Clinical Health Updates

Allergic rhinitis associated with increased risk of bronchial hyperreactivity (ECRHS)

Clinical Question:
Are patients with allergic rhinitis at increased risk of developing bronchial hyperreactivity (a euphemism for asthma)?

Bottom Line
This study shows that 9.7% of patients with allergic rhinitis will develop bronchial hyperreactivity within 9 years. Although this is the first study to prospectively assess this association, the low rate of follow up is concerning.

Reference:
Shaaban R, Zureik M, Soussan D, et al. Allergic rhinitis and onset of bronchial hyperresponsiveness: a population-based study. Am J Respir Crit Care Med 2007;176(7):659-666.

Study Design:
Cohort (prospective)

Synopsis:
Patients with allergic rhinitis have more frequent bronchial hyperresponsiveness (BHR) in cross-sectional studies. The authors estimated the changes in BHR in nonasthmatic subjects with and without allergic rhinitis during a 9-year period. BHR onset was studied in 3,719 subjects without BHR at baseline, who participated in the follow-up of the European Community Respiratory Health Survey. BHR was defined as a >or=20% decrease in FEV(1) for a maximum dose of 1 mg of methacholine. Allergic rhinitis was defined as having a history of nasal allergy and positive specific IgE (>or=0.35 IU/ml) to pollen, cat, mites, or Cladosporium. The cumulative incidence of BHR was 9.7% in subjects with allergic rhinitis and 7.0% in subjects with atopy but no rhinitis, compared with 5.5% in subjects without allergic rhinitis and atopy (respective odds ratios [OR] and their 95% confidence intervals [95% CI] for BHR onset, 2.44 [1.73-3.45]; and 1.35 [0.86-2.11], after adjustment for potential confounders including sex, smoking, body mass index and FEV(1)). Subjects with rhinitis sensitized exclusively to cat or to mites were particularly at increased risk of developing BHR (ORs [95% CI], 7.90 [3.48-17.93] and 2.84 [1.36-5.93], respectively). Conversely, in subjects with BHR at baseline (n = 372), 35.3% of those with allergic rhinitis, compared with 51.8% of those without rhinitis had no more BHR at follow-up (OR [95% CI], 0.51 [0.33-0.78]). BHR “remission” was more frequent in patients with rhinitis treated by nasal steroids than in those not treated (OR [95% CI], 0.33 [0.14-0.75]).