Development of a questionnaire to assess patient satisfaction with allergen-specific immunotherapy in adults: item generation, item reduction, and preliminary validation

Figures & data

Figure 1 Overview of study procedures.

Table 1 Demographic and disease characteristics of patients involved in quantitative item reduction (n = 257)

Gender, women, n (%)	133 (51.8)
Age, years, mean (SD) [min, max]	33.2 (10.7) [18, 7]
Educational level, n (%)
No formal education	9 (3.5)
Primary education	48 (18.7)
Secondary education	103 (40.1)
University or similar	94 (36.6)
Missing data	3 (1.1)
Time since diagnosis, years, mean (SD)	7.7 (7.4)
Allergen, n (%)
Mite	72 (28.0)
Pollen	162 (63.0)
Both	20 (7.9)
Missing data	3 (1.1)
Comorbidities, n (%)^a
Asthma	138 (53.7)
Conjunctivitis	190 (73.9)
Other comorbidities	11 (4.3)
Type of asthma, n (%)^b
Mild intermittent	82 (59.4)
Mild persistent	26 (18.8)
Moderate persistent	24 (17.5)
Severe persistent	2 (1.4)
Missing data	4 (2.9)
Type of allergic rhinitis, n (%)
Persistent	99 (38.5)
Intermittent	140 (54.5)
Missing data	18 (7.0)
Severity of allergic rhinitis, n (%)^c
Mild	83 (32.3)
Moderate	122 (47.5)
Severe	49 (19.1)
Missing data	3 (1.1)
Type of allergen-specific immunotherapy, n (%)^d
Sublingual	93 (36.2)
Subcutaneous	163 (63.4)
Both	1 (0.4)
Allergen-specific immunotherapy regimen, n (%)^d
Perennial	202 (78.6)
Preseasonal	44 (17.1)
Missing data	11 (4.3)
Symptomatic treatment, n (%)^d
Corticosteroids	26 (10,1)
Antihistamines	61 (23.7)
Both	128 (49.8)
Others	53 (20.6)

Notes:

a Patient could respond to more than one option;

b According to the Global Initiative for Asthma classification;¹⁷

c According to Valero et al;⁴²

d At inclusion.

Abbreviations: SD, standard deviation; min, minimum; max, maximum.

Figure 2 Items eliminated at different stages of the item reduction process.

Table 2 Highest scoring items of the original 70 items (n = 254)

	Mean (SD) frequency	Mean (SD) importance	Mean (SD) impact score^a
The vaccine is compatible with my life style	1.6 (0.9)	1.7 (0.9)	2.9 (2.3)
My vaccine is easy to administer	1.7 (1)	1.6 (0.8)	3 (2.7)
Generally speaking, I am satisfied with my allergy vaccine^b	1.8 (1.1)	1.5 (0.7)	3 (2.8)
My vaccine works^b	2.1 (1)	1.5 (0.7)	3.2 (2.5)
Since being vaccinated I have felt much better	2 (1)	1.5 (0.7)	3.3 (2.7)
Since being vaccinated for the allergy I present fewer symptoms^b	2.1 (1)	1.5 (0.7)	3.5 (2.4)
I have fewer allergy crises, thanks to the vaccine	2.1 (1.1)	1.5 (0.7)	3.5 (3.1)
In general, I would recommend the vaccine treatment^b	1.7 (1)	1.9 (0.9)	3.6 (3.4)
The medical treatment I receive helps me with the vaccine treatment	1.8 (0.9)	1.8 (0.9)	3.8 (4)
I have felt better since receiving the vaccine	2.1 (1)	1.7 (0.8)	3.8 (3.1)
My quality of life has improved since receiving the vaccine^b	2.2 (1.1)	1.6 (0.7)	4 (3.6)
My vaccine gives me independence	2 (1.2)	1.8 (0.9)	4.1 (4.2)
The information I received at the start of the vaccine treatment has helped me to understand how it works	1.9 (1.1)	19 (0.9)	4.2 (3.9)
The good performance of the vaccine compensates for having to take it daily	2.1 (1.2)	1.8 (1)	4.3 (4.1)
The good performance of the vaccine compensates for any inconveniences it could cause me^b	2.1 (1.1)	1.9 (0.9)	4.3 (3.7)
The good performance of the vaccine compensates for the financial challenge it causes me^b	2.2 (1.2)	1.8 (0.9)	4.4 (3.7)
The good performance of the vaccine compensates for all the things I have to do to obtain it (appointments, prescriptions, leave)^b	2.2 (1.2)	1.9 (1.5)	4.6 (3.9)
My vaccine doesn’t produce side effects	2.4 (1.6)	1.7 (1)	4.7 (5.6)
Thanks to the vaccine I can work or study better^b	2.5 (1.2)	1.9 (1)	5.4 (5.1)
Thanks to the vaccine I only need an inhaler or take pills at certain or isolated times	2.5 (1.4)	1.9 (1)	5.4 (5.3)
If I had known about the vaccine before I would have started with it earlier	2.3 (1–3)	1.9 (1)	5.4 (5.5)
Since receiving the vaccine I enjoy outdoor activities more^b	2.5 (1.2)	2 (1)	5.5 (4.9)
My vaccine helps me feel better physically	2.5 (1.1)	1.9 (0.9)	5.6 (4.8)
Getting vaccinated is easy and quite quick	2.5 (1.3)	2.1 (1)	5.7 (4.3)
My vaccine works faster than I had expected^b	2.8 (1.2)	1.9 (0.9)	5.8 (4.4)
Since being vaccinated I don’t continually interrupt my activities due to allergy symptoms	2.6 (1.2)	2 (0.9)	5.8 (4.9)
My vaccine helps me to carry out my daily activities^b	2.6 (1.3)	2 (1.1)	6.2 (6.1)
Since being vaccinated I can go anywhere with my family or friends^b	2.5 (1.4)	2.1 (1.2)	6.2 (6)
Getting vaccinated results in physical problems	2.7 (1.4)	2.1 (1)	6.2 (5)
Thanks to the treatment I understand my illness better	2.4 (1.3)	2.2 (1.1)	6.4 (6.2)
Since being vaccinated the physical problems related with the allergy (sneezing, runny nose, headaches, itching) don’t bother me	3 (1.2)	2 (1)	6.5 (5)
Thanks to the vaccine, I am less dependent on always having to carry other medication (pills, inhalers, etc)^b	2.9 (1.4)	2.1 (1.1)	6.8 (6)
Taking the vaccine daily does not involve any extra effort	3 (1.3)	2.3 (1.2)	6.8 (4.8)
Since taking the vaccine I do not find myself in compromising or uncomfortable situations caused by my allergy symptoms^b	2.8 (1.2)	2.3 (1.1)	6.9 (5.5)
I am happy with the vaccine and having to travel and organize myself to get vaccinated does not present a problem	2.9 (1.2)	2.2 (1)	7 (4.9)
Thanks to the vaccine I no longer have to leave certain places because of my allergy symptoms	2.9 (1.2)	2.2 (1.1)	7.4 (5.9)
Since being vaccinated I don’t have to avoid things that I like but which caused my allergy^c	3 (1.2)	2.3 (1.1)	7.6 (6.2)
Since being vaccinated I am no longer concerned about being in contact with the cause of my allergy	3.1 (1.2)	2.3 (2.8)	7.9 (11.9)

