EPIDEMIOLOGY, DIAGNOSIS AND CLINICAL CHARACTERISTICS OF GIANT CELL ARTERITIS IN PATIENTS INCLUDED IN THE ARTESER MULTICENTER STUDY

Background Epidemiological information on Giant Cell Arteritis (GCA) comes mainly from the Scandinavian countries of northern Europe, which show a higher incidence than the countries of southern Europe. GCA clinical manifestations can be divided into cranial, extracranial, and general syndrome. Objectives In a large series of GCA from Spain, we studied a ) the incidence of GCA, b ) clinical manifestations, and c ) comorbidities at the time of disease diagnosis. Methods ARTESER is a retrospective epidemiological observational study of GCA promoted by the Spanish Society of Rheumatology in which 26 hospitals participate. The inclusion criteria were: all new patients diagnosed with GCA by a) ACR criteria, b) positive diagnostic test (temporal artery biopsy, temporal artery ultrasound or other relevant imaging techniques) and/or c) investigator’s clinical judgment. The patient recruitment period ranged from June 1, 2013 to March 29, 2019. The overall incidence of GCA per 100,000 people ≥50 years for the whole period and the mean annual incidence were evaluated. The clinical variables were collected by reviewing the patient’s medical history. Results 1675 patients were included. The average annual incidence rate was 7.42 (95% CI: 6.57-8.27). All the cases were older than 50 years, and the age group with the highest annual incidence was that of 80 to 84 years, where it reached a value of 22.63 (95% CI: 22.04 -23.22). The mean annual incidence is higher in women than in men 10.07 (95% CI: 8.74-11.55) vs 4.81 (95% CI 3.84-5.93) (Table 1). Table 1. General characteristics, comorbidities and clinical manifestations Epidemiologic, demographic and diagnosis Men Women Total Gender, n (%) 497 (29.7) 1178 (70.3) 1675 Incidence annual rate (95% CI) 4.81 (3.84-5.93) 10.07 (8.74-11.55) 7.42 (6.57-8.27) Age at diagnosis, years, mean (SD) 76.9 (8.3) 76.9 (8.0) 76.9 (8.1) Diagnosis only by ACR Criteria 89 (17.91) 266 (22.58) 355 (21.19) Diagnosis only with objective tests 73 (14.69) 140 (11.88) 213 (12.72) Diagnosis ACR criteria + diagnosis objective tests 311 (62.58) 734 (62.31) 1045 (62.39) Diagnosis by clinical judgment 24 (4.8) 38 (3.2) 62 (3.7) Comorbidities at diagnosis Arterial hypertension, n (%) 330 (66.8) 749 (63.7) 1079 (64.6) Dyslipidemia, n (%) 238 (48.3) 563 (47.9) 801 (48.0) Cranial clinical manifestations New-onset headache, n (%) 382 (76.9) 955 (81.1) 1337 (79.9) Visual Clinic, n (%) 194 (39.0) 411 (34.9) 605 (36.1) Extracranial manifestations and general syndrome Polymyalgia rheumatica, n (%) 178 (35.8) 521 (44.3) 699 (41.8) Asthenia, n (%) 239 (48.1) 634 (53.9) 873 (52.2) Analysis at diagnosis Erythrocyte sedimentation rate mm/h, mean (SD) 72.3 (34.7) 77.4 (33.0) 75.9 (33.6) The principal clinical characteristics of the population is shown in Table 1, the mean age at diagnosis was 76.9±8.1 years, 1178 (70.3%) were women. 1045 patients (62.39%) had ACR criteria and some positive objective test, 355 patients (21.9%) presented only ACR criteria and 213 (12.72%) only had a positive diagnostic test; 62 (3.7%) of the patients underwent diagnosis based on clinical judgment. The more frequent comorbidity was arterial hypertension (n=1079; 64.6%), followed by dyslipidemia (n=801, 48%). The predominant cranial manifestation was headache (n= 1337; 79.9%) and 605 patients experienced visual symptoms (36.1%). Polymyalgia rheumatica (n=699; 41.8%) and asthenia (n=837; 52.2%) were the most frequent extracranial and general syndrome manifestation, respectively. Regarding laboratory parameters, the most characteristic data was the increase of ESR (75.9±33.6 mm/1st h). Conclusion The mean annual incidence of GCA in Spain, 7.42 (95% CI: 6.57-8.27), is lower than that of the Scandinavian countries. It is higher in people older than 80 years. More than 60% of the patients met the ACR criteria and had a positive diagnostic test. Cranial manifestations constituted the most clinical features. The most frequent clinical manifestations are cranial. Up to a third of patients had visual manifestations. Acknowledgements This study has been funded by ROCHE Farma. The funder has not participated in the design, analysis, or interpretation of the results Disclosure of Interests None declared