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Recent rapid responses
Rapid responses are electronic letters to the editor. They enable our users to debate issues raised in articles published on bmj.com. Although a selection of rapid responses will be included as edited readers' letters in the weekly print issue of the BMJ, their first appearance online means that they are published articles. If you need the url (web address) of an individual response, perhaps for citation purposes, simply click on the response headline and copy the url from the browser window.
Displaying 1-3 out of 3 published
6 August 2012
I cannot agree with Dr Spence’ evaluation on pharmacoeconomic studies because he misunderstands some important pharmacoeconomic methodologies.1 First, the National Institute for Health and Clinical Excellence (NICE) guidance appraised the cost-effectiveness analysis (CEA)2 rather than cost-benefit analysis (CBA).1 Though the CBA is well known since the 1970’s, the beginning of economic evaluation of public health programmes, they are different types of pharmacoeconomic studies. Second, pharmacoeconomics, including CBA, CEA and cost-utility analysis (measured by quality-adjusted life year, QALY, usually regarded as a subtype of CEA), is not a pseudoscience. Fraught with assumptions in pharmacoeconomic study is resulting from the uncertainties everywhere in the real-world clinical practice for various study subpopulations and their diversified responses to treatment alternatives (no treatment also an alternative).
The analysis in his first paragraph is a market forecasting with biases. The “astounding” monetary value, £4bn in the UK for 10 years, is showy and actually a pseudoscience. Why? As he states in the subsequent text, “In the real world warfarin clinics will still run,” no one drug will take 100% of the market share on which his extrapolation was based. Warfarin’s average monthly cost of £1 is not realistic either without taking blood monitoring cost into account. It is also inappropriate to compare a monthly cost per person to a 10-year cost of all patients, which would be definitely avoided in a good pharmacoeconomic report. And in fact the £4bn estimation for 10 years is incorrect without discounting for inflation. Please think about the following statement, “When the NHS was launched in 1948 it had a budget of £437 million (roughly £9 billion at today’s value).”3 His analysis lacks a thorough consideration of uncertainty and needs sensitivity analysis. Moreover, this budget impact would be primarily the NHS’ concerns. While the NICE works closely with the NHS, I believe a budget impact analysis has been conducted and the threshold has been accepted.
Admittedly, pharmacoeconomics still has limitations and thus is controversial, just as Dr Spence is concerned about.1 The problem is that we should evaluate a pharmacoeconomic study correctly and comprehensively while critically. After all, minimising bias is the groundwork of any quality research.
1. Spence D. Beware the cost-benefit analysis. BMJ 2012;345:e5040.
2. NICE. Rivaroxaban for the prevention of stroke and systemic embolism in people with atrial fibrillation. 2012. www.nice.org.uk/nicemedia/live/13746/59295/59295.pdf.
3. NHS. About the NHS. 2011. http://www.nhs.uk/NHSEngland/thenhs/about/Pages/overview.aspx.
Competing interests: None declared
University of Cincinnati College of Pharmacy, Cincinnati, OH 45267-0004, USA
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31 July 2012
It would be interesting to know what Dr Spence would wish to use by way of anticoagulation if he himself, or one of his parents, as he is clearly under 65 years of age, were to develop non-valvular atrial fibrillation. I have often been asked this type of question by patients, and indeed recently did this myself.
Whilst his analysis is probably correct in economic terms, the individual patient has other concerns. From my perspective, for instance, as a recent victim of paroxysmal atrial fibrillation, the possibility of additional reduction of the risk of stroke and the convenience of not requiring monitoring are distinctly advantageous. I am certainly attracted to dagibatran, as, according to a totally unscientific straw poll of former colleagues, would be a number of other physicians in my situation.
Competing interests: Having recently developed paroxysmal atrial fibrillation and been advised to commence anticoagulation, I have a personal interest in this area.
none, Court Farm, Bishampton, Pershore WR10 2LX
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In evaluating the new oral anticoagulants for atrial fibrillation, another factor that strongly influences the incremental benefit perceived for these new treatments is the use of relative risk as opposed to number need to treat (NNT). It is well known that relative risks tend to exaggerate the perception of benefits, while NNTs convey a more conservative message.
In the case of new agents for atrial fibrillation, the recent paper by Miller et al. (1) is the example of an analysis entirely based on relative risks that ultimately supports the concept of a relevant incremental benefit. If the same data are analysed using the NNT (2), the magnitude of the incremental benefit instead seems small, and the values of NNT not only are in the hundreds, as pointed out by Spence (3), but in some cases are in the thousands.
1. Miller CS, Grandi SM, Shimony A, Filion KB, Eisenberg MJ. Meta-analysis of efficacy and safety of new oral anticoagulants (dabigatran, rivaroxaban, apixaban) versus warfarin in patients with atrial fibrillation. Am J Cardiol. 2012 Aug 1;110(3):453-60. Epub 2012 Apr 24.
2. Messori A, Fadda V, Maratea D, Trippoli S. Simplified figure to present the results of indirect comparisons: re-visitation based on the number needed to treat (Rapid Response). eBMJ (published on 31 August 2011 and republished for technical reasons on 2 July 2012), available at http://www.bmj.com/content/343/bmj.d4909/rr/592254
3. Spence D. Beware the cost-benefit analysis. BMJ 2012;345:e5040
Competing interests: None declared
HTA Unit, Area Vasta Centro Toscana, viale Michelangelo, 50100 Firenze (ITALY)
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