Introduction: Increased body weight has been recognized as an independent coronary risk factor and is present in over 80% of patients entering cardiac rehabilitation. The influence of increasing adiposity on cardiac risk factors has not been determined when patients with coronary artery disease (CAD) are treated with evidence-based preventive pharmacologic therapies.
Methods: The study population consisted of 74 individuals with chronic CAD; 60 males and 14 females, mean age 64 +/- 9 years. All patients had a BMI of > 27 kg/m2 (mean 32+/-4, range = 27-45). Patients with diabetes were excluded. Of the 74 patients, 73 were taking aspirin, 62 were taking a statin, 53 were taking a [beta]-blocker, 23 were taking an ACE-inhibitor, and 21 were taking clopidogrel. Obesity measures included weight, BMI, waist circumference, fat mass by dual-energy x-ray absorptiometry and intra-abdominal and skeletal muscle fat by CT scanning. Risk factors measured included insulin sensitivity measured by euglycemic insulin clamp, lipid profiles, blood pressure, high-sensitivity C-reactive protein (CRP), plasminogen activator inhibitor (PAI-1) and in vitro measures of platelet reactivity.
Results: In this population of overweight patients with CAD, greater BMI (R = .35), waist (R = .41), and fat mass (R = .25) were associated with decreased insulin sensitivity (each P < .01). Peak aerobic capacity was inversely associated with fasting insulin levels (P < .05). Increased visceral fat, measured by CT scanning, was associated with increased CRP (P = .02). Insulin sensitivity was the best predictor of PAI-1, triglycerides, HDL levels, and cholesterol/HDL levels (all P < .01). Neither indices of obesity nor insulin sensitivity were associated with measures of blood pressure or platelet reactivity (both assessed on medication).
Conclusions: In overweight patients with CAD treated in accordance with evidence-based guidelines, increasing adiposity and insulin resistance continue to be important predictors of cardiac risk. These findings support the notion that weight loss would further improve cardiac risk factor profiles in patients receiving optimal pharmacologic therapies.