Background and Aims Vitamin D has a regulatory role in innate and adaptive immune processes. Previous studies have reported that low pre-treatment vitamin D concentrations are associated with primary non-response (PNR) and non-remission to anti-TNF therapy. This study aimed to assess whether pre-treatment 25-hydroxyvitamin D concentrations predicted PNR and non-remission to infliximab and adalimumab in patients with active luminal Crohn’s disease. Methods 25-hydroxyvitamin D concentrations were measured in stored baseline samples from 659 infliximab- and 448 adalimumab-treated patients in the Personalised Anti-TNF Therapy in Crohn’s disease (PANTS) study. Cut-offs for vitamin D were: deficiency < 25nmol/L, insufficiency 25-50nmol/L and adequacy/sufficiency > 50nmol/L. Results 17.1% (189/1107; 95% confidence interval [CI] 15.0 - 19.4%) and 47.7% (528/1107; 95% CI 44.8 - 50.6%) patients had vitamin D deficiency and insufficiency, respectively. 22.2% (246/1107) patients were receiving vitamin D supplementation. Multivariable analysis confirmed that sampling during non-summer months, South Asian ethnicity, lower serum albumin concentrations and nontreatment with vitamin D supplements were independently associated with lower vitamin D concentrations. Pre-treatment vitamin D status did not predict response or remission to anti-TNF therapy at week 14 (infliximab Ppnr = 0.89, adalimumab Ppnr = 0.18) or non-remission at week 54 (infliximab p = 0.13, adalimumab p = 0.58). Vitamin D deficiency was, however, associated with a longer time to immunogenicity in patients treated with infliximab, but not adalimumab. Conclusion Vitamin D deficiency is common in patients with active Crohn’s disease. Unlike previous studies, pre-treatment vitamin D concentration did not predict PNR to anti-TNF treatment at week 14 or non-remission at week 54.

Cases of acute gastrointestinal bleeding dropped significantly during national lockdowns. Concomitant gastrointestinal bleeding and COVID‐19 had a very poor prognosis. Endoscopy services rose to the challenge of the COVID‐19 pandemic.

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