BMI (25.9 vs. 24.5 kg/m², p < 0.001), and longer ICU stays (6 vs. 4 days, p = 0.001). They more frequently required invasive mechanical ventilation (87.8% vs. 23.1%, p < 0.001), vasopressor therapy (82.7% vs. 26.9%, p < 0.001), and renal replacement therapy (19.8% vs. 7.5%, p < 0.001). Laboratory findings in non-survivors showed higher ferritin (680 vs. 412.6 ng/mL, p = 0.001), LDH (486 vs. 365 U/L, p < 0.001), fibrinogen (611.5 vs. 517 mg/dL, p = 0.023), NLR (15 vs. 11, p < 0.001), and lactate (1.7 vs. 1.4 mmol/L, p < 0.001), as well as lower PaO₂/FiO₂ ratio (104 vs. 164.8, p < 0.001). Multivariate Cox regression identified invasive mechanical ventilation (HR 5.15, 95% CI 3.25–8.15, p < 0.001), malignancy (HR 1.44, 95% CI 1.04–2.01, p = 0.031), and APACHE II score (HR 1.03, 95% CI 1.01–1.05, p = 0.001) as independent predictors of mortality.ConclusionsICU mortality among COVID-19 patients remains high. Advanced age, obesity, high APACHE II score, mechanical ventilation, vasopressor use, and certain comorbidities significantly increase mortality risk. Early identification of high-risk patients and targeted interventions may improve outcomes.