Fig. 1.

Search strategy and flow chart of study selection. MeSH and free-text entries of IS/WS and epidemiological outcomes were applied to Medline and EMBASE databases for screening. In total, 1015 articles were identified during the primary search, and then systematically assessed for relevance to the research question. 54 articles were included [15–68], 3 of which reported both the incidence and prevalence of IS [15, 19, 30]. Thus, 57 data points were abstracted: 39 incidence figures. [15–53] and 18 prevalence figures. [15, 19, 30, 54–68]