Higher risk of thyroid disease seen with ANCA-associated vasculitis
Findinigs underscore need for regular monitoring of thyroid function in AAV
People with ANCA-associated vasculitis (AAV) have a higher frequency of thyroid diseases, that is, those that affect the hormone-production function of the thyroid gland, than the general population, a study in China suggests.
Being female, having coronary artery disease, which is marked by reduced blood flow in the arteries that deliver blood to the heart, and testing positive for anti-Ro/SSA self-reactive antibodies, which are linked to other autoimmune diseases, were independent risk factors of thyroid disease among AAV patients.
The findings show “regular monitoring of thyroid function is advised for AAV patients, particularly for women, those with coronary artery disease, and those who are positive for anti-Ro/SSA antibodies,” the researchers wrote.
The study, “Clinical associations with thyroid disease in ANCA-associated vasculitis,” was published in Clinical Rheumatology.
In AAV, self-reactive antibodies, or ANCAs, that overly activate certain cells of the immune system called neutrophils cause inflammation and damage to small blood vessels. The disease can lead to symptoms in several organs, including the kidneys and lungs. AAV patients have a higher rate of coexisting conditions than the general population, which can negatively affect survival and quality of life. People with AAV have a higher prevalence of thyroid disease, increasing evidence suggests.
The thyroid gland in the neck produces hormones that are essential for controlling bodily functions such as weight and appetite, heartbeat, and blood pressure. Thyroid diseases can be mainly classified as hypothyroidism, where there is insufficient hormone production; hyperthyroidism, when there’s excessive hormone production; and autoimmune thyroid disease, which occurs when self-reactive antibodies target thyroid cells, causing inflammation.
“However, there is a lack of comprehensive understanding regarding AAV patients with concurrent thyroid disease, particularly in the Chinese population,” the researchers wrote.
Evaluating thyroid disease among Chinese AAV patients
Here, researchers at The Second Affiliated Hospital of Chongqing Medical University in China sought to assess the frequency of thyroid disease and its potential risk factors in AAV patients and retrospectively analyzed data from 305 newly diagnosed AAV patients hospitalized there between October 2010 and December 2023. The patients were an average age of 63 and 50.8% were women.
Fifty-two patients (17%) had thyroid disease — 40 with hypothyroidism, eight with hyperthyroidism, and eight with autoimmune thyroid disease. Four patients had both hypothyroidism and autoimmune thyroid disease.
The rate of thyroid disease “is notably higher than the prevalence in the general population (6.71%-11.9%),” the researchers wrote.
The group of AAV patients with coexisting thyroid disease had a significantly higher proportion of women (67.3% vs. 47.4%), coronary artery disease (21.2% vs. 8.7%), and kidney disease (75% vs. 60.5%) than those without thyroid disease.
The thyroid disease group was also significantly more likely to have antibodies related to other autoimmune diseases called anti-Ro/SSA antibodies (26.9% vs. 7.5%) and anti-Ro52 antibodies (21.2% vs. 9.5%).
Data from the 103 patients tested for self-reactive antibodies linked to autoimmune thyroid disease showed that those with thyroid disease were significantly more likely to have anti-Tg antibodies (57.1% vs. 11%) and anti-TPO antibodies (52.4% vs. 9.8%).
“Given the high prevalence of thyroid disease in AAV patients, we suggest regular thyroid testing for AAV patients with positive anti-thyroid antibodies in order to take targeted measures,” the researchers wrote.
A statistical analysis adjusted for potential influencing factors indicated that being female, having coronary heart disease, and testing positive for anti-Ro/SSA antibodies were significantly linked to a higher likelihood of having thyroid disease among AAV patients.
Being female significantly increased the risk of having coexistent thyroid disease by about two times, while coronary heart disease was linked to a three time higher risk and anti-Ro/SSA antibodies to a nearly five times higher risk.
Thyroid disease is more frequent in women than men, with hormonal and genetic factors possibly playing a role. “Therefore, it is reasonable to screen for thyroid function in AAV patients, especially among female patients,” the researchers wrote.
Thyroid hormones affect heart function and research has suggested “coronary artery disease in AAV patients with thyroid dysfunction may preexist and be aggravated by thyroid dysfunction,” they wrote, adding “the presence of anti-Ro52 antibodies is commonly linked to a worse prognosis and autoimmune dysfunction,” with “the disorder of the immune environment” the possible “reason for the link between AAV patients and thyroid disease.”
The researchers said their findings enhance “our understanding of thyroid disease in AAV and provides relevant clinical information and a reliable foundation” for more research.
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