Association of Serum Albumin and Copeptin with Early Clinical Deterioration and Instability in Community-Acquired Pneumonia

Background: There is a paucity of data on biomarkers for the early deterioration and clinical instability of patients in community-acquired pneumonia (CAP), as treatment failure occurs in the first seven days in 90% of patients. Aim: To evaluate serum albumin and copeptin with CURB-65, PSI scoring and ATS/IDSA minor criteria for the prediction of early mortality or ICU-admission (7 days) and clinical instability after 72 h. Methods: In 100 consecutive hospitalized adult CAP patients, PSI-scores, CURB-65 scores, ATS/IDSA 2007 minor criteria, copeptin and albumin on admission were evaluated. Univariate and multivariate Cox regression analysis was performed to assess independent risk factors for early combined mortality or ICU admission. Predictive powers of albumin and copeptin were tested with ROC curves and ICU-free survival probability was tested using Kaplan–Meier analysis. Results: Albumin was lower and copeptin higher in patients with short-term adverse outcomes (p < 0.05). Cox regression analysis showed that albumin [HR (95% CI): 0.41 (0.18–0.94, p = 0.034)] and copeptin [HR (95% CI): 1.94 (1.03–3.67, p = 0.042)] were independent risk factors for early combined mortality or ICU admission (7 days). The Kaplan–Meier analysis observed that high copeptin (>27.12 ng/mL) and low albumin levels (<2.85 g/dL) had a lower (p < 0.001) survival probability. The diagnostic accuracy of albumin was better than copeptin. The inclusion of albumin and copeptin into ATS/IDSA minor criteria significantly improved their predictive power. Conclusions: Both biomarkers serum albumin and copeptin can predict early deterioration and clinical instability in hospitalized CAP patients and increase the prognostic power of the traditional clinical scoring systems.