Olfactory outcomes in chronic rhinosinusitis with nasal polyposis after medical treatments: a systematic review and meta‐analysis

BACKGROUND: Olfactory dysfunction is common among patients with chronic rhinosinusitis and has a negative impact upon quality of life. Olfactory dysfunction can be both subjective and objective and appears to be more predominant in patients with concomitant nasal polyposis. The efficacy of medical interventions on olfaction among patients with CRS with nasal polyposis (CRSwNP) is not well known. Our aim was to perform a systematic review with meta-analysis of the efficacy of medical therapies on objective and subjective hyposmia among patients with CRSwNP. METHODS: Olfaction specific outcomes from randomized controlled trials evaluating medical interventions on patients with CRSwNP were evaluated. Interventions included corticosteroids, antibacterials, antifungals, diuretics, herbals and anti-immunoglobulin E (IgE) medications. RESULTS: A total of 28 randomized control trials evaluation olfaction in CRSwNP was identified and systematically reviewed. Sufficient data for meta-analysis was retrieved for 5 trials. In the meta-analysis, oral steroids showed significant improvement in subjective olfaction scores compared to placebo (standardized mean difference [SMD] -2.22; 95% confidence interval [CI], -3.94 to -0.49). Oral steroids also showed significant improvement in objective olfaction scores compared to placebo (SMD 0.65; 95% CI, 0.28 to 1.01). In the systematic review, both topical steroids and combined topical and oral steroid groups showed overall improvement in subjective olfaction outcomes. Antibacterials, antifungals, herbals, and anti-IgE medications had no impact on overall olfaction scores. CONCLUSION: The results of this meta-analysis demonstrated that oral and topical steroids significantly improve olfaction in patients suffering from CRSwNP.