Increased Infection Risk After Giant Cell Arteritis Diagnosis

Patients with giant cell arteritis (GCA) have an increased risk of severe infections or infection-related mortality during their first year following diagnosis, according to data recently published by the Giant Cell Arteritis Group in Arthritis & Rheumatology.

Although treatment with corticosteroids can suppress symptoms of GCA, relapses of the disease are common, which could lead to prolonged treatment with higher doses. Additional treatment options have been explored, but it is difficult to ascertain the risk factors of infection for these treatments. In this study, researchers examined the cause of infections, the incidence of infections that led to hospitalization, and the mortality rate related to infections.

“Severe infections and infection-related mortality are increased during GCA course, especially during the first year of the disease, among patients with diabetes and in older patients,” the authors wrote. “Septic shock, infectious colitis, and tuberculosis are more frequent in these patients.”

The researchers enrolled 486 participants with GCA who met the American College of Rheumatology criteria for diagnosis.  The cohort comprised 75% women, and the mean age was 74.5 ± 8 years. Participants were also selected for an additional cohort based on age and gender at the time of diagnosis.

Over a 5-year follow-up period, researchers observed that severe infections occurred more frequently in GCA patients during the first year of diagnosis (incidence rate ratio 2:1). The incidence rate of severe infection for patients with GCA was 11.1 per 100 person-years compared with 5.9 per 100 person-years among participants without GCA.

Among patients with GCA, the researchers observed more cases of septic shock, infectious colitis, and mortality caused by infections (log rank test, P<.0001). Patients with diabetes (hazard ratio [HR]: 3.3) and those taking >10 mg/d of corticosteroids after 12 months of treatment (HR: 4.61) also had an increased risk of mortality from infection.

The researchers noted that prior to 1997, overall mortality was increased among patients with GCA (log rank test, P=.0001), but after that time the mortality rate was the same as the general population.

“Close clinical monitoring, early antibiotic treatment, and specific screening for tuberculosis before treatment may be ways to reduce severe infections in patients with GCA,” the authors noted. “Further trials testing strategies to spare corticosteroid treatments may be of interest, with particular attention in potential infectious complications caused by immunosuppressant drugs.”

Summary and Clinical Applicability

Patients experienced severe infection more frequently during the first year following a diagnosis of GCA.  Patients with CGA and diabetes, and those treated with >10 mg/d for more than 12 months are at increased risk of mortality from infection. Additional research would be beneficial in determining alternative treatment strategies to spare patients from prolonged corticosteroid use.

Reference

Schmidt J, Smail A, Roche B, et al. Severe infections during giant cell arteritis course: incidence and mortality. The prospective, multicenter double cohort GRACG study. Arthritis Rheum. 2016; doi: 10.1002/art.39596. In press.