title: Normative equations for central augmentation index: assessment of inter-population applicability and how it could be improved.
abstract: Common reference values of arterial stiffness indices could be effective screening tool in detecting vascular phenotypes at risk. However, populations of the same ethnicity may differ in vascular phenotype due to different environmental pressure. We examined applicability of normative equations for central augmentation index (cAIx) derived from Danish population with low cardiovascular risk on the corresponding Croatian population from the Mediterranean area. Disagreement between measured and predicted cAIx was assessed by Bland-Altman analysis. Both, cAIx-age distribution and normative equation fitted on Croatian data were highly comparable to Danish low-risk sample. Contrarily, Bland-Altman analysis of cAIx disagreement revealed a curvilinear deviation from the line of full agreement indicating that the equations were not equally applicable across age ranges. Stratification of individual data into age decades eliminated curvilinearity in all but the 30-39 (men) and 40-49 (women) decades. In other decades, linear disagreement independent of age persisted indicating that cAIx determinants other than age were not envisaged/compensated for by proposed equations. Therefore, established normative equations are equally applicable to both Nordic and Mediterranean populations but are of limited use. If designed for narrower age ranges, the equations' sensitivity in detecting vascular phenotypes at risk and applicability to different populations could be improved.
authors.affiliation: Department of Research in Biomedicine and Health, University of Split School of Medicine, Split, Croatia.
authors.forename: Ana
authors.initials: A
authors.lastname: Jeroncic
authors.affiliation: Department of Pharmacology, University of Split School of Medicine, Split, Croatia.
authors.forename: Grgo
authors.initials: G
authors.lastname: Gunjaca
authors.affiliation: Department of Pharmacology, University of Split School of Medicine, Split, Croatia.
authors.forename: Danijela Budimir
authors.initials: DB
authors.lastname: Mrsic
authors.affiliation: Department of Pharmacology, University of Split School of Medicine, Split, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Mudnic
authors.affiliation: Department of Pharmacology, University of Mostar School of Medicine, Mostar, Bosnia and Herzegovina.
authors.forename: Ivica
authors.initials: I
authors.lastname: Brizic
authors.affiliation: Department of Public Health, University of Split School of Medicine, Split, Croatia.
authors.forename: Ozren
authors.initials: O
authors.lastname: Polasek
authors.affiliation: Department of Pharmacology, University of Split School of Medicine, Split, Croatia.
authors.forename: Mladen
authors.initials: M
authors.lastname: Boban
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000503:physiopathology; D017523:Croatia; D003430:Cross-Sectional Studies; D003718:Denmark; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D063177:Pulse Wave Analysis / Q000379:methods / Q000706:statistics & numerical data*; D012016:Reference Values; D012307:Risk Factors; D012737:Sex Factors; D059289:Vascular Stiffness