Page 104 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

ADULT-ONSET ASTHMA – PREDICTORS OF CLINICAL COURSE AND SEVERITY
METHODS
PATIENTS
Two hundred adults with new-onset asthma were recruited from one academic and two non-academic pulmonary outpa ent clinics between 2009 and 2011 and were prospec vely followed for 5 years. All pa ents had a recent (<1 year) doctor’s diagnosis of new-onset asthma. Adult-onset asthma was de ned as asthma with an onset of the disease at >18 years of age. Asthma diagnosis was based on typical asthma symptoms and documented reversibility in FEV1 of > 12% of predicted value and/or a posi ve inhaled methacholine provoca on test (PC20 < 8mg/ml).15 Pa ents were excluded if they had a self-reported history of childhood asthma or other chronic respiratory diseases in childhood, frequent episodes of dyspnea as a child, or use of bronchodilator or other asthma medica on in childhood.
Current smoking and ex-smoking were allowed. Pa ents with a smoking history of >10 pack years were included only if they showed reversibility in FEV1 ≥12% of the predicted value, and had a normal CO di usion capacity (DLCO >80%).
The study was approved by the AMC Medical Ethics Board and registered in the Dutch trial register (NTR1846). All par cipants were informed and gave wri en informed consent.
STUDY DESIGN
This prospec ve longitudinal cohort study was part of the ADONIS-study (Adult-onset asthma and in ammatory subphenotypes).16 At baseline, pa ents underwent a comprehensive assessment of clinical, func onal and in ammatory parameters (Figure 1). Therea er, they were treated in regular healthcare facili es. Pa ents were contacted and invited for a limited reassessment at yearly intervals. Between 4 to 5 years post diagnosis an extensive reassessment of baseline measurements was done. If pa ents could not be reached by phone, email or postal mail, basic informa on about asthma symptoms and medica on was collected via their general prac oner.
STUDY MEASUREMENTS
Clinical measurements – A comprehensive history was taken, including ques ons about asthma symptoms, medica on use and healthcare u liza on in the past year. Pa ents completed ques onnaires including the asthma control ques onnaire (ACQ-6; uncontrolled asthma de ned as ACQ-score ≥1.5),17 asthma quality of life ques onnaire (AQLQ), and the Sino-nasal Outcome Test (SNOT-22).18 Obesity was de ned as a BMI ≥ 30kg/m2.
Lung func on measurements – Pre- and post-bronchodilator spirometry (FEV1 and forced vital capacity (FVC)) was performed according to interna onal standards.19 Di usion capacity of the lungs for carbon monoxide divided by alveolar volume (DLCOc/VA) was measured with single breath measurement.20 Total lung capacity (TLC) and residual volume (RV) were
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