Measure of the Rate at which Mortality in Type 2 Diabetes Mellitus Occurs: Protocol for a Systematic Review.

Introduction: Type 2 diabetes is the third largest cause of mortality in the United Kingdom, with about 50% of patients’ having developed complications at time of diagnosis. We consider that the evidence which explores the actual hazard ratios of mortality has not been consistent. n this paper we discuss methodology and review the most recent accurate data on mortality in type 2 diabetes. Methods: A systematic review will be undertaken aimed at synthesis of evidence of relative risk of mortality in type 2 diabetes, using the Centre for Reviews and Dissemination guidelines. We will explore conflicting and unanswered questions in relation to mortality. The primary outcome is all-cause, overall-cause or total mortality expressed as hazard ratios. Sub-groups will also be explored; age, gender, socio-economic factors and causes of death. We will review abstracts published after 1990 in the English language. Our data source will include electronic databases; the Cochrane library, the Centre for Reviews and Dissemination, Medline/PubMed, and other grey literature. The study populations are type 2 diabetes patients whose mortality outcome, expressed as hazard ratio, has been evaluated. Data extraction will be undertaken by one reviewer and triangulated by the second and third reviewer. The quality of the included studies will be evaluated in accordance with the inclusion/exclusion criteria; methodological quality that meets the critical appraisal framework and the relevance to the research questions. Evidence from data will be synthesised through a descriptive epidemiological review from included studies; meta-analysis will be used if appropriate. Result & Conclusion: We expect to pool homogenous studies of large population cohorts which explore the hazard ratio of mortality, and to summarise the evidence of the actual mortality risk in type 2 diabetes, with limited bias. This will help direct future research in areas of unanswered questions and may influence healthcare policy decisions.