Study design
GEIRD is a multicase–control study on respiratory health, involving seven Italian centres. Cases and controls were identified through a two-stage screening process in pre-existing cohorts and in new random samples from the Italian general population.
In the first stage (2007–2010), eligible subjects were administered a screening questionnaire on respiratory symptoms. In the second stage (2008–2016) all the responders with symptoms suggestive of asthma, chronic obstructive pulmonary disease (COPD) or chronic bronchitis (CB) and a random sample of subjects without respiratory symptoms or with symptoms suggestive of rhinitis, were referred to clinical centres to undergo the “phenotypization” protocol. Protocol and descriptive characteristics of the GEIRD study are available on the web site
http://www.geird.org [
9].
Study population and procedures
For the present study we used clinical data belonging to 2606 subjects, who completed the stage 2 of the GEIRD study. Clinical data were obtained by means of a structured medical interview through the Clinical Questionnaire, a modification of the European Community Respiratory Health Survey (ECRHS) questionnaire (
http://www.ecrhs.org) including detailed questions on respiratory symptoms, medical history, medication, use of services, occupation, social status, home environment and lifestyle. For the evaluation of regular ICS use and patient adherence to anti-asthmatic treatment the questions: “
Since the last survey have you used inhaled corticosteroids?”, “
How old were you when you first started to use inhaled corticosteroids?”, “
Have you used inhaled corticosteroids every year since the last survey?”, “
If you are prescribed medicines for your breathing,
do you normally take: A) all of the medicines? B) most of the medicines? C) some of the medicines? D) none of the medicines” were used [
10].
On the basis of the answers to the Clinical Questionnaire, a woman was considered to have asthma if she answered affirmatively to both questions: “Have you ever had asthma?” and ‘‘Was this confirmed by a doctor?’’.
The asthma course during pregnancy was evaluated with the specific question: “What happened to your asthma during your pregnancies? A) got better B) got worse C) stayed the same D) not the same for all pregnancies E) don’t know”.
Participants were considered to have allergic rhinitis if they answered positively to this question: “Do you have any nasal allergies including hay fever?”.
Atopy was assessed by skin prick tests (SPT). Individuals with at least one positive SPT were considered to be atopic. The allergens selected in all centres were Cupressus arizonica, Graminacee mix Dermatophagoides pteronyssinus, Artemisia vulgaris, Dermatophagoides farina, Ambrosia artemisifolia, Alternaria tenuis, Parietaria Judaica, Dog dander, Corylus avellana, Cat hair, Olea europea, Betula verrucosa, Cladosporium herbarum (ALK diagnostics, Denmark) (Mailing 1993).
In a subsample of 50 asthmatic women, we also evaluated the asthma control by means of the Asthma Control Test (ACT™). Patients assigned scores of 1–5 to each item, resulting in the following grading system: uncontrolled/partly controlled asthma with score ≤ 20; well controlled asthma with score > 20 [
11]. These data refer to the time of the clinical interview and they cannot be used as an indicator of asthma control before pregnancy.
No clinical data before pregnancy are available.
Statistical analysis
Women who answered “D) not the same (asthma) for all pregnancies” were excluded from the statistical analyses. The sample who answered “E) don’t know” was included in the group of those unchanged/improved asthma. The relationship of the main determinants of unchanged/improved asthma during pregnancy and worsened asthma during pregnancy was evaluated by Fisher’s exact test for categorical variables and by Wilcoxon–Mann–Whitney non-parametric test for continuous variables. The statistical analyses were performed using Stata 14.0 (StataCorp, College Station, TX, USA).