Abstract 275: Association Between Pulse Pressure and A1c

Abstract

Background: Increased pulse pressure (PP) is an independent risk factor for cardiovascular disease (CVD) morbidity and mortality in men and women. Increased PP has also been shown to be a stronger predictor of CVD mortality, than systolic (S), diastolic (D), or mean blood pressure (BP). Changes in PP amplitude are also associated with other metabolic syndrome components. PP is increased in obesity and increases at a greater rate in patients with diabetes mellitus (DM); and may contribute to the risk and "opinion" that labels DM-CVD-risk as equivalent to previous myocardial infarction. The purpose of this study is to determine whether the metabolic marker, Hemoglobin A1c (A1c), during the early stage of DM development is also associated with a readily available clinical vascular marker, PP. Such an observation may provide an opportunity to detect and start preventive treatment earlier and provide a possible path to begin investigating the mechanisms of hypertensive-diabetic CVD. Methodology: Complete baseline metabolic panels and 24-hour ambulatory BP (AMBP) recordings were obtained on 102 African Americans, 65.9% females, aged 40-90 years, and with Stage-I hypertension. Participants were categorized in two groups according to A1c < 5.7 or A1c ≥5.7. T-test was used to examine difference in BP levels between the two groups. In addition, we examine the independent effect of A1c levels on PP in a linear regression model that adjusts for age and BMI. Results: There were 61 non-diabetic subjects with A1c <5.7, and 41 pre-diabetics or diabetics with A1c ≥5.7. Results showed no significant difference in SBP between the groups (126.2±15.2 mmHg versus 127±16.6mmHg, p=0.70). However, DBP was significantly lower in the group with an HbA1c ≥ 5.7, (75.3±11.3 versus 67.9±10.4mmHg, p<0.03). This resulted in a significantly higher PP in the A1c≥5.7 group, (50.9±10.6 versus 59.0±14.8, p<0.03). Regression analysis showed independent association of PP with A1c (β=5.84, p=0.026) after adjusting for age and BMI. Conclusion: There was an association between A1c levels and changes in PP even in the early stages of DM. This suggests that changes in vascular health, as reflected in increase in PP, may start earlier than previously appreciated.