Research into the costs and effectiveness of injection treatments (immunotherapy) in patients with an allergy to tree pollen, grass pollen and/or house dust mites/ Onderzoek naar de kosten en werkzaamheid van injectiekuren (immunotherapie) bij patiënten met een allergie voor boompollen, graspollen en/of huisstofmijt

INTERVENTION: Subcutaneous immunotherapy with tree pollen and/or grass pollen and/or house dust mite extract (Alutard SQ 197/293/503; ALK‐Abello) + usual care vs usual care only. CONDITION: Cost‐effectiveness, Immune therapy, Adults, Allergic rhinitis. PRIMARY OUTCOME: 1. Cost‐effectiveness: The costs per successfully treated patient, where success is based on a global assessment of efficacy by the patient after the allergen peak period in year 2 for the group that starts in 2009 and year one for the group that starts in 2010. The global assessment of efficacy is based on a rating of general improvement on a 6‐point ordinal scale (much worse, a little worse, no change, a little better, much better, completely recovered). The response options “much better” and “completely recovered” define treatment success. In case of multiple allergens treatment success is defined as follows: the response option “much better” or “completely recovered” for at least one allergen and for the remaining allergens “no change”, “better”, “much better” or “completely recovered; 2. Clinical effectiveness; A. The mean daily total rhinitis symptom score in the first year for multi‐sensitized patients; B. Daily symptom scores will be recorded during the peak exposure periods: tree pollen April 1 ‐ May 15; grass pollen May 15 ‐ June 30; house dust mite September 1 ‐ October 30. (If the patient is treated with two or three allergens, symptom scores will be recorded during two or three periods) For tree and grass pollen: only days with sufficient exposure will be analyzed; C. The intensity of 4 rhinitis symptoms (nasal blockage, watery runny nose, sneezing, itching nose) will be subjectively assessed by the patient on a scale grading from 0 = no complaints to 3 = serious complaints. SECONDARY OUTCOME: 1. Cost‐effectiveness; A. The costs per unit of difference between groups in the mini Rhinitis Quality of Life Questionnaire score (mini‐RQLQ‐score; disease specific quality of life) during the allergen peak period in year one and two; B. The costs per symptom‐free day during the first and the second year; C. The cost per QALY, using the EQ‐5D and SF‐36v2 questionnaire to derive utilities. 2. Clinical effectiveness; A. Symptom scores after two years and in several subgroups; B. Percentage of days with rescue medication use; C. Percentage of ‘well days’; D. Visual analogue scale; E. Disease specific quality of life (mini‐RQLQ); F. Generic quality of life (EQ‐5D and SF‐36); G. Global assessment; H. Safety; I. Adherence; J. IgG and IgG4. INCLUSION CRITERIA: 1. 18‐45 years; 2. Clinically relevant moderate to severe allergic rhinitis due to a sensitization for one, two or three of the following allergens: tree pollen (TP), grass pollen (GP) and/or house dust mite (HDM). For each allergen (TP, GP, HDM) the following 3 criteria are evaluated. A sensitization for an allergen is considered clinically relevant and the rhinitis moderate‐severe if: A. Specific IgE >= 0.7 kU/l (Phadia); C. The presence of >=1 of the following complaints due to rhinitis during the previous season: sleep disturbance; impairment of daily activities; leisure and/or sport; impairment o B. Retrospective total symptom score >=4: participants will score 4 nose symptoms (sneezing, itching nose, watery running nose, nasal blockage) during the previous peak exposure period (TP April 1‐May 15; GP May 15‐ June 30; HDM September 1‐October 31) on a 0‐3 scale (0=none, 1=mild, 2=moderate, 3=severe; maximum total score=12);