Effect of early vasopressin combined with norepinephrine on short-term mortality in septic shock: A retrospective study based on the MIMIC-IV database

Background: Septic shock is a leading cause of death in intensive care units (ICUs), with short-term mortality rates of 35-40%. Vasopressin (AVP) is a second-line vasoactive agent for septic shock, and recent studies suggest that early AVP use can be beneficial. However, differences between early initiation of AVP combined with norepinephrine (NE) and nonearly AVP with NE are unclear. A retrospective cohort research was designed to explore the effects of early AVP initiation versus nonearly AVP initiation. Methods: This retrospective single-center cohort study included adult patients with septic shock from the MIMIC (Medical Information Mart for Intensive Care)-IV database. According to whether AVP was used early in the ICU (intensive care unit), patients were assigned to the early- (within 6 h of septic shock onset) and non-early-AVP (at least 6 h after septic shock onset) groups. The primary outcome was 28-day mortality. The secondary outcomes were ICU and hospital mortality, the numbers of vasopressor-free and ventilation-free days at 28 days, ICU length of stay (LOS), hospital LOS, sequential organ failure assessment (SOFA) score on days 2 and 3, and renal replacement therapy (RRT) use on days 2 and 3. Univariate and multivariate cox proportional-hazards regression, propensity-score matching were used to analyze the differences between the groups. Results: The study included 531 patients with septic shock: 331 (62.5%) in the early-AVP group and 200 (37.5%) in the non-early-AVP group. For 1:1 matching, 158 patients in the early-AVP group were matched with the same number of patients with nonearly AVP. Regarding the primary outcome, there was no significant difference between the early- and non-early-AVP groups in 28-day mortality (hazard ratio [HR] = 0.91, 95% confidence interval [CI] = 0.68-1.24). For the secondary outcomes, there were no differences between the early- and non-early-AVP groups in ICU mortality (HR = 0.95, 95% CI = 0.67-1.35), hospital mortality (HR = 0.95, 95% CI = 0.69-1.31), the numbers of vasopressor-free and ventilation-free days at 28 days, ICU LOS, hospital LOS, SOFA score on days 2 and 3, and RRT use on days 2 and 3. Conclusions: There was no difference in short-term mortality between early AVP combined with NE and nonearly AVP with NE in septic shock.