| Abstract: | Background - This paper is a concrete example of the problems raised by the need of constructing the time-qualified reference limits (chronodesms) for blood pressure (BP), in order to clinically estimate the hemodynamic parameter in its intrinsic nychtohemeral variability. Methods - Assuming that the noninvasive ambulatory BP monitoring (ABPM) is the eligible technique for this need, it must be realized that the BP chronodems may be of two types, depending on the sample being used for their calculation. The first type may be regarded as “ a priori ” because of the fact that they are derived by a sample of normotensive subjects who are unavoidably recruited via “ causal ” sphygmomanometric measurements and reclassified as normotensive by comparing their ABPM to the fixed reference limits (monodesms) given by WHO (monodiagnosis). Therefore, the “ a priori ” BP chonodesms are by principle derived by subjects who could not be correctly classified as normotensive, their ABPM being not tested versus the time-varying physiological limits. The second type may regarded as “ a posteriori ” in virtue of the fact that they may be constructed on a sample which contemplates the previous subjects who result to be true normotensive via the reassessment of their ABPM versus the “ a priori ” BP chronodesms (chronodiagnosis). The “ a posteriori ” chronodesms may be regarded as biometrically reliable, whether the sample for their construction is additionally constituted by those subjects of the local population who have been erroneously monodiagnosed as hypertensive, while they result to be true normotensive via the chronodiagnostic comparison of their ABPM versus the “ a priori ” BP chronodesms. Results - The biometric reliability of the “ a posteriori ” BP chronodems is demonstrated by the fact that their upper limits are statistically significantly less pronounced due to the fact that they are provided by a sample which has been depured by the falsely monodiagnosed normotensives. Conclusions - The “ a posteriori ” BP upper chronodesms are the time-qualified reference limits which should be used in clinical practice for the chronodiagnosis of hypertension. |
