Comparison between office and ambulatory blood pressure in young and elderly subjects with isolated systolic hypertension

BACKGROUND: It has been claimed that isolated systolic hypertension (ISH) in the elderly is not a sustained condition but a short-lasting increase in office systolic blood pressure magnified by arterial stiffness. DESIGN: Office and ambulatory blood pressures werecompared at baseline and after 3 months of observation of young and elderly subjects with ISH. METHODS: The study was carried out in 39 young (mean age 27.1+/-9.8 years) and 37 elderly patients (mean age 72.5+/-5.7 years). Office blood pressure was defined as the mean of six readings. All subjects underwent two non-invasive 24 h blood pressure monitorings performed 3 months apart and echocardiography (n = 50). RESULTS: The difference between office and mean 24 h systolic/diastolic blood pressure was 27.9/8.2 mmHg in the young and 18.9/6.9 mmHg in the elderly patients (P < 0.01 for systolic blood pressure). Twenty-four-hour (P < 0.001), daytime (P = 0.001) and night-time (P < 0.001) systolic blood pressures were higher in the elderly and the difference between daytime and night-time systolic blood pressure was greater in the young (P < 0.05). Office and ambulatory heart rates were significantly higher in the young subjects. The elderly patients showed a greater left ventricular wall thickness ( P = 0.005 for posterior wall; P < 0.005 for septum), relative wall thickness (P = 0.01) and left ventricular mass index (P = 0.001) and impaired left ventricular filling rate ( P = 0.05), whereas systolic performance and stroke volume were no different in the two groups. Due to the higher heart rate, cardiac output was greater in the young (P = 0.03). CONCLUSION: These data show that larger differences between office and ambulatory systolic blood pressure are not unique to elderly patients with ISH. Increased ambulatory blood pressure levels and a decreased nocturnal blood pressure fall were associated with left ventricular structural and functional abnormalities in the elderly subjects.