The Effect of Tocilizumab on Inflammatory Markers in Survivors and Non-survivors of Severe COVID-19.

To determine the effects of tocilizumab (TCZ) on inflammatory markers, laboratory indices; and short-term outcome in patients with severe COVID-19. Cross-sectional analytical study. Place and Duration of the Study: Hayatabad Medical Complex, Peshawar, Pakistan from 10th June till 31st August 2020. Fifty-four patients with severe COVID-19 fulfilled the inclusion criteria and were included. All patients had received TCZ (4 mg/kg) in addition to standard treatment. Serum C-reactive protein (CRP), lactate dehydrogenase (LDH), D-dimer levels, full blood count, and liver function tests (LFTs) were checked before and 24 hours after receiving TCZ. Short-term outcome, defined as survival at day 28, was determined from hospital record/telephonic contact. Paired t-test was employed to assess the statistical significance of mean differences between the pre- and post-TCZ variables, considering a p-value of <0.05 as significant. Overall, the mean pre- and post-TCZ CRP was 18.7 ± 10.7 and 10.2 ± 8.6 mg/dl (p <0.001). It was 18.0 ± 10.3 and 10.3 ± 8.8 mg/dl (p=0.003) in survivors; and 19.4 ± 11.4 and 10.2 ± 8.7 mg/dl (p=0.005) in non-survivors, respectively. Overall, mean D-dimer level decreased from 12.5 ± 23 to 10.3 ± 12.2 µg/ml following TCZ (p=0.643); it decreased from 15.8 ± 29.8 to 11.4 ± 10.6 µg/ml (p=0.612) in survivors; and 9.0 ± 12.8 to 9.2 ± 14.1 µg/ml (p=0.961) in non-survivors, respectively. There were no significant differences in the pre- and post-TCZ LDH levels overall and between the groups. The 28-day mortality was 46.3%. Tocilizumab results in a significant reduction in CRP, while mean change in LDH and D-dimers was not substantial. The mean change in inflammatory markers did not predict survival. Key Words: Tocilizumab, COVID-19, Biomarkers, Outcome, Mortality.