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Patients with giant cell arteritis (GCA) have a slightly increased mortality risk in the first 2 years after diagnosis and again after 10 years, a Danish study found.

During the first 24 months after being diagnosed with biopsy-proven giant cell arteritis, patients had a mortality rate ratio of 1.17 (95% CI 1.01-1.36) compared with population controls, according to , and colleagues from Rigshospitalet in Copenhagen.

Then, after 10 years, mortality again was slightly elevated, with a mortality rate ratio of 1.22 (95% CI 1.05-1.41), the researchers reported in the January issue of

Giant cell arteritis is a vasculitis of older adults that is characterized by inflammation of the extra-cranial branches of the carotid artery and also involvement of the aorta in many cases. It can predispose patients to events such as aortic aneurysms and diseases of the circulatory system.

"The pathogenic events underlying the increased risk of cardiovascular deaths in the present cohort cannot be determined from our data. It is tempting to speculate that inflammation in the larger arteries may be of importance for the increased mortality observed in the first 2 years after GCA diagnosis, while relapsing or persistent vasculitis activity may have contributed pathogenically to the increased number of deaths from diseases of the circulatory system observed after prolonged follow-up," Baslund and colleagues wrote.

examining mortality rates in GCA have yielded conflicting results and have been limited by small numbers and the inclusion of patients whose diagnosis had not been confirmed through a biopsy showing inflammation of giant cells in the temporal artery.

Because Denmark has national registries of all inpatient and outpatient diagnoses and pathology findings, the researchers were able to conduct a thorough study of all patients having confirmed GCA between 1993 and 2011, along with matched population controls.

Their analysis included 1,787 patients and 33,953 controls. Three-quarters of the patients were women, median age was 74 at the time of diagnosis, and median follow-up was slightly under 7 years.

A total of 846 patients died, as did 15,484 controls.

In the first 2 years, death rates for the GCA patients were 56.3 per 1,000 patient-years (95% CI 48.7-65.1), while after 10 years, rates were 112.4 per 1,000 patient-years (95% CI 97.3-129.7).

No differences were seen in mortality between patients and controls during years 2 to 10, when the mortality rate ratio was 0.96 (95% CI 0.88-1.05), the researchers found.

Relative risks of death were not significantly different in patients older versus younger than 75, or according to gender or calendar year of diagnosis.

Mortality risks did show some differences by cause of death. For instance, during the first 2 years after diagnosis, the mortality rate ratio for circulatory disease was 1.32 (95% CI 1.04-1.68) and was again elevated after 10 years (MRR 1.47, 95% CI 1.10-1.95).

Ischemic heart disease risk also was increased among patients in the first 2 years, though not significantly so (MRR 1.39, 95% CI 0.97-1.98), but no difference was seen for stroke between patients and controls.

There also was an increased risk of mortality from disorders of the digestive system in the first 2 years (MRR 2.48, 95% CI 1.79-3.43) and between years 2 and 10 (MRR 1.64, 95% CI 1.31-2.07).

And mortality associated with aortic aneurysm also was greater for patients during the first 2 years (MRR 3.69, 95% CI 1.27-10.75).

In contrast, cancer-associated mortality was lower among patients, with a mortality rate ratio of 0.47 (95% CI 0.29-0.75) in the first 2 years and 0.68 (95% CI 0.53-0.87) between years 2 and 10.

While mortality risks were increased, the differences compared with controls was small, according to the authors.

"Our study demonstrates that the increased risk of death in GCA patients is minimal. Therefore, patients can be reassured that their prognosis concerning risk of death is good," Baslund and colleagues concluded.

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