Use of anti-TNF-α therapy in Crohn's disease is associated with increased incidence of multiple sclerosis

Objective: We investigated if anti-tumor necrosis factor-α (anti-TNF-α) drugs used in the treatment of inflammatory bowel disease (IBD) alter the incidence of MS and if so, to understand the magnitude of such an effect. Methods: This is a retrospective cohort study of data from Truven Health Market Scan administrative claims database. The patients included in the study had to be ≥ 18 years of age. The presence of IBD was based on at least 2 claims of International Classification of Diseases (ICD-9 or 10) diagnosis codes. The IBD diagnosis index date had to precede the MS diagnosis index date for inclusion in the study. The diagnosis of multiple sclerosis (MS) was defined as having at least 2 claims for the disease (ICD 9, 340 and ICD 10 codes, G35) and at least one prescription claim for any of the drugs that were defined as MS therapy. Results: Patients with IBD had 1.32 times the risk of MS incidence compared to healthy controls (adjusted incidence rate ratio (IRR): 1.32; 95% CI: 1.03 – 1.71; p = .0312). Patients with IBD exposed to anti-TNF-α therapies had a 43% increase in the incidence of MS compared to those with IBD without exposure (adjusted incidence rate: 1.43; 95% CI: .062 – 3.32; p = .3989). Among CD patients treated anti-TNF-α medications an increase in the incidence of MS, compared to CD patients not exposed to such medications was observed (IRR = 2.62; 95% CI: 1.00 to 6.83; p = 0.049), statistically significant. After adjusting for age/gender, patients with CD using anti-TNF-α agents had an increase of incidence in MS (adjusted IRR: 2.24; 95% CI: 0.85 – 5.94; p = .1035) but it was not statistically significant. Conclusions: Use of anti-TNF-α drugs in CD was associated with a statistically significant increase in the incidence of MS but this effect was lost when controlled for age/gender.