It was shown that parameters of metabolic syndrome as predictors of lethal vascular outcomes of arterial hypertension (AH) in Belarus are significantly different fiom those proposed in WHO recommendations (1999). The glucose level of informative value in WHO recommendations is 6.1 mmol/l versus 5.6 mmol/l in Belarus, total cholesterol 5.0 and 5.9 mmol/l respectively. A more detailed verification of the value of both parameters is needed for the patients in Belarus and Russia depending on age and sex using non-linear models. We used a comprehensive approach to prognosis of the risk of vascular lethal outcomes of AH as a component of metabolic syndrome with the evaluation of results of clinical and laboratory examination as well as orthostatic reactions in patients of different age groups. Construction of the prognostic algorithm "Classification tree" taking account of orthostatic reactions enhances the correctness of lethal outcome prognosis up to 81.8%. The study revealed the prognostic value of systolic and diastolic arterial pressure in the supine position (15 min of active aortostatic sample) for prognostication of vascular lethal outcomes. Further studies are needed on the role of orthostatic reactions in AH patients of old age together with clinical and laboratory parameters in the prognostication of outcomes of various cardiovascular diseases.