Role of C-reactive protein and interleukin-6 in predicting the prognosis of ICU-admitted patients with acute exacerbation of COPD

Background and Objective: Chronic obstructive pulmonary disease (COPD) is a leading and increasing cause of worldwide morbidity and mortality. No universal predictor of mortality and outcome was defined especially in intensive care unit (ICU)-admitted patients with acute exacerbation of COPD (AECOPD). The objective was to detect the possible role of C-reactive protein (CRP) and interleukin-6 (IL-6) levels in predicting the prognosis of ICU-admitted patients with AECOPD. Methods: This prospective cohort study enrolled 50 adult patients with AECOPD who were admitted in the ICU. Serum CRP and IL-6 levels were measured on admission. The primary endpoint was any-cause mortality during ICU stay or 28 days after discharge. Lengths of ICU and hospital stay besides complications encountered were recorded. Results: Serum CRP level was significantly elevated in patients with prolonged mechanical ventilation (MV) days, ICU stay and hospital stay (r = 0.406, p = 0.007; r = 0.411, p = 0.006; r = 0.387, p = 0.010, respectively). Similar results were noted for serum IL-6 level (r = 0.554, p=<0.001; r = 0.533, p=<0.001; r = 0.508, p = 0.001, respectively). Combined CRP and IL-6 serum levels predicted 28 day mortality at a cut-off value of 110 mg/dl and 347.8 pg/ml respectively (AUC = 0.851, p = 0.006) with 83.33% sensitivity, 75.68% specificity, 35.71% PPV and 96.55% NPV. This was significantly greater than that for CRP alone (p = 0.040) or IL-6 alone (p = 0.004). Conclusions: Serum levels of CRP and IL-6 (either individually or combined) were useful markers in predicting the mortality, complications and outcome in ICU-admitted patients with AECOPD