Giant cell arteritis: A population-based retrospective cohort study exploring incidence and clinical presentation in Canterbury, Aotearoa New Zealand

Abstract

Background/aimTo determine the epidemiology and clinical features of giant cell arteritis (GCA) in Canterbury, Aotearoa New Zealand, with a particular focus on extra-cranial large vessel disease.MethodsPatients with GCA were identified from radiology and pathology reports, outpatient letters and inpatient hospital admissions in the Canterbury New Zealand from 1 June 2011 to 31 May 2016. Data was collected retrospectively based on review of electronic medical records.ResultsThere were 142 cases of GCA identified. 65.5% of cases were female with a mean age of 74.2 years. The estimated population incidence for biopsy-proven GCA was 10.5 per 100,000 people over the age of 50 and incidence peaked between 80 and 84 years of age. 10/142 (7%) people were diagnosed with large vessel GCA, often presenting with non-specific symptoms and evidence of vascular insufficiency including limb claudication, vascular bruits, blood pressure and pulse discrepancy, or cerebrovascular accident. Those with limited cranial GCA were more likely to present with the cardinal clinical features of headache and jaw claudication. Patients across the two groups were treated similarly, but those with large vessel disease had greater long-term steroid burden. Rates of aortic complication were low across both groups, although available follow-up data was limited.ConclusionThis study is the first of its kind to describe the clinical characteristics of large vessel GCA in a New Zealand cohort. Despite small case numbers, two distinct subsets of disease were recognized, differentiating patients with cranial and large vessel disease. Our results suggest that utilization of an alternative diagnostic and therapeutic approach may be needed to manage patients with large vessel disease.

Giant cell arteritis: incidence and phenotypic distribution in Western Norway 2013–2020

“…Though headache was significantly more common in patients with cranial and unclassifiable phenotype, more than 50% of patients with non-cranial phenotype also had new localized headache. Some other studies have reported similar findings ( 10 , 29 , 30 ). Constitutional symptoms were more common in non-cranial and mixed phenotype, with borderline significance (depending on method of multiple-testing correction).…”

“…A major difference between these studies and our study is the study design, with the possibility of missing imaging data for some patients in our study causing a possible underestimation of non-cranial involvement. A retrospective study from Japan found that 18 out of 36 (50%) patients had involvement of non-cranial arteries ( 33 ), while another retrospective study from New Zealand found documented involvement of non-cranial arteries in only 10 out of 142 (7%) patients ( 29 ).…”

Incidence of biopsy-proven giant cell arteritis (GCA) in South Australia 2014–2020

“…The reasons for the lower incidence rate in our population is not entirely clear and cannot be attributed to geographical reasons alone. A recent study from New Zealand reported their incidence rate for biopsy-proven GCA at 10.5 per 100,000 people over the age of 50 ( 17 ).…”

Epidemiology of systemic vasculitis

“…Two studies conducted in different regions in New Zealand reported similar incidence rates despite using different methodologies. In the first study from Canterbury, Aotearoa New Zealand, the mean annual incidence was 10.5 (95% CI 8.7–12.8) for biopsy-proven GCA and 15 (95% CI 12.6–17.6) per 100 000 for all cases including biopsy-negative cases and extracranial GCA [6]. In the second study from Counties Manukau District Health Board, New Zealand, it was 11.4 (95% CI 7.8–16.7) per 100 000 when all biopsy-proven and biopsy-negative cases were included.…”