2.1. Objectives
To perform a systematic review of the beneficial and harmful effects of onabotulinumtoxinA injection (Botox) for the prophylaxis of headaches in adults with CM.
2.2. Methods
Studies were selected for inclusion in the systematic review based on the selection criteria presented in .
Inclusion Criteria for the Systematic Review.
The literature search was performed by an information specialist using a peer-reviewed search strategy. Published literature was identified by searching the following bibliographic databases: MEDLINE (1946– ) with in-process records and daily updates through Ovid; Embase (1974– ) through Ovid; and PubMed. The search strategy consisted of both controlled vocabulary, such as the National Library of Medicine’s MeSH (Medical Subject Headings), and keywords. The main search concepts were Botox (onabotulinumtoxinA) and migraine.
Methodological filters were applied to limit retrieval to randomized controlled trials and controlled clinical trials. Where possible, retrieval was limited to the human population. Retrieval was not limited by publication year or by language. Conference abstracts were excluded from the search results.
The initial search was completed on October 17th, 2013. Regular alerts were established to update the search until the meeting of the Canadian Drug Expert Committee (CDEC) held on March 19th, 2014. Regular search updates were performed on databases that do not provide alert services.
Grey literature (literature that is not commercially published) was identified by searching relevant websites from the following sections of the Grey Matters checklist (http://www.cadth.ca/en/resources/finding-evidence-is/grey-matters): Health Technology Assessment Agencies, Health Economics, Clinical Practice Guidelines, Databases (free), Internet Search and Open Access Journals. Google and other Internet search engines were used to search for additional Web-based materials. These searches were supplemented by reviewing the bibliographies of key papers and through contacts with appropriate experts. In addition, the manufacturer of the drug was contacted for information regarding unpublished studies.
Two CDR clinical reviewers independently selected studies for inclusion in the review based on titles and abstracts, according to the predetermined protocol. Full-text articles of all citations considered potentially relevant by at least one reviewer were acquired. Reviewers independently made the final selection of studies to be included in the review, and differences were resolved through discussion.
