A series of search keywords were chosen for each of the three topics. Starting with these initial keywords, the search strategies were further refined so that the nine target papers identified by the pilot search could also be identified by the full literature search. Figure 3. presents the full process of refining the search strategies. Some health-related keywords such as multi-drug, treatment, regimen and therapy were also included in the final search strategies in order to improve the specificity of the search and to make sure the full search would pick up all the target papers identified in the pilot search.
The final search strategies and the search keywords were A’’, B’ and C in Figure 3.. The three topics were combined using the “AND” Boolean operator. Search fields were limited to title, abstract and keyword. Literature not written in English, published before 1990 and conference, symposium or workshop papers, books, letters, editorials or corrections were excluded using the limit function in the database. The electronic database search was conducted on 22nd March 2012.
