Influence of age on the development of stress hyperglycemia during first-onset ST-elevation myocardial infarction.

INTRODUCTION: Stress hyperglycemia is associated with adverse outcomes in ST-elevation myocardial infarction (STEMI), but whether age influences its development or prognostic significance remains unclear. We examined the association between age and stress hyperglycemia and whether age modifies its relationship with mortality. METHODOLOGY: We studied non-diabetics with first-onset STEMI from the Singapore Myocardial Infarction Registry (SMIR) (2008-2020). The stress hyperglycemia ratio (SHR) was calculated as random plasma glucose (mmol/L)/[1.59 × HbA1c (%) - 2.59], with stress hyperglycemia defined as SHR ≥1.51. Logistic regression identified factors independently associated with stress hyperglycemia. Restricted cubic splines assessed non-linearity between age and odds of stress hyperglycemia. Multivariate Cox regression evaluated associations with 30-day, 1-year, and 10-year all-cause mortality. Analyses were stratified by age and sex. RESULTS: Among 8,779 patients, 1,718 (19.6%) developed stress hyperglycemia. Patients with stress hyperglycemia were older and more likely to present with advanced heart failure. Increasing age was independently associated with higher odds of stress hyperglycemia, with no evidence of non-linearity. Stress hyperglycemia conferred higher short- and long-term mortality across all age groups, although the relative association attenuated with advancing age (P for interaction <0.001). Similar trends were observed in both sexes. CONCLUSION: In non-diabetic patients with first-onset STEMI, the likelihood of stress hyperglycemia increased with age. However, stress hyperglycemia was associated with the greatest risk of mortality in younger patients.