engleski

External validation of the gender specific equation for augmentation index on the Croatian low risk population sample facilitates identification of high cardiovascular risk subjects

BACKGROUND: Arterial stiffness is an independent predictor of major cardiovascular events. A Danish research team proposed an equation for prediction of augmentation index (AIx) values, based on age, sex, height and heart rate as input data. We tested the “Danish equation” on Croatian population-based sample, Dalmatia region, comparing calculated AIx values with actual measured values. MATERIALS AND METHODS: Among 1012 apparently healthy volunteers, we selected a low risk cohort (n=538, 28% male, 72% female) according to the “Danish” inclusion criteria. AIx was measured noninvasively with radial artery tonometry. Predicted Aix was calculated using the equation: AIx=79.70 + 0.63 (age) – 0.002 (age2) -0.28 (heart rate) -0.39 (height) ; for men and: AIx=56.28 + 0.90 (age) - 0.005 (age2) -0.34 (heart rate) -0.24 (height) for women. We used two-sample t-test and the chi-square test to examine differences between populations, and Pearson’s correlation and Bland Altman (BA) agreement analyses to examine association and agreement between calculated and actual AIx values in the Croatian population. RESULTS: Predicted AIx was 24.20%±7.05 for women, and 11.78%±6.86 for men, whereas measured AIx was 23.71±13.87 for women and 10.46±13.46 for men. A strong positive correlation was found between observed and predicted AIx (r=0.75, P<0.001). However, substantially different regression lines were observed within different age classes. CONCLUSIONS: The “Danish equation” for reference AIx generally proved to be true after external validation on Croatian low risk population. Although inter-individual differences cannot be eliminated, the predicted AIx provides valuable information about subject’s tendency towards development of arterial stiffness related cardiovascular risk.

Arterial stiffness ; Cardiovascular ; AIx

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