Effectiveness of Air Filters in Allergic Rhinitis: A Systematic Review and Meta-Analysis

Previous studies have evaluated the effectiveness of air filters in mitigating the symptoms of allergic rhinitis (AR). However, these studies have yielded inconsistent results. This systematic review and meta-analysis was conducted to assess the effectiveness of air filters for patients with AR. For this, we comprehensively searched the PubMed, Embase, and Cochrane Library databases to identify relevant articles. The results are presented in terms of standardized mean difference (SMD) and 95% confidence intervals (CI) values with the fixed-effects model (FEM) and random-effects model (REM). Eight randomized controlled trials were included in our meta-analysis. Of these, three had a parallel design and five had a crossover design. Regarding clinical outcomes, pooled analyses performed using patients' nighttime and daytime symptom scores revealed SMD values of -0.21 (95% CI: -0.35 to -0.07 (FEM) and -0.35 to -0.08 (REM)) and -0.16 (95% CI: -0.30 to -0.03 (both FEM and REM)), respectively. However, no significant changes were noted in the SMD values when assessing medication use, quality of life (QoL), or peak expiratory flow rate (PEFR). In conclusion, air filters may help alleviate symptoms associated with AR; however, their effects on medication use, QoL, and PEFR appear to be limited. This systemic review and meta-analysis is registered with CRD42022380560.