Effects of a low-energy diet and an insulin-sensitizing agent on ambulatory blood pressure in overweight hypertensive patients.
OBJECTIVE
To clarify the role of insulin resistance and hyperinsulinaemia in the pathogenesis of obesity-related hypertension.


METHODS
An open study comparing the effects of weight reduction by low-energy diet and treatment with troglitazone, an insulin-sensitizing agent.


METHODS
A tertiary teaching hospital.


METHODS
Thirty overweight hypertensive patients (15 men and 15 women, mean age 61 years, mean body mass index 29.1 kg/m2).


METHODS
Fifteen patients were assigned to a weight-reduction programme by low-energy diet (3360 kJ/day) for 3 weeks; the remaining 15 patients were treated with troglitazone (400 mg/day) for 8 weeks.


METHODS
Casual and ambulatory blood pressures, glucose and lipid metabolism, and insulin sensitivity.


RESULTS
The baseline values of body mass index, fasting and post-glucose plasma insulin, and casual and ambulatory blood pressures were comparable between the two groups. Weight reduction (4.1 +/- 0.3 kg, mean +/- SEM) was associated with significant decreases in plasma insulin, blood glucose, homeostasis model assessment (HOMA) insulin resistance index, serum triglyceride, casual blood pressure (7.7 +/- 2.3/ 3.9 +/- 1.4 mmHg) and 24 h blood pressure (8.3 +/- 1.9/ 4.3 +/- 1.1 mmHg). Treatment with troglitazone caused comparable decreases in the metabolic parameters and HOMA index, but did not change casual or 24 h blood pressure (0.8 +/- 3.4/0.8 +/- 2.1 and 1.5 +/- 2.4/ 1.0 +/- 1.9 mmHg, respectively).


CONCLUSIONS
Insulin resistance/hyperinsulinaemia may not have an important role in the pathogenesis of obesity-related hypertension. The antihypertensive effect of weight reduction seems to be mediated mainly by other mechanisms.
Kawano
Y
Y
Division of Hypertension and Nephrology, National Cardiovascular Center, Suita, Osaka, Japan.
Okuda
N
N
Minami
J
J
Takishita
S
S
Omae
T
T
D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D002839:Chromans / Q000494:pharmacology*; D004038:Diet, Reducing; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000628:therapy*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D013844:Thiazoles / Q000494:pharmacology*; D045162:Thiazolidinediones; D000077288:Troglitazone; D015431:Weight Loss
D002839:Chromans; D007004:Hypoglycemic Agents; D013844:Thiazoles; D045162:Thiazolidinediones; D000077288:Troglitazone