Methodology of the global and regional burden of stroke study

Setting priorities for the prevention of stroke requires an empirical understanding of the pattern of disease burden and exposure to major risk factors. In this manuscript we aim to report the methodology of a systematic review of the epidemiological literature on stroke and how this information will be synthesized to produce updated estimates of the global burden of stroke.

We will use multi-state models implemented in the software program DisMod III to estimate age-specific prevalence, incidence, and early case-fatality (defined as either 28-day, 30-day or 1-month case fatality) for stroke by the 21 global burden of disease (GBD) regions as well as by gender and pathological stroke type based on information obtained from a systematic review. We conducted a two-stage search strategy in order to identify studies published between 1980 and 2011 for the GBD stroke review. Eligible studies: (a) distinguished between stroke and transient ischaemic attack (TIA); (b) distinguished between 1st ever and recurrent stroke; (c) reported on age-specific rates; (d) if reported, provided survival status within 28 days, 30 days or 1 month of onset for fatal and nonfatal events; (e) specified methods for ascertaining stroke cases, and (f) described imaging modalities to determine stroke subtypes. Details of included studies were recorded on a detailed data extraction form by trained reviewers. We will gather information on demographics, natural history and clinical outcomes (e.g. Rankin scale, Glasgow Coma Scale), after stroke which will be used to facilitate the estimation of epidemiological parameters. Reporting and methodological quality was rated. Populations were coded as urban, rural, or combined and studies classified as national, subnational, healthcare system-based, or community level. Studies published in non-English languages were translated and coded centrally.

In international health research, there is a crucial need for accurate assessment of global health patterns. A thorough GBD reassessment of stroke will ensure that global health policy decisions are based on the most up-to-date, valid and reliable epidemiological information available.