Comparison between visit-to-visit office and 24-h blood pressure variability in treated hypertensive patients

In any treated hypertensive patient office blood pressure (BP) values may differ between visits and this variability (V) has an adverse prognostic impact. However, little information is available on visit-to-visit 24-h BPV.

In 1114 hypertensives of the ELSA and PHYLLIS trials we compared visit-to-visit office and 24-h mean BPV by coefficient of variation (CV) of the mean systolic (S) and diastolic (D) BP obtained from yearly measurements during a 3-4 year treatment period. Visit-to-visit BPV during daytime and night-time were also compared.

Twenty-four-hour SBP-CV was about 20% less than office SBP-CV ( P  < 0.0001). SBP-CV was considerably greater for the night-time than for the daytime period (20%, P  < 0.0001). Results were similar for DBP and in males and females, older and younger patients, patients under different antihypertensive drugs or with different baseline or achieved BP values. In the group as a whole and in subgroups there was significant correlations between office and 24-h BP-CV but the correlation coefficients was weak, indicating that office SBP or DBP CV accounted for only about 1-4% of 24-h SBP or DBP-CV values.

Twenty-four-hour mean BP across visits is more stable than across visit office BP. Visit-to-visit office and 24-h BPV are significantly related to each other, but correlation coefficients are low, making visit-to-visit office BP variations poorly predictive of the concomitant 24-h BP variations and thus of on-treatment ambulatory BP stability.