Background In 1977, How et al.¹ described the case of a simultaneous presentation of giant cell arteritis (GCA) and hypothyroidism. In the following decades, numerous studies have attempted to determine whether a significant interaction exists between GCA and autoimmune thyroid dysfunction, with conflicting results^2–5.

Objectives To evaluate whether a genuine association exists between GCA and autoimmune thyroid disease.

Methods Utilizing the medical database of Clalit Health Services, we compared the proportion of autoimmune thyroid disease between patients with GCA and age- and gender-matched controls in a cross-sectional study. Univariate analysis was performed using Chi-square and student t-test and a multivariate analysis was performed using a logistic regression model.

Results 5,663 GCA patients and 23,308 age- and gender-matched controls were included in the study. The proportion of hypothyroidism amongst GCA patients was increased in comparison with controls (18.2% vs. 6.91%, respectively, p-value <0.001), as was hyperthyroidism (2.56% and 1.19% respectively, p-value <0.001). After controlling for confounders, GCA demonstrated a robust independent association with hypothyroidism on multivariate logistic regression (OR 1.297, 95% CI 1.187–1.418, Table 1). In contrast, when a similar model was performed in order to assess the nature of the association between GCA and hyperthyroidism, it was found to be non-significant, with an OR of 1.097.

Conclusions GCA patients have a higher proportion of hypothyroidism in comparison with matched controls. A significant association between GCA and hyperthyroidism was not found. Physicians treating GCA patients should consider screening for thyroid dysfunction on a regular basis.

References

1. How J, Bewsher PD, Walker W. Giant-cell arteritis and hypothyroidism. Br Med J. 1977;2(6079):99.

2. Wiseman P, Stewart K, Rai GS. Hypothyroidism in polymyalgia rheumatica and giant cell arteritis. BMJ. 1989;298(6674):647.

3. Bowness P, Shotliff K, Middlemiss A, Myles AB. Prevalence of hypothyroidism in patients with polymyalgia rheumatica and giant cell arteritis. Rheumatology. 1991;30(5):349–351.

4. Duhaut P, Bornet H, Pinède L, et al. Giant cell arteritis and thyroid dysfunction: multicentre case-control study. BMJ. 1999;318(7181):434–435.

5. Myklebust G, Gran JT. A prospective study of 287 patients with polymyalgia rheumatica and temporal arteritis: clinical and laboratory manifestations at onset of disease and at the time of diagnosis. Rheumatology. 1996;35(11):1161–1168.

References

Disclosure of Interest None declared