LAUSR

Objective: The prognostic significance of orthostatic hypertension (BP) in young individuals is still controversial. This study aims to evaluate the association of hyperreactivity to standing with major adverse cardiovascular and renal events (MACE) in a cohort of young-to-middle-age subjects. Design and method: This investigation was performed in 1207 untreated stage 1 hypertensive subjects with a mean age of 33.1 ± 8.6 years. Supine and standing BPs were measured during two visits performed two weeks apart. At each visit, three supine BP measurements and three orthostatic measurements were taken at 1-minute intervals. The orthostatic BP response to standing was calculated as the average of the standing-lying BP differences obtained during the two visits. Hyperreactors to standing were defined people with a standing-supine systolic BP difference in the top decile (>6.5 mmHg). The mean difference in the whole group was -2.5 ± 7.3/4.6 ± 5.4 mmHg. In 630 participants 24 h urinary epinephrine was measured. Results: Hyperreactors to standing were more frequently smokers (p = 0.003) and coffee drinkers (p = 0.05), and had higher 24 h urinary epinephrine (118.4 ± 185.6 versus 77.0 ± 90.1 nmol/mol, p = 0.005). Hyperreactors also had a greater orthostatic response of diastolic BP (p < 0.001). Ambulatory hypertension evaluated with 24-hour recordings was more common in Hyperreactors than Normoreactors (90.8% versus 76.4%, p = 0.001). During a 17.2-year follow-up, 105 MACE were accrued. In multivariate Cox analysis adjusted for age, gender, parental history of cardiovascular disease, smoking, alcohol drinking, coffee use, physical activity habits, body mass index, office systolic and diastolic BP, postural diastolic BP change, office heart rate, serum glucose, and total cholesterol, Hyperreactors to standing had an almost doubled risk of MACE compared to Normoreactors with a hazard ratio of 1.97 (95%CI, 1.10–3.52). Hyperreactivity remained an independent predictor of MACE even when ambulatory BP data and incident hypertension during follow-up were included in the Cox model (hazard ratio: 1.94; 95%CI, 1.10–3.44). Conclusions: Our data indicate that in young-to-middle-age hypertensive subjects an exaggerated systolic BP response to standing is associated with sympatho-adrenergic hyperreactivity and is an independent predictor of MACE. Orthostatic BP assessment gives the advantage of simple acquisition and future guidelines should encourage measurement of BP on standing in young individuals.