A systematic review including 20 studies with a total of 9,702 subjects was abstracted in DARE. The included studies used a variety of reference standards which the review categorised into the following groups: left ventricular ejection fraction (LVEF) less than 30%; LVEF less than 40%; LVEF less than 45 to 55%; clinical diagnosis; diastolic failure; systolic or diastolic failure. LVEF less than 40% (8 studies): the pooled diagnostic odds ratio (DOR) was 11.6 (95% CI: 8.4 to 16.1). Pooling only those studies that used a cut-off for BNP of between 14 and 19 pmol/L (5 studies) gave an estimated positive LR of 4.1 (95% CI: 2.6 to 6.6) and a negative LR of 0.35 (95% CI: 0.17 to 0.72). LVEF 45 to 55% (7 studies): the pooled DOR was 5.6 (95% CI: 3.7 to 8.5) but there was statistically significant heterogeneity (P<0.01). Clinical criteria (7 studies): the pooled DOR was 30.9 (95% CI: 27.0 to 35.4). The largest study in this group had a cut-off for BNP of 14.4 pmol/L with a positive LR of 2.6 (95% CI: 2.3 to 2.8) and a negative LR of 0.05 (95% CI: 0.03 to 0.07). Diastolic failure (3 studies): the pooled DOR 28.3 (95% CI: 2.66 to 300.5), but there was significant heterogeneity (P<0.001). Systolic or diastolic failure (2 studies): the pooled DOR was 37.7 (95% CI: 5.9 to 237.2) but there was significant heterogeneity (P=0.02). There was no significant difference between the pooled DORs of studies carried out in general practice or community settings and those performed in hospital. The 3 studies comparing the diagnostic accuracy of BNP with N-terminal ANP found BNP to be marginally more accurate as a diagnostic marker of heart failure (P=0.048).
Comment: The quality of evidence is downgraded by inconsistency (variability in results across studies and heterogeneity in the reported outcomes).
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