Introduction
As well as having a major impact on bone metabolism, vitamin D (vitD) is recognised as an immunomodulatory hormone with a pivotal role in the pathogenesis of inflammatory bowel disease (IBD). Low vitD levels in patients with IBD are associated with active inflammation, disease severity, poor quality of life and adverse clinical outcomes. Furthermore, lower vitD levels in patients with IBD were shown to be associated with higher pro-inflammatory cytokine profiles. Therefore, it is plausible that vitD may have use as a therapeutic agent in IBD. Our previous work suggests that pre-treatment with vitD may improve effectiveness of biologic drugs such as TNF-α inhibitors and the anti-integrin agent vedolizumab (VDZ). However, data in this context is limited.
Aims & Methods
The aim of this study was to explore potential effects of serum vitD levels on biologic treatment response in IBD patients. A retrospective cohort study was conducted to monitor ambulant treatment of IBD patients with biologics in relationship to their vitD levels. Medical records and routine blood and stool samples of 162 adult IBD patients were assessed at therapy start and 8-weekly thereafter. Samples were analysed for standard blood count, total 25OHD, albumin and inflammation parameters (hsCRP, ESR and faecal calprotectin (FC)) by standard methods. Biologic treatments (infliximab (IFX), its biosimilars (IFX-s), VDZ and ustekinumab (UST)) were administered over 1 year. Drug and anti-drug antibody (ADA) levels were measured with systems provided by Immundiagnostik AG, Bensheim, Germany. VitD values were dichotomized into deficient (≤ 30ng/mL) and sufficient (>30ng/mL). A positive treatment response was defined according to evidence of inflammation as shown by change in hsCRP-levels from baseline to the last two samples monitored. IBM SPSS Statistics 24 was used for statistical analysis.
Results
162 patients with IBD (91 with Crohn’s disease (CD)/ 71 with ulcerative colitis (UC); 81 f/81 m; age 40.2±11.5y) were enrolled. At baseline, 40.7 % used vitD supplementation, 10.5 % were biologic naïve and 50.6 % were vitD deficient. No conclusive relations were found between baseline vitD or supplementation status with drug or ADA levels. However, higher vitD levels over time were associated with positive treatment response for patients on IFX and UST (p<0.05). Treatment specific analysis revealed no significant associations between drug TCs and overall vitD status or treatment response. In descriptive analysis, pre-treatment vitD status was not associated with demographic or clinical characteristics but positively associated with mean corpuscular volume (MCV) and FC and inversely related to transferrin. Ultimately, 72.8 % of patients responded to biologic treatment. Response was related to disease location in CD (p = 0.011) and positively associated with naivety to biologics (p = 0.040). Treatment responders had significantly higher Hb, iron, TSAT and significantly lower ESR, hsCRP and FC.
Conclusion
Our results support a protective role of vitD in IBD patients treated with the biologic agents IFX and UST, shown here for the first time for UST. Interestingly, not the initial vitD status, but permanently sufficient vitD levels were decisive for improved treatment response. Therefore, regular vitD monitoring and long-term vitD substitution in patients with low vitD levels is indicated.
Disclosure
Olivia Schütte, Lea Tessmer and Julia Stötzel have nothing to disclose. Aysegül Aksan is an employee of Immundiagnostik AG.
Oliver Schröder: Lecturing fees: Abbvie, Falk, Janssen, Takeda, Norgine and Pfizer. Congress expenses: Falk, Pfizer.
Jürgen Stein: Consulting: Abbvie, Bristol Myers Squibb, Dr Schär, Falk, Ferring, Fresenius Kabi, Immundiagnostik, Janssen, Medice, MSD, Pfizer, Pharmacosmos, Shire, Takeda, Thermofisher, Vifor. Board member: Abbvie, Bristol Myers Squibb, Dr Schär, Ferring, Fresenius Kabi, Immundiagnostik, Janssen, MSD, NPS, Pharmacosmos, Takeda, Vifor and Shield. Lecturing fees: Vifor Pharma