Association Between 24-Hour Blood Pressure Variability and Mortality in Acute Ischemic Stroke Patients admitted in Intensive Care Units: A MIMIC-IV Study

Acute ischemic stroke (AIS) patients in the intensive care unit (ICU) face high mortality. This study examined the association between systolic blood pressure variability (SBPV), specifically average real variability (SBP-ARV), and short-term mortality in critically ill AIS patients. We conducted a retrospective cohort study using the MIMIC-IV database. The primary outcomes were 28-day and 90-day all-cause mortality. Cox regression, Kaplan-Meier curves, restricted cubic spline (RCS) models, and subgroup analyses were used to assess associations. A total of 861 AIS patients were included. The 28-day and 90-day mortality rates were 20.9% and 23.3%, respectively. Higher SBP-ARV was independently associated with increased mortality. Compared with the lowest tertile, the highest tertile of SBP-ARV had significantly increased 28-day mortality (HR: 1.53; 95% CI: 1.03–2.27; P = 0.035). SBP-ARV as a continuous variable was also significantly associated with 28-day and 90-day mortality. RCS analysis showed that mortality risk increased when SBP-ARV exceeded 11.63. Our findings suggest that elevated systolic blood pressure variability, particularly higher SBP-ARV within the first 24 hours of ICU admission, is significantly associated with increased 28-day and 90-day mortality in AIS patients. SBP-ARV may serve as a valuable prognostic marker for risk stratification and early clinical intervention in critically ill stroke patients. Stroke is a leading cause of death and disability worldwide. Some patients with severe strokes need to be treated in the intensive care unit (ICU), where close monitoring and advanced medical support are provided. However, many of these patients still face a high risk of death within a short period. Doctors are looking for reliable signs that can help predict which patients are at greater risk so that they can receive timely and targeted care. This study looked at changes in blood pressure over time—known as blood pressure variability (BPV)—in patients who had a severe ischemic stroke and were admitted to the ICU. Using data from a large hospital database, we found that patients with greater fluctuations in their systolic blood pressure (the top number in a blood pressure reading) during the first 24 hours in the ICU were more likely to die within 28 and 90 days. We also identified a specific threshold: once the fluctuation level exceeded a certain point, the risk of death increased steadily. This finding is important because blood pressure is a vital sign that is already measured routinely. Recognizing dangerous levels of blood pressure variability early could help doctors identify high-risk stroke patients sooner. By doing so, healthcare teams could adjust treatments—such as blood pressure management—more effectively and potentially improve survival outcomes.