Objective: Rheumatoid arthritis (RA) patients have an increased risk of developing cardiovascular diseases (CVD). Other autoimmune diseases like hypothyroidism are also associated with an enhanced risk for CVD. Our objective was to determine, firstly, the prevalence of hypothyroid disorders in RA patients and, secondly, the risk of CVD in RA patients with hypothyroid abnormalities.
Methods: Subjects were RA patients who participated in an ongoing prospective cohort study of cardiovascular mortality and morbidity (n = 358) in which hypothyroid abnormalities were assessed. CVD was defined as a verified medical history of coronary, cerebral or peripheral arterial disease.
Results: Clinical hypothyroidism was observed in 16/236 female RA patients (6.8%), which is significantly higher than in the general population of the Netherlands. Subclinical hypothyroidism was detected in 6/236 RA women (2.5%). In female RA patients, CVD was present in 6/16 (37.5%) of all hypothyroid women. The odds ratio for CVD comparing female hypothyroid RA patients with female euthyroid RA patients was 4.1 (95%-CI: 1.2-14.3) after adjustment for sex, age, diabetes, smoking ever, hypertension and statin use.
Conclusions: Clinical hypothyroidism was observed three times more often in female RA patients than in females of the general population. In female RA patients, clinical hypothyroidism was associated with a fourfold higher risk of CVD in comparison with euthyroid female RA patients independently of the traditional risk factors.
- cardiovascular disease
- rheumatoid arthritis
- systemic inflammation