Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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Risk scores should not dictate treatment choices
- J. Lennert Veerman (27 June 2008)
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Risk is in the eye of the beholder
- James P McCormack (27 June 2008)
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risk management
- Gerry E Burns (30 June 2008)
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Drop the A from the ABCD2 Stroke Score?
- Owen J. David, Fairmile Road, Christchurch, Dorset, UK, BH23 2JX (3 July 2008)
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A new score for assessing cardiovascular risk
- Alan Wallace (6 July 2008)
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informed consent?
- Patrick J Bower (8 July 2008)
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Right question, wrong answer
- Anthony Rodgers, Rod Jackson, Sue Wells, Anushka Patel (15 July 2008)
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J. Lennert Veerman, Research Fellow University of Queensland, School of Population Health, Herston Rd, Herston QLD 4006, Australia
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Christiaens posits that treatment decisions should not be based directly on cardiovascular risk tables. His arguments are that the decision at what level to treat should be based on consensus and that ageing means that nearly all older people would qualify for treatment, which leads to medicalisation. I share his conclusion but not his argumentation. The fact that cut- off values for risk scores based on concensus are necessary is not an argument against the use of such scores. The argument that older people should be treated less than the risk score indicates amounts to ageism. If a treatment has proven effectiveness, it seems unfair to deny people that benefit just because they are old. The only argument that holds is that few drugs are tested in that age group. However, taking a health economic perspective, I would agree that risk scores do not even give half of the information needed to decide whether to treat or not. Firstly, the costs of treatment should be taken into account. For an expensive treatment the threshold should be high, and it can be lower for a cheap drug. Secondly, I would argue that not only the number of events that are prevented matter, but also the gains in quality and years of life (Essink-Bot, Kruijshaar et al. 2007). The risk score values an event at age 90 equal to one at age 50, but the 50-year old loses many more potential life years. An economist would do a cost-effectiveness analysis to determine who should have what treatment. Professor Christiaens will be glad to learn that this analysis will show that older people need a higher risk score to qualify: with increasing age, the potential health gain diminishes and the cost-effectiveness of treatment becomes less favourable. After NHS has decided what society will pay for, concensus on whether to treat should be between patients and their doctors. Reference: Essink-Bot, M. L., M. E. Kruijshaar, et al. (2007). "Evidence-based guidelines, time-based health outcomes, and the Matthew effect." Eur J Public Health 17(3): 314-7. Competing interests: None declared |
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James P McCormack, Professor Faculty of Pharmaceutical Sciences, University of British Columbia V6T1Z3
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Dr Christiaens is correct in suggesting the key problem with risk tables is how we use them when making individual treatment decisions in practice. I also very much share his concern with guidelines that suggest specific risk percentage thresholds for treatment. (1) Paradoxically, Dr Christiaens appears, near the end of his article, to come up with an almost equally arbitrary recommendation with his example of using a risk of three times the minimal risk for the patient’s age as a treatment threshold. It seems to me, treatment decisions should only be made after a discussion with the patient of his/her specific risks and the potential benefits and harms associated with treatment. For example, if someone was to train two individuals in a similar fashion to skydive, the two individuals would likely have a similar risk of harm should they decide to jump out of an airplane. However, despite virtually identical risks some people choose to skydive while others would never consider such an endeavour. This is because, as individuals, we all have an inherent system of values that affect the decisions we make. With the selection of any arbitrary threshold we lose the concept of individual patient values and the ability for shared-informed decision making. (1) In my opinion, we should use cardiovascular risk tables/calculators to make a reasonable estimate of, say, a patient’s 10-year risk of cardiovascular disease. If desired, one could also show the patient how that risk compares to an “average” patient of a similar age. Then, and most importantly, we need to provide the patient with a reasonable estimate of the potential benefit (and harms) in absolute terms of a specific treatment. This is not difficult and really doesn’t take a lot of time. (2) If, after this discussion, they choose to take a medication we should fully support them and if they do not wish to take the treatment we should also fully support that decision. In my experience almost all patients are capable of making decisions once they are given this type of information. However, a number of patients will still also ask me “well, what would you do”, and then I tell them. Doing this type of shared-informed decision-making is, in my mind, what the “art” of clinical practice is all about. The sooner guidelines give up creating specific treatment breakpoints (i.e; blood pressure or specific percent risk levels) and using terms like “high risk” the better. (1) 1) McCormack JP, Loewen P. Adding “value” to clinical practice guidelines. Can Fam Physician 2007;53:1327-35 2) Therapeutics Initiative Letter #63. Using Framingham for primary prevention cardiovascular risk assessment. http://ti.ubc.ca/en/node/152 Competing interests: None declared |
