Association Of Blood Pressure Variability With Death And Discharge Destination Among Stroke And Non-stroke Critical Illness Patients

Introduction: High blood pressure variability (BPV) is associated with worse prognoses among critically ill stroke and non-stroke patients. It is unclear if higher BPV’s association with worse outcomes is a unique sequela of stroke or a modifiable risk factor among all critically-ill patients. Methods: Using data from 7,939 ICU patients hospitalized between 2001 and 2012 in the Medical Information Mart for Intensive Care III (MIMIC-III) database, we examined (1) differences in BPV between stroke and non-stroke patients, (2) BPV’s associations with in-hospital death and favorable discharge destination in stroke and non-stroke patients after adjusting for confounders, and (3) how minimum systolic blood pressure (SBP) - a correlate of illness severity and cerebral perfusion - affected these associations. Results: BPV was higher in stroke patients compared to non-stroke patients. In regression analyses, higher BPV was significantly associated with higher odds of in-hospital death and unfavorable discharge amongst stroke and non-stroke patients. After adjusting for minimum tertile of SBP to account for illness severity and cerebral perfusion, higher BPV was significantly associated with higher odds of in-hospital death and lower odds of favorable discharge destination only in patients with ischemic stroke (OR in-hospital death 2.1, 95% CI: 1.0-4.1; OR favorable discharge 0.6, 95% CI: 0.4-0.9) or intracerebral hemorrhage (OR in-hospital death 3.3, 95% CI: 1.8-6.1; OR unfavorable discharge 0.4, 95% CI: 0.3-0.7). Conclusion: Among critically ill stroke patients, BPV seems to represent both generalized critical illness as well as a specific feature of stroke. BPV in critically ill stroke patients may be in part a function of injury to the central autonomic network or modulation of sympathetic outflow.