Association of tocilizumab use with mortality and clinical outcomes in critically Ill patients followed in the intensive care unit for COVID-19 pneumonia: a single-center retrospective cohort study.

OBJECTIVES: Randomized trials show tocilizumab reduces mortality in selected COVID-19 patients treated early; its association with outcomes in real-world intensive care, where treatment is often delayed, remains uncertain. We evaluated this association in critically ill patients. METHODS: Single-center retrospective cohort of adults admitted to the intensive care unit (ICU) with PCR-confirmed COVID-19 pneumonia and acute respiratory failure (March 2020-September 2021; n = 393), grouped by tocilizumab use: Group T (received tocilizumab, n = 117) and Group N (did not receive tocilizumab, n = 276). Outcomes were mortality (primary), ICU stay, and mechanical ventilation. Baseline imbalance was assessed with standardized mean differences (SMD); associations were adjusted by covariate adjustment, propensity score weighting, and 1:1 matching. RESULTS: Overall mortality was 60.6%. Group T patients were younger with fewer comorbidities (age SMD -0.95). Unadjusted mortality was lower with tocilizumab (odds ratio [OR] 0.55; 95% CI 0.35-0.86), but this disappeared after adjustment (covariate-adjusted OR 1.28, 0.70-2.34; weighting OR 1.41, 0.89-2.24; matching OR 1.52). ICU stay did not differ. Independent mortality predictors were older age, cytokine apheresis, higher C-reactive protein, and lactate dehydrogenase. Median time to tocilizumab was 10 days. CONCLUSION: After adjustment, tocilizumab was not independently associated with mortality. Findings are observational and not causal; any benefit may depend on patient selection and timing.