Study objective: To determine the prevalences of symptomatic gastroesophageal reflux (GER), reflux-associated respiratory symptoms (RARS), and reflux-associated β-agonist inhaler use in asthmatics.
Design: Questionnaire-based, cross-sectional analytic survey.
Setting: Outpatient asthma and clinical research clinics attached to the University of Calgary tertiary care centre and two family practices.
Patients: Asthma group consisted of 109 patients referred to an outpatient asthma clinic. First control group consisted of 68 patients visiting their family physicians. Second control group consisted of 67 patients with thyroid disease, hypercholesterolemia, or diabetes participating in drug trials.
Results: Among the asthmatics, 77%, 55%, and 24% experienced heartburn, regurgitation, and swallowing difficulties, respectively. Symptoms were less prevalent in the control groups. At least one antireflux medication was required by 37% of asthmatics (p<0.001, vs controls). None of the asthma medications were associated with an increased likelihood of symptomatic GER. In the week prior to completing the questionnaire, 41% of the asthmatics noted RARS, including cough, dyspnea, and wheeze and 28% used their inhalers while experiencing GER symptoms. Inhaler use correlated with the severity of heartburn (r=0.28, p<0.05) and regurgitation (r=0.40, p<0.05)
Conclusions: The questionnaire demonstrated a greater prevalence of GER symptoms, RARS, and reflux-associated inhaler use in asthmatics. This excessive inhaler use may explain how GER indirectly causes asthma to worsen.