The association of gout with incident giant cell arteritis in older adults.

Abstract

To assess whether gout is associated with a higher or lower risk of a new diagnosis of giant cell arteritis (GCA) in older adults, adjusting for known risk factors of GCA. We used the 5% Medicare claims to conduct a multivariable Cox regression analyses to assess the association of gout with incident GCA in adults 65 years or older adjusting for age, gender, race (known risk factors for GCA) and Charlson-Romano comorbidity score, the use of medications for cardiovascular diseases (statins, beta-blockers, diuretics, ACE-inhibitors) and gout (allopurinol, febuxostat). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated. There were 3004 incident cases (new diagnosis) of GCA with crude incidence rates of GCA of 28.0/100,000 person-years in patients without gout and 63.8/100,000 person-years in patients with gout. Multivariable-adjusted analyses showed that preexisting gout was associated with a higher risk of incident/new GCA diagnosis with a hazard ratio of 2.05 (95% CI: 1.76, 2.40), confirmed in sensitivity analyses that substituted continuous Charlson-Romano comorbidity score with categorized score or individual comorbidities (plus hypertension, hyperlipidemia, and coronary artery disease). Older age, female gender, white race and higher comorbidity index, were also associated with a higher hazard of GCA. Subgroup analyses did not show any significant variation of the association of preexisting gout with incident GCA by age, race or sex. Gout was associated with more than 2-fold higher risk of incident GCA in older adults, independent of known risk factors of GCA. Future studies should explore the underlying mechanisms for this association.