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Gerry E Burns, GP Duncairn Medical Practice
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Watching the lovely Carol on BBC at Wimbledon in the morning explaining to us there is a 20 % chance of rain reminded me of the recent editorial by Christiaens on cardiovascular risk. What does she mean when she says there is a 20% chance of rain at Wimbledon today. Does she mean there is a 1 in 5 chance it will rain today at Wimbledon or does she mean it will rain for 20% of the day or does she mean something else and how accurate is her informed guestimate. Similarly what does it mean when you tell a patient after consulting one of the risk tables that they have a 20% cardiovascular disease risk in next 10 years. A 20% 10 year CVD risk in a 35 year old would obviously be considered high whilst the same risk in a 75 year old might be considered low as such a degree of risk would be expected in this age group. So to a certain degree the idea of CVD risk or any risk is all relative and arbitrary By arbitrary I mean that nearly all the numbers used in CVD risk are multiples of the number 5 as is the 3 times minimal risk figure used in the editorial, whatever the concept minimal risk means. Also the idea of accurate risk doesn’t actually apply to an individual patient. Take a population with the usual spread of low medium and high risk patients, the next most likely CVD event is likely to occur in the medium risk group than the high risk group as there are more patients in this group but we have no way of predicting who this patient will be. Also in example given with statins of NNT to prevent a CVD event the numbers quoted mirrors other studies where a NNT of 100 is needed in 1 year to prevent one CVD event and a NNT of ~ 300 is needed to prevent one death This means that 99 patients will go on medication for a whole year with no benefit for them whatsoever So in many respects taking preventative medication is more like an insurance scheme rather than treating a disease. As doctors in the front line our daily task with patients is to make a risk assessment and then manage that risk accordingly. Why is this all intellectual discussion important. It is because if we have to explain the concept of risk to patient and the reason why they should consider taking medication to help prevent adverse bad clinical events then we need to know the reasons why ourselves. Competing interests: None declared |
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Owen J. David, Consultant Physician in General, Geriatric & Stroke Medicine The Royal Bournemouth and Christchurch Hospitals NHS Trust, Fairmile Road, Christchurch, Dorset, UK, BH23 2JX
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Christiaens editorial 1 asking the profession to re-think the relationship between age, risk and subsequent treatment is most timely. The National Stroke Strategy 2 is now driving the modernisation of stroke services and advocates the use of age as part of its risk stratification. The ABCD2 score is determined from a points system accruing with age (A), blood pressure (B), clinical features (C), duration of symptoms and diabetes (D). 3 Those with a high score will need to be seen within 24 hours, which is admirable given the marked seven day stroke risk of these patients. While this is a valiant attempt to buffer stroke services from demand, the use of age needs to be questioned. Brey et al. found that removing the age component reduces the number of false positive scores but does not prevent it predicting future stroke risk. 4 As Christiaen warns, including age in risk assessment threatens to under treat younger patients. Stroke medicine is rightly moving forwards, but is it too late for the BCD3 score? Owen David 1 Christiaens T, Cardiovascular risk tables. BMJ 2008;336:1445-6. (28 June.) 2 National Stroke Strategy, Department of Health. 5 December 2007. www.dh.gov.uk/publications 3 Johnston SC, Rothwell PM, Nguyen-Huynh MN et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet. 2007; 369(9558):283-292 4 Bray JE, Coughlan K, Bladin C. Can the ABCD Score be dichotomisedto identify high-risk patients with transient ischaemic attack in the emergency department? Emergency Medicine Journal. 2007; 24(2):92-95. Competing interests: None declared |
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Alan Wallace, GP Grangewood Surgery, Houghton le Spring, Tyne and Wear, DH4 4RB
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As a practicing GP in practice where we have recently introduced cardiovascular screening I found Thierry Christiaen’s comments welcome and pertinent. I am now faced daily with the problem of counselling 70 year old patients with a cholesterol of 3.7 that they need to go on a statin, or 45 year olds with multiple risk factors and a cholesterol of 7.0 that they don’t need a statin as their risk score is less than 20%. On a practical level it is very difficult to explain risk scores to patients and doctors can use methods to push people towards the outcome they want, eg to a patient with a 24% 10 year cardiovascular risk score you might say "take a statin and you will reduce your risk of a stroke, heart attack or angina episode by a third" or alternatively, "we would need to treat 13 people like you with statins for 10 years to prevent one episode of stroke, heart disease or angina". The use of risk scores is also inherently ageist as all patients over 75 would need to be on a statin and this problem has been 'solved' by simply excluding them from cardiovascular risk assessment. What would be far more useful would be to convert the risk score into a score of disease free added years – similar to Quality Added Life Years but simpler. We would therefore be able to say to the forty five year old in the above scenario –"taking a statin for the rest of your life will extend the number of years lived free of heart disease and stroke by (eg) 3 years." To an 85 year old with a high risk score we might tell them that a statin will increase their disease free life by three months. Patients and doctors would therefore have a far better idea of what the intervention is intended to achieve. I have no idea how to do this calculation but I am sure it is relatively simple if you know the patient’s age, sex and risk score and I am sure somebody out there will know how to do it. Competing interests: None declared |
