Raised blood pressure is a risk factor for heart disease and stroke. Most studies investigating this association look at average blood pressure as the indicator of risk. Blood pressure, however, is known to vary over time and this variability in itself has been flagged as a potential risk factor.
Few studies have analysed variability in blood pressure associated with cardiovascular outcomes as it is often difficult to measure and isolate. Researchers analysed the existing literature that measured the association between blood pressure variability and cardiovascular outcomes, independent of mean blood pressure.
The blood pressure variability measured in included studies was categorised into either long term monitoring (in clinics), mid term monitoring (at home) or short term monitoring (through ambulatory monitoring).
The outcomes of interest were all cause death, cardiovascular events (including stroke, heart attach, coronary heart disease and heart failure) or cardiovascular death.
Long term variability was found to be associated with both all cause and heart disease death, heart disease events, stroke and heart attack, independent of mean blood pressure. Mid term and short term variability were also associated with death rates.
In this study, long term variability in blood pressure was associated with both all cause and heart deaths. Further research is required to confirm this link however it may emerge as an important risk factor to measure alongside mean blood pressure in people at risk of adverse heart events.