Prognostic Utility of Procalcitonin and Lactate Clearance for In-Hospital Mortality in Sepsis

Razan Diab¹Ralphe Bou Chebl¹Nour Barmo¹Reem Siblini¹Maha Makki¹Hani Tamim^1,2Gilbert Abou Dagher^1*

• ¹Faculty of Medicine, American University of Beirut, Beirut, Lebanon
• ²Alfaisal University College of Medicine, Riyadh, Saudi Arabia

Sepsis remains a significant global health burden and a leading cause of in-hospital mortality. Recent research has focused on the prognostic value of biomarker kinetics,particularly clearance rates and inflammatory markers such NLR.This study aimed to compare the utility of procalcitonin and lactate clearance in predicting in-hospital mortality among septic patients and to identify an optimal PCTc-cutoff to differentiate survivors from non-survivors.This was a retrospective cohort study of adult patients who presented with sepsis or septic shock to a tertiary care ED in Lebanon between November2018 and March2024.Procalcitonin and lactate readings were recorded along with demographics,comorbidities and therapeutic interventions. PCTc andlactate-clearance were calculated as percentage-change between the first andsecond readings, and lactate-clearance was considered positive if>10%.The primary outcome was in-hospital mortality;secondary outcomes included ED,ICU and HLOS.ROC curve was used to assess prognostic accuracy of biomarkers and derive an optimal PCTc cutoff.Multivariable-logistic regression was conducted to evaluate the association of in-hospital mortality with lactate-clearance and PCTc.574 patients with sepsis and septic shock were included.Mean age was 71.4±16.5years with male predominance(55.4%).Optimal cutoff for PCTc was found to be23.1%(94.0%sensitivity,7.0%specificity).Patients were then stratified based on lactate-clearance and PCTc above and below the cutoffs to compare baseline parameters,interventions and outcomes.Patients with lactate-clearance>10 had significantly lower rates of CKD(p=0.006), CHF(p=0.02),and COPD(p=0.04).Only CRP showed a statistically significant difference with respect to PCTc. Therapeutic interventions were similar in both PCTc groups and lactate-clearance groups except for 24-hour IV fluid administration(p=0.04).Mortality was significantly associated with lactate-clearance>10(p=0.045) but not with PCTc(p=0.65).The area under the ROC curve was 0.40(95%CI:0.34–0.45,p=0.56) for lactate-clearance, 0.39(95%CI:0.33–0.45,p=0.56) for PCTc and 0.51(95%CI:0.46–0.56,p=0.67) for NLR, with a significant difference among the AUCs(p<0.001).Multivariate-analysis showed a borderline significant association of in-hospital mortality with lactate-clearance(OR=0.66,95% CI 0.42–1.04,p=0.07) but not with PCTc(OR=1.13,95% CI 0.43–2.95,p=0.81).Vasopressor use was associated with reduced odds-of-death, while steroid use was independently associated with increased mortality.Lactate-clearance with 10% cutoff is a better predictor of in-hospital mortality in patients presenting to the ED with sepsis or septic shock compared to PCTc.An optimal PCTc-cutoff of23.1% was identified;however, it didn't reach statistical significance for survival.Future prospective studies are needed to better define optimal biomarker cutoffs and compare their predictive accuracy for in-hospital mortality.