SAT0580 HEALTHCARE BURDEN AND COST OF ILLNESS OF GIANT CELL ARTERITIS IN THE ITALIAN REGION OF FRIULI VENEZIA GIULIA: A 17-YEAR INTEGRATIVE ANALYSIS OF DIGITAL ADMINISTRATIVE DATABASES

Abstract

Background: Giant cell arteritis (GCA) is the most common systemic vasculitis in persons aged 50 and above (1). Data on incidence and prevalence of GCA are welcomed. Further information is also needed on the healthcare burden and resource consumption. The use of multiple digital databases with the integration of clinical data from a formalized network of specialists is needed. Objectives: To estimate incidence, prevalence and costs of GCA by an integrative analysis of multiple administrative databases of the healthcare system of the Italian Region of Friuli Venezia Giulia (about 1,2 millions of inhabitants), cooperating with the existing local Rheumatology Network. Methods: A 17-year retrospective study was conducted through the following administrative health regional digital databases of the Friuli Venezia Giulia Region: the Database of Regional Potential health Care Beneficiaries, the Hospital Discharge Database, the Ambulatory Care Database, the Pharmaceutical Prescription Database, the Emergency Department Database, the Mortality Database, the Anatomical Pathology Database, the Database of Exemptions from Medical Charges, and the Regional Rare Disease Registry. All the databases were integrated at the individual patient level using a univocal stochastic key. Results: From 2001 to 2017, 208 patients with GCA were registered. The crude identification rate of patients identified with GCA until 2017 in the population ≥45 years of age was 3.8/100,000 person-years (95%CI: 2.5-5.5). The maximum incidence rate was observed in the age group 70-74 years. The prevalence of GCA in the population ≥45 years of age as of December 31st, 2017 was 27.2/100,000 (95%CI 23-5-31.4). The mean medical observation was 4.5±3.6 years per patient, totaling 940.8 years of observation. 192 patients had at least one ambulatory specialist visit, resulting in a total of 3182 specialist visits (338 per 100 patient-years). The most frequent medical specialties involved were Rheumatology (N=610, 19.2%), Internal Medicine (N=564, 17.7%), Ophthalmology (N=292, 9.2%), and Orthopedics (N=191, 6%). 108 (52%) patients had at least one hospitalization, resulting in 287 hospitalizations (30 per 100 patient-years). Circulatory Cardiovascular diseases were the most common discharge diagnoses, followed by musculoskeletal conditions. 199 subjects were prescribed medications for a total of 9588 prescriptions (1019 per 100 patient-years). Notably, an immunosuppressive drug, usually methotrexate, was prescribed in more than half of the patients. Cardiovascular medications were prescribed to 154 (74%) patients; bisphosphonates or other anti-osteoporotic drugs to 123 patients (59%). The average annual direct cost of GCA was 2374 Euros per patient-year (61 for outpatient visits, 1661 for hospitalizations, 312 for prescribed medications and 340 for medications directly dispensed by the hospital pharmacies). The overall estimated direct healthcare cost for 940.8 patient-years was 2,234,070 Euros. Conclusion: Novel epidemiologic data in GCA are reported after a very long-term observation, and by integrating data from multiple databases with clinical data from a Regional network of specialists (Rheumatology being the major contributor to disease clinical follow-up). Cost of illness is high in GCA. Both the diseases itself and cardiovascular manifestations, and, possibly, the complications of glucocorticoids, may contribute the to the healthcare burden of GCA. Despite a high use of immunosuppressors in our Region, new drugs (2) and novel treatment strategies are required.