Long-term reproducibility of ambulatory blood pressure in unselected elderly subjects

The aim of this study was to evaluate the long-term reproducibility and val idity of 24-h ambulatory blood pressure measurements (ABPM) in an unselecte d elderly population. In a rural Finnish community 503 randomly chosen invi ted persons over 65 years of age participated and went through 24-h ABPM. A s part of the validation of the methodology, the reproducibility study was conducted in 26 persons (age 65-76 years). Two identical sets of measuremen t were performed at 4-12 (median 8) month intervals. The agreement between measurements was assessed by correlation coefficients and standard deviatio n (SD) of the differences. There were no significant differences in 24-h, d aytime and night-time average diastolic blood pressure (DBP) and day-time a verage systolic blood pressure (SBP) between the two measurements. During t he second measurement, 24-h SBP and night-time average SBP were slightly hi gher than those obtained by the first monitoring. Average 24-h SBP and DBP were 18 and 7 mmHg lower, respectively, than office blood pressure averages . The correlation coefficients were significantly higher for 24-h ambulator y blood pressure than for office blood pressure. The SD of the mean differe nce between visits was significantly lower for 24-h ambulatory blood pressu re than for office blood pressure measurements. These findings show that th e long-term reproducibility of ambulatory blood pressure is good in an elde rly unselected population and better than the office blood pressure reprodu cibility.