Impact of intranasal corticosteroids on asthma outcomes in allergic rhinitis: a meta-analysis
Given the relationship between allergic rhinitis (AR) and asthma, it can be hypothesized that reducing inflammation in the upper airway with intranasal corticosteroid (INCS) medications may improve asthma outcomes. The goal of this study was to perform a systematic review with meta-analysis of the efficacy of INCS medications on asthma outcomes in patients with AR and asthma. Asthma-specific outcomes from randomized, controlled studies evaluating INCS medications in patients with AR were evaluated, including studies that compared INCS sprays to placebo, INCS sprays plus orally inhaled corticosteroids to orally inhaled corticosteroids alone, and nasally inhaled corticosteroids to placebo. Sufficient data for meta-analysis were retrieved for 18 trials with a total of 2162 patients. Asthma outcomes included pulmonary function, bronchial reactivity, asthma symptom scores, asthma-specific quality of life, and rescue medication use. The subgroup of studies comparing INCS spray to placebo had significant improvements in FEV1 (SMD = 0.31; 95% CI, 0.04-0.58), bronchial challenge (SMD = 0.46; 95% CI, 0.12-0.79), asthma symptom scores (SMD = -0.42; 95% CI, -0.53 to -0.30), and rescue medication use (SMD = -0.29; 95% CI, -0.58 to -0.01). Nasal inhalation of corticosteroids significantly improved morning and evening peak expiratory flow. There were no significant changes in asthma outcomes with the addition of INCS spray to orally inhaled corticosteroids. Thus, the results of this meta-analysis demonstrated that intranasal corticosteroid medications significantly improve some asthma-specific outcome measures in patients suffering from both AR and asthma. This effect was most pronounced with INCS sprays when patients were not on orally inhaled corticosteroids, or when corticosteroid medications were inhaled through the nose into the lungs. Overall, intranasal corticosteroid medications improve some asthma-specific outcome measures in patients with both AR and asthma. Further research is needed to clarify the role of INCS sprays as asthma-specific therapy, as well as the role of the nasal inhalation technique as a monotherapy in patients suffering from both asthma and AR.