Article Text

B type natriuretic peptide testing was more cost effective than conventional diagnosis in patients with acute dyspnoea
1. Kanaka Shetty, MD,
2. Alan Garber, MD
1. Veterans Affairs Palo Alto and Center for Health Policy/Primary Care, Outcomes Research, Stanford University, Stanford, California, USA

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Q In patients who presented to the emergency department (ED) with acute dyspnoea, is a diagnostic strategy based on rapid measurement of B type natriuretic peptide (BNP) concentrations more cost effective than conventional diagnosis?

Clinical impact ratings Respirology ★★★★★★☆ Internal medicine ★★★★★★☆ Emergency medicine ★★★★★☆☆ Cardiology ★★★★★☆☆

## METHODS

### Design:

cost effectiveness analysis of a randomised {allocation concealed*}†, blinded (outcome assessors*), controlled trial (B Type Natriuretic Peptide for Acute Shortness of Breath Evaluation [BASEL] study) with follow up of 180 days.

### Setting:

ED in a university hospital in Basel, Switzerland.

### Patients:

452 patients (mean age 71 y, 58% men) who presented to the ED with acute dyspnoea. Exclusion criteria included trauma, severe renal disease, and cardiogenic shock.

### Intervention:

diagnostic strategy with rapid measurement of BNP concentrations (n = 225) or conventional diagnostic strategy (n = 227).

### Outcomes:

included all cause mortality, use of intensive care, days in hospital, and total cost of treatment.

*See glossary.

†Information provided by author.

## MAIN RESULTS

At initial presentation, fewer patients in the BNP group than in the conventional group were admitted to hospital (75% v 85%, p = 0.008) and required intensive care (15% v 24%, p = 0.01). The BNP group incurred $1854 less initial total treatment cost than the conventional group (mean$5410 v $7264, p = 0.006). At 180 days, the BNP group had fewer days in the hospital (median 10 v 14 d, p = 0.005) and incurred$2573 less total treatment cost (mean $7930 v$10 503, p = 0.004) than the conventional group. Groups did not differ for all cause mortality at initial hospital visit and at 180 days. Incremental cost effectiveness analysis at 180 days showed that diagnosis based on BNP concentrations led to lower mortality and lower cost in 81%, higher mortality and lower cost in 19%, and higher or lower mortality and higher cost in <0.1% of bootstrap replications.

## CONCLUSION

In patients who presented to the emergency department with acute dyspnoea, a diagnostic strategy based on rapid measurement of B type natriuretic peptide concentrations was more cost effective than conventional diagnosis.

# Commentary

Diagnosing acute heart failure in EDs has often been difficult, but recent reports suggest that BNP testing could improve diagnostic accuracy and management.1 The study by Mueller et al showed that a clinical strategy driven by BNP testing led to equivalent short term mortality and lower overall costs. A reduced hospital admission rate and fewer admissions to the intensive care unit accounted for most of the cost differences. Because all primary data came from a single study conducted in a single centre, BNP testing may not improve management of dyspnoea in other settings. In particular, unblinded BNP test results may have influenced treatment decisions and led to inaccurate inferences. Despite random allocation, the BNP group might have been healthier than the control group because of the relatively small number of patients in the study. However, the authors used a bootstrap analysis to estimate the uncertainty in their results. BNP testing was nearly always cost saving and was the dominant strategy in most analyses (ie, it delivered equal or better clinical outcomes at reduced cost). In addition to any reduction in hospital admissions, BNP testing may have created cost savings by reducing use of more expensive diagnostic tests.

Generalisability might be limited because other centres might not modify patient management as effectively. Cost effective use of BNP testing requires that providers correctly interpret and appropriately act on test results, which may be less common in non-study settings. Further studies are needed in more diverse settings to obtain more definite information on both costs and clinical effectiveness. Larger studies might be able to more confidently exclude the possibility that BNP testing leads to lower costs but higher mortality. None the less, the results indicate that broader use of appropriate BNP testing could improve clinical care while reducing costs from unnecessary tests and hospital admissions.

## References

View Abstract

## Footnotes

• For correspondence: Dr C Mueller, University of Basel, Basel, Switzerland. chmueller{at}uhbs.ch

• Sources of funding: Swiss National Science Foundation; Swiss Heart Foundation; Novartis Foundation; Krokus Foundation; University of Basel.

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