Higher blood pressure variability during hospitalisation is associated with lower cerebral white matter integrity in COVID-19 patients

High blood pressure variability (BPV) is associated with cerebrovascular damage and dementia, but it is unknown whether short-term BPV during hospitalisation is also associated with cerebral white matter (WM) damage. We examined whether BPV, measured in-hospital using continuous monitoring, is associated with WM microstructural integrity in COVID-19 patients. We included hospitalised COVID-19 patients from the CORONavirus and Ischemic Stroke (CORONIS) study who underwent continuous vital signs monitoring using a wearable device during hospital admission and had an MRI shortly after discharge. Systolic BPV was calculated as Average Real Variability (ARV) and Coefficient of Variation (CV) with 1-, 5- and 20-minute intervals. We used diffusion tensor imaging to assess fractional anisotropy (FA) and peak width of skeletonised mean diffusivity (PSMD) as markers of WM integrity. Associations between BPV and WM integrity were examined with linear regression adjusted for age, mean systolic blood pressure (BP), number of BP measurements and type of respiratory support. We included 47 COVID-19 patients (mean age: 59.6 years). BP was measured 6306 ± 4343 times per patient (median admission: 11 days (Interquartile Range [IQR] 7.5–15.0). Both higher ARV and CV were associated with lower WM microstructural integrity, reflected by lower FA (ARV: <i>β</i> = −0.40, <i>p</i> = .010; CV: <i>β</i> = −0.33, <i>p</i> = 0.026) and higher PSMD (CV: <i>β</i> = 0.28, <i>p</i> = .038) after adjustment for confounders. Correction for WM hyperintensities did not change these results. High BPV during hospitalisation is associated with lower WM integrity in COVID-19 patients, although causality needs to be demonstrated. Our findings need validation in hospitalised patients without COVID-19 to examine generalisability. Hypertension is very common in older individuals and is a risk factor for strokes and dementia. BP fluctuates over time rather than remaining constant. This is called BP variability.Earlier research has revealed that higher BP variability is linked to an increased risk of dementia, strokes, cardiovascular events and even death. Significant BP swings are likely harmful to the brain. When patients are hospitalised, their BP often becomes more unstable, but whether this instability can harm the brain is unclear. This study explored whether large BP variations during hospital stays are connected to brain damage.To investigate this, we measured BP continuously in COVID-19 patients in the hospital with a wearable monitoring system on the arm. Afterwards, we conducted MRI scans to examine the integrity of the brain.Our results indicate that patients with greater BP variability exhibit lower brain integrity after hospitalisation.This implies that BP fluctuations can indeed harm the brain.However, based on these results, it is not possible to determine whether BP variability causes brain damage or results from it. Additional research is needed to establish the chronological order of this association.If BP variability may indeed damage the brain, we should focus more on maintaining stable BP levels in hospitalised patients. Hypertension is very common in older individuals and is a risk factor for strokes and dementia. BP fluctuates over time rather than remaining constant. This is called BP variability. Earlier research has revealed that higher BP variability is linked to an increased risk of dementia, strokes, cardiovascular events and even death. Significant BP swings are likely harmful to the brain. When patients are hospitalised, their BP often becomes more unstable, but whether this instability can harm the brain is unclear. This study explored whether large BP variations during hospital stays are connected to brain damage. To investigate this, we measured BP continuously in COVID-19 patients in the hospital with a wearable monitoring system on the arm. Afterwards, we conducted MRI scans to examine the integrity of the brain. Our results indicate that patients with greater BP variability exhibit lower brain integrity after hospitalisation. This implies that BP fluctuations can indeed harm the brain. However, based on these results, it is not possible to determine whether BP variability causes brain damage or results from it. Additional research is needed to establish the chronological order of this association. If BP variability may indeed damage the brain, we should focus more on maintaining stable BP levels in hospitalised patients.