Modelling the Costs of Sublingual Immunotherapy versus Subcutaneous Immunotherapy Based on Clinical Appointments and Impacts of Patient Travel in Sweden

Aim: In Sweden, allergy immunotherapy (AIT) is available as either subcutaneous immunotherapy (SCIT) injections or sublingual immunotherapy (SLIT) tablets and is used to treat moderate-severe allergic rhinitis (AR). This study sought to determine direct and indirect annual costs stemming from treatment-related travel, appointments, waiting times and medication costs, before exploring likely CO₂ emission-related cost-savings for 20,330 patients receiving SCIT or SLIT-tablets in Sweden.

Methods: A model was developed in Python to capture each category of costs in the target patient population. Absenteeism costs arising from treatment-related travel were determined by obtaining average hourly pay data from Swedish Government sources. Absenteeism costs were also calculated for 30-minute post-dose observation times, which occurred during one clinical appointment for SLIT patients, and all clinical appointments for SCIT patients. Clinical appointment costs were obtained from healthcare price lists for Sweden. Medication costs were retrieved from the Pharmaceutical Specialities in Sweden (Fass) website, and treatment doses required for SCIT and SLIT-tablets were determined based on product labels and previously-calculated dosage regimes. High-cost protection and reimbursement scheme payment caps were applied when determining patient appointment and medication costs, respectively, and when identifying financial burdens for individual payers.

Results: Mean total annual costs for SCIT were Swedish Krona (SEK) 604.1 million (m), with clinical appointments contributing the largest share of these costs (52.7%), followed by medication (34.4%), travel-related absenteeism (8.9%), waiting time-related absenteeism (2.7%) and private transportation (1.3%). Mean total annual costs for SLIT-tablets were SEK 336.2m. Medication contributed the most to these costs (72.3%), followed by clinical appointments (22.7%), travel-related absenteeism (3.8%), waiting time-related absenteeism (0.6%) and private transportation (0.6%).

Conclusion: For patients with moderate-severe AR receiving AIT in Sweden, SLIT-tablets displayed large potential cost savings to patients, the healthcare system, and the government, whilst possessing reduced societal costs of carbon emissions relative to SCIT.