key: cord-0857504-zesvrzgu authors: Zhang, Lina; Han, Huanqin; Li, Xuan; Chen, Caozhen; Xie, Xiaobing; Su, Guomei; Ye, Shicai; Wang, Cuili; He, Qing; Wang, Fang; Huang, Fang; Wang, Zhaoqin; Wu, Jiayuan; Lai, Tianwen title: Probiotics use is associated with improved clinical outcomes among hospitalized patients with COVID-19 date: 2021-08-04 journal: Therap Adv Gastroenterol DOI: 10.1177/17562848211035670 sha: 79ff86507b68afc4f209301c158381a02ba5a004 doc_id: 857504 cord_uid: zesvrzgu 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. The coronavirus disease 2019 (COVID-19) has been considered a global pandemic. 1 Fever, fatigue, and cough are the most common clinical features of COVID-19, but gastrointestinal symptoms (e.g., diarrhea, nausea, vomiting) are increasingly recognized among COVID-19 patients. 2, 3 Previous studies have shown that positive severe acute respiratory syndrome coronavirus (SARS-CoV-2) in the stool of COVID-19 patients was associated with longer illness duration. 4 Angiotensin-converting enzyme 2 has been found to be abundant in the epithelia of the lungs and intestine, suggesting that there is a subtle link between them. 4 The gut microbiota have been proved to play a critical role in health through the "gut-lung axis". Thus, SARS-CoV-2 might also affect the gut microbiota in COVID-19. Indeed, microbial dysbiosis was found in some patients with COVID-19. 5 Imbalance of intestinal flora can lead to dysbiosis, which might influence the outcome of the clinical features. A novel and more targeted method may be needed to modulate gut microbiota as one of the treatments for COVID-19 and its comorbidities. Currently, no definitive drugs are recommended for the treatment of COVID-19. Developing effective new therapies for curing COVID-19 is time-consuming. Therefore, using existing approved therapies or treatment modalities is seen as a more cost-effective strategy for reducing the severity of COVID-19. In early February 2020, China's National Health Commission and National Administration (version 5) recommended the use of probiotics, gut microecological modulators, in COVID-19 patients to maintain the balance of intestinal microecology. 6 Probiotics have shown good results in regulating innate immunity and improving inflammatory conditions. 7 We hypothesized that probiotics modulate the gut microbiota to protect the respiratory system and would be related to clinical improvement in COVID-19. Thus, we conducted a propensityscore matched retrospective cohort study to assess the association of in-hospital use of probiotics with clinical outcomes. We performed a propensity-score matched retrospective cohort study at the Shenzhen Third People's Hospital (Guangdong, China) from 11 January 2020 to 1 April 2020. Adults (age 18 years or older) were eligible for the study if they tested positive for SARS-CoV-2 according to World Health Organization (WHO) interim guidance. Exclusion criteria were pregnancy or lactation; conditions with gastrointestinal or systemic diseases known to affect gut microbiota composition such as gastrointestinal cancer, inflammatory bowel disease; incomplete information. The definition of disease severity of COVID-19 was based on the Chinese guideline for the management of COVID-19. 6 The study protocols were approved by the Ethics of Research Committee of the Shenzhen Third People's Hospital (No. 2020-193) . A STARD checklist is shown in the Supplemental material online. Standard care comprised, as necessary, supplemental oxygen, high-flow nasal cannula (HFNC), antiviral agents, antibiotics, corticosteroids, mechanical ventilation, according to the Chinese guideline for the management of COVID-19. 8 Inclusion criteria for the adjuvant probiotics treatment were: mild to severe patients with COVID-19; there was no history of probiotics or antibiotics use for at least 1 month; did not have allergy to probiotics. Probiotic treatment was administered as 630 mg (three pills) twice daily, using live combined Bifidobacterium, Lactobacillus, and Enterococcus capsules (Bifico) (Shanghai, China). Each capsule is of 210 mg, which contains Bifidobacterium, Lactobacillus and Ente rococcus (1.0 × 10 7 CFU for each ingredient). There was no connection with the probiotic treatment with the gastrointestinal symptoms of COVID-19 patients. The primary exposure was use of probiotics, classified as present if probiotics were received within 48 h of hospital admission and otherwise as absent. The duration of oral probiotics administration was defined as the time from probiotics treatment initiation to viral shedding or death. In the control group, the initial time for the patients without probiotics administration was defined as the time of viral shedding or death. Clinical data were collected from the Shenzhen Third People's Hospital (Guangdong, China). Data reliability was verified by two researchers (TWL and LNZ) and difference in interpretation was adjudicated by a third researcher (JYW). The primary outcome was the time (days) to clinical improvement. The definition of time to clinical improvement was the time from any treatment initiation to live discharge or an improvement of two points on a seven-point scale, whichever came first according to the previous study. 