Savings associated with high-dose hypoallergenic house dust mite immunotherapy in rhinitis and/or asthma patients in Spain

José Carlos García Robaina,1 Carlos Polanco Sánchez,2 Elvira Estella Pérez,2 1Allergy Department, University Hospital Nuestra Señora de Candelaria, Santa Cruz de Tenerife, 2Health Economics & Outcomes Research, Corporate Affairs, Merck S.L., Madrid, Spain Objectives: To quantify the cost difference between conventional symptomatic treatment of mite allergy and specific subcutaneous immunotherapy (SCIT). Methods: Observational, retrospective, and multicenter study was carried out in Spain in 2013. The medical records of 419 patients diagnosed with rhinitis and/or bronchial asthma for mite allergy were retrieved. Mean age was 24.9 years (standard deviation 14.4). The use of symptomatic medication (rescue and daily), diagnostic tests, unscheduled medical care, and sick leave days associated with SCIT treatment versus no-SCIT treatment was compared. Also measured was the SCIT treatment to no-SCIT treatment costs ratio: used resources (symptomatic medication, unscheduled medical care, diagnostic tests, and 3 years SCIT treatment and sick leave days) were quantified in euros. Efficacy (decreased resource usage) of first-year treatment was assumed during the remaining 2 years and also during the 3-year follow-up period. Results: After a single year of SCIT, all quantified resources diminished significantly (P<0.05) from baseline. Estimated reduction in cost items included hospital resources (100% in hospitalizations, 82% in visits to the allergist, and 79% in emergency room visits), therapies (56% in rescue medication and 63% in daily medication), diagnostic tests (77%), and sick leave days (94%). Ratio of comparative calculation described as SCIT treatment versus non-SCIT treatment (or conventional symptomatic treatment) is 0.8. Conclusion: Direct costs are reduced by 64% and indirect costs by 94%. SCIT of hypoallergenic preparation of dust mite (Acaroid®) allows cost savings versus conventional treatment. Estimated savings for the public National Health System are 5.7 times the cost of immunotherapy. Keywords: asthma, economic evaluation, immunotherapy, rhinitis