Thymosin α1 therapy in critically ill patients with COVID-19: A multicenter retrospective cohort study

Background: COVID-19 characterized by refractory hypoxemia increases patient mortality because of immunosuppression effects This study aimed to evaluate the efficacy of immunomodulatory with thymosin α1 for critical COVID-19 patients Methods: This multicenter retrospective cohort study was performed in 8 government-designated treatment centers for COVID-19 patients in China from Dec 2019 to Mar 2020 Thymosin α1 was administrated with 1 6 mg qd or q12 h for >5 days The primary outcomes were the 28-day and 60-day mortality, the secondary outcomes were hospital length of stay and the total duration of the disease Subgroup analysis was carried out according to clinical classification Results: Of the 334 enrolled COVID-19 patients, 42 (12 6%) died within 28 days, and 55 (16 5%) died within 60 days of hospitalization There was a significant difference in the 28-day mortality between the thymosin α1 and non-thymosin α1-treated groups in adjusted model (P = 0 016), without obvious differences in the 60-day mortality and survival time in the overall cohort (P > 0 05) In the subgroup analysis, it was found that thymosin α1 therapy significantly reduced 28-day mortality (Hazards Ratios HR, 0 11, 95% confidence interval CI 0 02–0 63, P=0 013) via improvement of Pa02/FiO2 (P = 0 036) and prolonged the hospital length of stay (P = 0 024) as well as the total duration of the disease (P=0 001) in the critical type patients, especially those aged over 64 years, with white blood cell >6 8×109/L, neutrophil >5 3×109/L, lymphocyte 3, and acute physiology and chronic health evaluation (APACHE) II > 7 Conclusion: These results suggest that treatment with thymosin α1 can markedly decrease 28-day mortality and attenuate acute lung injury in critical type COVID-19 patients