Notes:

a Impact score = frequency × importance;

b Item included in the final version;

c The item included in the prevalidated version of the new questionnaire is a linguistic reform of this item; the table includes 39 items after excluding the 11 items eliminated because of response distribution and the 20 worst score ranking items; the original tool has been developed entirely in Spanish; this is not an official version in English, but a translation for informational purposes only.

Table 3 Factor analysis for the 16 retained items of the new questionnaire (n = 254)^a

	Item loading 1st factor	Item loading 2nd factor	Item loading 3rd factor	Item loading 4th factor
Since being vaccinated I can go anywhere with my family or friends	0.645	0.206	0.082	0.441
Since being vaccinated I no longer have to avoid things that I like but which caused my allergy	0.858	0.071	0.213	0.074
My vaccine helps me to carry out my daily activities	0.561	0.493	0.135	0.292
Thanks to the vaccine I can work or study better	0.688	0.404	0.120	0.298
Since being vaccinated I enjoy outdoor activities more	0.659	0.379	0.179	0.300
Since taking the vaccine I do not find myself in compromising or uncomfortable situations caused by my allergy symptoms	0.813	0.123	0.200	0.117
The good performance of the vaccine compensates for all the things I have to do to obtain it (appointments, prescriptions, leave)	0.178	0.835	0.224	0.207
The good performance of the vaccine compensates for the financial challenge it causes me	0.199	0.784	0.272	0.270
The good performance of the vaccine compensates for any inconveniences it could cause me	0.240	0.785	0.280	0.111
Generally speaking, I am satisfied with my allergy vaccine	0.305	0.463	0.635	0.322
In general, I would recommend the vaccine treatment	0.131	0.208	0.850	0.083
My quality of life has improved since receiving the vaccine	0.343	0.368	0.557	0.447
Since being vaccinated against my allergy I have fewer symptoms	0.117	0.262	0.377	0.725
My vaccine works	0.257	0.414	0.543	0.533
Thanks to my vaccine, I am less dependent on always carrying other medication (pills, inhalers)	0.394	0.157	0.070	0.723
My vaccine works faster than I had expected	0.328	0.347	0.484	0.441
R^2, %	55.60	9.46	5.45	4.27
Overall R^2, %	74.79

Notes:

a The items belonging to each factor/dimension are highlighted in bold gray. Only the five items, highlighted in bold, substantially contributed (load ≥0.45) to a second factor. The final allocation of these five items to their respective dimensions was made by means of clinical criteria; the original tool was developed entirely in Spanish; this is not an official version in English, but a translation for informational purposes only.

