Giant cell arteritis and inflammatory bowel disease - Is there a connection? Results from a population-based study.

BACKGROUND: Giant cell arteritis (GCA) is an autoimmune disorder which primarily affects large vessels, whilst inflammatory bowel diseases (IBD) mainly target the gut. Co-existence of the two maladies has been reported sporadically in the literature; therefore the purpose of this study was to assess the authenticity of such an association in a large, cross-sectional study.

METHODS: Utilizing data derived from the Clalit Health Services' registry, the largest health maintenance organization in Israel, we compared the proportion of CD and UC in GCA patients with age- and gender-matched controls. Univariate analysis was performed using Chi-square and student t-test and a multivariate analysis was performed using a logistic regression model.

RESULTS: The study included 3938 GCA patients and 21,623 age- and gender-matched controls. GCA patients had a significantly increased proportion of both CD and UC in comparison with controls (0.79% vs. 0.12% and 0.84% vs. 0.21%, P-value < .001, respectively). The strength of the association between GCA and IBD was negatively correlated with the patients' age; thus the association was more robust amongst middle-aged patients (ages 50-69, OR = 8.13) than in elderly patients (ages 70-85, OR = 3.81). The association between GCA and IBD remained significant when evaluated independently of confounding factors (OR = 2.63, P-value < .001).

CONCLUSIONS: The probability that GCA patients also suffer from IBD is increased in comparison with age- and gender-matched controls. Our findings indicate that this association is more prominent in middle-aged patients (50-69 years of age). Screening for IBD amongst GCA patients in this age group may be warranted.