Incidence of stroke in the diabetic compared with the non-diabetic population: A systematic review protocol

People with diabetes have a largely increased risk of stroke compared with people without diabetes. Exact data on incidence of stroke in people with and without diabetes are important for improvements in preventive diabetes care, avoidance of fatal outcomes and as a solid basis for health policy and the economy. However, published data are conflicting, underlining the necessity for this systematic review of population-based studies on incidence, relative risks (RRs) and changes in stroke rates over time. The purpose of our review is to evaluate the incidence of stroke in the diabetic population and its differences with regard to sex, ethnicity, age and regions; to compare the incidence rate (IR) in the diabetic and non-diabetic populations and to investigate time trends. We will perform a systematic literature search in MEDLINE, Embase and LILACS designed by an experienced information scientist. Two review authors will independently screen the abstracts and full texts of all references on the basis of inclusion criteria regarding types of study, types of population and the main outcome. Data extraction and assessment of risk of bias will be undertaken by two review authors working independently. We will assess IR or cumulative incidence (CumI) and RR of stroke comparing the diabetic and non-diabetic populations. The attributable risk (AR = proportion of stroke among persons with diabetes that is attributable to diabetes) and the population attributable risk (PAR = proportion of stroke in the whole population that is attributable to diabetes) will be considered where available. In conclusion, this review will help to summarize the available evidence for incidence of stroke in the diabetic and nondiabetic population. The publication of this protocol will contribute to making the search strategy, methods, and assessment of reviews transparent and accessible for all involved professional groups.