How Age of Onset Affects Giant Cell Arteritis Save

Giant cell arteritis (GCA) has a different phenotype when diagnosed late in life compared with earlier onset, a large Italian cohort study indicated.

Features of what might be called "senior GCA" include increased rates of cranial symptoms, a markedly higher risk for aortic aneurysm and dissection, and less frequent diagnosis with large-vessel disease, according to Sara Monti, PhD, of the Universita degli Studi di Pavia in Italy, and colleagues.

Of special importance was that cohort members with late diagnosis tended to receive fewer immunosuppressant medications, which may reflect undertreatment, the group reported in Annals of the Rheumatic Diseases. This, along with the increased risks for serious complications, "make GCA a very challenging disease in the oldest patients," they wrote.

Monti and colleagues, commissioned by the Italian Society of Rheumatology to examine the issue of age in GCA, drew on data from a prospective cohort first set up in 1988, with enrollment continuing into 2020. A total of 1,004 patients were included in the current analysis.

Mean age at diagnosis was 72; about 20% were younger than 65, 60% were 65-79, and the rest were 80 or older. About 70% were women. Median follow-up after diagnosis was 49 months (interquartile range 23-91).

Some 77% of the 80+ group had cranial disease, versus 35% of those younger than 65 (P=0.0001). Other factors more prevalent in older patients included:

• Ischemic onset: 41% at 80+ vs 15% at <65
• Diagnosis on clinical signs only: 24% vs 7%
• Serious infections within 12 months of diagnosis: 7.3% both for those 80 and up and for those 65-79, versus 1.9% for patients younger than 65
• Aortic aneurysm/dissection within 12 months: OR 2.03 for age 80+ vs <65 (P=0.023)

Mortality was also greater with older age, and was worsened with increased burden of comorbidities and complications, although these findings were not unexpected.

However, the younger group was far more likely to show large-vessel GCA (65% vs 36% of those 65-79 and 23% of those 80+). Systemic symptoms at onset were also more common in younger patients.

Younger patients also got high-dose corticosteroids at higher rates: 28% were started on doses greater than 50 mg/day as compared with 15% of those 80 and older (P=0.004). Also, 53% of the younger group were started on antiplatelet medications versus 38% of those 80 and up, but this fell short of statistical significance.

But not everything about GCA differed by age. Time to first relapse and the number of relapses were similar across age groups, after adjustment for covariates. Furthermore, there was little difference between groups in time to reduce steroid doses to 5 mg/day or less, and in time to onset of steroid-related complications such as hypertension and osteoporosis.

Monti and colleagues noted that blindness is a common and "dreadful" GCA complication, and this, too, was more common with older age (37% at 80+, 18% at 65-79, and 6.2% at <65). The researchers credited "the introduction of fast-track clinics" with reducing incidence of blindness in GCA patients relative to historical trends but, nevertheless, "our data suggest that further efforts to improve the knowledge of the disease should be dedicated to elderly patients who carry the highest risk of referral after [permanent vision loss] has already occurred." The investigators called for additional research focusing on older GCA patients with the aim of elucidating causal connections.

Limitations to the analysis included the study's observational nature, the authors acknowledged, along with the cohort's recruitment through specialty clinics that may lead to overrepresentation of "more severe or complicated cases."

Source Reference: Monti S, et al "Age at diagnosis influences the clinical phenotype, treatment strategies and outcomes in patients with giant cell arteritis: Results from the observational GCAGE study on a large cohort of 1004 patients" Ann Rheum Dis 2023; DOI: 10.1136/ard-2023-223895.