Increased risk of asthma attacks and emergency visits among asthma patients with allergic rhinitis: a subgroup analysis of the improving asthma control trial

BACKGROUND: Inadequately controlled allergic rhinitis (AR) in asthmatic patients can contribute towards increased asthma exacerbations and poorer symptom control, which may increase medical resource use. We assessed asthma-related medical resource use and attacks in asthmatic patients who did and did not have concomitant AR and were adding montelukast or salmeterol to baseline treatment with inhaled fluticasone. METHODS: A post hoc resource use analysis of a 52-week, double-blind multicentre clinical trial (Investigation of Montelukast as a Partner Agent for Complementary Therapy) [corrected] including 1490 adults with chronic asthma, aged 15-72 years, with FEV(1) 50-90% of predicted and > or =12% increase in FEV(1) after salbutamol administration, treated with either montelukast 10 mg daily or salmeterol 50 microg twice daily in addition to fluticasone 200 microg, was undertaken. Asthma-related medical resource use included medical visits (defined as either an unscheduled visit [to a general practitioner, a specialist or a non-medical provider] or a specialist visit), emergency room visits and hospitalizations during follow-up. Asthma attacks were defined as the worsening of asthma requiring unscheduled visit, emergency visit, hospitalization or oral/intravenous/intramuscular corticosteroids. RESULTS: A self-reported history of concomitant AR was identified in 60% of the patients (n=893). Univariate analysis suggests that significantly more patients with concomitant AR experienced emergency room visits (3.6% vs. 1.7%, P=0.029) and asthma attacks (21.3% vs. 17.1%, P=0.046). Multivariate analysis adjusting for treatment group, age and baseline asthma severity confirmed these results since the presence of concomitant AR in patients with asthma increases the likelihood of emergency room visit (odds ratio (OR)=2.35, 95% confidence interval (CI)=1.12-4.80) and asthma attack (OR=1.35, 95% CI=1.03-1.77). Patients with asthma alone compared with patients with both conditions did not differ in terms of unscheduled or specialist visits and hospitalizations. CONCLUSIONS: Presence of self-reported concomitant AR in patients with asthma resulted in a higher rate of asthma attacks and more emergency room visits compared with asthma patients without concomitant AR.