Assessing the global burden of ischemic heart disease: Part 1: Methods for a systematic review of the global epidemiology of ischemic heart disease in 1990 and 2010

Background: Ischemic heart disease (IHD) is the leading cause of death worldwide. The GBD (Global Burden of Disease, Injuries, and Risk Factors) study (GBD 2010 Study) conducted a systematic review of IHD epidemiology literature from 1980 to 2008 to inform estimates of the burden on IHD in 21 world regions in 1990 and 2010. Methods: The disease model of IHD for the GBD 2010 Study included IHD death and 3 sequelae: myocardial infarction, heart failure, and angina pectoris. Medline, EMBASE, and LILACS were searched for IHD epidemiology studies in GBD high-income and low- and middle-income regions published between 1980 and 2008 using a systematic protocol validated by regional IHD experts. Data from included studies were supplemented with unpublished data from selected high-quality surveillance and survey studies. The epidemiologic parameters of interest were incidence, prevalence, case fatality, and mortality. Results: Literature searches yielded 40,205 unique papers, of which 1,801 met initial screening criteria. Upon detailed review of full text papers, 137 published studies were included. Unpublished data were obtained from 24 additional studies. Data were sufficient for high-income regions, but missing or sparse in many low- and middle-income regions, particularly Sub-Saharan Africa. Conclusions: A systematic review for the GBD 2010 Study provided IHD epidemiology estimates for most world regions, but highlighted the lack of information about IHD in Sub-Saharan Africa and other low-income regions. More complete knowledge of the global burden of IHD will require improved IHD surveillance programs in all world regions.