Endocrine Abstracts

Obesity is independently associated with poor control of blood pressure (BP) and weight reduction is generally recommended as the first line of treatment. However, the challenge remains to find the appropriate approach for weight reduction to influence BP status. The aim was to investigate the effect of non-pharmacologically and pharmacologically (metformin) induced weight loss on BP in obese hypertensive patients (HP).

Methods: 100 HP (mean body mass index (BMI) 32.2 kg/m²) were included in the study (antihypertensive treatment with a mean of 1,9 ± 1.4 drugs). All followed hypocaloric diet (D) for 3 months, after that 50 patients started on metformin (M) at a mean daily dose of 2.1± 0.45 g with D and 50 patients followed on D for 6 months. Anthropometry, metabolic profile, including lipids and oral glucose tolerance test with insulin, uric acid, plasma aldosterone (AS) were performed at baseline and after 3, 9 months. Homeostatic model assessment HOMA-R was calculated for insulin resistance. At baseline and after 6 months HP underwent 24-hour BP measurements.

Results: At baseline was an excellent correlation between BMI and HOMA-R (r=0.45, P < .01), AS and HOMA-R (r =0.31, P < .05). Also, asymptomatic hyperuricemia was observed in 24.9%, dyslipidemia in 43.1%, impaired glucose tolerance in 21%. 29% of the HP had > 3 metabolic syndrome components. There was a modest no significant reduction in BMI and BP after 3 months of D in whole group. Patients on M experienced greater weight loss (-3.4 ± 2.3 versus -2.3 ± 1.2 kg, P < .05) and reduction in BMI (-1.9 ± 1.1 versus -1.0 ± 0.9 kg/m², P < .05). A 6-month M therapy significantly changed the levels of glucose, insulin, lipids, uric acid, HOMA-R and resulted in significantly reduced AS (P < .01). BP decreased more in M-treated patients than in the D group (SBP -6.7 ± 5.1 versus -2.2 ± 4.2 mmHg; DBP. -6.4 ± 3.1 versus -1,9 ± 4.2 mmHg, P < .05 for both). By linear regression analysis changes in BP on M was associated with HOMA-R and AS changes (0.362, P < .05; 0,423, P < .05 respectively).

Conclusions: The diet alone wasn’t enough for a reduction in weight and BP in obese hypertensive patients. Weight-loss program with metformin is more effective and shows an additional antihypertensive effect in those individuals. The reduction of BP on metformin is mediated by improvement insulin/glucose homeostasis, it is accompanied by lowering of aldosterone, uric acid and lipid-lowering effects, what results in cardiovascular risk reduction.