Xerostomia and hyposalivation in patients with obstructive sleep apnoea

Objective (a) To report the xerostomia prevalence and severity in patients with obstructive sleep apnoea (OSA). (b) To assess the saliva pH in patients with OSA. Design Simultaneous cohort observational clinical study. Setting In Sleep Medicine Centre at Lomonosov Moscow State University from March to June 2019. Participants The study was conducted on 30 patients with OSA aged from 35 to 65 years. Main outcomes measures The diagnosis of sleep apnoea was made after standard polysomnography using the Domino programme. The severity of OSA was indicated using the Apnoea-Hypopnea Index. Xerostomia was evaluated using Fox's test. Hyposalivation was evaluated by measurement of salivary flow rate. Determination of the saliva pH was carried out with a pH metre. Statistical analysis was performed by one-way ANOVA and Tukey-Kramer multi-comparison test. Results Twenty-two out of 30 (73.3%) patients were diagnosed with dry mouth. Hyposalivation was observed in 6 out of 30 (20%). Dry mouth on awakening was observed in 60.0%, 72.7% and 88.9% of patients with mild, moderate and severe OSA, respectively. The average salivary flow rate was 0.28 mL/min, 0.24 mL/min and 0.14 mL/min, respectively. The average pH value in patients with mild, moderate and severe apnoea was 6.40 +/- 0.017, 6.15 +/- 0.27 and 5.87 +/- 0.24, respectively. Conclusions In patient with mild and moderate OSA, the saliva amount and rate are similar (P > .05). With the increase of OSA severity, both these parameters change (P < .001). The acidity of the saliva was correlated with the level of OSA, and it statistically increased with the increment of the OSA severity (P P < .001).

Automated summary

This study aimed to report the prevalence and severity of xerostomia in patients with obstructive sleep apnoea (OSA) and to assess saliva pH in these patients. Results showed that 73.3% of patients had dry mouth, with average salivary flow rate and pH decreasing with the severity of OSA. The study suggested a correlation between salivary parameters and OSA severity.