Increased risk of adverse cardiovascular events by strict glycemic control after percutaneous coronary intervention (HbA1c < 6.5% at 2 years) in type 2 diabetes mellitus combined with acute coronary syndrome: a 5-years follow-up study

Objective This study assessed the association between HbA1c level measured 2 years after percutaneous coronary intervention (PCI) and long-term clinical outcomes in type 2 diabetes mellitus combined with acute coronary syndrome (ACS) who underwent PCI.Methods This prospective observational study analyzed 2877 ACS patients with type 2 diabetes mellitus whose baseline HbA1c ≥ 7.0% and underwent PCI. All patients were divided into 6 groups according to the HbA1c level at 2 years after PCI. The clinical outcome was major adverse cardiovascular events (MACEs), defined as all-cause death, all myocardial infarction, any revascularization, congestive heart failure, ischemic stroke. The median follow-up duration was 4.1 years.Results All 2877 patients were divided into 6 groups: 2-year after PCI HbA1c < 6.0% (n = 219), 6.0–6.5% (n = 348), 6.5–7.0% (n = 882), 7.0–7.5% (n = 567), 7.5–8.0% (n = 441), ≥8.0% (n = 420). The 5-year incidence rate of MACEs in HbA1c <6.0% and 6.0–6.5% groups were similar to 7.5–8.0% and ≥8.0% groups, which were significantly higher than in 6.5–7.0% and 7.0–7.5% groups (p = .044). The cumulative incidence rate of MACEs significantly differed among the groups (p = .046). Multivariate Cox regression analysis revealed a U-shaped relationship between 2-year HbA1c level after PCI and risk of MACEs. 2-year HbA1c <6.5% after PCI was an independent risk factor for MACEs in type 2 diabetes mellitus combined with ACS who underwent PCI (p < .001).Conclusions The findings indicated an increased risk of MACEs by strict glycemic control after PCI (2-year HbA1c < 6.5% after PCI) in type 2 diabetes mellitus combined with ACS who underwent PCI.