Systolic blood pressure time in target range within 24 h and in-hospital death of critically ill patients and the role of ventricular arrhythmias: a MIMIC-IV analysis with external validation in the eICU-CRD database.

backgroundThe stability of blood pressure control is crucial in critically ill patients. Systolic blood pressure (SBP) time in target range (TTR) has been recognized as an emerging dynamic assessment indicator of blood pressure, but its prognostic value in critically ill patients remains unclear.

methodsThis retrospective cohort study utilized data from the MIMIC-IV database, including adult patients with their first intensive care unit (ICU) admission. SBP TTR within 110-140 mmHg during the first 24 h was calculated. The primary outcome was in-hospital all-cause mortality, and the secondary outcome was ventricular arrhythmias (VA, including FPVCs, VT, and VF). Logistic regression, restricted cubic splines, subgroup analyses, receiver operating characteristic (ROC) curve analyses, and Karlson-Holm-Breen mediation analysis were performed. Furthermore, the findings were externally validated using the multicenter eICU-CRD database.

resultsA total of 42,648 patients were included in the primary analysis. Higher SBP TTR was significantly associated with lower in-hospital all-cause mortality (adjusted OR 0.94 per 10% increase, 95% CI 0.93-0.95) and reduced risk of VA (adjusted OR 0.97 per 10% increase, 95% CI 0.95-0.98). When compared with the lowest quartile, patients in the highest SBP TTR quartile demonstrated the lowest risk of in-hospital all-cause mortality (OR 0.66) and VA (OR 0.78). Mediation analysis suggested that VA mediated a small proportion (1.96%) of the effect of SBP TTR on in-hospital all-cause mortality. Furthermore, SBP TTR provided prognostic information independent of SBP coefficient of variation, and combining both metrics improved predictive accuracy (AUC = 0.62). Finally, the association between SBP TTR and the primary outcome (in-hospital all-cause mortality) was successfully validated in the multicenter eICU-CRD cohort (n = 55,155).

conclusionsHigher SBP TTR (110-140 mmHg) during the first 24 h of ICU admission was independently and inversely associated with in-hospital mortality and ventricular arrhythmias. This metric provides information complementary to blood pressure variability. The association with in-hospital mortality was consistently validated in the multicenter eICU-CRD database, suggesting SBP TTR may serve as a useful biomarker for risk stratification in ICU patients.