Abstract 384: Association of Insulin Resistance With Ambulatory Blood Pressure in Normotensive and Prehypertensive Patients
Introduction Hypertension and insulin resistance are well established risk factors for atherosclerosis. Accumulated evidence also suggests that insulin resistance plays a contributory role in the development of essential hypertension. Previous studies have focused on patients with established hypertension, using clinic blood pressure (BP) measurements. Ambulatory Blood Pressure Monitoring (ABPM) records BP at 20-30 minute intervals over 24 hours, providing an average BP exposure over time. We tested the hypothesis that insulin resistance and blood pressure are associated in normotensive and prehypertensive patients, using ABPM to quantify average BP.
Methods Data were collected for 140 subjects (87 female, 53 male; 117 non-black, 23 black). In addition to clinic BP, ABPM was used to obtain average SBP and DBP over 24 hours. Insulin resistance (IR) was quantified using the QUantitative Insulin sensitivity ChecK Index (QUICKI), calculated from fasting glucose and insulin levels with the formula QUICKI = 1/(log [Fasting insulin in mU/l] + log [Fasting plasma glucose in mg/dl]). Multiple linear regression was used to assess IR as a predictor of ABPM-derived BP measures, controlling for BMI, gender, age, and race.
Results In the entire cohort using ABPM, there was a significant association of IR with DBP24 (p=0.012) but not SBP24 (p=0.11). The association between IR and clinic SBP was marginally significant (p=0.09); DBP NS (p=0.33). After stratifying by gender, IR was significantly associated with SBP24, Daytime SBP (p=0.064, 0.044), DBP24 and Daytime DBP (p=0.02 and p=0.015) in males; no association was found in females.
Conclusions This study demonstrates a significant association of IR with average 24-hour DBP in males and females combined. Stratified by gender, our finding using ABPM of a significant association of IR with SBP in males but not in females supports previous findings using clinic BP in the NHANES cohort. In conclusion, these data demonstrate the presence of IR in prehypertension, and lend support to the theory that IR may contribute to later development of sustained hypertension, particularly in males. Additionally, our study highlights the importance of further research using ABPM for a more precise estimate of average BP level.
- © 2013 by American Heart Association, Inc.