Hyperinsulinemia in hypertension - Associations with race, abdominal obesity, and hyperlipidemia

Objective: To determine the relative contributions of race, sex, abdominal obesity, and hyperlipidemia to the development of hyperinsulinemia among patients with hypertension. Design: Cross-sectional survey. Setting: A large family practice ambulatory care unit in Winston-Salem, NC. Patients: One hundred and forty adult patients with essential hypertension (systolic blood pressure greater than or equal to 160 mm Hg or diastolic blood pressure at or above 90 mm Hg on 2 or more occasions) or who were receiving antihypertensive treatment. Main Outcome Measures: Fasting insulin, lipid, and glucose levels; glycosylated hemoglobin; waist-hip ratio; and resting blood pressure. Methods: Among 4 patient subgroups (hypertension alone; hypertension and abdominal obesity; hypertension and hyperlipidemia; and hypertension, abdominal obesity, and hyperlipidemia) logistic regression analysis was used to determine correlates of elevated fasting insulin levels. Results: Controlling for age and blood pressure, black males had the highest fasting insulin levels (135+/-70 pmol/L [18.8+/-9.6 pU/mL] and 265 pmol/L [37.0+/-0.0 mu U/mL] [mean+/-SD] for obese and nonobese black males, respectively); nonobese white males had the lowest fasting insulin levels (23+/-22 pmol/L [3.2+/-3.0 mu U/mL]). Multivariate logistic regression indicated that the addition of abdominal obesity or hyperlipidemia to pure hypertension more than doubled the risk of hyperinsulinemia (adjusted odds ratio, 2.69; 95% confidence interval, 1.04-6.89; and adjusted odds ratio, 2.62; 95% confidence interval, 0.37-8.6, respectively). The combination of abdominal obesity and hyperlipidemia exerted additive effects among patients with hypertension for elevated insulin levels (adjusted odds ratio, 5.1; 95% CI, 1.59-16.4). Conclusions: Race, sex, abdominal obesity, and hyperlipidemia interact to produce increases in fasting insulin levels. This knowledge may help physicians prevent sequelae from hyperinsulinemia syndrome among their patients with hypertension.