Prognostic value of procalcitonin in hospitalized patients with lower respiratory tract infections

Lower respiratory tract infections are common and potentially lethal conditions and are a major cause of inadequate antibiotic prescriptions. Characterization of disease severity and prognostic prediction in affected patients can aid disease management and can increase accuracy in determining the need for and place of hospitalization. The inclusion of biomarkers, particularly procalcitonin, in the decision taken process is a promising strategy. This study aims to present a narrative review of the potential applications and limitations of procalcitonin as a prognostic marker in hospitalized patients with lower respiratory tract infections. The studies on this topic are heterogeneous with respect to procalcitonin measurement techniques, cutoff values, clinical settings, and disease severity. The results show that procalcitonin delivers moderate performance for prognostic prediction in patients with lower respiratory tract infections; its predictive performance was not higher than that of classical methods, and knowledge of procalcitonin levels is most useful when interpreted together with other clinical and laboratory results. Overall, repeated measurement of the procalcitonin levels during the first days of treatment provides more prognostic information than a single measurement; however, information on the cost-effectiveness of this procedure in intensive care patients is lacking. The results of studies that evaluated the prognostic value of initial procalcitonin levels in patients with community-acquired pneumonia are more consistent and have greater potential for practical application; in this case, low procalcitonin levels identify those patients with a low risk of adverse outcomes.