Pioglitazone reduces blood pressure in non-dipping diabetic patients

The association between insulin resistance and hypertension is firmly established and has been extensively investigated. Thiazolidinediones (TZD), a class of oral hypoglycemic agents that act as insulin sensitizers have been demonstrated, in many in vivo and in vitro studies, to possess antihypertensive properties. Whether the ability of TZD to lower blood pressure (BP) should be ascribed to a reduction of insulin resistance, or to a direct vasodilating effect, is matter of debate. Since blunted BP nocturnal dipping precedes overt hypertension and is associated with an increased risk of adverse cardiovascular events, we evaluated the pioglitazone effects on BP in non-dipper type 2 diabetic patients.

Forty non-dipper diabetic patients were randomly assigned to metformin + placebo (M) or metformin + pioglitazone 30 mg (MP) and submitted to 24 hours blood pressure monitoring at the beginning and after 8 weeks.

After 8 weeks of treatment in subjects on metformin + pioglitazone 30 mg (group MP1), we found a reduction of nocturnal blood pressure values (mean nocturnal systolic BP 128.05+/- 1.23 vs 122.8+/-2.3 mmHg; p<0.02; mean nocturnal diastolic BP 81.2+/-0.99 vs 75.65+/-0.93 mmHg; p<0.005). The observed improvements in BP were independent from changes in metabolic parameters.

The obtained data show that pioglitazone was effective in reducing BP values in non-dipping diabetic patients. The reduction of BP values was independent from amelioration of the metabolic picture: that suggest the hypothesis that these ameliorations may be also due to a direct antihypertensive action exerted by pioglitazone.