Thanks Ash for this important discussion.I could not agree more. Part of the problem is that ethical dilemmas should not be discussed at the point of sickness but they nearly always are. Should we tax the young (currently spending much on frivolous holidays in places like Ibiza) to pay for hip replacements in the elderly? Put a lager lout next to a sweet old lady who makes scones at the local Women's Institute and there is no contest. Granny wins every time. Give it a Rawlsian perpective however, and the answer is very different. Do you want a life in which there is no fun while you are young but when you are old there is a guaranteed hip replacement? Much of the so-called debate on health care 'rationing' in the press is nothing but cant. Rationing is inevitable and logical and the only question is how do we do it appropriately.
A similar point, by the way, applies to the discussion of the use of clinical trials. Many seem to start from the illogical point of view (in my opinion) that patients are morally entitled to any treatment they wish to take, including experimental ones. An alternative view is that your only right to an experimental (as opposed to an approved) treatment is by entry onto a clinical trial a condition of which may be that you only have a 50% chance of receiving it. Equipoise is then not a point of departure for a clinical trial but an arrival. The trial continues until either the investigator convinces society that the new treatment is indeed better than the existing one or the investigator discovers it is no better and stops. Again a Rawlsian viewpoint applies. You might well prefer a society in which a physician is allowed to back his best hunch when you are desperately ill. But as long as you are healthy you prefer one in which medicines are tested rationally so that you can benefit when you fall ill.
Stephen
Stephen Senn
Professor of Statistics
School of Mathematics and Statistics
Direct line: +44 (0)141 330 5141
Fax: +44 (0)141 330 4814
Private Webpage: http://www.senns.demon.co.uk/home.html
University of Glasgow
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The University of Glasgow, charity number SC004401
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From: Evidence based health (EBH) [[log in to unmask]] On Behalf Of Ash Paul [[log in to unmask]]
Sent: 13 February 2011 18:17
To: [log in to unmask]
Subject: Re: Question about screening and denominators
Thanks Klim and Martin.
What is urgently needed is a fundamental rethink of medical school education in the USA, Canada and the rest of Europe, and throughout the world.
Med school students and clinicians are struggling to grasp the very grave truth that the 21st century is going to be very different from the 20th century. The biblical years of 'plenty' have, indeed, given way to the years of 'lean', which will last throughout an entire generation.
There is a very good recent Perspective about this in the recent edition of the NEJM:
Transforming Graduate Medical Education to Improve Health Care Value
http://healthpolicyandreform.nejm.org/?p=13728&query=home
There was yet another very good NEJM Perspective on this in a February 2010 NEJM:
Cottage Industry to Postindustrial Care — The Revolution in Health Care Delivery
http://www.nejm.org/doi/full/10.1056/NEJMp0911199
Clinicians who have not been properly trained in the fundamental principles of clinical epidemiology and population medicine during their formative medical school years, just don't understand the difference between 'healthcare needs' and 'healthcare wants'. And I'm not blaming them at all, it's our med school education system which has left them so unprepared to deal with the stark future which has already engulfed us, and will smother us in the future, for many years to come.
This has been further compounded by the influence of global management consultancy firms who nowadys are emerging as major healthcare policy consultants to many governments in the Western world, with multimillion pound contracts, and who seem to have no understanding of the fundamental tenets of public health policy.
Overheard recently by a Public Health medical consultant colleague at a meeting with a high powered and highly respected private management consultancy firm, was the following: "The demand for this service has been calculated as X. We shall use this as a proxy for need."
All publicly funded and finitely funded healthcare systems like the NHS will be well on their way to financial bankruptcy if health policy experts in government adopt such a position.
The private management consultancy firm in question needs to go back to basics and consult an English dictionary.
According to the Merriam-Webster Dictionary, a "want" is defined as having a strong desire for something. The word "need" is defined as the means of lack of subsistence. In every arena of life, including healthcare, the two concepts are opposing elements (Merriam-Webster online).
The difference between a need and a want is pretty simple -- until you set yourself loose in a supermarket aisle. Double chocolate chip ice cream? It's a food, so why not mark it as a need? That designer t-shirt that fits you perfectly? Well, you need more shirts, so why shouldn’t it count too?
Count up the damage caused by a few justifications like these, and suddenly you've spent far more than you intended.
In the context of a publicly funded healthcare system, in discussing healthcare "needs" and healthcare "wants", almost the first lesson of economics is that if price is reduced, demand increases. Although all publicly provided healthcare must eventually be paid for through taxation, as it is in the NHS, to the consumer of healthcare, the price of healthcare at the point of consumption is essentially zero. When the price of a good is zero, demand will be unconstrained.
Christie Ashwanden, an award-winning US journalist, and a member of this Group, had written a very thought provoking article in 2010 'Convincing the Public to Accept New Medical Guidelines'
<http://www.miller-mccune.com/health/convincing-the-public-to-accept-new-medical-guidelines-11422/>
The article doesn't speak directly about healthcare "wants" and healthcare "needs", but any intelligent person reading the article will immediately cotton onto exactly what Christie is trying to portray in her article ie the dichotomy between healthcare "wants" and healthcare "needs", and how that dichotomy is leading onto more and more expensive, unwarranted and unjustified healthcare.