Table 4 Score distributions, floor/ceiling effects, interscale correlations and internal consistency of the 16-retained items (n = 254)

	GS	PE	AE	CBB	OS
Items (n)	16	4	6	3	3
Mean	56.8	13.9	19.9	11.2	12.2
SD	14.7	3.8	6.3	3.3	2.8
Theoretical range^a	16–80	4–20	6–30	3–15	3–15
Observed range	16–79	4–20	6–30	3–15	3–15
Floor^b (%)	0.4	2.4	4.3	2.4	0.4
Ceiling^c (%)	0	3.9	3.1	22.8	15.7
CA	0.94	0.79	0.89	0.89	0.83
Interscale correlation range	0.822–0.904 (CBB-AE)	0.686–0.900 (CBB-GS)	0.623–0.904 (OS-GS)	0.632–0.822 (AE-GS)	0.623–0.86 (AE-GS)
Inter-item correlation range^d	0.537–0.805	0.489–0.698	0.690–0.787	0.765–0.805	0.621–0.743

Notes:

a Overall score ranges from 16 (low satisfaction) to 80 (high satisfaction). Low dimension score indicates low satisfaction while high dimension score indicates high satisfaction;

b Percentage of patients with the worst possible score;

c Percentage of patients with the best possible score;

d Correlation of corrected item-total.

Abbreviations: GS, Global score; PE, Perceived efficacy; AE, Activities and environment; CBB, Cost-benefit balance; OS, Overall satisfaction; CA, Cronbach’s alpha.

Table 5 Mean (SD) of the 16-retained items^a, based on symptomatic manifestations of allergy (n = 254)

	Global score	Perceived efficacy	Activities and environment	Cost-benefit balance	General satisfaction
Type of allergic rhinitis
Intermittent	58.3 (14.3)	14.3 (3.7)	20.4 (6.3)	11.7 (3.3)	12.5 (2.7)
Persistent	53.5 (15.2)	13.1 (3.9)	18.9 (6.3)	10.5 (3.3)	11.5 (2.9)
P-value^b	0.042	0.009	0.055	0.002	0.027
Intensity of allergic rhinitis (ARIA)
Mild	60.1 (13.2)	14.9 (3.4)	19.9 (6.8)	11.8 (3.3)	12.8 (2.6)
Moderate/severe	55.2 (15.2)	13.5 (3.9)	20 (6.1)	11 (3.3)	11.9 (2.8)
P-value^b	0.049	0.008	0.922	0.039	0.031
Presence of bothersome symptoms (ARIA)
No	59.6 (13.3)	14.7 (3.5)	20.4 (6.7)	11.7 (3.2)	12.6 (2.6)
Yes	54.8 (15.3)	13.4 (3.9)	19.7 (6)	10.9 (3.3)	11.8 (2.8)
P-value^b	0.039	0.010	0.223	0.033	0.058
Rhinorrhea
No	61.6 (12.2)	15.3 (3.2)	21.5 (6.9)	12.8 (3)	13.1 (2.1)
Yes	55.8 (15)	13.6 (3.8)	19.6 (6.2)	10.9 (3.2)	12 (2.8)
P-value^b	0.064	0.011	0.036	0.000	0.073
Intensity of rhinorrhea
Absence of symptoms	61.6 (12.2)	15.3 (3.2)	21.5 (6.9)	12.8 (3)	13.1 (2.1)
Mild symptoms	57.7 (14.2)	13.9 (4.1)	19.8 (6.3)	11.5 (3.3)	12.5 (2.7)
Moderate symptoms	54.3 (14.7)	13.4 (3.4)	19.3 (6)	10.5 (3.1)	11.4 (2.9)
Severe symptoms	53.9 (16.9)	13.4 (4)	19.7 (6.2)	10.5 (3.2)	11.7 (3)
P-value^c	0.150	0.038	0.180	0.000	0.044
Sneezing
No	63.2 (11.9)	16.2 (2.7)	21 (7.3)	12.8 (3)	13.7 (1.6)
Yes	55.9 (14.8)	13.5 (3.8)	19.7 (6.1)	11 (3.3)	12 (2.8)
P-value^b	0.051	0.000	0.177	0.002	0.010
Intensity of sneezing
Absence of symptoms	63.2 (11.9)	16.2 (2.7)	21 (7.3)	12.8 (3)	13.7 (1.6)
Mild symptoms	56.4 (14)	13.6 (3.7)	19.7 (6.4)	11.5 (3.3)	12.1 (2.6)
Moderate symptoms	56.2 (13.9)	13.5 (3.5)	20.3 (5.6)	10.7 (3.1)	11.8 (2.8)
Severe symptoms	55 (17.3)	13.5 (4.3)	19.1 (6.5)	10.8 (3.3)	12.1 (3.2)
P-value^c	0.281	0.006	0.410	0.004	0.050

Notes:

a Overall score ranges from 16 (low satisfaction) to 80 (high satisfaction). Low dimension score indicates low satisfaction while high dimension score indicates high satisfaction;

b U Mann–Whitney;

c Kruskal–Wallis Test.

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