Our finding was that pleural NAMPT levels were markedly higher in empyemas than in CPPEs and UCPPEs, and higher in CPPEs than in UCPPEs, along with a positive correlation between pleural fluid NAMPT levels and neutrophil percentage and LDH levels, and an inverse correlation with glucose levels, indicating that NAMPT might be implicated in the escalation of parapneumonic effusions. Here, NAMPT is linked to empyema.