Long-term mortality following acute myocardial infarction among those with and without diabetes: A systematic review and meta-analysis of studies in the post reperfusion era.

Aims: Considerable medical advances have seen an improved survival following an acute myocardial infarction (AMI), whether these benefits extend to those with diabetes remains less clear. This systematic review and meta-analysis aim to provide robust estimates of the association between diabetes and long-term mortality (≥one year) following AMI. Material and Methods: Medline, Embase and Web of Science databases were searched (January 1985 - July 2016) for terms related to long-term mortality, diabetes and AMI. Two authors independently abstracted the data. Hazard ratios (HR) comparing mortality in people with and without diabetes were pooled across studies using Bayesian random effects metaanalysis. Results: Ten randomised controlled trials and 56 cohort studies, including 714,780 patients, reported an estimated total of 202,411 deaths over the median follow-up of 2.0 years (range 1 to 20). The risk of death over time was significantly higher among those with diabetes compared to those without (unadjusted Hazard Ratio (HR) 1.82; 95% Credible Interval (CrI) 1.73 to 1.91). Mortality remained higher in the analysis restricted to 23/64 cohorts which had adjusted for confounders (adjusted HR 1.48 (1.43 to 1.53)). The excess long-term mortality in diabetes was evident irrespective of the phenotype and modern treatment of AMI, and persisted in early survivors (unadjusted HR 1.82 (1.70 to 1.95)). Conclusions: Despite medical advances, individuals with diabetes have a 50% increased long-term mortality compared to those without. Further research to understand the determinants of this excess risk are important for public health, given the predicted rise in global diabetes prevalence.