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Patrick J Bower, GP Principal Balham Park Surgery SW17 7AW
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Christiaens is wrong. Treatment should not be offered when there is a threefold increase in relative risk. Patients should choose their own treatment threshold, but need to be sufficiently well informed to make this decision. For this they need to know the probability of benefit, i.e absolute risk reduction, which is often best presented as numbers needed to treat. Sadly, this information is unavailable. The risk caculators merely indicate the absolute risks on no treatment. Given the cardiovascular damage already done prior to treatment, it is intuitively unlikely that reducing cholesterol from 7 to 5 in a 60 year old, will reduce his risk to that of a man whose cholesterol has always been 5. Politicians tell the public that most illness is preventable. This is nonsense, but until we have risk calculators the tell us and our patients what we really need to know, we and they will probably continue vastly to overestimate the benefit of preventative treatment. Bad news maybe for the public health, but good news for drug companies, who, no doubt, will do their best to make sure we remain ill informed. Patrick Bower Competing interests: None declared |
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Anthony Rodgers, Professor of Epidemiology University of Auckland, Rod Jackson, Sue Wells, Anushka Patel
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Dear Sir We entirely agree with Professor Christiaens (28 June) on one point: estimating risk is not the problem, using it to tailor treatment to individuals is the major challenge. Indeed the proliferation of risk charts since the first one1 has potential to cause confusion now that we have a proliferation of data sources, calibrations, outcome clusters and timeframes. We entirely disagree however with Professor Christiaens suggestions on how to use risk. These suggestions seem to be driven by a combination of selective attention to evidence and a pre-conceived notion that in general young people should be treated and old people should not. The totality of the evidence2 3 confirms there is nothing magic about age that makes drugs work differently – proportional reductions are about the same, and so absolute benefits go up exponentially with age. Side effects do also tend to increase with age, but not to an extent that necessarily outweighs benefits. The suggestion that people should be treated if they are at, say, threefold times the minimal risk age and sex-matched counterparts makes no sense clinically or economically – treating the same proportion of people in each age and sex group would be a spectacularly inefficient use of health resources, involving under-treatment of many high risk people and over-treatment of many, many low-risk people. We share Professor Christiaens emphasis on prevention, and wish to avoid over-treatment of healthy (ie. low risk) people. There is no question that prevention should start from a very early age. But, preventive therapy involves much more than medication – there are many evidence-based methods available to, for example, increase smoking cessation and improve nutrition and exercise. Benefits of medications accrue rapidly, but adherence decreases steadily over time – hence, there is a sound clinical rationale to “keep your powder dry”. The majority of premature cardiovascular deaths occur in a relatively small group of high-risk individuals, most of whom are over 50 years of age. Inexpensive, safe and widely available drugs can more than halve cardiovascular risk within just a few years in these people.4 5 Targeting treatment to absolute risk provides the best net benefits for individuals, and the best use of resources for society.6 At present, treatment rates bear little relation to absolute risk levels, and When the infamous bank robber, Willie Sutton, was asked why he robbed banks, he replied ‘because that’s where the money is.’ Perhaps there is a lesson in this for the individualised management of cardiovascular risk. Absolute risk should be the key guide to treatment decisions. Anthony Rodgers, Rod Jackson, Sue Wells
Anushka Patel
1. Jackson R, Barham P, Bills J, Birch T, McLennan L, MacMahon S, et al. Management of raised blood pressure in New Zealand: a discussion document. British Medical Journal 1993;307:107-110. 2. Blood Pressure Lowering Treatment Trialists C. Effects of different regimens to lower blood pressure on major cardiovascular events in older and younger adults: meta-analysis of randomised trials. BMJ 2008;336(7653):1121-1123. 3. Cholesterol Treatment Trialists' (CTT) Collaboration. Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90 056 participants in 14 randomised trials of statins. Lancet 2005;366:1267-78. 4. Wald N, Law M. A strategy to reduce cardiovascular disease by more than 80%. British Medical Journal 2003;326:1419-1424. 5. Yusuf S. Two decades of progress in preventing vascular disease. Lancet 2002;360:2-3. 6. Murray CJL, Lauer JA, Hutubessy RCW, Niessen L, Tomijima N, Rodgers A, et al. Effectiveness and costs of interventions to lower systolic blood pressure and cholesterol: a global and regional analysis on reduction of cardiovascular-disease risk. Lancet 2003;361:717-25. Competing interests: None declared |
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