Health-economic analyses of subcutaneous specific immunotherapy for grass pollen and mite allergy.

OBJECTIVE To investigate the health and monetary consequences of treating allergy with specific immunotherapy (SIT) compared with symptomatic treatment/standard care among patients with grass pollen or mite allergy. METHODS We performed an economic analysis based on 253 grass- and/or mite allergic patients who started SIT from 1.1.1996 to 1.1.2002 at the Allergy Unit, Aarhus University Hospital and at a specialist practice in Aarhus. Relevant data were collected before, during and after SIT treatment from the national health service based on each patient's personal identification number and medical records and from a specifically designed questionnaire. A cost-benefit analysis including direct and indirect costs before, during and after SIT was performed. In addition direct costs were related to the clinical effect (improvement in well-being) in the form of a cost-effectiveness analysis. RESULTS The direct cost per patient/year before SIT (equivalent to standard care) was DKK 2,580. The investment in SIT was DKK 27,545 (in present values) per patient over a 4-year period. After SIT the cost was reduced to DKK 1,072 per patient/year. In the long term, prospective introduction of SIT incurred additional present-value direct costs of DKK 13,676 per patient treated and DKK 2,784 per patient/year of improved well-being. However, when indirect costs were included in the economic evaluation SIT was shown to be net beneficial. CONCLUSION This study reveals that SIT is associated with initial resource investments and subsequent resource savings in the long term compared with standard care. When all consequences are measured in monetary terms, and assuming that sick days are associated with a loss of productivity, this analysis suggests that SIT increases societal welfare. This conclusion also holds if there is no loss of productivity.