Infections up risk of subsequent giant cell arteritis

Infections, specifically those of the respiratory tract, may contribute to the development of biopsy-confirmed giant cell arteritis (GCA), suggests a study.

The authors identified patients diagnosed with biopsy-confirmed GCA between 2000 and 2016 through the database of the Department of Pathology in Skåne, Sweden, in order to examine the link between infections and subsequent development of GCA in a large population-based cohort.

Ten controls were randomly selected from the general population for each GCA case, matched according to sex, age, and area of residence. The authors used the Skåne Healthcare Register to identify all infection events prior to the patients’ date of GCA diagnosis and the controls’ index data.

A conditional logistic regression model was used, with infection as exposure, to estimate odds ratio (OR) for developing GCA. The types of infections contracted nearest in time to the GCA diagnosis/index data were also identified.

The analysis included a total of 1,005 patients with biopsy-confirmed GCA (71 percent female) and 10,050 controls. Infections occurred more frequently among patients subsequently diagnosed with GCA than in controls (51 percent vs 41 percent; OR, 1.78, 95 percent confidence interval [CI], 1.53–2.07).

GCA was associated with the following infections: acute respiratory tract infection (OR, 1.77, 95 percent CI, 1.47–2.14), influenza and pneumonia (OR, 1.72, 95 percent CI, 1.35–2.19), and unspecified infections (OR, 5.35, 95 percent CI, 3.46–8.28). Skin and gastrointestinal infections did not show an association.

“Our findings support the hypothesis that a range of infections may trigger GCA,” the authors said.