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

Saline nasal irrigation provides symptom relief in allergic rhinitis (AR), 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 AR. 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 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.