Inflammatory Bowel Disease and the Risk of Autoimmune Diseases.
BACKGROUND
An increased risk of autoimmune disease has been reported in patients with inflammatory bowel disease [IBD]. Using data from the Clinical Practice Research Datalink [CPRD], this study set out to further examine this relationship.


METHODS
Patients with a first-time IBD diagnosis were randomly matched to an equal-sized IBD-free comparison group. Incidence rates for new-onset autoimmune diseases were estimated. A nested case-control analysis comprising IBD patients was conducted, using conditional logistic regression to assess whether IBD severity, duration, or treatment influences the risk of developing autoimmune diseases.


RESULTS
During follow-up, 1069 IBD and 585 IBD-free patients developed an incident autoimmune disease. An increased incidence of autoimmune disease was observed in IBD patients (incidence rate [IR] 9.65, 95% confidence interval [CI] 9.09-10.24) compared with the non-IBD comparison group [IR 5.22, 95% CI 4.82-5.66]. In IBD patients, increased disease severity was associated with an increased risk of autoimmune disease development (odds ratio [OR] 1.62, 95% CI 1.28-2.05). Current antibiotic use was also associated with an increased risk [adjusted OR 1.72, 95% CI 1.07-2.78]. A reduced risk of incident autoimmune diseases was observed for current long-term users of aminosalicylates [adjusted OR 0.72, 95% CI 0.57-0.91].


CONCLUSIONS
Individuals with IBD had an increased risk of developing an autoimmune disease. Increased disease severity and current antibiotic use were associated with an increased relative risk of developing additional autoimmune diseases in IBD patients. Long-term current aminosalicylate use was associated with a reduced risk.
Basel Pharmacoepidemiology Unit, Department of Pharmaceutical Sciences, University of Basel, Switzerland.
J Claire
JC
Wilson
University Children's Hospital Basel, Basel, Switzerland.
Raoul I
RI
Furlano
Boston Collaborative Drug Surveillance Program, Boston University School of Public Health, Lexington, MA, USA.
Susan S
SS
Jick
Basel Pharmacoepidemiology Unit, Department of Pharmaceutical Sciences, University of Basel, Switzerland University Hospital Basel, Basel, Switzerland christoph.meier@usb.ch.
Christoph R
CR
Meier
D000293:Adolescent; D000328:Adult; D001327:Autoimmune Diseases / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D015551:Autoimmunity; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D015212:Inflammatory Bowel Diseases / Q000150:complications* / Q000453:epidemiology / Q000276:immunology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
IBD; autoimmune disease; observational study