Economic evaluation of sublingual immunotherapy vs. symptomatic treatment in allergic asthma.

BACKGROUND: The worldwide increased prevalence of allergic diseases, and especially of respiratory allergy, is paralleled by increased health costs. This requires consideration of the cost to efficacy ratio of the available treatment to identify the optimal choice. OBJECTIVE: To compare the different economic relevance, over a long evaluation time, of symptomatic pharmacologic therapy and sublingual immunotherapy (SLIT) in patients with allergic asthma. METHODS: Seventy patients with perennial allergic asthma, sensitized to dust mites, were enrolled; 50 of these patients were treated with SLIT against house dust mites and 20 were treated with symptomatic drugs. The patients were evaluated for 2 years after discontinuing immunotherapy, which was performed for 3 years, to obtain a more complete follow-up. Symptom scores, medication scores, and all other direct medical costs were evaluated with a specific questionnaire. RESULTS: Patients treated with SLIT plus drugs had a higher mean annual cost in the first year of SLIT treatment compared with patients only receiving drug treatment, but the mean annual cost became significantly lower since the end of SLIT both in the whole population and in the subgroups defined by disease severity. CONCLUSION: The economic advantage measured alongside this prospective observational study was long lasting and still present at the fifth year of the follow-up (2 years after discontinuing SLIT) and could positively be related to the persistent good clinical control of patients.