Table 2

Reasons not to participate in the consecutive recruitment phases

Reasons not to participate
Total
(n)
Percentage

Letter returned (n = 1483)


Few or no complaints
710
48.4%
Other allergy
240
16.4%
Study too burdensome
202
13.8%
No interest in the study
186
12.6%
No reason
145
9.8%
Telephone screening (n = 572)


No HDM allergy
159
27.8%
Low symptom score (<4/12)
158
27.6%
Not interested in study
57
10.0%
Severe asthma
39
6.8%
Language barrier
27
4.7%
Use of immunotherapy in the last 3 years
19
3.3%
Refusing blood sample to be taken
17
3.0%
Age (out of range)
15
2.6%
Allergic complaints <1 year
12
2.1%
History of severe allergic reaction
9
1.6%
Systemic disease
8
1.4%
Use of nasal corticosteroids 1 month before baseline
7
1.2%
Answer forms received after deadline of inclusion period
45
7.9%
Screening visit (n = 249)


Only grass pollen or tree pollen sensitization
81
32.5%
No sensitization detectable
75
30.1%
Sensitive to pet at home (confirmed by RAST)
60
24.1%
No informed consent
29
11.7%
Use of unallowed co-medication
4
1.6%

de Bot et al. BMC Family Practice 2008 9:59   doi:10.1186/1471-2296-9-59