8 Second outcomes included the duration of hospital stay, fever, viral shedding, and gastrointestinal symptoms. Throat-swab samples were collected for SARS-CoV-2 detection according to WHO interim guidance. Complete blood count, D-dimer, serum biochemical tests, interleukin-6 (IL-6), procalcitonin, CD4 + and CD8 + T cell count were journals.sagepub.com/home/tag 3 examined. The reference values were as follows: white blood cell (WBC) count: (4-10) × 10 9 ; platelet count: (100-300) × 10 9 /l; lymphocyte count: (0.8-4.0) × 10 9 /l; IL-6: (0-7) pg/ml; albumin: 40-55 g/l; D-dimer: 0-0.5 μg/ml; aspartate aminotransferase (AST): 0-45 g/l; alanine transaminase (ALT): 0-45 g/l; procalcitonin: <0.1 ng/ml; cluster of differentiation (CD) 4 + T cell count: >400/mm 3 ; CD8 + T cell count: >150/mm 3 . Patients in the cohort were classified according to whether probiotics were used or not (probiotics versus non-probiotics). Continuous and categorical variables were shown as medians [interquartile ranges (IQRs) or standard deviations (SDs)] and n (%), respectively. No imputation was performed for missing data, because the patients with insufficient information had been removed during the patient selection. Patients who had a probiotics approach were matched to those who did not receive probiotics therapy 1:1 by greedy matching on the logit of propensity scores with a caliper of 0.2 SD. 9 Variables thought to be potential confounders were enrolled into the propensity score and included socio-demographics [age, sex, body mass index (BMI)], clinical characteristics (disease severity, hypertension, diabetes, coronary disease, radiological findings), laboratory tests (WBC counts, lymphocyte count, IL-6, D-dimer, ALT, AST, CD4 + and CD8 + T cell count), clinical treatments [antibiotics, corticosteroid, intravenous immunoglobin, oxygen therapy, HFNC, non-invasive mechanical ventilation (NIMV), invasive mechanical ventilation (IMV)], and ICU admission. Standardized differences for all covariates were calculated before and after matching, with 10% or more considered indicative of imbalance. 10 The primary outcome was described by Kaplan-Meier plot and compared with a log-rank test after matching. For all outcomes, time to different clinical events was treated as continuous variable, and the difference between the probiotics and non-probiotics groups was analyzed by Hodges-Lehmann estimation in the matched cohort. To further validate the effects of probiotics on clinical improvement, Cox proportional hazard model with hazard ratio (HR) and 95% confidence interval (CI) was used in the unmatched cohort after adjustment for confounding factors. Analysis were performed by R software (version 3.6.1, Vienna, Austria). All tests were two-sided with a significance level of 0.05. A total of 411 COVID-19 patients were enrolled. Eighteen patients were excluded as they were less than 18 years old, 15 patients had both gastrointestinal disease and tumor, and 10 patients had incomplete information. The final cohort included 375 patients, among which 179 patients received standard care plus probiotics (the probiotics group) and the other 196 cases were treated with standard care alone (the non-probiotics group). The clinical characteristics are shown in Table 1 . Before probiotics treatment, the number of patients with diarrhea was 20 (10.2%) in the nonprobiotics group and 13 (7.3%) in the probiotics group (p = 0.10); the number of patients with abdominal pain was three (1.5%) in the non-probiotics group and three (1.7%) in the probiotics group (p = 0.12); the number of patients with nausea and vomiting was eight (4.1%) in the nonprobiotics group and four (2.2%) in the probiotics group (p = 0.12). After probiotics treatment, gastrointestinal symptoms of these patients improved and symptoms disappeared. We did not observe any side effects of probiotic usage. Compared with patients who received probiotics therapy, those who had