Aim: Plasma adiponectin levels are well associated with metabolic syndrome. However, the relationship between hypertension and plasma adiponectin levels is not clear. Also, there is not enough data about the effects of different antihypertensive regimens on plasma adiponectin levels.
Methods: Ninety-six hypertensive patients (48 male, 48 female) who fulfil the diagnostic criteria of metabolic syndrome were enrolled. Patients were treated for 3 months with metoprolol (n = 18, 100 mg/day), amlodipine (n = 20, 10 mg/day), doxazosin (n = 18, 4 mg/day), ramipril (n = 20, 5 mg/day) and valsartan (n = 20, 80 mg/day). Blood biochemistry and plasma adiponectin concentrations were measured both before and after the study. Insulin resistance was measured by homeostasis assessment index (HOMA).
Results: Plasma adiponectin levels were correlated with the total cholesterol (r = -0.244, P = 0.017), triglyceride (r = -0.306, P = 0.002), high-density lipoprotein-cholesterol (r = 0.286, P = 0.005), body mass index (r = -374, P < 0.001), systolic (r = -502, P < 0.001) and diastolic blood pressures (r = -235, P = 0.021). The independent predictors of plasma adiponectin levels were HOMA (beta = -0.199, P = 0.02), body mass index (beta = -0.313, P < 0.001) and systolic blood pressures (beta = -0.483, P < 0.001). Ramipril and valsartan increased the plasma adiponectin levels significantly higher than the other regimens (P < 0.05 for both) while metoprolol did not make a significant effect.
Conclusion: According to the results, plasma adiponectin levels are associated with the arterial blood pressures, body fat content and the lipid parameters in hypertensive patients with metabolic syndrome. The effects of antihypertensive drugs on plasma adiponectin levels are parallel to their effects on blood pressures and insulin sensitivities. The different effects of several regimens on plasma adiponectin levels and insulin sensitivities may account for the diversity of the cardiovascular outcomes in patients with hypertension.