C54-11 Evaluating Readmission Lactate as a Surrogate Endpoint for Sepsis Outcomes

Abstract Rationale Sepsis is a dysregulated host response to infection often leading to death. Approximately 20-25% of sepsis survivors are readmitted to the hospital within 30 days. Serum lactate can help prognosticate and guide therapy. However, the value of serum lactate after the index admission has not been explored, particularly for outcomes of patients with sepsis who were readmitted within 30 days. We hypothesize that elevated lactate on readmission, high clearance of lactate from index hospitalization, and a large difference between the lowest lactate from the index hospitalization and the lactate on readmission are associated with high odds of 30-day mortality after readmission. Methods We performed a retrospective cohort study of patients presenting with severe sepsis or septic shock at UCSD between 1/20-7/24, including those readmitted within 30 days of hospital discharge and had lactate levels measured on both admissions. Data analysis was performed using R, version 4 (SPSS, Armonk, NY). The primary outcomes included 30-day mortality, admission to ICU, SOFA score on readmission, and use of pressors. Multivariate logistic regression models were used to identify independent predictors of outcome amongst the various measures of lactate dynamics, adjusted for age, gender, SOFA score on index hospitalization, and comorbidities via the Charlson Comorbidity Index. In all analyses, a p of 0.05 was considered statistically significant. Results We identified 192 patients with severe sepsis or septic shock who had a corresponding unplanned 30-day readmission of which 100 had a measured serum lactate at both admissions. The average age was 61.5yrs, with 61 males and 39 females. The average Charlson comorbidity score was 8.52, with average mortality of 18%. Readmission lactate was significantly associated with higher odds of greater SOFA score on readmission (OR: 1.38, 95% CI: 1.10-1.72, p = 0.00606) and 30-day mortality (OR: 1.87, 95% CI: 1.27- 2.74, p = 0.00146). The magnitude of change between the lowest lactate from the index hospitalization and the lactate on readmission was significantly associated with higher odds of 30-day mortality (OR: 1.91, 95% 1.31-3.05, p = 0.00221). Conclusions Lactate on readmission and the change in lactates between hospitalizations were associated with increased odds of 30-day mortality, while lactate clearance was not. These findings show potential value in tracking lactate dynamics for post-discharge monitoring and predicting readmission for sepsis patients. Further prospective studies are needed to validate these findings. This abstract is funded by: UCSD Summer Research Grant