New research involving more than 57,000 UK Biobank participants has found that people whose blood pressure fluctuates between visits face an almost three times higher risk of death compared with those whose readings remain steady. The findings were presented at the Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy.
The study, led by Dr Fariba Ahmadizar of the Department of General Practice at Amsterdam University Medical Centre in the Netherlands, included 57,611 participants who had blood pressure measured at their initial assessment and at least one later visit. Their average age was 55.4 years, and 52% were women.
Study details and key findings
At the start of the study, 50,744 participants had normal blood sugar, 5,397 had prediabetes (blood sugar levels higher than normal but not high enough to be classed as diabetes), and 1,470 had type 2 diabetes. Researchers assessed how much blood pressure varied between visits, accounting for the time between measurements.
Participants were followed for a median of 5.1 years from the first visit at which variability could be calculated. During this period, 319 participants developed dementia, 571 had a stroke, and 1,460 died.
Association with death and stroke
Greater variability in each of the four blood pressure measures studied (systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure) was associated with a higher risk of death from any cause. These associations remained after adjusting for average blood pressure, blood sugar status, and other factors.
Each one standard deviation increase in systolic blood pressure variability was associated with an 11% higher risk of death, while the corresponding increase was 8% for diastolic blood pressure variability. Greater variability in diastolic blood pressure and mean arterial pressure was also associated with strokes.
Impact of diabetes and prediabetes
Compared with participants with normal blood sugar and low systolic blood pressure variability, those with type 2 diabetes and high systolic blood pressure variability were almost three times (2.8 times) more likely to die during the follow-up period. Participants with prediabetes and high systolic blood pressure variability had a 62% higher risk of death than those with normal blood sugar and low systolic blood pressure.
However, the authors noted that because these comparisons combine differences in blood sugar status and blood pressure variability, the increased risk cannot be attributed to blood pressure variability alone. The estimated 10-year risk of death was approximately 1.0% among participants with normal blood sugar and low systolic blood pressure variability, compared with approximately 2.9% among those with type 2 diabetes and high variability.
No statistically significant associations were found for dementia. Dr Ahmadizar said: “Our findings suggest that changes in blood pressure over time may provide information beyond the average blood pressure readings in routine care.” She added that more research is needed before blood pressure variability can be recommended for routine clinical use, including whether it is possible to reduce these fluctuations and if doing so reduces the risk of stroke or death. She also noted the study only tracked people's habits, so it cannot prove a definite cause-and-effect.
