Unstable Blood Pressure Tied to Higher Death and Stroke Risk

One cuff, one snapshot. But what if the story lives in the gaps between visits?

A large observational study of more than 57,000 UK Biobank participants suggests that the way blood pressure swings from one appointment to the next carries real information about future risk — especially for people with elevated blood sugar. Short-term rises and falls in systolic and diastolic pressure were linked to higher chances of death and, for some measures, to stroke.

The research team, led by Dr. Fariba Ahmadizar at Amsterdam University Medical Centre, followed 57,611 adults who returned for at least one repeat blood pressure check after their baseline visit. Average age was 55.4 years and 52% were women. With a median follow-up of 5.1 years, 1,460 participants died, 571 had a stroke and 319 went on to develop dementia.

What stood out most was the interaction with blood sugar status. Participants with type 2 diabetes and high variability in systolic blood pressure faced nearly three times the risk of death compared with people who had normal blood sugar and low variability. Those with prediabetes and large systolic swings also showed elevated mortality, about 62% higher than the same low-risk reference group. In concrete terms, the investigators estimated a 10-year death probability of roughly 1.0% for people with normal glucose and stable systolic readings versus about 2.9% for those with type 2 diabetes and unstable systolic pressure.

The study did not stop at systolic numbers. Researchers examined four different measures: systolic and diastolic pressure, mean arterial pressure (the average pressure across a heartbeat) and pulse pressure (the gap between the top and bottom numbers). Greater variability across all four was associated with higher all-cause mortality, and the relationships held even after accounting for average blood pressure, glucose status and other health factors. Statistically, each standard-deviation increase in systolic variability corresponded to an 11% higher risk of death, while each SD increase in diastolic variability translated to an 8% rise.

Strokes tracked a slightly different pattern. Variability in diastolic pressure and in mean arterial pressure were the two measures tied to higher stroke risk: about 12% and 10% higher per standard-deviation increase, respectively. No clear link emerged between blood pressure variability and dementia in this cohort.

Blood pressure is not just a number on one day; its ups and downs may flag people at hidden risk.

Why might variability matter? Think of blood pressure like traffic flow. A steady stream is easier to predict than sudden jams and detours. Repeated surges could strain arteries or reflect instability in the systems that regulate circulation. Still, observational data can point to signals without proving cause. The team cautions that blood pressure swings could be a marker — not necessarily the driver — of poor outcomes.

That caveat matters for clinicians weighing changes in practice. Could routine monitoring of variability help identify patients who need closer surveillance or different therapy? And if doctors do manage to smooth out those swings, will that lower the risk of stroke or death? Those are the next questions researchers want answered before variability becomes a standard metric in clinics.

Presented at the annual European Association for the Study of Diabetes meeting, the analysis opens a practical line of inquiry: patients already have repeat measurements; we may simply need to pay attention to the pattern, not only the average. Will watching the swings change care? Time — and trials — will tell.