Level 2: Mid-level evidence
A numerical scoring system may be useful for diagnosing heart failure in elderly patients with stable chronic obstructive pulmonary disease (COPD) (BMJ. 2005;331:1379; full text available free of charge athttp://bmj.bmjjournals.com/cgi/content/full/331/7529/1379, accessed December 7, 2006). The system was derived from a study of 405 participants at least 65 years of age who had chronic bronchitis or emphysema. However, there was no study of external validation. Based on an expert consensus panel using clinical findings, echocardiography, and ECG, 20.5% of participants had heart failure.
The system assigns points based on history, laboratory, and exam findings. A history of ischemic disease is 2 points, a BMI >30 3 points, a laterally displaced apex beat 3 points, heart rate >90 beats per minute 2 points, an N-terminal pro-brain natriuretic peptide (BNP) >14.75 pmol/L (125 pg/mL) 4 points, and an abnormal ECG 3 points. Scorable ECG findings included abnormal Q waves, left bundle branch block, left ventricular hypertrophy, atrial fibrillation, ST-segment and/or T-wave abnormalities, and sinus tachycardia.
Based on the cumulative number of points, participants were considered to be at very low risk of heart failure if they had 0 points; four of 81 participants (5%) with 0 points had heart failure. A score between 2 and 5 points was considered low risk; of 142 participants who had 2-5 points, 15 (11%) had heart failure.
Medium risk was categorized as a score of 6-9 points; 32 of 126 participants (25%) with 6-9 points had heart failure. A score of 10-14 points was considered high risk; 32 of 56 participants (57%) with scores in this range had heart failure.