Impact of diastolic blood pressure time under range on mortality and acute kidney injury in septic patients: a retrospective cohort study.

BACKGROUND: Current guidelines for sepsis management focus on maintaining mean arterial pressure, while the impact of low diastolic blood pressure (DBP) exposure remains unclear. This study investigated whether the time under range of DBP (DBP-TUR) is associated with clinical outcomes in septic patients who achieved conventional blood pressure targets. METHODS: In this retrospective cohort study using the MIMIC-IV database, we included 12,114 adult patients with sepsis. DBP-TUR was defined as the proportion of time with DBP < 50 mmHg while maintaining systolic blood pressure > 90 mmHg or mean arterial pressure > 65 mmHg during the first 48 h after ICU admission. Primary outcome was 28-day mortality, and secondary outcome was acute kidney injury (AKI). RESULTS: Among the cohort, 6,192 patients (51.1%) experienced low DBP exposure. Patients were stratified into quartiles based on DBP-TUR (Q1: ≤5%, Q2: 5-15%, Q3: 15-50%, Q4: >50%). After adjusting for confounders, compared with Q1, both Q3 (OR:1.25, 95% CI:1.02-1.54) and Q4 (OR:1.27, 95% CI:1.02-1.57) showed significantly higher 28-day mortality. Similarly, AKI risk increased in Q3 (OR:1.47, 95% CI:1.14-1.91) and Q4 (OR:1.60, 95% CI:1.20-2.14). DBP-TUR demonstrated moderate predictive value for both mortality (AUC:0.73) and AKI (AUC:0.71). CONCLUSION: Low DBP exposure, despite achieving conventional blood pressure targets, was independently associated with increased mortality and AKI risk in septic patients. Monitoring DBP-TUR might provide additional value in hemodynamic management of sepsis.