Diabetes Associated With Increased Mortality Rate After Acute Myocardial Infarction

Diabetes mellitus (DM) is associated with a 32% increased risk of all-cause mortality among patients hospitalized with acute myocardial infarction (AMI) at 3 years, and younger patients with DM have more than a 2-fold higher risk compared with those without DM, according to a study published in Diabetes & Metabolism.

Investigators analyzed the prevalence of diabetes and related clinical outcomes in patients aged 55 years or younger with AMI and compared baseline characteristics and clinical outcomes of diabetic and nondiabetic patients with AMI by age.

Data were obtained from the Korea Acute Myocardial Infarction Registry–National Institutes of Health database. Patients with AMI were enrolled at 20 major percutaneous coronary intervention centers in Korea from November 2011 to December 2015.

The overall cohort included 12,600 patients. The “young” group (aged ≤55 years) included 3590 participants, of whom 953 (mean age, 48.6±5.2 years; 9.0% women) had diabetes and 2637 (mean age, 47.9±5.7 years; 6.6% women) did not have diabetes. The “old” group (aged >55 years) included 9010 patients, of whom 3341 (mean age, 69.7±8.2 years; 36% women) had diabetes and 5669 (mean age, 69.9±8.9 years; 31% women) did not.

The primary outcome was 3-year all-cause mortality. The cohort had an overall DM prevalence of 34.1%, and 19.7% of participants were newly diagnosed with diabetes at the index admission.

Among all participants, all-cause mortality (12.6% vs 6.8%; adjusted hazard ratio [HR], 1.32; 95% CI, 1.14-1.53; P <.001), cardiac mortality (6.6% vs 3.4%; adjusted HR, 1.29 [1.05-1.59]; P =.016), recurrent myocardial infarction (5.1% vs 3.0%; adjusted HR, 1.38 [1.13-1.69]; P =.002), and major adverse cardiac events (19.8% vs 11.6%; adjusted HR, 1.17 [1.05-1.31]; P =.005) were significantly higher in patients with DM compared with non-DM patients, respectively, during the follow-up.

Diabetes was associated strongly with long-term all-cause mortality in both age groups after multivariable adjustment, especially in the young group (P value for the interaction between age and diabetes =.008). Patients with diabetes had 107% higher hazards of 3-year mortality compared with those without diabetes if they were aged 55 years or younger. Patients with diabetes had a 25% higher risk of 3-year all-cause mortality vs those without diabetes if they were 55 years or older after adjustment.

In analysis using age as a continuous variable, similar results were observed, with a P value of .003 for the interaction between age and diabetes in the multivariate-adjusted model for all-cause mortality. Similar findings were found for cardiac mortality and major adverse cardiovascular events.

Study limitations include the retrospective design, and the data were limited on diabetic duration, treatment, severity, control, and complications. Also, heterogeneity occurred in the laboratory and clinical practice parameters, which could have affected clinical outcomes.

“This study emphasizes that diabetes is not rare in young patients with AMI, and the adjusted hazard for all-cause mortality as a result of diabetes is pronouncedly higher in younger patients,” the researchers wrote. “These findings highlight the need for a major research effort to identify aggressive new strategies managing AMI and preventing post-AMI adverse cardiovascular events, especially in young diabetic patients.”

Reference

Song PS, Ahn KT, Kim MJ, et al. Age-related difference in the impact of diabetes mellitus on all-cause mortality after acute myocardial infarction. Diabetes Metab. Published online April 20, 2022. doi: 10.1016/j.diabet.2022.101349