Abstract
BACKGROUND: Emerging evidence has demonstrated the unfavourable cardiovascular risk of individuals with lean type 2 diabetes mellitus (T2DM). Our study aims to investigate the prognostic value of lean T2DM in patients with acute myocardial infarction (AMI), stratified by sex. METHODS: The study cohort examines the clinical characteristics and long-term outcomes of individuals with AMI, stratified by four phenotypes based on T2DM and lean body category-lean T2DM, non-lean T2DM, lean non-T2DM and non-lean non-T2DM. The primary outcome was long-term all-cause mortality. Cox regression model was constructed to investigate the associations of lean and non-lean T2DM phenotypes with mortality, adjusted for age, ethnicity, previous AMI, AMI type, chronic kidney disease, angiotensin converting enzyme inhibitor or angiotensin receptor blockers, beta-blockers, and smoking status. RESULTS: A cohort of 9545 AMI patients was examined, with a mean follow-up duration of 3.4 ± 2.4 years. Majority had the non-lean T2DM phenotype (40.4%), followed by non-lean non-T2DM (29.8%), lean non-T2DM (15.9%), and lean T2DM (13.9%). In the T2DM group, one-quarter was lean (N = 1324), while the vast majority (74.5%) was non-lean. Individuals with lean T2DM tended to be female and older. Patients with lean T2DM had the highest rates of heart failure (23.3%, p < 0.001), cardiogenic shock (9.1%, p = 0.036), and long-term all-cause mortality (32.6%, p < 0.001). Cox regression demonstrated that lean T2DM was an independent predictor of mortality (adjusted hazard ratio [aHR] 1.171, 95% CI 1.040-1.319, p = 0.009) after adjustment. The presence of higher mortality risk following AMI was present in males (aHR 1.201, 95% CI 1.037-1.391, p = 0.015), but not in females (aHR 1.066, 95% CI 0.869-1.308, p = 0.538). CONCLUSIONS: The lean T2DM phenotype was present in one-quarter of the AMI cohort with T2DM. The lean T2DM phenotype was an independent predictor of long-term mortality following AMI, although this association was stronger in males than in females.