Correlation between changes of blood pressure with insulin resistance in type 2 diabetes mellitus with 4 weeks of pioglitazone therapy

OBJECTIVE: To examine effects of pioglitazone (PIO) on systolic, diastolic, pulse and mean blood pressures (SBP, DBP, PP and MP, respectively) in type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: One hundred and six normotensive patients with T2DM with mean fasting blood glucose (FBS; 183 ± 6 mg/dl) were randomly divided into two groups. Test group was treated with 15 mg of PIO in addition to metformin 500 mg three times per day in both groups. SBP, DBP, PP and MP and fasting insulin, FBS and lipid profiles were measured before and after PIO therapy. RESULTS: There was a significant reduction in SBP (123 ± 2 vs. 118 ± 2 mmHg, P < 0.05), PP (41 ± 1 vs. 37 ± 1 mmHg, P < 0.05), and MP (95 ± 1 vs. 91 ± 1, P < 0.05). Clinical reduction in DBP was observed but not significant (82 ± 2 vs. 81 ± 1 mmHg, P > 0.05). There was a significant correlation between decline in SBP and DBP with respective baseline values (r = 0.76, P < 0.001 and r = 0.62, P < 0.001, respectively). Changes in PP and MP strongly correlated with baseline values (r = 0.51, P < 0.05 and r = 0.56, P < 0.05, respectively). There was a parallel reduction of FBS (183 ± 2 vs. 121 ± 3, P < 0.001) but reduction in IR or lipid profiles was not significant in test group. Changes in BP were not significant in control group ( P > 0.05). CONCLUSION: PIO treatment of T2DM showed early reduction of SBP and MP within first 4 weeks. Results suggest that pharmacodynamic effects of PIO mainly affect the systolic component. We hereby suggest that reduction of BP by PIO is independent from mechanisms of changes in IR and dyslipidaemia in normotensive diabetic patients.