Frequency, diagnosis, and pharmacological treatment of giant cell arteritis in Germany: database analysis of medical insurance data.

BACKGROUND

For giant cell arteritis (GCA), a north-south gradient in incidence and prevalence has been described, peaking in Scandinavia.

OBJECTIVE

This analysis aimed to obtain up-to-date, representative data on the prevalence and incidence of GCA in Germany, updating the old, regional information on low incidence and prevalence rates.

DESIGN

Cross-sectional analysis using a large German health insurance database.

METHODS

This study is based on a cross-sectional analysis of claims data from the InGef (Institute for Health Research Berlin GmbH) research database, which includes a representative sample of 4.8 million insured individuals. Individuals aged ⩾50 years with continuous insurance coverage for a 3-year baseline period and the subsequent 2 years for longitudinal analysis were included. Estimates were standardised and projected to the German population.

RESULTS

Each year from 2018 to 2021, 1.7 million insured individuals met the inclusion and exclusion criteria. Extrapolated to the German population ⩾50 years in 2021, the incidence was 24/100,000, and the prevalence was 146/100,000. Diagnosis was made predominantly in outpatient settings by general practitioners (GP, 31.9%) and internists (19.5%), followed by rheumatologists (13.1%) and ophthalmologists (5.7%). Within 2 years, 16.3% of incident patients were referred to rheumatologists for treatment after diagnosis. Treatment was most commonly initiated by GPs (45.8%), followed by rheumatologists (36.1%), and included glucocorticoids (88.2%), methotrexate (26.7%), and tocilizumab (14.1%). Most common comorbidities of prevalent patients comprised arterial hypertension (77.2%), dyslipidaemia (55.0%), diabetes mellitus (28.8%), osteoporosis (34.6%), and cataract (31.2%).

CONCLUSION

Contrary to previous reports, Germany has higher incidence and prevalence rates of GCA than previously assumed. Only approximately one-third of the incident patients were initially treated by rheumatologists. Comorbidities such as diabetes or cardiovascular diseases were common.