Glycemic Variability and Hemoglobin A1c and Their Associations with Blood Pressure Among Overweight Adults with Prediabetes or Type 2 Diabetes (P12-008-19)

Abstract

ObjectivesHemoglobin A1c (HbA1c) is associated with hypertension in prediabetes (PD) and type 2 diabetes (T2D), both of which are associated with increased cardiovascular disease (CVD) risk. Traditionally, HbA1c is the standard approach to assessing glycemic status, however, glycemic variability (GV)—the daily fluctuations in blood glucose concentrations—may be more predictive of CVD. Little is known regarding the relationship between GV and blood pressure (BP). Therefore, we examined GV and HbA1c and their associations with BP in overweight adults with PD and early stage T2D enrolled in a weight loss study. MethodsParticipants had a history of PD or T2D treated with lifestyle alone or lifestyle and metformin. Data for this report were obtained at baseline and included sociodemographics, height, weight, BP, and HbA1c. Up to two weeks of continuous glucose monitoring data were collected using the Abbott Freestyle Libre Pro, and mean amplitude of glycemic excursions (MAGE) was computed using EasyGV. Linear mixed models were used to test the associations of MAGE and HbA1c with BP, with adjustment for sociodemographic characteristics, as well as to compare MAGE on weekdays versus weekends. Repeated measures ANOVA was used to investigate the within-subject and between-subject variation of MAGE. All analyses were performed using R software. ResultsStudy participants (n = 35) were mostly female (66%) and non-Hispanic white (69%), with a mean (SD) age of 57 (11) years, BMI of 33.0 (4.0) kg/m2, HbA1c of 5.6 (0.5) %, and systolic and diastolic BP (SBP, DBP) of 124 (14) and 71 (8) mmHg, respectively. MAGE differed significantly between participants (P < 0.001), however within person was fairly stable (P = 0.14). There were no significant differences in MAGE on weekdays versus weekends (P = 0.27). MAGE, but not HbA1c, was positively associated with SBP (P = 0.02 vs P = 0.44), while adjusting for age, gender, race and BMI. When HbA1c was added to the model, the association of MAGE with SBP remained significant (P = 0.03). ConclusionsAmong overweight adults with PD and early-stage T2D, MAGE was found to be associated with SBP. This suggests that a measure of daily GV may be a good alternative measure of metabolic health outcomes in this population. Funding SourcesThis work was funded by the American Heart Association.