Presentation (CTI)

OBJECTIVES: To assess concordance of healthcare resource utilization (HRU) and cost reporting between national and regional healthcare data in Sweden, to inform data source selection in observational studies.
METHODS: Data were obtained from the National Patient Register (NPR) and Stockholm Regional Healthcare Data Warehouse (VAL) for patients diagnosed with autoimmune hemolytic anemia (AIHA) in Region Stockholm (2005-2023). NPR includes inpatient and physician‑led outpatient care, while VAL additionally captures primary care and non-physician outpatient visits. Records were matched based on individual, care setting, and date. Factors associated with unmatched events were evaluated. Agreement between DRG-based costs in NPR and total reimbursed costs in VAL was assessed using Bland-Altman analyses.
RESULTS: This study included 199,325 VAL records and 44,982 NPR records from 631 patients with AIHA. Inpatient care showed near-complete agreement (98%), whereas outpatient secondary care (hereafter ‘outpatient care’) showed substantially lower concordance (48.4%). VAL-only outpatient records (50.7% of all outpatient records) were more common in specific care units (e.g., community-based, diagnostic/technical, rehab/supportive), specific visit types (e.g., outside clinic, group), and zero-/low-cost visits. Primary care was captured exclusively in VAL, as expected. At the population level, mean inpatient costs were higher in VAL than NPR; €593 more per-person-per-year (PPPY). Outpatient costs were similar overall (+€73 PPPY in VAL); a result of two counterbalancing effects: lower costs among matched visits in VAL (-€738 PPPY), and additional cost from VAL-only encounters (+€835 PPPY). Primary care contributed <5% of total cost. At the individual visit level, Bland-Altman analysis indicated poor agreement between VAL and NPR cost, with wide variability and systematic differences.
CONCLUSIONS: In this cohort, inpatient HRU showed high concordance between VAL and NPR, while outpatient HRU and costs differed; driven by coverage and costing methods. VAL provides a comprehensive view of total HRU (primary and secondary care), while NPR remains suitable for studies of physician-led secondary care.