Abstract: We included two RCTs (116 adult participants). One compared large-volume (150 ml) hypertonic (2%) saline irrigation with usual treatment over a six-month period; the other compared 5 ml nebulised saline twice a day with intranasal corticosteroids, treating participants for three months and evaluating them on completion of treatment and three months later. Large-volume, hypertonic nasal saline versus usual care One trial included 76 adult participants (52 intervention, 24 control) with or without polyps.Disease-specific HRQL  was reported using the Rhinosinusitis Disability Index (RSDI; 0 to 100, 100 = best quality of life). At the end of three months of treatment, patients in the saline group were better than those in the placebo group (mean difference (MD) 6.3 points, 95% confidence interval (CI) 0.89 to 11.71) and at six months there was a greater effect (MD 13.5 points, 95% CI 9.63 to 17.37). We assessed the evidence to be of low quality for the three months follow-up and very low quality for the six months follow-up. Patient-reported disease severity  was evaluated using a "single-item sinus symptom severity assessment" but the range of scores is not stated, making it impossible for us to determine the meaning of the data presented. No adverse effects  data were collected in the control group but 23% of participants in the saline group experienced side effects including epistaxis. General HRQL  was measured using SF-12 (0 to 100, 100 = best quality of life). No difference was found after three months of treatment (low quality evidence) but at six months there was a small difference favouring the saline group, which may not be of clinical significance and has high uncertainty (MD 10.5 points, 95% CI 0.66 to 20.34) (very low quality evidence). Low-volume, nebulised saline versus intranasal corticosteroids One trial included 40 adult participants with polyps. Our primary outcome of disease-specific HRQL  was not reported. At the end of treatment (three months) the patients who had intranasal corticosteroids had less severe symptoms  (MD -13.50, 95% CI -14.44 to -12.56); this corresponds to a large effect size. We assessed the evidence to be of very low quality. The two studies were very different in terms of included populations, interventions and comparisons and so it is therefore difficult to draw conclusions for practice. The evidence suggests that there is no benefit of a low-volume (5 ml) nebulised saline spray over intranasal steroids. There is some benefit of daily, large-volume (150 ml) saline irrigation with a hypertonic solution when compared with placebo, but the quality of the evidence is low for three months and very low for six months of treatment.

Plain-language summary: We included two randomised controlled trials with a total of 116 adult participants in this review. One compared large-volume (150 ml) hypertonic saline irrigation with usual treatment over a six-month period. The other compared 5 ml of nebulised saline twice a day with intranasal corticosteroids, treating participants for three months and evaluating them on completion of treatment and three months later. Both of these studies had important limitations in their methodology and we considered them to have a high risk of bias. Large-volume, hypertonic nasal saline versus usual care In the small trial of 76 participants our primary outcome of 'disease-specific health-related quality of life' was reported using a 0- to 100-point scale. At the end of three months of treatment, patients in the saline group were better than those in the placebo group and at six months of treatment there was a greater effect. We assessed the evidence to be of low quality for the three months follow-up and very low quality for the six months follow-up. Patient-reported disease severity was also evaluated but the trialists did not state the range of scores used, which made it impossible for us to determine the meaning of the data presented. No adverse effects data were collected in the control group but 23% of participants in the saline group experienced side effects including nosebleeds (epistaxis). General health-related quality of life was also measured in this study. No difference was found after three months of treatment but at six months there was a small difference (although the result is uncertain). We assessed the evidence to be of low quality. Low-volume, nebulised saline versus intranasal corticosteroids One small trial had 20 patients in each of the two arms being compared. Our primary outcome of disease-specific health-related quality of life was not reported. At the end of treatment (three months) there was an improvement in symptoms. The two studies were very different in terms of included populations, interventions and comparisons and so it is therefore difficult to draw conclusions for practice. The evidence suggests that there was no benefit of a low-volume (5 ml) nebulised saline spray over intranasal steroids, but there may be some benefit of daily, large-volume (150 ml) saline irrigation with a hypertonic solution compared with placebo, although the quality of the evidence was low for three months and very low for six months of treatment.