Reduced Prognostic Role of Serum PCT Measurement in Very Frail Older Adults Admitted to the Emergency Department

background: this study aims to evaluate the prognostic role of serum PCT in older patients with suspect sepsis or infective diagnosis in the emergency department (ED) with a particular focus on the clinical consequences and characteristics due to frailty status. methods: this is a observational retrospective study conducted in the ED of a teaching hospital. we identified all consecutive patients aged & GE; 80 years admitted to the ED and subsequently hospitalized for clinical suspicion of infection. Inclusion criteria were: age & GE; 80 years and clinical suspicion of infection; availability of a PCT determination obtained < 24 h since ED access; and clinical frailty scale (CFS) determination. study endpoints were the diagnostic accuracy of PCT for all-cause in-hospital death, infective diagnosis at discharge, and bloodstream infection. diagnostic accuracy was calculated via ROC analysis and compared in the patients with severe frailty, measured by CFS > 6, and patients with low or moderate frailty (CFS 1-6). a multivariate analysis was performed to calculate the adjusted odds of raised PCT values for the study endpoints. results: In total, 1459 adults & GE; 80 years with a clinical suspicion of infection were included in the study cohort. the median age of the sample was 85 years (82-89), with 718 (49.2%) males. the multivariate models revealed that, after adjusting for significant covariates, the PCT values at ED admission were significantly associated with higher odds of infective diagnosis only in the fit/moderately frail group (odds ratio [95% CI] 1.04 [1.01-1.08], p 0.009) and not in very frail patients (odds ratio [95% CI] 1.02 [0.99-1.06], p 0.130). similarly, PCT values were significantly associated with higher odds of in-hospital death in the fit/moderately frail group (odds ratio [95% CI] 1.01 [1.00-1.02], p 0.047), but not in the very frail ones (odds ratio [95% CI] 1.00 [0.98-1.02], p 0.948). conversely, the PCT values were confirmed to be a good independent predictor of bloodstream infection in both the fit/moderately frail group (odds ratio [95% CI] 1.06 [1.04-1.08], p < 0.001) and the very frail group (odds ratio [95% CI] 1.05 [1.03-1.07], p < 0.001). conclusions: The PCT values at ED admission do not predict infective diagnosis, nor are associated with higher odds of in-hospital death. still, in frail older adults, the PCT values in ED could be a useful predictor of bloodstream infection.