Sarcoidosis diagnosis and treatment in Sweden: A register-based assessment of variations by region and calendar period

Background: In Sweden, sarcoidosis prevalence varies geographically, but it is unclear whether diagnosis and treatment patterns vary by geographical area and calendar period. We sought to investigate differences in sarcoidosis diagnosis and treatment by healthcare region and calendar period using nationwide register data. Methods: We included 4777 adults who had at least two ICD-coded visits for sarcoidosis in the National Patient Register (2007-2012). We compared patterns of healthcare use (visits and medication dispensations), and data on sarcoidosis diagnosis and treatment spanning two years before to two years after diagnosis stratified by healthcare region and calendar period at diagnosis. Results: Compared to other regions, individuals diagnosed in Stockholm were younger, more likely female, and had a higher education level. In all regions, there was an increase in healthcare use at least six months before sarcoidosis diagnosis with small variation among regions. Most patients were diagnosed in pulmonary and internal medicine outpatient clinics, but compared to the national average more patients were diagnosed in rheumatology in the West and ophthalmology and cardiology in the South. Corticosteroid dispensations at diagnosis varied widely by region (48% in the South/Southeast vs. 30% in Stockholm/North). Demographic factors could not explain these differences. We found no differences by calendar period. Conclusion: Our findings suggest a six-month delay in sarcoidosis diagnosis irrespective of region. The observed regional variation likely reflects differences in diagnosis and treatment patterns. Stakeholders should ensure diagnosis and treatment recommendations are closely followed.