Background: It remains uncertain whether vitD3 supplementation is beneficial for remission of Crohn's disease (CD). The influence of vitD3 supplementation on Infliximab (IFX) efficacy was retrospectively analyzed in Chinese CD patients. Methods: Patients with moderate-to-severe CD, who were bio-naïve and prescribed with IFX treatment for at least 54 weeks were recorded. VitD3 supplementation was defined as patients additionally took oral vitD3 (125 IU/d) within 3 days after the first infusion and persisted in the whole follow-up period. Disease activity was assessed using Harvey-Bradshaw Index (HBI). Serum cytokine profiles were quantitatively analyzed in a subset of all patients at baseline and 54-week after intervention.

Inclusion Criteria:

• moderate-to-severe CD
• Treated with Infliximab
• bio-naïve at the time of diagnosis

Exclusion Criteria:

• had recent supplementation of vitD3
• had prior or concomitant use of other biologic agent, glucocorticoid and/or immunomodulators at the time of enrollment
• pregnant
• had cognitive/developmental disorders that affected their ability to complete the study procedures
• had medical illness or therapies potentially affecting bone, nutrition or growth status

Chinese

Data sets will be made available on relevant requests and in accordance with journal guidelines when publishing results from this study.