Do stroke clinical practice guideline recommendations for the intervention of thickened liquids for aspiration support evidence based decision making? A systemetic review and narrative synthesis

Background Aspiration is a common sequela post stroke as a result of oropharyngeal dysphagia. It is primarily managed by recommending thickened liquids whereby a thickening agent is added to liquids to increase viscosity and slow bolus speed. However, the evidence supporting this intervention is not strong and clinicians may rely on tools such as clinical practice guidelines to support clinical decision-making. The purpose of this systematic review and narrative synthesis was to evaluate the evidentiary bases of recommendations made by clinical guidelines regarding the thickened liquids intervention. Methods A systematic review was conducted on stroke clinical guidelines retrieved via searches conducted across a range of databases including Academic Search Complete, CINAHL, MEDLINE and the Cochrane Library as well as through association websites. Guidelines were eligible for inclusion if they focused on adult stroke populations, made recommendations relating to the intervention of thickened liquids and were published after January 2010 and before December 2018. Four independent reviewers rated the methodological quality of the guidelines using the AGREE-II instrument. Intervention recommendations were extracted and analysed using the Criteria for Levels of Evidence Reported from the Canadian Stroke Best Practice Recommendations and a framework examining the evidence used by guidelines to support intervention recommendations. Results Thirteen clinical guidelines were included in the review. The methodological quality of included guidelines was variable but generally good-excellent overall. Thirty recommendations regarding the intervention were extracted. Of these, 16 recommendations were classed as a recommendation to use the treatment and all guidelines made this recommendation. Much of the evidence used to scaffold recommendations did not directly support the intervention and the evidence used was inconsistent across recommendations. Conclusions Despite the limited evidence base for the thickened liquid intervention, there was consensus evident among stroke guidelines in recommending it. This is despite limited empirical support. Further, much of the evidence used to support recommendations was not appropriate, suggesting less than satisfactory evidence-based practices in formulating recommendations. In this case, clinical guidelines may not be reliable decision-support tools for facilitating clinical decision-making.