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- HbA1c, glycosylated haemoglobin
- LDL-C, low density lipoprotein cholesterol
- MACE, major adverse cardiovascular events
- PCI, percutaneous coronary intervention
Patients with type 2 diabetes mellitus account for approximately 20% of patients undergoing percutaneous coronary interventions (PCI). PCI is less effective in diabetic than in non-diabetic patients.1,2 Glycaemic and lipid control may have an impact on the clinical outcome in type 2 diabetic patients following elective PCI.
From January 2000 to June 2001, 280 consecutive patients with type 2 diabetes mellitus successfully underwent their first elective PCI at one of our institutions. Optimal metabolic control was defined as a glycosylated haemoglobin (HbA1c) concentration of < 7.0% and a low density lipoprotein cholesterol (LDL-C) concentration < 100 mg/d (< 2.6 mmol/l). Three groups were identified: (1) optimal group (n = 45, 16% of patients) with optimal glycaemic and lipid control; (2) suboptimal group (n = 126, 45% of patients) with only one target value reached; (3) poorly controlled group (n = 109, 39% of patients) who failed to reach either glycaemic or lipid target values. The end point of the study was the rate of major adverse cardiovascular events (MACE), defined as death of any cause, non-fatal myocardial infarction, and target vessel revascularisation, at 12 months in the three groups of patients. All patients received aspirin (325 mg daily, indefinitely) and ticlopidine (250 mg twice daily, for at least 30 days) or clopidogrel (75 mg daily, for at least 30 days). Glycoprotein IIb/IIIa inhibitors were administered according to operator discretion.
Clinical, angiographic, and procedural characteristics are summarised in table 1. At mean (SD) 12 (4) months, MACE occurred in 6 (13.3%) patients in the optimal group, in 40 (32%) patients in the sub optimal group, and in 55 (50.5%) patients in the poorly controlled group (p < 0.001). Variables entered into the Cox regression analysis were: age ⩾ 70 years, sex, insulin treatment, statin treatment, nephropathy, optimal glycaemic and lipid control, small vessel, elective glycoprotein IIb/IIIa inhibitors, left ventricular ejection fraction < 40%, complete revascularisation, and multivessel PCI. The independent predictors of MACE at follow up were: insulin treatment (hazard ratio (HR) 3.43, 95% confidence interval (CI) 1.59 to 7.42; p = 0.002), optimal group (HR 0.29, 95% CI 0.09 to 0.97; p = 0.045), and age ⩾ 70 years (HR 2.10, 95% CI 1.10 to 4.25; p = 0.045).
We showed that an HbA1c concentration of < 7% and an LDL-C concentration of < 100 mg/dl favourably influenced the outcome in diabetic patients after PCI. A very low event rate was observed in patients with both a strict glycaemic and blood lipid control. Our study highlights shortcomings in the effectiveness of treatment and prevention of risk factors that are associated with high morbidity and mortality. It may be that a stricter surveillance, a better lifestyle, and a more aggressive pharmacological approach would allow us to improve metabolic control.3,4 The present study was not a randomised controlled trial. We cannot therefore exclude the fact that patients with poorer glycaemic and lipid profiles were in a more advanced stage of coronary atherosclerosis. Furthermore, the potential impact of glycoprotein IIb/IIIa antagonists and statins may not be apparent as the study was not powered to address this.