24-HOUR AMBULATORY BLOOD-PRESSURE IN OLD AND VERY OLD SUBJECTS

Objective: To compare clinic and 24-h blood pressure levels and profil es in young elderly (aged 65-79 years) and old elderly (aged greater t han or equal to 80 years) subjects. Subjects and methods: A cross-sect ional observational study was conducted on 108 ambulant subjects (51 m ales) aged 65-95 years with no known history of hypertension, recruite d from the community (55%) and hospital outpatients (35%) and inpatien ts (10%). Three clinic blood pressure measurements were taken, followe d by 24-h ambulatory blood pressure monitoring and then a further thre e clinic measurements, the mean of these being defined as the clinic b lood pressure.Results: Clinic systolic blood pressure was significantl y higher in females than males (148+/-20 versus 136+/-23 mmHg, P=0.02) , but 24-h systolic blood pressure was similar. Mean 24-h and daytime blood pressure levels were significantly lower than clinic blood press ure in females but in males only 24-h systolic blood pressure was lowe r than the clinic level. In young elderly compared to old elderly fema les the clinic-daytime ambulatory systolic blood pressure difference w as significantly reduced (14+/-22 versus 1+/-17 mmHg, respectively; P= 0.04). A significant nocturnal systolic/diastolic blood pressure fall was seen in young elderly and old elderly males (9+/-12/7+/-7 versus 6 +/-11/7+/-8 mmHg) but in females the nocturnal systolic blood pressure fall was inversely related to age (r=-0.32, P=0.02). Conclusions: The white-coat effect is common in young elderly females, but uncommon in very elderly females and males aged greater than or equal to 65 years ; a decline in casual blood pressure in the very elderly may partly ar ise from a reduction in the white-coat effect. Nocturnal blood pressur e falls also decline in the very elderly, especially in females.