not received probiotics had lower rates of mild type (5.6% versus 8.4%; standardized difference, 0.11) and normal radiological findings ( a patient who had not received probiotics therapy with standardized difference of less than 10% for all covariates, suggesting an adequate match (Table 1) . Compared with the non-probiotics group, the cumulative improvement rate was higher in the probiotics group with a log-rank p value of 0.028 ( Figure 1 ). Patients in the probiotics group also have an accelerated time to clinical improvement after matching [median, 18 days (IQR: 14-28) versus 21 days (IQR: 17-29)] with a median difference of −3 days (95% CI: −4 to −1; p = 0.022) [ Figure 2 (a) and Table 2 ]. The secondary outcomes of the probiotics and non-probiotics groups after matching are shown in Table 2 . Among patients who experienced fever symptoms, the duration of fevers in the probiotics group was also shorter than that in the non-probiotics group (median, 6 days versus 7 days) with a significant difference in median −1 day (IQR: −2 to 0 days; p = 0.025) [ Figure 1 Table 2) . The effects of probiotics on clinical improvement analyzed by Cox regression analyses in the unmatched cohort are shown in Table 3 In the present study, we found that probiotics added to standard care was superior to standard care alone in time to clinical improvement. The significant reduction in duration of viral shedding was related to clinical improvement as shown by the significant reductions in duration of fever and hospital stay. Gastrointestinal symptoms with a 70% relative increased risk for positive detection of COVID-19. The presence of diarrhea was associated with the severity of respiratory symptoms. 2 The gut microbiota are considered to have an important role on the innate and adaptive immune system. 16 Gutlung crosstalk may affect the gut microbiota in patients with COVID-19. 4 It has been shown that modulating intestinal flora can avoid early replication of influenza virus in lung epithelia and reduce ventilator-associated pneumonia. 17, 18 Currently, no specific treatment has been recommended for COVID-19. Probiotics have been recommended for maintain the balance of gut microbiota in COVID-19 patients and prevent secondary bacterial infection. 6 Probiotics, including bacteria and yeast, are living microorganisms that have been shown to be beneficial to human health. 17 In vivo experiments and clinical trials expand our current understanding of the critical role of probiotics in human intestinal flora-related diseases. Many clinical trials have shown that probiotics can shape the intestinal flora, making it possible to control a variety of intestinal diseases and promote overall health. 19 The presence of gastrointestinal symptoms was related to a 70%increased risk for positive detection of COVID-19. COVID-19 infection affects lung tissue and intestines, thereby activating inflammation. Probiotics supplementation may improve the ability of the gastrointestinal microbiota to regulate immune activity, thereby preventing viral infections, including COVID-19. Although many experimental and clinical studies support the possible role of probiotic microorganisms in protecting the host against viral infections (e.g., colds and flu), [20] [21] [22] [23] no research has reported the use of probiotics to treat or prevent COVID-19. In our study, higher percentages of antibiotics, antiviral treatment corticosteroids, intravenous immunoglobin, oxygen therapy, HFNC, NIMV, IMV, and ICU admission in the non-probiotics group before matching imply that disease was much more severe in the non-probiotics group compared with the probiotic group. Similarly, higher percentages of antibiotics were found in the non-probiotics group after matching. We found that patients in the probiotics plus standard care group had shorter time to clinical improvement. The significant reduction in duration of viral shedding was related to clinical improvement as shown by the significant reductions in duration of fever and hospital stay. These results may lead to a better understanding of probiotics use in COVID-19 patients. According to our study, the indication of probiotics is mild to severe patients with COVID-19 and the contraindication is patients who are allergic to probiotics. The strains selection may contain Bifidobacterium, Lactobacillus, and Enterococcus, based on our current study. The dosage of probiotics is given according to the specifications. However, these findings are observational, and we cannot exclude the possibility of unmeasured confounders or hidden bias that account