Introduction
Methods
Selection of study population
Lowest FEF50%tertile | Highest FEF50%tertile | |||
---|---|---|---|---|
(n= 398) | (N= 491) | |||
Age (years) | 54 | (12) | 48 | (13) |
Gender (%female) | 72 | 62 | ||
BMI (kg/m2) | 28 | (5) | 29 | (6) |
Smoking (%current/ex/never ) | 26/37/37 | 15/42/43 | ||
ICS (%yes) | 53 | 50 | ||
FEV1 (%predicted) | 89 | (9.8) | 109 | (12) |
FEV1/FVC (%) | 70 | (5.7) | 83 | (4.3) |
FEF50% (%predicted) | 51 | (9.9) | 104 | (17) |
ACQ total score | 1.3 | (0.9) | 1.2 | (0.9) |
In-depth interviews and focus groups
Methods of interviews and focus groups
Results
In-depth interview group | Focus group | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
With SAD (n= 7) | Without SAD (n= 3) | With SAD (n= 6) | Without SAD (n= 5) | |||||||
median | (range) | median | (range) | p-value | median | (range) | median | (range) | p-value | |
Age (years) | 45 | (25-73) | 52 | (20-63) | 0.833 | 54 | (25-73) | 47 | (36-51) | 0.247 |
Gender (female/male) | 5/2 | 2/1 | 1.000 | 5/1 | 4/1 | 1.000 | ||||
BMI (kg/m2) | 28 | (23-39) | 36 | (32-38) | 0.117 | 29 | (23-52) | 32 | (24-38) | 0.792 |
Smoking (current/ex/never%) | 1/4/2 | 1/1/1 | 0.728 | 0/5/1 | 0/1/4 | 0.080 | ||||
ICS (yes/no) | 5/2 | 3/0 | 1.000 | 4/2 | 3/2 | 0.497 | ||||
FEV1 (%predicted) | 79 | (66-104) | 99 | (94-123) | 0.117 | 81 | (76-88) | 112 | (97-127) | 0.004 |
FEV1/FVC (%) | 62 | (52-73) | 83 | (81-89) | 0.017 | 64 | (52-77) | 83 | (80-88) | 0.004 |
FEF50% (%predicted) | 37 | (23-62) | 107 | (89-115) | NA | 40 | (23-55) | 114 | (82-122) | NA |
RV (%predicted) | 120 | (88-160) | 72 | (71-89) | 0.033 | 120 | (88-160) | 88 | (77-98) | 0.017 |
IOS R20 (kPa/l/s) | 0.39 | (0.29-0.50) | 0.33 | (0.32-0.40) | 0.517 | 0.39 | (0.34-0.67) | 0.38 | (0.26-0.49) | 0.429 |
IOS R5-R20 (kPa/l/s) | 0.27 | (0.10-0.44) | 0.19 | (0.11-0.25) | 0.383 | 0.25 | (0.14-0.29) | 0.05 | (0.01-0.08) | NA |
IOS X5 (kPa/l/s) | -0.22 | (-0.49;-0.12) | -0.23 | (-0.26;-0.11) | 1.000 | -0.23 | (-0.49;-0.22) | -0.07 | (-0.12;-0.06) | 0.004 |
PC20 methacholine# (mg/ml) | 1.1 | (0.1-6.4) | 3.5 | (1.3-23.9) | 0.183 | 1.13 | (0.14-5.55) | 9.8 | (2.8-20.9@) | 0.017 |
ACQ (total score) | 0.5 | (0.0-1.5) | 2.0 | (0.0-2.2) | 0.383 | 0.6 | (0.0-1.3) | 1.0 | (0.3-2.2) | 0.177 |
BHQ symptoms (score) | 0.4 | (0.0-2.5) | 1.8 | (0.3-3.1) | 0.383 | 1.3 | (0.0-2.7) | 1.9 | (1.3-2.7) | 0.329 |
BHQ stimuli (score) | 1.2 | (0.0-4.3) | 1.8 | (0.0-4.3) | 0.833 | 2.5 | (0.1-3.8) | 2.5 | (0.9-4.1) | 0.662 |
Item organization and selection
Without SAD | With SAD | |
---|---|---|
Domain 1: Asthma symptoms
| Concentrating on my breathing helps me when I feel asthmatic. | I'm not able to breathe in deeply when I feel asthmatic. |
People often tell me they can hear me breathing, even in a calm situation. | I sometimes wheeze when I'm at ease or in rest. | |
I only wheeze when I feel very asthmatic. | When I'm physically active (like walking the stairs), I sometimes wheeze. | |
I often cough unexpectedly. | I can feel suddenly asthmatic without having any other symptoms. | |
I often cough superficially (tickling cough) before I get bothered by coughing more deeply. | ||
I can see it coming when I get my asthma. | I almost always feel slightly asthmatic and I take a rescue puff regularly. | |
I often have a period without feeling asthmatic and without needing rescue puffs. | I have suffered from bronchitis. | |
