Vitamin D has been linked to disease activity among patients with inflammatory bowel diseases (IBD). Prior investigation has also suggested that vitamin D levels may affect duration of therapy with anti-tumour necrosis factor-α (anti-TNF-α) medications among patients with IBD.
To evaluate the relationship between vitamin D levels and odds of reaching remission while on an anti-TNF-α medication.
A total of 521 IBD patients enrolled in the Brigham and Women's IBD Centre database were eligible for inclusion. Patients treated with anti-TNF-α therapy who had vitamin D levels drawn within 6 months prior or 2 weeks after initiation of anti-TNF-α medication and who had reported remission status at 3 months were included. A logistic regression model adjusting for age, gender, IBD diagnosis, anti-TNF-α medication (infliximab vs. adalimumab) and first or subsequent anti-TNF-α medication was used to identify the effect of vitamin D level on initial response to anti-TNF-α therapy.
A total of 173 patients were included in the final analysis. On logistic regression, patients with normal vitamin D levels n = 122 at the time of anti-TNF-α medication initiation had a 2.64 increased odds of remission at 3 months compared to patients with low vitamin D levels n = 51 when controlling for age, gender, diagnosis, type of anti-TNF-α medication and first or subsequent anti-TNF-α medication (OR = 2.64, 95% CI = 1.31-5.32, P = 0.0067).
These findings suggest that vitamin D levels may influence initial response to anti-TNF-α medication and that low vitamin D levels may pre-dispose patients to decreased odds of remission.