Impact of Gastroesophageal Reflux Disease on Salivary Flow Rate, pH and Buffer Capacity: A Systematic Review and Meta-Analysis.

Objectives: This systematic review and meta-analysis aimed to assess the impact of gastroesophageal reflux disease (GERD) on salivary parameters, including salivary pH (SpH), stimulated salivary flow rate (SSFR), unstimulated salivary flow rate (USFR), and salivary buffer capacity (SBC).

Methods: A thorough review of the literature was carried out across various databases, following rigorous inclusion and exclusion criteria. Studies that focused on patients with GERD and assessed the specified salivary parameters were included. The data was synthesised and analysed using standard meta-analytical techniques.

Results: The meta-analysis included 21 studies. GERD patients exhibited significantly lower SpH (MD = -0.18, 95% CI: -0.34 to -0.02), SSFR (MD = -0.35, 95% CI: -0.51 to -0.18), and SBC (MD = -0.43, 95% CI: -0.67 to -0.19) compared to healthy controls. No significant reduction was observed in USFR (MD = -0.10, 95% CI: -0.25 to 0.05). Subgroup analyses indicated significant reductions in SpH, SSFR, and SBC in both Reflux Esophagitis and Non-Erosive Reflux Disease groups. Proton pump inhibitor usage was associated with further reductions in SpH (MD = -0.22, 95% CI: -0.37 to -0.06) and SBC (MD = -0.54, 95% CI: -0.80 to -0.27), but did not significantly impact USFR. Excluding studies with high and moderate risk of bias confirmed the robustness of the significant reductions.

Conclusions: While GERD may reduce SpH, SSFR, and SBC, the evidence supporting these conclusions is uncertain due to inherent weaknesses in the existing studies. Regular monitoring of these parameters is essential for effective oral health management in patients diagnosed with GERD.