Page 46 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

ADULT-ONSET ASTHMA – PREDICTORS OF CLINICAL COURSE AND SEVERITY
METHODS
PATIENTS
We collected data from 571 pa ents with adult-onset asthma (onset of asthma a er the age of 18) who had been included in three separate observa onal clinical trials (Netherlands Trial Register numbers: NTR2217, NTR1846 and NTR1838) 18, 19 between 2009 and 2012. These prospec ve trials aimed at phenotyping pa ents with adult-onset asthma based on an extensive set of clinical, func onal and in ammatory parameters. Pa ents aged 18 years or older were eligible if they had a con rmed diagnosis of asthma based on interna onal guidelines (history of variable respiratory symptoms and documented variable expiratory airflow limitation) 20. Patients with other pulmonary diseases, non-related major co- morbidi es, pregnancy or a smoking history of > 10 pack years combined with xed air ow obstruc on/reduced di usion capacity were excluded. Detailed in- and exclusion criteria have been reported elsewhere (18, 19 and NTR2217). All eligible pa ents visi ng the pulmonology outpa ent department of four secondary and one ter ary referral clinic in the Netherlands were invited to par cipate. All three trials were reviewed and approved by medical ethical boards before their ini a on. All pa ents gave informed consent. The present addi onal analysis was registered in the Netherlands Trial Register under number NTR 4589.
ASSESSMENT OF SPECIFIC PHENOTYPIC CHARACTERISTICS
a. Asthma severity
Asthma severity was assessed according to the IMI-criteria, 21 based on medica on use and degree of asthma control. Severe asthma was de ned by the use of ≥1000 μg/ day u casone equivalent and/or daily oral cor costeroids plus a second controller, combined with an asthma control score >1.5 22 on the Juniper Asthma Control Ques onnaire (ACQ)23 or at least 2 exacerba ons in the past 12 months. Pa ents who did not ful ll these criteria were considered as having mild-moderate asthma.
b. Obesity
Obesity was de ned as a body mass index (BMI) ≥30 kg/m2.
c. Atopy
Speci c IgE to common aeroallergens was measured by ImmunoCAP; atopy was de ned as speci c IgE >0.35 Ku/L for at least one allergen.
d. Smoking status
Smoking status was recorded during history taking. (Ex-)smokers were either current or previous smokers. Non-smokers were pa ents that had never smoked.
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