Domain 2: Ear/nose/ throat complaints
| My asthma symptoms are preceded by the flu or a cold. | I usually have runny or painful eyes when I have hay fever. |
When I feel asthmatic, I almost always have symptoms comparable to a cold. | ||
I usually get a cold first, and thereafter start coughing. | ||
I often suffer with my ears. | ||
I often have runny or painful eyes without having hay fever. | ||
I frequently have a hoarse or husky voice. | ||
When I feel asthmatic, it often comes with symptoms of my throat, nose, ears or eyes. | ||
When I feel asthmatic, I often, also suffer from a sore throat. | ||
My tonsils or adenoids have been removed. | ||
Domain 3: Localization of symptoms
| When I feel asthmatic, I feel it in the middle of my back. | When I feel asthmatic, I have a pressing and oppressive feeling. |
When I feel asthmatic, I feel it in the top of my back. | When I feel asthmatic, I feel it in my chest. | |
When I feel asthmatic, I feel a stab or a sting in my back or my ribs. | ||
When I feel asthmatic, I sometimes feel bloated. | ||
Domain 4: BHR to exercise
| As a child, I always participated in all games and sports. | Actually, I cannot perform strenuous exercise or sport, because I will become asthmatic. |
I am able to walk a long distance without resting. | Physical activities always make my asthma worse. | |
When I'm not ill, I can easily do physical activities such as walking the stairs. | ||
When I feel asthmatic when exercising, it is very often due to the environment (grass, trees, flowers…). | ||
When I feel asthmatic when exercising, it is very often due to the weather. | ||
Sometimes I go running or jogging. | ||
Domain 5: BHR to allergens
| I cannot stand woolen blankets or clothes. | I have an immediate reaction to birds. |
I cannot stand the down filling in pillows. | I have an immediate reaction to cats. | |
Domain 6: BHR to weather changes
| I tire more rapidly due to weather changes. | My asthma worsens in autumn. |
My breathing becomes easier in cold air. | I feel asthmatic more rapidly due to weather changes. | |
I always sleep with an open window, otherwise I feel asthmatic. | I feel asthmatic when I suddenly enter a cold environment. | |
Domain 7: Stress and fatigue
| I rapidly get tired due to my asthma symptoms. | In stressful situations, I get particularly asthma symptoms. |
Feeling tired is as much part of my asthma as feeling short of breath. | In stressful situations I have physical symptoms such as complaints of the nose, throat or voice. | |
I tire more rapidly due to my asthma symptoms. | ||
When I'm feeling tired I will probably get asthmatic in a few days. | ||
When I feel asthmatic, I often, also have a headache. | ||
Domain 8: Gastro-intestinal tract
| Sometimes I feel asthmatic or out of breath because of heartburn. | |
Sometimes, when I'm short of breath, it can be a relief to burp. | ||
Sometimes I have stomach problems which can make me feel asthmatic. | ||
Domain 9: Skin
| I get eczema because of weather changes. | |
I get skin problems (like eczema) when touching some kinds of food (e.g. fruit or vegetables). | ||
My asthma symptoms and eczema alternate. | ||
Domain 10: Miscellaneous
| I often get car sick or travel sick. | |
I have more than three close relatives suffering from asthma or comparable illnesses. | ||
At what age did you first suffer from asthma symptoms? |