key: cord-0789419-csr784p6 authors: Chen, Hui‐Yuan; Wang, Shiow‐Ing; Chang, Renin; Wei, James Cheng‐Chung title: Letter: association between COVID‐19 and inflammatory bowel disease date: 2022-04-16 journal: Aliment Pharmacol Ther DOI: 10.1111/apt.16814 sha: ed7c715ea893217cc2b9f628aeee6ac272300bf6 doc_id: 789419 cord_uid: csr784p6 This article is linked to Hadi et al. papers. To view these articles, visit https://publons.com/publon/10.1111/apt.16730 https://doi.org/10.1111/apt.16900 We read with great intriguing the research TriNetX network analysis by Yousaf Hadi et al. 1 They described a decreased risk of infection in the IBD patients with incidence rate ratio of 0.79; another breakthrough was about no increased risk for new-onset IBD after COVID-19 infection. This research has produced valuable results. However, we believe that some methodological issues should be considered that would add strength to the article. First, because the authors selected IBD cases by ICD-10 codes plus IBD therapeutic drugs, we suggest specific procedures such as endoscopy with biopsy should be included to avoid selection bias. 2 Since ICD-10 codes for COVID-19 change and update during the pandemic, we would like the authors to describe the exact codes they used rather than gloss over, so that other researchers can replicate them afterwards. Second, patients with immune-mediated inflammatory diseases are encouraged to receive the SARS-CoV-2 vaccine. We recommend that the authors take into account individual vaccine status to make their report more closely related to real-world practice. 3, 4 Third, the authors had included anti-TNF, biologics and steroids in their analysis, but should consider including antibiotics in their adjustment when investigating the risk of IBD after COVID-19 infection, because antibiotics play important role in the development of IBD. 5, 6 Although a causal and definitive effect of COVID-19 on IBD will require future studies to reach a final conclusion, we thank Yousaf Hadi et al. for their excellent article and look forward to their response. Declaration of personal interests: None. Data sharing is not applicable to this article as no new data were created or analyzed in this study. Incidence, outcomes, and impact of COVID-19 on inflammatory bowel disease: propensity matched research network analysis ECCO-ESGAR guideline for diagnostic assessment in IBD part 1: initial diagnosis, monitoring of known IBD, detection of complications SARS-CoV-2 vaccination in IBD: more pros than cons Review article: prevention, diagnosis and management of COVID-19 in the IBD patient maximum of 500 words, may contain one table or figure, and should have no more than 10 references Environmental triggers in IBD: a review of progress and evidence Systematic review on inflammatory bowel disease patients with coronavirus disease 2019: it is time to take stock