The Prevalence of Oropharyngeal Dysphagia in Adults: A Systematic Review and Meta-analysis

To determine the global prevalence of oropharyngeal dysphagia (OD) in adults. Six electronic databases (Embase, LILACS, LIVIVO, PubMed/Medline, Scopus, and Web of Science) were searched, in addition to gray literature (ASHA, Google Scholar, ProQuest Dissertation, and Theses). A random-effects model for meta-analysis of proportions was conducted, and heterogeneity was evaluated according to the moderator variable through subgroup analysis and meta-regression. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist and the certainty of the evidence was assessed using the GRADE tool. Thirty papers were included for qualitative and quantitative synthesis. The combined prevalence estimate was 60% [CI 95% = 50%-70%; I² = 95%], accounting for different baseline conditions. However, the wide variation that exists between the different baseline conditions (underlying disease or risk factor) tended to overestimate this prevalence when considering the general population. Only one study evaluated healthy individuals, which showed a prevalence of 31% [CI95% = 27%-36%]. The risk of bias was considered low for all studies. None of the variables were considered predictors for the observed variance between the effect sizes of the included studies. For the prevalence of OD, the GRADE rating was considered very low. Despite the high prevalence observed, with over half of the individuals affected, the evidence regarding this outcome remains uncertain due to an overestimation of the generated estimates caused by the baseline condition of the sample.