Ultrasound-guided synovial tissue biopsy for people with rheumatoid arthritis: a micro-costing study.

Objective: Identify and quantify the resource use and cost per patient of performing a US-guided synovial tissue biopsy for people with RA within a routine healthcare setting. Method: A micro-costing study was performed from a healthcare system perspective (National Health Service England). A service pathway conceptual model described how the procedure will be embedded within routine care to inform management decisions. Consumables were estimated from existing standard operating procedures for synovial biopsies. Staff time was estimated by expert input (clinical rheumatologist and patient). The time for tissue sample acquisition was obtained from data within the biopsy-driven R4RA trial. Unit costs were sourced from historic purchase prices, published salary scales and public-facing list prices. One-way sensitivity analysis identified key drivers of total cost per patient. Scenario analyses explored the cost impact if less senior healthcare staff performed the biopsy or if an additional outpatient appointment was required to identify joint suitability. Results: The total cost of US-guided synovial tissue biopsy was £356.24/patient (best-case estimate: £185.30; worst-case estimate: £812.46). The key driver of total cost was the time taken to perform tissue sample acquisition. The total cost was lower if a registrar performed the biopsy (£294.24) and higher if an additional outpatient appointment was required for joint selection (£438.98). Conclusion: Interventions requiring synovial tissue samples to inform treatment selection or prognosis are emerging. The findings can inform cost parameters for future cost-effectiveness analyses. These results will help resource allocation and clinical decisions to improve the value of treatments for RA.