Reproducibility of blood pressure variability assessed by home blood pressure monitoring.

OBJECTIVE

Although blood pressure (BP) variability (BPV) derived from home BP monitoring (HBPM) is a recognized cardiovascular risk marker, limited data on its reproducibility hinder its clinical application. This study aimed to address this gap.

METHODS

We compared HBPM-derived BPV at two time points using three metrics [standard deviation (SDVar), coefficient of variation (CoV), and variability independent of the mean (VIM)] among 495 individuals not using antihypertensive medications (No-AH) (median time-span between HBPM exams = 392 [308-519] days) and 588 individuals using antihypertensive medications (AH) (time-span between HBPM exams = 400 [319-510] days).

RESULTS

No significant changes were observed across the time points in systolic HBPM-derived BPV metrics: SDVar (8.55 ± 3.14 vs. 8.71 ± 3.52 in No-AH; 9.67 ± 3.62 vs. 9.50 ± 3.47 in AH), CoV (7.01 ± 2.47 vs. 7.10 ± 2.65 in No-AH; 7.65 ± 2.77 vs. 7.57 ± 2.62 in AH), and VIM (5.76 ± 2.10 vs. 5.87 ± 2.35 in No-AH; 6.29 ± 2.34 vs. 6.18 ± 2.24 in AH) (all p >.05). Similarly, diastolic HBPM-derived BPV metrics remained stable between the time points: SDVar-DBP (5.65 ± 2.32 vs. 5.62 ± 2.33 in No-AH; 5.99 ± 2.50 vs. 5.90 ± 2.37 in AH), CoV-DBP (7.26 ± 3.03 vs. 7.24 ± 3.13 in No-AH; 7.66 ± 3.20 vs. 7.63 ± 3.06 in AH) and VIM-DBP (4.78 ± 1.96 vs. 4.75 ± 1.97 in No-AH; 4.64 ± 1.93 vs. 4.58 ± 1.83 in AH) (all p >.05). However, the test-re-test correlation of all HBPM-derived BPV metrics was only modest (r ≈ .27-.45), revealing substantial intra-individual variability. In addition, similar results were obtained in an alternative sample of 498 individuals (265 using AH and 233 not using AH) who underwent OBP and HBPM measurements at four different time points.

CONCLUSION

These findings demonstrate that BPV parameters derived from HBPM had high reproducibility at the population level, but limited reproducibility at the individual level.