Gout — a form of inflammatory arthritis that causes sudden attacks of severe pain and swelling around the joints — increases the risk for Sjögren’s syndrome among elderly patients, a U.S.-based, large-scale study shows.
The study, “The Risk of Sjogren’s Syndrome in the Older adults with Gout: A Medicare Claims Study,” was published in the journal Joint Bone Spine.
Sjögren’s syndrome is a chronic autoimmune disorder characterized by infiltration of immune cells into the salivary and lacrimal glands, causing dry eyes and mouth, and systemic inflammation. This disorder often coexists and shares mechanisms with other autoimmune diseases, such as lupus, scleroderma, and rheumatoid arthritis.
Gout also seems to share some molecular and inflammatory processes with Sjögren’s, but a potential relationship between these two diseases has not been explored.
To fill this gap, researchers at the University of Alabama at Birmingham aimed to determine if gout influenced the risk for Sjögren’s syndrome, and which factors participated in this association.
Gout is the most common type of inflammatory arthritis in adults. It is characterized by the formation and accumulation of crystals in the joints and systemic inflammation.
Researchers examined 5% of all Medicare claims registered from 2006 to 2012, covering a total of 1,736,901 individuals 65 or older in the U.S. They identified 3,186 cases of Sjögren’s syndrome — 3,036 in individuals without gout and 150 in patients with gout.
People affected by Sjögren’s syndrome were more likely to be female, white, and to have a higher prevalence of secondary disorders — particularly chronic pulmonary disease and connective tissue disease — than individuals without this autoimmune disease.
The presence of a medical comorbidity — defined as a secondary disorder unrelated to Sjögren’s — significantly increased the risk for Sjögren’s, researchers reported. Compared to patients without any comorbidity, the risk raised by 40% for those with one comorbidity, and by 70% for patients with two or more.
Gout, in particular, made patients 73% more likely of having Sjögren’s, an association that was independent of the presence of connective tissue diseases. The association, however, was higher for women (75%) than for men (67%).
“We found that gout was associated with 1.7-fold higher risk of Sjögren’s syndrome in the elderly, independent of other factors,” researchers stated. “Younger age, female sex, white race, and higher medical comorbidity were associated with a higher risk of incident Sjögren’s syndrome.”
Additional studies are still warranted to explore the common disease mechanisms that underlie this association, which may be linked to the inflammatory process, researchers suggested.