Procalcitonin Kinetics and Nosocomial Pneumonia in Older Patients

BACKGROUND: Early identification of treatment failure for nosocomial pneumonia remains a major challenge. The goal of this study was to test whether procalcitonin kinetics can be used to assess the clinical efficacy in older critically ill patients with nosocomial pneumonia. METHODS: A prospective observational study was conducted with 60 subjects (≥ 65 y old) admitted to the ICU with severe nosocomial pneumonia. Serum procalcitonin was measured on days 0, 3, and 7 and at the end of treatment. The procalcitonin time course was analyzed according to the therapeutic efficacy. RESULTS: Procalcitonin levels were elevated in all subjects ( n = 60) on day 0, and the median level (range) was 2.5 (0.85–42.7) μg/L. There were no differences in procalcitonin between the improved subjects ( n = 41) and those without improvement ( n = 19) on day 0 ( P > .05). However, lower procalcitonin levels on days 3 and 7 and at the end of treatment (all P .05). Indeed, the combination of ΔPCTd3% > 26.2% and a modified Clinical Pulmonary Infection Score of < 6 points improved the predictive value (area under the curve of 0.89, sensitivity of 81.3%, specificity of 86.5%). CONCLUSIONS: Procalcitonin levels were not influenced by aging, and procalcitonin kinetics might help to identify treatment failure. ΔPCTd3% in combination with the Clinical Pulmonary Infection Score has been shown to be a marker of clinical efficacy at an earlier stage.