The Hydration Status of Adult Patients with Oropharyngeal Dysphagia and the Effect of Thickened Fluid Therapy on Fluid Intake and Hydration: Results of Two Parallel Systematic and Scoping Reviews

Background: The effect of oropharyngeal dysphagia (OD) and thickened fluid (TF) therapy on hydration status has not been well defined in the literature. We aimed to assess the hydration status in patients with OD and the effect TF therapy has on it. Methods: Two literature reviews following PRISMA methodology (each one including a systematic and a scoping review) were performed: (R1) hydration status in adult patients with OD; (R2) effect of TF therapy on fluid intake and dehydration. Narrative and descriptive methods summarized both reviews. Quality assessment was assessed by Joanna Briggs Institute tools and GRADE. Results: (R1) Five out of twenty-two studies using analytical parameters or bioimpedance showed poorer hydration status among OD and 19–100% prevalence of dehydration; (R2) two high quality studies (total of 724 participants) showed positive effects of TF on hydration status. Among the articles included, nine out of ten studies that evaluated fluid intake reported a reduced TF intake below basal water requirements. Conclusions: Dehydration is a highly prevalent complication in OD. There is scientific evidence on the positive effect of TF therapy on the hydration status of patients with OD. However, strict monitoring of fluid volume intake is essential due to the low consumption of TF in these patients.