Biochemical markers of cardiac dysfunction predict mortality in acute exacerbations of COPD.

BACKGROUND: Retrospective studies suggest that plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin T are often elevated in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) and are associated with increased mortality. These cardiac biomarkers were investigated in an unselected cohort of patients admitted to hospital with exacerbations of COPD. METHODS: Consecutive patients with physician-diagnosed COPD exacerbation but without clinical evidence of acute cardiac disease admitted to a public hospital over a 1 year period were studied prospectively. NT-proBNP and troponin T were measured on admission. The primary end point was all-cause mortality at 30 days. RESULTS: Elevated NT-proBNP (>220 pmol/l) was present in 65/244 patients (27.5%) and significantly predicted 30-day mortality (OR 9.0, 95% CI 3.1 to 26.2, p<0.001). Elevated troponin T (>0.03 µg/l) was found in 40/241 patients (16.6%) and also predicted 30-day mortality (OR 6.3, 95% CI 2.4 to 16.5, p<0.001). These associations persisted after adjusting for other clinical and laboratory predictors of mortality (arterial CO(2) pressure (Paco(2)), body mass index and CURB65 score). NT-proBNP and troponin T levels appeared to have additive associations with mortality: 30-day mortality among patients with abnormalities of both NT-proBNP and troponin T was 15-fold higher than among patients with normal values. CONCLUSION: Elevated levels of NT-proBNP and troponin T are strong predictors of early mortality among patients admitted to hospital with acute exacerbations of COPD independently of other known prognostic indicators. The pathophysiological basis for this is unknown, but indicates that cardiac involvement in exacerbations of COPD may be an important determinant of prognosis.

Predicting early mortality in acute exacerbation of chronic obstructive pulmonary disease using the CURB65 score.

BACKGROUND AND OBJECTIVE: Hospitalization for exacerbation of COPD is associated with a high risk of mortality. A risk-prediction model using information easily obtained on admission could help to identify high-risk individuals. The CURB65 score was developed to predict mortality risk in community acquired pneumonia. A retrospective study found that this score was also associated with mortality in COPD exacerbations. We conducted a prospective study to assess the utility of the CURB65 score in acute COPD exacerbations. METHODS: Consecutive patients with physician diagnosed COPD exacerbations admitted to a public hospital during a 1-year period were studied prospectively. The CURB65 scores were calculated from information obtained at initial hospital presentation. CURB65 = one point each for Confusion, Urea > 7 mmol/L, Respiratory rate ≥ 30/min, low Blood pressure, age ≥ 65 years. RESULTS: 30-day mortality data were available for 249 of 252 patients. CURB65 scores on admission significantly predicted risk of death during the hospital admission and at 30 days. The 30-day mortality by score groups were: low risk (scores 0-1) 2.0% (2/98), moderate risk (score 2) 6.7% (6/90) and high risk (scores 3-5) 21.3% (13/61). CURB65 scores were not predictive of 1-year mortality. CONCLUSIONS: A simple 6-point score based on confusion, blood urea, respiratory rate, blood pressure and age can be used to stratify patients with COPD exacerbation into different management groups. The CURB65 score was as effective in predicting early mortality in our cohort of acute COPD exacerbations as it was in previous cohorts with community acquired pneumonia. Our findings suggest that CURB65 scores can help clinicians to assess patients with exacerbation of COPD.