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  1. W. Schmidt1,2,3,
  2. K. Pawlak-Bus1,2,
  3. P. Leszczynski1,2
  1. 1Jozef Strus Municipal Hospital, Department of Rheumatology and Osteoporosis, Poznan, Poland
  2. 2Poznan University of Medical Sciences, Department of Rheumatology, Rehabilitation and Internal Diseases, Poznan, Poland
  3. 3Poznan University of Medical Sciences, Doctoral School, Poznan, Poland


Background Aberrant immune response is hallmark of severe COVID-19, irrespectively from viral replication. Immunomodulatory therapies such as interleukin-6 (IL-6) receptor inhibitors were proven to be beneficial in reducing in-hospital mortality1. Yet, it remains unclear which patients can benefit most from such therapy.

Objectives To identify predictors of clinical response to tocilizumab (TCZ) added to dexamethasone in patients hospitalized with severe COVID-19.

Methods We prospectively assessed clinical and laboratory details of 120 patients hospitalized due to severe COVID-19 treated with TCZ (two doses of 8 mg/kg 24h apart) in our ward between 1st Feb 2021 and 31st Dec 2021. Severe COVID-19 was defined as SpO2 <94% on room air with ground glass opacities in chest computed tomography (CT). Clinical response was defined as respiratory improvement on day 5 after TCZ infusion compared to day of treatment initiation, no further deterioration and survival. Decision of adding TCZ to dexamethasone as emergency therapy was made collectively by rheumatologists experienced in COVID-19 treatment. Laboratory and clinical parameters from hospital admission day and from TCZ institution day were analyzed. Statistical analysis was conducted with PQStat v.1.8.2 and predictors were identified in univariate logistic regression.

Results We identified 86 (71.7%) clinical responders and 34 (28.3%) non-responders. 20 (58.8%) of the second group needed ICU admission, 18 (52.9%) died on ICU and 2 patients (5.9%) died on the ward. Responders were significantly younger (mean age 56.1 vs. 63.5 years, p=0.006), had lesser comorbidity burden (median Charleson Comorbidity Index 2 vs. 3, p=0.005), lower median lung involvement (50 vs. 70%, p<0.001), higher median baseline PaO2/FiO2 index (203 vs. 106, p<0.001) and less of them needed high-flow oxygen therapy on TCZ initiation day (12.7% vs 32.4%, p=0.025).

Identified predictors of clinical response are shown in Table 1.

Table 1.

Predictors of good response to TCZ therapy in severe COVID-19. Apart from PaO2/FiO2 all parameters identified as predictors were measured on TCZ initiation day.

Conclusion Administration of TCZ early in severe disease, with moderate IL-6 concentration and low organ damage indices is most beneficial in patients with severe COVID-19, especially in younger patients without respiratory and cardiac comorbidities.

References [1]RECOVERY Collaborative Group. Tocilizumab in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial. Lancet Lond Engl. 2021;397:1637-1645.

Disclosure of Interests None declared

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