Abstract 2693: An Inflammatory Paradox in Acute Respiratory Distress Syndrome? Plasma C-reactive Protein Concentrations are Strongly Associated with Survival in ARDS
C-reactive protein (CRP) is a marker of systemic inflammation, and potently predicts adverse outcome in a number of diseases, but little is known about its characteristics in Acute Respiratory Distress Syndrome (ARDS). Experimental data suggest CRP may play a protective role in alveolitis; clinical correlates are lacking. We measured CRP in 177 patients within 48 hours of ARDS onset and tested the association of protein level with 60-day mortality, 28-day daily organ dysfunction scores, and number of ventilator-free days. CRP was significantly lower in non-survivors when compared with survivors (176.5 [IQR 173.0] vs.133.5 [IQR 161.0] mg/L; P = .02). Mortality rate decreased with increasing C-reactive protein decile (P = .02). After adjustment for age, APACHE score, and relevant covariates in a multivariable model, plasma CRP concentrations independently and potently predicted survival in ARDS (Hazard ratio=0.996; P = .009). When stratified into groups by higher or lower CRP level, patients with CRP had significantly higher probability of survival at 60 days (P = .005). Also, patients with higher CRP levels had lower organ dysfunction scores (P = .001) and more ventilator-free days (P = .02). Consistent with experimental data suggesting a possible protective role of CRP in experimental alveolitis, higher plasma levels of CRP within 48 hours of ARDS are associated with improved survival, lower organ failure scores, and fewer days of mechanical ventilation. These data appear to be contrary to the established view of CRP solely as a non-specific marker of systemic inflammation, and raise the potential for a therapeutic role for CRP in ARDS.