Impact of Tocilizumab on Inflammatory Markers and Oxygen Status in Severe COVID-19 Patients: A Single Centre Retrospective Study.

Objective: This retrospective study aims to investigate the impact of tocilizumab on inflammatory markers in patients with severe COVID-19. The effect on oxygenation was also assessed.

Methods: This study is a single-centre, retrospective cohort study conducted at NIMS hospital. Data of the eligible patients with severe COVID-19 pneumonia who received injection tocilizumab (max 800 mg) were charted and analysed. Oxygenation and inflammatory markers were compared before and after (day 3 and day 7) tocilizumab injection. Effect of dysglycemia on the efficacy of tocilizumab was assessed. Outcomes were analysed in the form of discharge without oxygen, discharge with oxygen, and death. Data were analysed by SPSS v22.

Results: The mean age of the subjects was 57.8 ± 12.2 years, and 78.57% were male. Forty-four percent of the patient had type 2 diabetes. Tocilizumab treatment was associated with reduction in the oxygen requirement [median:10 L/min (IQR6- 14)] v/s 4 L/min (IQR 3-7, p-0.005]. Peripheral oxygen saturation also improved after tocilizumab [92 % (IQR 90-96)] v/s [95 % (IQR 94-96), p-0.01)], respectively. Serum CRP level decreased significantly when evaluated after three days (44±5 v/s 20 ±3 mg/dl, p=< 0.001). Out of the 42, 12 (29%) patients died due to severe COVID-19 or its complications. When compared with the patients who survived, patients who died had a higher level of D-dimer (1.2 ± 0.51 v/s 3.1 ±1.2 ng/dl, p-value- 0.04), and LDH: (845 ±55 v/s 1364 ±198 U/L, p - 0.01). At day seven of the tocilizumab injection, diabetic patients (n-13) had higher IL-6 serum level than nondiabetic patients (n-16) [(median- 311(IQR-1245.5) v/s (209 (IQR-546.2), p-value- 0.048].

Conclusion: In this retrospective pre-post analysis, tocilizumab injection was associated with reduced inflammation and improved oxygenation in severe COVID-19. Despite high IL-6 levels, diabetes had no impact on the efficacy of the tocilizumab.