0755: Sex Differences in Subtypes of Vascular Involvement and Clinical Manifestations in Giant Cell Arteritis

Background/Purpose: Recognizing gender-specific differences in diseases is critical to improve diagnostic and therapeutic strategies. Giant cell arteritis (GCA) has been traditionally considered a predominantly female disease, but this predominance may be declining with new classification criteria and advanced imaging. While gender-related differences in cranial and extra-cranial GCA phenotypes have been observed, most studies have focused mainly on clinical patterns. The objective of this study is to assess gender-specific differences in GCA clinical presentation, particularly patterns of vascular involvement, age at diagnosis and clinical manifestations.

Methods: This is a retrospective population-based study including consecutive unselected GCA cases from a cohort diagnosed since 2017. Standardized bilateral ultrasound (US) of cranial arteries (common temporal artery and branches) and extra-cranial arteries (carotid, subclavian, axillary) were performed in all patients. Subtypes were categorized as cranial, extracranial, or mixed according to the pattern of vascular involvement identified by ultrasound (US) and/or positron emission tomography-computed tomography (PET-CT). Demographic and clinical data were obtained from medical records, and a confirmed diagnosis required a minimum of six months of clinical follow-up.

Results: A total of 249 GCA cases (table 1) were analyzed (mean age 78.9±8.3 years, range 58–105), with 134 females (53.8%). Cranial involvement was present in 195/249 cases (78.3%), significantly more common in males (84.3%) than females (73.1%, p=0.03). Large vessel involvement was detected in 128/249 patients (51.4%) without significant sex differences (56.5% males vs. 47.0% females, p=0.16)
Analysis by subtype showed isolated cranial involvement in 121 patients (48.6%), isolated large vessel vasculitis in 54 (21.7%), and mixed patterns in 74 (29.7%). Significant sex differences were observed: mixed pattern was more frequent in males (40.9% vs. 20.1%, p< 0.01), while isolated large vessel vasculitis was more common in females (26.9% vs. 15.7%, p=0.03). Isolated cranial involvement was also more frequent in females, though not statistically significant.
No significant age differences were found between sexes (78.6±8.5 years in females vs. 79.4±8.1 in males) or within vascular subtypes. Clinical manifestations (table 2) were generally more common in women, with significant differences in headache (p< 0.01) and jaw claudication (p=0.04). Women also tended to present more relapses, though this did not reach statistical significance.

Conclusion: GCA shows only a mild female predominance (53.6%). Important sex differences exist in vascular involvement patterns: cranial involvement was more common in males, isolated large vessel vasculitis more frequent in females, and mixed patterns predominated in males (p< 0.01). Age at diagnosis did not differ between sexes. Women tended to present significantly more headache (p< 0.001) and jaw claudication (p=0.04). These findings highlight the need for sex-specific considerations in the diagnosis and management of GCA.