Hypertonic Saline Versus Isotonic Saline Nasal Irrigation: Systematic Review and Meta-analysis

Background: Saline nasal lavage is one of the treatments of sinonasal diseases. Evidence from basic research favors hypertonic saline (HS) over isotonic saline (IS) for mucociliary clearance, but evidence from clinical studies is controversial. Conversely, HS may carry greater side effects. Objective: To compare the effects of HS and IS nasal irrigation in treating sinonasal diseases. Methods: Systematic search with Ovid MEDLINE, Scopus, PubMed, Google Scholar, and Manual additional sources was conducted. Randomized controlled trials comparing HS with IS nasal irrigation in treating any sinonasal diseases, including rhinitis and rhinosinusitis, were included. Data were pooled for meta-analyses. Outcomes were symptom scores, sinonasal outcome test (SNOT), and adverse events. Heterogeneity was explored by subgroup analyses. Results: Nine studies (740 patients) were included. HS nasal irrigation brought greater benefits over IS in symptom reduction (standardized mean difference (SMD) -0.58; 95% confidence interval [CI]: -0.76, -0.40); however, no difference was shown in SNOT-20 improvement (mean difference 1.81; 95% CI: -0.68, 4.30). In subgroup analyses, effects favoring HS on symptoms were larger in 4 subgroups. These were (1) patients with rhinitis (SMD -1.09; 95% CI: -1.42, -0.76) compared with rhinosinusitis (SMD -0.37; 95% CI: -0.58, -0.15), P<.01; (2) patients under the age of 18 years (SMD -1.22; 95% CI: -1.53, -0.91) compared with patients over the age of 18 years (SMD -0.26; 95% CI: -0.49, -0.04), P<.01; (3) saline irrigation using high volume (SMD -0.89; 95% CI: -1.18, -0.60) compared with low volume (SMD -0.39; 95% CI: -0.62, -0.16), P<.01; and (4) saline irrigation with hypertonicity of < 3% (SMD -1.09; 95% CI: -1.42, -0.76) and hypertonicity of 3%-5% (SMD -1.20; 95% CI: -1.61, -0.78) compared with hypertonicity of >5% (SMD 0.20; 95% CI: -0.15, 0.55), P<.01. Buffered saline and operative status did not have impact. HS brought greater minor adverse effects. No major adverse effects were reported. Conclusion: HS improves symptoms over IS nasal irrigation in treating sinonasal diseases. There is no difference in diseasespecific quality of life. However, HS brings greater minor side effects than IS.