Influence of age, sex, and place of residence on clinical expression of giant cell arteritis in northwest Spain.

Objective: To investigate the epidemiology of giant cell arteritis (GCA), we examined whether differences in clinical and laboratory features exist in patients with biopsy-proven GCA from Northwest Spain according to sex, place of residence, and age at disease onset.

Methods: Retrospective study of biopsy-proven GCA diagnosed from January 1, 1981, to December 31, 2001, at the single hospital for a well defined population of 250,000. A comparative analysis was conducted of clinical and laboratory features according to sex, place of residence (rural or urban), and age at the onset of symptoms (< 70 yrs; >or= 70 yrs).

Results: Between 1981 and 2001, 210 patients from the Lugo region were diagnosed with biopsy-proven GCA. In urban areas GCA was significantly more common in women (rate ratio 1.58, 95% CI 1.00-2.53, p = 0.05). Women presented manifestations of polymyalgia rheumatica (PMR) more commonly than men. However, no statistically significant difference in the frequency of visual manifestations or permanent visual loss were observed between the sexes. GCA was slightly more common in rural than in urban areas (annual adjusted incidence rate in rural areas 10.4/100,000 in people age >or= 50 years vs 9.1/100,000 in urban areas; p = 0.34). GCA was more common among men in rural areas (rate ratio 1.73, 95% CI 1.10-2.70, p = 0.02). Patients younger than 70 years at the time of diagnosis (20%) had a trend to a longer delay to diagnosis and a marginal increase in the frequency of PMR compared with those with disease onset at age >or= 70 years. A higher inflammatory response was observed in the patients younger than 70 years.

Conclusion: In patients with biopsy-proven GCA from Northwest Spain PMR manifestations are more commonly observed in women. The higher inflammatory response and the longer delay to diagnosis in younger patients call for a higher physician awareness of this vasculitis among individuals younger than 70 years.