Factors predicting poor outcomes of patients treated with tocilizumab for COVID‑19‑associated pneumonia: A retrospective study

ABSTRACT

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic is a significant global issue that has major implications for the healthcare system. The mortality rates associated with SARS-CoV-2 infection vary according to the geographical region and are associated with age, comorbidities and vaccination status. Organ damage is caused by the cytokine release syndrome, which plays a crucial role in the course of coronavirus disease 2019 (COVID-19) infection. Innate and adaptive immune system stimulation in patients with COVID-19 results in inappropriate cytokine release. The anti-IL-6 receptor antagonist, tocilizumab, is used in the treatment of connective tissue diseases. The present single-center retrospective study on patients with COVID-19 admitted to hospital between September, 2020 and April, 2022 aimed to identify predictors of mortality and other unfavorable outcomes in patients treated with tocilizumab for COVID-19-associated pneumonia. Demographics, vaccination status against SARS-CoV-2, the Charlson comorbidity index (CCI), laboratory data and chest X-ray scores were recorded upon admission. In total, 174 subjects (121 males;mean age, 62.43±13.47 years) fulfilling the inclusion criteria were included. Among the 174 participants, 58 (33.3%) were intubated. The mortality rate was 35.1%. The non-survivors were older, mostly females, and had a higher CCI score. At the evaluation upon admission, the survivors presented with higher levels of alanine transferase and gamma glutamyl-transferase and with a greater number of platelets (PLTs), while patients that were intubated were also older, mostly females, and had a higher CCI score (P<0.05). Age was identified as the only independent factor predicting mortality in the Cox proportional hazards multivariate regression analysis. By performing a sub-analysis regarding sex, it was revealed that the value of PLTs was an independent factor predicting intubation and 90-day mortality in male patients, and the lymphocyte count was the only factor associated with intubation in female patients. On the whole, the data of the present study may be used to identify patient subpopulations responding to treatment with tocilizumab in prospective clinical trials.