Factors related to exercise capacity in asymptomatic middle-aged type 2 diabetic patients

Aim: We aimed to look at the relationship between exercise capacity and metabolic variables in unselected consecutive asymptomatic middle-aged type 2 diabetic patients as a potential marker for undiagnosed coronary heart disease. Method: Ninety patients (49 ± 6 years) were included in the study. All patients performed a treadmill exercise test using the Bruce protocol. According to achieved EC, patients were separated into three groups; Group I (n, 24) 8 > metabolic equivalents (METs) ≥ 5, Group II (n, 54) 11 > METs ≥ 8 and Group III (n, 12) METs ≥ 11. Results: Patients in group I are more likely to be of female gender and to have a family history of coronary heart disease (CHD) than in group III (P = 0.015, P = 0.009, respectively). When compared to group III, patients in group I had higher fasting insulin and fibrinogen levels (P = 0.049 and P = 0.01, respectively). Homeostasis model assessment for insulin resistance (HOMA-IR) index (P = 0.03) was also higher in group I than in group III. We found a significant negative correlation between achieved exercise capacity and age (r = −0.204, P = 0.048), fasting insulin (r = −0.209, P = 0.048), HOMA-IR (r = −0.204, P = 0.048) as well as fibrinogen (r = −0.301, P = 0.007). Conclusion: Reduced exercise capacity was associated with increased insulin resistance as assessed by HOMA-IR index in asymptomatic middle-aged type 2 diabetic patients.