Abstract: 1035670 research-article20212021 TAG0010.1177/17562848211035670Therapeutic Advances in GastroenterologyL Zhang, H Han Therapeutic Advances in Gastroenterology Original Research Probiotics use is associated with improved clinical outcomes among hospitalized patients with COVID-19 Ther Adv Gastroenterol 2021, Vol. 14: 1–9 https://doi.org/10.1177/17562848211035670 DOI: 10.1177/ https://doi.org/10.1177/17562848211035670 17562848211035670 © The Author(s), 2021. Article reuse guidelines: sagepub.com/journalspermissions Lina Zhang*, Huanqin Han*, Xuan Li*, Caozhen Chen*, Xiaobing Xie, Guomei Su, Shicai Ye, Cuili Wang, Qing He, Fang Wang, Fang Huang, Zhaoqin Wang, Jiayuan Wu and Tianwen Lai Abstract Background and aims: Currently, there are no definitive therapies for coronavirus disease 2019 (COVID-19). Gut microbial dysbiosis has been proved to be associated with COVID-19 severity and probiotics is an adjunctive therapy for COIVD-19. However, the potential benefit of probiotics in COVID-19 has not been studied. We aimed to assess the relationship of probiotics use with clinical outcomes in patients with COVID-19. Methods: We conducted a propensity-score matched retrospective cohort study of adult patients with COVID-19. Eligible patients received either probiotics plus standard care (probiotics group) or standard care alone (non-probiotics group). The primary outcome was the clinical improvement rate, which was compared among propensity-score matched groups and in the unmatched cohort. Secondary outcomes included the duration of viral shedding, fever, and hospital stay. Results: Among the propensity-score matched groups, probiotics use was related to clinical improvement rates (log-rank p = 0.028). This relationship was driven primarily by a shorter (days) time to clinical improvement [difference, −3 (−4 to −1), p = 0.022], reduction in duration of fever [−1.0 (−2.0 to 0.0), p = 0.025], viral shedding [−3 (−6 to −1), p < 0.001], and hospital stay [−3 (−5 to −1), p = 0.009]. Using the Cox model with time-varying exposure, use of probiotics remained independently related to better clinical improvement rate in the unmatched cohort. Conclusion: Our study suggested that probiotics use was related to improved clinical outcomes in patients with COVID-19. Further studies are required to validate the effect of probiotics in combating the COVID-19 pandemic. Keywords: clinical improvement, COVID-19, gut microbiota, probiotics Received: 11 April 2021; revised manuscript accepted: 29 June 2021.