Hypothyroidism in vasculitis

Objective To study the prevalence, risk and clinical associations of hypothyroidism among several forms of vasculitis. Methods Patients with GCA, Takayasu's arteritis (TAK), PAN and the three forms of ANCA-associated vasculitis [AAV; granulomatosis with polyangiitis (GPA), microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis (EGPA)] enrolled in a prospective, multicentre, longitudinal study were included. Results The study included data on 2085 patients [63% female, 90% White] with a mean age of 54.6 years (S.d. 17.2). Diagnoses were GCA (20%), TAK (11%), PAN (5%), GPA (42%), microscopic polyangiitis (8%) and EGPA (14%). Hypothyroidism was present in 217 patients (10%) (83% female), with a mean age 59.8 years (S.d. 14.5). Age- and sex-adjusted risk of hypothyroidism was GCA, odds ratio (OR) 0.61 (95% CI 0.41, 0.90); TAK, OR 0.57 (95% CI 0.31, 1.03); PAN, OR 0.59 (95% CI 0.25, 1.38); GPA, OR 1.51 (95% CI 1.12, 2.05); microscopic polyangiitis, OR 1.81 (95% CI 1.18, 2.80) and EGPA, OR 0.82 (95% CI 0.52, 1.30). Among patients with AAV, age- and sex-adjusted risk of hypothyroidism was higher with positive MPO-ANCA [OR 1.89 (95% CI 1.39, 2.76)]. The clinical manifestations of vasculitis were similar in patients with and without hypothyroidism, except transient ischaemic attacks, which were more frequently observed in patients with GCA and hypothyroidism (12% vs 2%; P = 0.001). Conclusions Differences in the risk of hypothyroidism among vasculitides may be due to genetic susceptibilities or immune responses. This study confirms an association of hypothyroidism with MPO-ANCA.

Automated summary

This study included 2085 patients with vasculitis and found that 10% of patients also had hypothyroidism, with a higher prevalence among female patients. The risk of hypothyroidism varied among different types of vasculitis, possibly due to genetic susceptibilities or immune responses. The study also confirmed an association of hypothyroidism with MPO-ANCA in ANCA-associated vasculitis.