Correction and transparency of BNF risk chartsBMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b2330 (Published 09 June 2009) Cite this as: BMJ 2009;338:b2330
- Rupert A Payne, lecturer in clinical pharmacology1,
- David J Webb, professor of clinical pharmacology and therapeutics1,
- Simon R J Maxwell, senior lecturer in clinical pharmacology and therapeutics2
- 1Clinical Pharmacology Unit, Centre for Cardiovascular Science, University of Edinburgh, Queen’s Medical Research Institute, Edinburgh EH16 4TJ
- 2Clinical Pharmacology Unit, University of Edinburgh, Clinical Research Centre, Western General Hospital, Edinburgh EH4 2XU
The Joint British Societies’ (JBS) charts use a “traffic lights” system to emphasise different categories of cardiovascular risk.1 They were published in 2005 in conjunction with the societies’ guidelines2 and are reproduced biannually in the BNF.
We recently observed that the green (<10% risk) area was missing from the charts for non-diabetic male non-smokers aged 50-59, and to a minor degree in the charts for similarly aged non-diabetic male smokers, and older non-diabetic male non-smokers. The charts were inaccurately reproduced in this form for over three years. We estimate that 16% of the 2.5 million non-smoking men aged 50-59 in the UK would be wrongly categorised into the higher (10-20%) risk category.3 Patients may have been caused unnecessary concern, and lifestyle advice may have differed for low and moderate risk patients. Also, lower (10%) drug treatment thresholds are a future possibility, given the increasing evidence for treating lower risk populations.
The BNF published revised charts in March 2009. Although this change was mentioned briefly on the British Hypertension Society website, it should have been publicised more widely, given the charts’ extensive use. That this error persisted for so long probably reflects the lack of transparency surrounding the methods used to calculate risk in the original publication.2 The lack of a widely available risk calculator also hampers cross checking of the calculation. A computer calculator can be individualised for patients while still providing a useful graphical representation of risk.4
The JBS charts remain a valuable tool, but we hope that the publication of the further revisions currently being proposed by the BHS will be more open.
Cite this as: BMJ 2009;338:b2330
Competing interests: RAP is author of a website which produces patient specific risk calculations including charts similar to those of the Joint British Societies.
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