Efficacy of hypertonic saline nasal irrigation in allergic rhinitis: A systematic review and meta-analysis

Saline nasal irrigation provides symptom relief in allergic rhinitis, but the optimal saline concentration remains uncertain. The comparative efficacy of 3% hypertonic saline nasal irrigation (HSNI) versus 0.9% isotonic saline is still debated. We conducted a meta-analysis to evaluate nasal symptom scores from studies comparing HSNI with control (isotonic saline or no saline) in patients with allergic rhinitis. A systematic search of PubMed, Scopus, and Cochrane Central was performed for randomized controlled trials (RCTs) comparing 3% HSNI with control from inception to May 8, 2024. Primary outcomes were total nasal symptom scores and antihistamine use. We pooled mean differences (MD) and odds ratios (OR) with 95% confidence intervals (CI) using a random-effects model and assessed heterogeneity with I². Nine RCTs involving 645 patients met the inclusion criteria. Follow-up ranged from 4 weeks to 2 months. The mean age was 35.49 years in adults and 9.3 years in children. HSNI significantly reduced nasal symptom scores compared with control in adults (MD = -2.09; 95% CI: -3.86 to -0.33; p = 0.02; I² = 97%) and children (MD = -0.97; 95% CI: -1.51 to -0.44; p = 0.0004; I² = 42%). Antihistamine use was also lower with HSNI than control (OR = 0.39; 95% CI: 0.21–0.70; p = 0.002; I² = 14%), but no significant difference was found between HSNI and isotonic saline alone (OR = 0.69; 95% CI: 0.41–1.16; p = 0.16; I² = 0%). HSNI appears effective in reducing symptoms and medication use in allergic rhinitis across age groups.