(1484) RAAS Versus Non-RAAS Therapy in Propensity Score-Weighted Septic Shock Patients

Introduction: Patients with septic shock are at high risk of death. Standard of care includes antibiotic therapy, fluid resuscitation, and vasopressor support. Recently, Angiotensin II (Ang II) has joined catecholamines and vasopressin (Conventional Therapy) as a third vasopressor class, but it is unknown whether its use is associated with improved outcomes. We sought to evaluate whether Ang II, when added to Conventional Therapy, was associated with differences in mortality in a large retrospective analysis of septic shock patients.

Methods: We performed a retrospective chart review of 1149 patients who received vasopressors for septic shock, including 297 who received Ang II plus Conventional Therapy and 852 who received only Conventional Therapy. Patient age/gender, sequential organ failure assessment (SOFA) score, serum lactate, and Charlson Comorbidity Index (CCI) were calculated at the time of initiation of Ang II (Ang II cohort) or at the time Ang II would have been initiated (based on a previously published protocol) in the Conventional Therapy cohort. We used propensity score weighting to achieve acuity balance in the covariates and multivariable logistic regression to compare the two cohorts with regard to 30-day mortality.

Results: Overall 30-day mortality was 56.9%. Groups were well distributed by age (median 64.0) and gender (51.7% male), but statistically differed by SOFA score, serum lactate, and CCI (all p values < 0.001). In multivariable logistic regression analysis after adjusting for all covariates, 30-day mortality was higher in the Ang II group than in the Conventional Therapy group (OR 1.29, 95% CI: 0.95-1.76, p=0.103). After propensity score weighting, age, gender, SOFA, CCI, and serum lactate were all well-balanced between groups, and the Ang II cohort was no longer associated with a mortality increase (OR 1.07, 95% CI: 0.82-1.40, p=0.609).

Conclusions: Ang II administration correlates with severity of illness and higher risk of death in septic shock patients. However, when propensity score weighting for severity of illness and comorbidity, those who received Ang II were no longer at higher risk of death. We conclude that the use of Ang II is not independently associated with worse outcomes when patients are balanced for acuity using propensity score weighting.