title: Assessment of vascular function in individuals with hyperglycemia: a cross-sectional study of glucose - induced changes in digital volume pulse.
abstract: BACKGROUND
  Arterial stiffness is an independent risk factor for cardiovascular disease and its progression may be accelerated in the presence of hyperglycemia, either fasting or postprandial. The current study assessed vascular function in subjects with pre-diabetes hyperglycemia, using digital volume pulse analysis technique.
  
  
  METHODS
  We conducted a cross-sectional study examining vascular function in the fasting and postprandial (glucose-induced) state in 44 adults, consisting of 17 subjects with pre-diabetic hyperglycemia and 27 normoglycemic volunteers. Photoplethysmography of the digital volume pulse (DVP) was used to determine stiffness index (SI) and reflective index (RI), as main measures of larger artery stiffness and vascular tone, respectively.
  
  
  RESULTS
  Our results showed a significantly higher (Ln) fasting SI in the hyperglycemic group compared with the control group (2.19 ± 0.32 vs. 1.96 ± 0.22, P = 0.005). However, this pattern reversed after adjustment for potential confounders. In multiple linear regression analysis, (Ln) SI was related to age (β = 0.01, 95% CI: 0.01-0.02, P < 0.001) and systolic blood pressure (SBP) (β = 0.01, 95% CI: 0.00-0.01, P < 0.05), but not with W/H, diastolic blood pressure (DBP), fasting plasma glucose (FPG) or serum lipids. Furthermore, age (β = 0.02, 95% CI: 0.01-0.03, P < 0.001) and mean arterial pressure (MAP) (β = 0.01, 95% CI: 0.00-0.02, P < 0.05) were found as the strong predictors of fasting SI in hyperglycemic group. Neither FPG nor 2-h plasma glucose was a significant predictor for SI in hyperglycemic group, after accounting for age and MAP. Subjects with hyperglycemia had a 15% blunted change in postprandial AUCs for RI, adjusted for the respective baseline measurements (-9.40 ± 3.59 vs. -11.00 ± 2.84%) but these did not attain statistical significance.
  
  
  CONCLUSIONS
  Increased arterial stiffness in pre-diabetic subjects is strongly associated with age and MAP. The increased DVP-derived SI reported in patients with pre-diabetic hyperglycemia may result from different frequently accompanied risk factors not just glycemic changes in this range.
authors.affiliation: School of Public Health, Curtin University, Kent Street, Bentley, Perth, Western Australia ; Iran University of Medical Sciences (IUMS), Tehran, Iran.
authors.forename: Fariba
authors.initials: F
authors.lastname: Alaei-Shahmiri
authors.affiliation: School of Public Health, Curtin University, Kent Street, Bentley, Perth, Western Australia.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Public Health, Curtin University, Kent Street, Bentley, Perth, Western Australia.
authors.forename: Jill
authors.initials: J
authors.lastname: Sherriff
keywords: Arterial stiffness; Digital volume pulse analysis; Hyperglycemia; Photoplethysmography; Reflection index; Stiffness index