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Objectives
The aim of this study was to determine whether the effects of weight loss on arterial function are differentially modified by insulin st
atus.
Background
Clinical studies suggest that plasma insulin levels may predict the extent of cardiovascular benefit achieved with weight loss in obese individuals, but mechanisms are currently unknown.
Methods
We prospectively followed 208 overweight or obese patients (body mass index [BMI]聽鈮?5 kg/m2) receiving medical/dietary (48%) or bariatric surgical (52%) weight-loss treatment during a median period of 11.7 months (interquartile range: 4.6 to 13 months). We measured plasma metabolic parameters and vascular endothelial function using ultrasound at baseline and following weight-loss intervention and stratified analyses by median plasma insulin levels.
Results
Patients age 45 卤 1 years, with BMI 45 卤 9 kg/m2, experienced 14 卤 14% weight loss during the study period. In individuals with higher baseline plasma insulin levels (above median >12 渭IU/ml; n聽= 99),聽鈮?0% weight loss (compared with聽<10%) significantly improved brachial artery macrovascular flow-mediated vasodilation and microvascular reactive hyperemia (p聽< 0.05 for all). By contrast, vascular function did not change significantly in the lower insulin group (鈮?2 渭IU/ml; n聽= 109) despite a similar degree of weight loss. In analyses using a 5% weight loss cut point, only microvascular responses improved in the higher insulin group (p聽= 0.02).
Conclusions
Insulin status is an important determinant of the positive effect of weight reduction on vascular function with hyperinsulinemic patients deriving the greatest benefit. Integrated improvement in both microvascular and macrovascular function was associated with聽鈮?0% weight loss. Reversal of insulin resistance and endothelial dysfunction may represent key therapeutic targets for cardiovascular risk reduction in obesity.
