Prevalence and determinants of silent myocardial ischemia in patients with type 2 diabetes in Cameroon: a cross-sectional study

Introduction: diabetes mellitus is a major health problem worldwide. It is associated with high cardiovascular morbi-mortality especially coronary artery disease. Myocardial ischemia is often asymptomatic (silent myocardial ischemia) in people with type 2 diabetes mellitus thus making early diagnosis difficult. Silent myocardial ischemia is defined as the objective evidence of myocardial ischemia in the absence of chest discomfort or other angina equivalents. This study aimed to determine the prevalence and determinants of silent myocardial ischemia in a population of people with type 2 diabetes using exercise stress electrocardiography. Methods: we carried out a cross-sectional study between January and April 2019 at the National Obesity Centre of the Yaounde Central Hospital. Patients with type 2 diabetes underwent a complete clinical evaluation, blood test, resting electrocardiogram (ECG), and exercise stress ECG according to the Bruce protocol. A positive stress test was defined as horizontal or down-sloping ST depression ≥ 1mm or upsloping ST depression of 2 mm or more 0.06 to 0.08 seconds after the J point. Results: a total of 112 patients with diabetes (63 males and 49 females) were screened. The median age was 58 (IQR: 51 - 64) years. The median time from diabetes diagnosis was 8 (IQR: 5 - 12) years. Fifty-seven (50.4%) had hypertension, 78 (69.0%) had dyslipidemia, 66 (58.4%) were obese, 70 (61.9%) had poor glycemic control, and 23 (20.2%) were smokers. Sixty-five (58%) patients had a positive exercise stress ECG test. Factors independently associated with a positive stress test were abdominal obesity (aOR: 4.2, [95% CI: 1.4 - 12.8]) and Female sex (aOR: 2.5, [95% CI: 1.1 - 5.7]). Conclusion: the prevalence of silent myocardial ischemia was high in a population of asymptomatic patients. This was independently associated with abdominal obesity and female sex.