Prognostic value of C-reactive protein in parapneumonic effusions
Article first published online: 24 JAN 2012
© 2011 The Authors. Respirology © 2011 Asian Pacific Society of Respirology
Volume 17, Issue 2, pages 308–314, February 2012
How to Cite
SKOURAS, V., BOULTADAKIS, E., NIKOULIS, D., POLYCHRONOPOULOS, V., DANIIL, Z., KALOMENIDIS, I. and GOURGOULIANIS, K. I. (2012), Prognostic value of C-reactive protein in parapneumonic effusions. Respirology, 17: 308–314. doi: 10.1111/j.1440-1843.2011.02078.x
- Issue published online: 24 JAN 2012
- Article first published online: 24 JAN 2012
- Accepted manuscript online: 13 OCT 2011 07:38AM EST
- Received 13 March 2011; invited to revise 19 April 2011, 7 August 2011; revised 26 June 2011, 12 August 2011; accepted 22 August 2011 (Associate Editor: Jose Porcel).
- C-reactive protein;
- complicated parapneumonic effusion;
- pleural infection;
- residual pleural thickening
Background and objective: Parapneumonic effusions (PPE) that require drainage are referred to as complicated parapneumonic effusions (CPPE). Following resolution of these effusions, residual pleural thickening (RPT) may persist. We hypothesize that the concentrations of CRP in pleural fluid (CRPpf) and serum (CRPser) can be used to identify CPPE and to predict RPT.
Methods: All patients with non-purulent PPE, who were admitted to two tertiary hospitals during a 30-month period, were enrolled in the study. Baseline CRPpf and CRPser levels were compared between patients with complicated or uncomplicated PPE, as well as between patients with or without RPT of >10 mm, 6 months after discharge from hospital. Cut-off values for identification of CPPE and prediction of RPT were determined by receiver operating characteristic curve analysis. Logistic regression analysis was performed to assess the association between CRP levels and RPT.
Results: Fifty-four patients were included in the study. Patients with CPPE (n = 23) had significantly higher levels of both CRPpf and CRPser than those with uncomplicated PPE. For identification of CPPE, a CRPpf level >78.5 mg/L and a CRPser level >83 mg/L gave 84% and 47% sensitivity, with 65% and 87% specificity, respectively. Classical criteria (pleural fluid pH <7.20, LDH >1000 IU/L, glucose <600 mg/L) were superior for this purpose. A combination of classical biomarkers with CRP levels using an ‘AND’ or ‘OR’ rule improved the positive and negative predictive values, respectively. CRPser was an independent predictor for development of RPT (adjusted OR 1.18). A CRPser level >150 mg/L had 91% specificity and 61% sensitivity for prediction of RPT.
Conclusions: This study demonstrated the value of CRPser for prediction of RPT in patients with PPE. Moreover, when used in combination with classical biomarkers, CRP levels may be a useful adjunct for decision-making in relation to treatment of patients with non-purulent PPE.