Age-related difference in the impact of diabetes mellitus on all-cause mortality after acute myocardial infarction

Abstract

Abstract Background Diabetes mellitus (DM) is highly prevalent among individuals hospitalized with acute myocardial infarction (AMI) and is associated with increased risk for cardiovascular complications and short-term and long-term mortality. However, most existing data are from older patients. Little is known about the incidence of diabetes in individuals who experience AMI at a young age. Whether the presence of DM is associated with worse outcomes in these patients is not clear. Purpose To test the hypothesis that the impact of DM on clinical outcomes after AMI can vary by age. Methods A total of 12,600 AMI patients from the Korea Acute Myocardial Infarction Registry-National Institute of Health (KAMIR-NIH) between November 2011 and December 2015 was classified into young (n=3,590 [28.5%]) and elderly (n=9,010 [71.5%]). Those less than 55 years of age were considered young. We performed comparisons of baseline characteristics, in-hospital treatments, and long-term clinical outcomes between patients with and without diabetes after stratification according to age group. Results The prevalence of diabetes mellitus was 26.5% in the young AMI group. In the multivariable-adjusted model of the entire cohort, diabetes mellitus was associated strongly with 3-year all-cause mortality (12.6% vs. 6.8%; adjusted hazard ratio [HR], 1.318; 95% confidence interval [CI], 1.138–1.526; P<0.001). When the entire cohort was subdivided into two age groups, young diabetic patients showed a 107.0% higher mortality rate than those without diabetes (adjusted HR, 2.070; 95% CI, 1.150–3.724; P=0.015). Meanwhile, elderly diabetic patients had a 25.3% higher risk of mortality than non-diabetic patients (adjusted HR, 1.253; 95% CI, 1.076–1.459; P=0.004). The interaction of diabetes with age was significant (adjusted P for interaction = 0.008). Conclusion DM is not uncommon in younger AMI patients, and the relative risk of long-term mortality is significantly higher in young patients than in older counterparts. More aggressive treatments are needed to prevent future cardiovascular events in younger patients after AMI. Funding Acknowledgement Type of funding sources: None.