Methodological quality and transparency of clinical practice guidelines for the pharmacological treatment of non-communicable diseases using the AGREE II instrument: a systematic review protocol.

Background: Non-communicable diseases (NCDs) are the leading cause of death worldwide. Clinical practice guidelines (CPGs) constitute an important tool for the promotion of evidence-based health, which may improve healthcare outcomes for individuals with NCDs. Studies have shown that many CPGs have poor or moderate quality. Therefore, the aim of the proposed study is to systematically identify and appraise CPGs for pharmacological treatment of the most prevalent NCDs in primary care.

Methods: A comprehensive literature search will be conducted in the following databases: MEDLINE, Embase and Cochrane Library. Twelve databases specific to CPGs will also be searched. Three appraisers will assess the quality of the CPGs using the Appraisal of Guidelines Research and Evaluation (AGREE) Instrument, version II. The AGREE II results will be checked for discrepancies. Differences between scores equal than or greater to 2 will be considered discrepant and the appraisers will decide the final score by consensus. If no consensus is reached, a fourth appraiser will decide the score. According to the AGREE II User's Manual, the six domains of the instrument are independent. Thus, each domain score will be calculated by the sum of the individual item scores and scaling the total as a percentage of the maximum possible score for the domain.

Discussion: The AGREE II instrument will be applied to evaluate the quality of CPGs and contribute to enhance the discussion and development of guidelines of high quality. The findings will be submitted for publication in high-impact, peer-reviewed scientific journals and will also be disseminated at international conferences.

Systematic Review Registration: PROSPERO CRD42016043364.