for the association between probiotics use and improved outcomes. Further randomized controlled trials (RCTs) are needed to prospectively explore the benefit of probiotics in combating the COVID-19 pandemic. Our study may also provide a theoretical basis for the next prospective randomized controlled studies. Currently, three registered trials to evaluate probiotics administration to COVID-19 patients are ongoing and these studies could help to address the scientific questions. [24] [25] [26] Our study has several limitations. First, the cohort study design limits interpretation of results and confirmation of efficacy will require controlled trials; second, this study was limited to one single medical institution in Shenzhen and therefore may have limited external generalizability to other medical settings; third, critically ill patients are underrepresented, which did not allow the generalization of our findings to critical cases. In summary, our study has demonstrated that the use of probiotics was associated with a shorter time to clinical improvement including fever, hospital stay, and viral shedding in hospitalized COVID-19 subjects. This information may help clinicians to consider the use of probiotics in patients with mild to severe COVID-19. Further RCTs are needed to prospectively explore the benefit of probiotics in combating the COVID-19 pandemic. Contributors: LNZ, HQH, XL, and CZC served as co-first authors. TWL, JYW, and ZQW served as co-corresponding authors. TWL and ZQW designed the study, interpreted the results, the accuracy of the data analysis, and drafted the manuscript. LNZ, JYW, XL, and HQH contributed to data collection, data analysis, and data interpretation. XBX, CLW, SCY, QH, FW, FH, and GMS contributed to literature search and data collection. All authors approved the final version of the manuscript. Characterization and clinical course of 1000 patients with coronavirus disease 2019 in New journals York: retrospective case series Gastrointestinal symptoms and COVID-19: case-control study from the United States Clinical characteristics of coronavirus disease 2019 in China Gut microbiota and Covid-19-possible link and implications Management of COVID-19: the Zhejiang experience (in Chinese) National Health Commission of the People's Republic of China Involvement of digestive system in COVID-19: manifestations, pathology, management and challenges A trial of lopinavir-ritonavir in adults hospitalized with severe Covid-19 An introduction to propensity score methods for reducing the effects of confounding in observational studies Balance diagnostics for comparing the distribution of baseline covariates between treatment groups in propensity-score matched samples Addressing multiple gastroenterological aspects of coronavirus disease 2019 Enteric involvement in hospitalised patients with COVID-19 outside Wuhan Epidemiological, clinical and virological characteristics of 74 cases of coronavirus-infected disease 2018 (COVID-19) with gastrointestinal symptoms Gastrointestinal manifestations of SARS-CoV-2 infection and virus load in fecal samples from Hong Kong Cohort and systematic review and meta-analysis Gastrointestinal symptoms as the first, atypical indication of SARS-CoV-2 infection Potential role of gut microbiota in induction and regulation of innate immune memory The role of the lung microbiota and the gut-lung axis in respiratory infectious diseases The microbiome and critical illness Obesity as a risk factor for COVID-19: an overview Probiotic effects on cold and influenza-like symptom incidence and duration in children Specific probiotics in reducing the risk of acute infections in infancy-a randomised, double-blind, placebocontrolled study Effect of long term consumption of probiotic milk on infections in children attending day care centres: double blind, randomised trial An update on the use and investigation of probiotics in health and disease Evaluation of the probiotic lactobacillus coryniformis K8 on COVID-19 prevention in healthcare Bacteriotherapy in the treatment of COVID-19 Oxygen-ozone as adjuvant treatment in early control of COVID-19 progression and modulation of the gut microbial flora Visit SAGE journals online journals.sagepub.com/ home/tag The authors declare that there is no conflict of interest. The data supporting the findings of this study are available from the corresponding author upon reasonable request. The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work is sup- Tianwen Lai https://orcid.org/0000-0001-9921-3425 Supplemental material for this article is available online.