Heart rate and double product in relation to insulin resistance in patients with hypertension and coronary artery disease.

Background: Elevated values of heart rate (HR) and insulin resistance (IR) reflect enhanced sympathetic nervous system activity and may be connected to the development of coronary artery disease (CAD) and diabetes.

Aim: To evaluate the relationship between HR, blood pressure (BP), double product and IR in nondiabetic hypertensive patients with stable CAD.

Methods: There were 73 patients included in the study. Ambulatory BP monitoring was recorded in all patients by a Spacelabs 90207 device. Homeostasis model assessment (HOMA-IR) was used to estimate IR. Double product was calculated by multiplying systolic BP and HR.

Results: In the study population (mean age 67.1 ± 8.4 years, 52% males) there was a positive correlation between HOMAIR and 24-h double product (r = 0.35, p < 0.01) and body mass index (BMI) (r = 0.45, p < 0.001). The receiver operating characteristic analysis of 24-h double product and BMI as predictive markers of IR did not reveal statistical differences between AUC (0.72 ± 0.09 vs. 0.72 ± 0.08, 24-h double product and BMI, respectively, p = NS). The best cut-off points in predicting IR were 8,978 mm Hg/min for 24-h double product and 33.02 kg/m2 for BMI. There were differences between the non obese (n = 44, mean age 67.9 ± 9.2 years) and obese (n = 29, mean age 65.8 ± 6.9 years) groups in: serum insulin level (7.3 ± 2.3 µU/mL vs. 12.0 ± 7.3 µU/mL, p < 0.01), HOMA-IR (1.8 ± 0.7 µU/mL × mmol/L vs. 3.0 ± 2.0 µU/mL × mmol/L, p < 0.01), and day systolic BP (128.0 ± 10.8 mm Hg vs. 134.1 ± 10.1 mm Hg, p < 0.02).

Conclusions: 24-h double product and BMI may be complementary parameters in the prediction of IR in hypertensive nondiabetics with CAD confirmed by percutaneous coronary interventions in history and/or at least one coronary artery stenosis ? 70% in elective coronary angiography.