37: Acute Heart Failure Patients Needing Antibiotic Therapy Can Be Identified by Procalcitonin Measurements: Observational Results From the BACH Multinational Trial

Procalcitonin (PCT) measurements have been used to diagnose bacterial infection and sepsis. Additionally PCT has been suggested as a surrogate marker reflecting the response to a clinically relevant bacterial infection requiring antibiotic treatment. However, PCT has never been used to identify possible bacterial infection co-morbidity in acute heart failure (AHF) patients. This observational study evaluates the association between PCT levels, patients who receive antibiotic therapy and all cause mortality within 90 days, the primary outcome of the BACH trial. The BACH trial was a prospective, 15-center multinational diagnostic and prognostic study of 1641 patients presenting to the ED with a primary complaint of dyspnea, 568 of which were diagnosed with AHF. Patients were included if they had a final diagnosis of AHF as the cause of their shortness of breath, determined by two cardiologists blinded to biomarker results and after reviewing all available clinical data 30 days after enrollment. Missing covariate data was imputed using the mean. PCT was significantly associated with all cause mortality within 90 days for patients diagnosed with AHF (p=0.0024, Cox regression). The proportion of antibiotic treatment during follow-up was significantly higher in patients with elevated PCT levels (p=0.0008, 2-fold increase). After adjusting for co-variates such as enrolling site, wheezing, history of stroke, creatinine level and neutrophil count to level out group differences, patients with a PCT level above 0.205 ng/ml (5th quintile of PCT in all AHF patients) had a significantly higher mortality if not treated with antibiotics (p=0.046). On the other hand, patients with very low PCT values (below 0.051 ng/ml, 1st quintile) had a significantly better 90-day survival if not treated with antibiotics (p=0.049). In all patients, as well as in patients with PCT levels between 0.051 and 0.205 ng/ml, the antibiotics treatment effect was not significant (p=0.58, p=0.36). These results suggest that in AHF patients, PCT may act as surrogate marker reflecting the response to a clinically relevant bacterial infection and the requirement for antibiotic treatment. Moreover, outcome results for patients with low PCT levels treated with antibiotics suggest that these individuals may be affected by adverse events from this therapy. As antibiotic therapy was not a randomized treatment in the BACH trial, these results need to be confirmed in a prospective randomized controlled trial.