Patients with AAV Have Higher Prevalence of Thyroid Disease, Study Finds

Patients with ANCA-associated vasculitis (AAV) have a higher prevalence of thyroid disease than the general population, a single-center retrospective analysis shows.

But the increase in thyroid disease is not related to the use of anti-thyroid medications, researchers said.

The study, “Increased Prevalence of Thyroid Disease in Patients with Antineutrophil Cytoplasmic Antibodies−associated Vasculitis,” was published in The Journal of Rheumatology.

Research has suggested that antithyroid medications taken by patients with thyroid disease may increase the risk for antineutrophil cytoplasmic antibody AAV in these patients.

Propylthiouracil, for example, is an oral medication used to manage hyperthyroidism (an overactive thyroid gland). The medicine works by decreasing the amount of thyroid hormone produced by the thyroid gland.

Now, researchers performed a retrospective analysis of AAV patients from a single center in the U.K. to assess the prevalence of thyroid disease.

They reviewed clinical data from 279 AAV patients diagnosed between 1991 and 2014. Among them, 21.5% were positive for thyroid disease, including 17.6% with hypothyroidism and 4% with hyperthyroidism.

“This is much higher than the reported population prevalence of hypothyroidism in the United Kingdom, which is around 1%,” researchers wrote.

Women were particularly affected, with hypothyroidism affecting 30.8% of the women in the study, compared to 2% in the general population.

While AAV patients had a higher incidence of thyroid disease, the results were not dependent on the use of antithyroid medications, researchers found. Only two of the 60 patients with thyroid disease patients had previously received propylthiouracil.

“This is similar to a previously reported prevalence of thyroid disease of 20% in 158 patients with AAV, and 38% in women with AAV, in an American case-control series,” researchers wrote. In this study the use of antithyroid drugs was also low — only two patients out of 219.

The findings suggest that AAV patients do have a higher prevalence of thyroid disease than the general population, but the reason is not linked to the use of antithyroid medications.

“Given the high prevalence of thyroid disease, particularly hypothyroidism, in our group of patients with AAV, we would suggest that patients diagnosed with AAV should be assessed for evidence of thyroid disease or antithyroid antibodies through periodic testing of thyroid function,” the study concluded.