Methodological factors affecting quantification of blood pressure variability: a scoping review

Objectives: Blood pressure (BP) variability (BPV) may offer independent prognostic information. However, data supporting this notion are inconsistent, and this may be due to the wide variety of methodologies used for measuring BPV. A systematic analysis on the effect of BPV methodologies on BPV itself has never been undertaken and was the aim of this study. We also sought to determine the effect of participant characteristics on BPV.

Methods: A scoping review process was used to identify the effect of BPV methodologies on BPV magnitude. Key methodological factors assessed were the number of BP readings or visits used to quantify BPV and the duration of BP monitoring. In addition, the relationship between age and mean BP level on BPV was investigated. Analyses were performed across studies that measured BPV over the short-term (using 24-h BP), mid-term (using home BP in the morning, evening or day-to-day) and long-term (using visit-to-visit clinic BP).

Results: Data were extracted from 96 studies. The number of BP readings and visits used to quantify BPV were positively associated with mid-term and long-term BPV. Duration was weakly associated with mid-term (morning) BPV. Age was positively associated with long-term and mid-term (day-to-day), but not short-term BPV. Mean BP level was positively associated with BPV, except mid-term BPV (morning and evening).

Conclusion: The methodology used to quantify BPV, as well as age and mean BP level, affects the magnitude of BPV itself. This highlights the need to standardize BPV protocols, particularly regarding the number of BP readings and visits.