Prediction of major coronary events by coronary risk profile and silent myocardial ischaemia: prospective follow-up study of primary prevention in 72 diabetic patients

Abstract

The aim of this study was to examine the predictive value of coronary risk profile (CRP) for major coronary events in patients screened for silent myocardial ischemia (SMI). We studied 72 diabetic patients, aged 41 to 65 years, recruited consecutively at the Poitiers diabetes clinic. All patients had at least one cardiovascular risk factor associated with diabetes mellitus (type 1 diabetes duration > or =15 years, dyslipidaemia, smoking, hypertension, micro/macro-albuminuria). A structured questionnaire, physical examination and resting electrocardiogram provided no evidence of coronary heart disease. SMI was defined as positive exercise electrocardiogram and/or dipyridamole thallium myocardial scintigraphy. CRP was estimated using the Framingham equation adapted to the French population. We defined a high CRP value as annual CRP > or =1.5%. Major coronary events (MCE) were defined as myocardial infarction, ischaemic heart failure, unstable angina or sudden death. Twenty-one patients with type 1, and 51 with type 2 diabetes were followed up for 39+/-12 months: 30 women and 42 men, aged 55+/-7 years with diabetes duration of 16 +/- 11 years (mean +/- SD). SMI was detected in 8 patients. Major coronary events occurred in 8 patients, 2 of whom had SMI. High CRP was found in 18 patients, 3 of whom had MCE. CRP was significantly higher in those patients with a major coronary event (1.71 +/- 1.11 versus 1.03 +/- 0.56%; p=0.048), but not in those with SMI (1.19 +/- 0.72 vs 1.09 +/- 0.67%; p=0.654). In Kaplan-Meier survival analysis, a high CRP was associated with the risk of a major coronary event (log-rank=5.36; p=0.021), whereas SMI was not (log-rank=2.02; p=0.155). The cumulative incidence of MCE in those patients with high and low CRP was 8.08 (0.49-15.67) vs 2.15 (0.06-4.22) events per 100 patient year of follow-up, respectively.

Conclusion: CRP had a good predictive value for major coronary events regardless the presence of SMI. Prevention should therefore be focused primarily on patients with high CRP, wether or not they have SMI.