Speakers - DEWC2025

Background and aims

Myocardial infarction (MI) is one of the major cardiovascular events in patients with diabetes. However, long-term follow-up data exceeding 30 years on MI in individuals with diabetes, particularly those with impaired glucose tolerance (IGT), remain limited. This study aimed to investigate the incidence of MI and case-fatality rates (CFR) for MI in adults with newly diagnosed diabetes (NDD), IGT, and normal glucose tolerance (NGT) over 34 years of follow-up.

Methods 

This observational study selected 1632 participants in Da Qing city, China, including 598 NDD participants, 405 IGT participants with 6-year lifestyle intervention, 135 IGT participants without intervention, and 494 NGT participants, who were initially identified in 1986 and followed up to 34-year. We compared incidence and hazard ratios for MI across these groups and estimated the difference of median delay time of MI onset from parametric Weibull distribution models. Moreover, we calculated the case-fatality rates of MI and analyzed the differences in mortality risk after MI among these groups. 

Results

During 34-year follow-up, in NGT, IGT-non-intervention, IGT-intervention and NDD groups, the cumulative incidence of MI was 16.7%, 31.8%, 24.0%, and 46.4%; the MI incidence rates was 14.3, 9.6, 7.1, and 4.9 per 1000 person-years, respectively. Compared with the NDD group, the median delay to onset of MI was 16.82 years in the NGT group (95% CI:25.69-39.71), 7.84 years in the IGT-intervention group (95% CI:4.19 - 11.48) and 2.28 years (95% CI:-2.05-6.62) in the IGT group. After adjusting for medications and the risk factors related to MI, including age, sex, BMI, blood pressure, smoking and plasma total cholesterol, the risk for MI were significantly higher in the NDD group (HR: 3.54; 95% CI: 2.59-4.83), IGT-non-intervention group (HR: 2.34; 95% CI: 1.52-3.70), and IGT-intervention group (HR: 1.86; 95% CI: 1.32-2.64) compared to the NGT group. Moreover, compared to the NDD group, the incidence of MI was significantly lower in the IGT-intervention group (HR: 0.56; 95% CI: 0.42-0.73), while the IGT-non-intervention group (HR: 0.68; 95% CI: 0.47-1.00) showed no significant difference. Case-fatality rates (CFR) from MI (per 100 person-years) were 39.50(31.76-472.42) in the NDD group, 9.84(5.63-140.48) and 31.64(17.03-462.65) in IGT with and without intervention groups, and 14.46(7.96-209.64) in the NGT group. After adjustment for multiple risk factors, the case-fatality for MI was significantly higher in individuals with NDD (1.62; 95% CI: 1.14–2.28), and showed a non-significant increase in those with IGT without intervention (1.50; 95% CI: 0.92-2.47), compared to NGT participants. Conversely, individuals with IGT who received a 6-year lifestyle intervention demonstrated a lower CFR (0.83; 95% CI: 0.54-1.27), indicating a potential protective effect.

Conclusions

Our 34-year follow-up study demonstrated that individuals with NDD and IGT exhibited a significantly increased incidence and risk of MI, as well as elevated post-MI mortality. Notably, early lifestyle intervention in IGT individuals to prevent diabetes onset could effectively reduce the occurrence and fatality of MI.