Background
Hypertension is a syndrome with elevated blood pressure as the main clinical manifestation, with or without a variety of cardiovascular risk factors, which can cause a variety of cardiovascular and cerebrovascular diseases, and can even cause heart, brain, kidney and other organ failures1. Elderly patients are the population with a high incidence of hypertension2. The pathogenesis of hypertension is not clear. Related factors of hypertension include thickening of the arterial wall and decreased elasticity3. Studies4,5 have shown that blood pressure fluctuations and pulse pressure index changes in elderly hypertensive patients can cause cognitive impairment(CI), yet the potential mechanisms remain unclear.
CI refers to a series of pathological phenomena caused by abnormal brain functions related to learning, memory and thinking judgment6. It has significant physical, psychological, social and economic consequences for patients, caregivers and health care systems, and with the aging of the population, the burden of disease has increased exponentially7,8. Studies9,10 have shown that the probability of CI turning into dementia is extremely high, and the progress is extremely fast. According to statistics11,12, China currently has more than 10 million dementia patients, becoming one of the fastest growing countries in the world, resulting in high economic and social resource burdens. Studies13-15 have shown that persistent hypertension is an important risk factor for cognitive impairment. At the same time, more and more scholars have found that there is a certain correlation between blood pressure variability and cognitive function, but the results of the study are not consistent. Therefore, we aimed to conduct a meta-analysis to explore the association between blood pressure variability and cognitive function, and to provide reliable evidence support for the early intervention of hypertension and the prevention of CI.