Prevalence of allergic rhinitis and its associated morbidity in adults with asthma: a multicentre study.

OBJECTIVES To assess the prevalence of allergic rhinitis in adult patients with asthma in Hong Kong, and to compare the morbidity endured by asthma patients with and without allergic rhinitis. DESIGN Cross-sectional study. SETTING Respiratory clinics of four major public hospitals in Hong Kong. PATIENTS A total of 600 adults with asthma were recruited from March to May 2007. MAIN OUTCOME MEASURES Doctors and patients completed separate questionnaires evaluating symptoms, treatment, and health care utilisation. Spirometry data were obtained for a subgroup of patients at the time of survey completion. RESULTS The patients consisted of 267 males and 333 females, with 251 having spirometry data. The mean pre-bronchodilator 1-second forced expiratory volume predicted among those who had spirometry performed was 88% (standard deviation, 28%). In all, 50% of the patients had intermittent and 50% had persistent asthma. Over three quarters (463/600; 77%) of patients had experienced allergic rhinitis symptoms in the past 12 months, of whom 96% had a previous diagnosis of allergic rhinitis. Asthmatics without allergic rhinitis symptoms had higher rates of visits to doctors, pharmacy visits, emergency department attendances, and hospitalisations for asthma than those with both conditions. Among subjects with asthma and allergic rhinitis, those taking nasal steroid (226/463; 49%) had lower rates of emergency department visits (13 vs 25%, P=0.002) and hospitalisations (7 vs 13%, P=0.045) for asthma than those who were not. CONCLUSION Allergic rhinitis is a common co-morbid condition of asthma in this hospital clinic cohort. Treatment of allergic rhinitis with intra-nasal steroid was associated with less health care utilisation for asthma.