[Factors influencing cardiac complications in patients with type-2 diabetes mellitus and silent myocardial ischaemia: five-year follow-up]

Abstract

Silent myocardial ischaemia (SMI), a common disorder, has been studied by different research groups for the last 25 years. It is known that SMI is more common in patients with type 2 diabetes mellitus (type 2 DM) than in the general population, even though pathological mechanisms responsible for SMI are unclear. The aim of the study was to assess the role of SMI and other conditions in predicting adverse outcome in patients with type 2 DM during five years of follow-up.

Materials and methods: 67 males with type 2 DM were enrolled into the study group. 55-healthy men were used as a control group (CG). Precise clinical examinations (medical history, physical examination, laboratory tests) were conducted. Coronary risk factors and the level of diabetes control were assessed. Noninvasive cardiological tests: ETT, 24 h ECG and echocardiography were performed. The prevalence of the following complications: ischaemia, unstable angina, myocardial infarction, heart failure, death and need for invasive procedures was recorded for five years. Parameters responsible for the complications were analyzed with the use of univariate logistic regression test; odds ratio was calculated.

Results: The silent myocardial ischaemia was found in 32.8% of patients with type 2 DM and in 9.1% men in control group (p < 0.001). The complications were observed in 24% of men with DM and in 16% in control group (NS). It was found that 25 parameters in the studied group and 16 parameters in the control group were statistically significant for the prediction of complications (among analyzed 92 parameters). The most important of them in type 2 DM group are: duration of diabetes (years) OR--1.18 (p < 0.01), fasting glucose (mg/dl) OR--1.017 (p < 0.01), SMI episodes (ETT) OR--4.72 (p < 0.01), diastolic dysfunction (E/A), OR--0.003 (p < 0.02) and left ventricle hypertrophy OR--3.86 (p < 0.05), whereas in CG--SMI episodes, OR--17.72 (p < 0.002).

Conclusions: (1) The silent myocardial ischaemia is common in patients with type 2 DM. It was diagnosed in 33% of the patients. (2) The presence of SMI significantly increases the risk of complications both in patients with diabetes mellitus and the control group. (3) There are many other factors predisposing to the complications. In patients with diabetes mellitus they included, besides SMI, the duration of diabetes, chronic hyperglycemia and left ventricular diastolic dysfunction.