Sixty-six patients with type 2 diabetes, obesity and no known history of cardiovascular disease were recruited to a lifestyle-intervention study. The aims of this study were to quantify the presence of silent and symptomatic ischaemia using a Bruce protocol treadmill-test, and to identify factors associated with a positive stress-test in these patients. Ethical approval was obtained from the local ethics committee.
54/66 patients had blood pressure (BP) greater than 130/80mmHg. Mean age was 57 plus/minus 10 years and body mass index (BMI) 35.4 plus/minus 4.0 Kilograms per meter squared (mean plus/minus SD). No patient experienced symptoms of chest pain or dyspnoea during exercise, however 6/66 patients had a positive stress test by electrocardiographic criteria suggestive of silent ischaemia. Evaluation of cardiovascular risk factors revealed a significantly greater baseline diastolic BP in those with a positive stress-test (93 plus/minus 5mmHg vs 83 plus/minus 10mmHg) (p less than 0.005). Peak systolic BP was elevated in 39/66 patients consistent with exercise-induced hypertension (greater than 210mmHg (men), 190mmHg (women)). There was also a greater rise in diastolic BP at peak exercise in the whole patient group than expected from studies in a nondiabetic population (10 plus/minus 7mmHg vs 3 plus/minus 2mmHg). Examination of the relationship of baseline risk factors with this BP rise revealed a significant relationship between waist circumference and diastolic BP increment (p equals 0.008, r equals 0.33).
These findings suggest that exercise-stress-testing is important to detect the presence of silent ischaemia and exercise-induced hypertension, before commencing asymptomatic obese patients with type 2 diabetes on an exercise program. Diastolic BP is an important risk factor for cardiovascular disease in these patients.The relationship between waist circumference and diastolic BP rise during exercise could explain part of the increased risk associated with central obesity.
22 - 24 Mar 2004
British Endocrine Societies