I've rambled on enough about my grouses, and I'll call it a day now!
Regards,
Ash
Dr Ash Paul
Medical Director
NHS Bedfordshire
21 Kimbolton Road
Bedford
MK40 2AW
Tel no: 01234897224
Email: [log in to unmask]<mailto:[log in to unmask]>
From: "Dawes, Martin" <[log in to unmask]>
To: [log in to unmask]
Sent: Sunday, 13 February 2011, 16:00
Subject: Re: Question about screening and denominators
here is the document - http://www.cardiovascres.wisc.edu/airp/vaschealth/sampleimages/SHAPEguideline.pdf,
no- the Wilson Criteria are not mentioned
yes Pfizer people are in the paper as editors
but dont worry - our medical students are very bright - this should restore some balance to your Sunday http://www.youtube.com/watch?v=xskFo75Wdhs
Martin
On 13 Feb 2011, at 03:26, Klim McPherson wrote:
Absolutely! And I am not sure there is much room for complacency with the flagship mammography service in the UK. It seems to rest on misleading information in their very attractive official leaflets, cf BMJ 2011;342; d791. We wrote to the National Screening Committee a month ago asking if the quality of their publicity complied with the high standards they espouse and whether the information provided complied with GMC guidelines on informed consent. We still await a response.
Best regards
Klim McPherson
From: Ash Paul <[log in to unmask]<mailto:[log in to unmask]>>
Reply-To: Ash Paul <[log in to unmask]<mailto:[log in to unmask]>>
Date: Sat, 12 Feb 2011 23:14:14 -0800
To: <[log in to unmask]<mailto:[log in to unmask]>>
Subject: Re: Question about screening and denominators
Dear Richard,
What about the claptrap being promoted by the Screening for Heart Attack Prevention and Education (SHAPE) Task Force in the USA?
The SHAPE Guideline calls for noninvasive screening of all asymptomatic men 45–75 years of age and asymptomatic women 55–75 years of age (except those defined as very low risk) to detect and treat those with subclinical atherosclerosis.
And now the Texas Government has fallen for this hook, line and sinker and passed into law a measure to provide reimbursement for MI screening.
Is it any wonder that the US healthcare system costs are spiralling out of control?
Regards,
Ash
Dr Ash Paul
Medical Director
NHS Bedfordshire
21 Kimbolton Road
Bedford
MK40 2AW
Tel no: 01234897224
Email: [log in to unmask]<mailto:[log in to unmask]>
From: Richard Saitz <[log in to unmask]<mailto:[log in to unmask]>>
To: [log in to unmask]<mailto:[log in to unmask]>
Sent: Sat, 12 February, 2011 21:49:15
Subject: Re: Question about screening and denominators
Simon,
One of my favorite examples of this issue was published in the NEJM in 1987, a classic. And still relevant today re HIV screening. I’ll excerpt below and here is the reference:
Screening for HIV: Can We Afford the False Positive Rate?
Klemens B. Meyer, M.D., and Stephen G. Pauker, M.D.
N Engl J Med 1987; 317:238-241July 23, 1987<http://www.nejm.org/toc/nejm/317/4/>
Bottom line re HIV testing example: 100% sensitive test, 99.995% specificity. Positive predictive value (chance the patient has the disease) of test if prevalence is 0.01%=67% (one third with a positive test don’t have the disease).
Best,
Rich Saitz
Richard Saitz MD, MPH, FACP, FASAM
Editor, Evidence-based Medicine (EBM)
Professor of Medicine and Epidemiology
http://ebm.bmj.com/
[log in to unmask]<mailto:[log in to unmask]>
PREVALENCE OF INFECTION
What do we know about the prevalence of HIV infection? Perhaps 50 percent of homosexual men in San Francisco have serologic evidence of the infection. The prevalence of seropositivity among intravenous drug abusers and among patients with hemophilia who received factor VIII concentrate pooled before the advent of heat inactivation is similar.3<http://www.nejm.org/doi/full/10.1056/NEJM198707233170410#ref3> , 8<http://www.nejm.org/doi/full/10.1056/NEJM198707233170410#ref8> At somewhat lower risk are patients who received repeated transfusions of red cells, platelets, and plasma before routine HIV testing of donated blood began in 1985. Antibody testing of one group of patients with leukemia treated between 1978 and 1985 showed that about 5 percent became seropositive. The patients who became seropositive had received an average of 164 units of blood products.26<http://www.nejm.org/doi/full/10.1056/NEJM198707233170410#ref26>
Other segments of the population are at much lower risk. Screening of military recruits has shown 0.16 percent of the men and 0.06 percent of the women to be seropositive.27<http://www.nejm.org/doi/full/10.1056/NEJM198707233170410#ref27> When antibody screening of donated blood began in 1985, 1 unit of blood in 2500 had HIV antibody.28<http://www.nejm.org/doi/full/10.1056/NEJM198707233170410#ref28> At that rate, the chance of infection from 2 units of blood donated before antibody screening began would be about 0.08 percent. Among female blood donors, as noted, the reported prevalence of seropositivity is 0.01 percent. Some of these donors may have had sexual contact with members of known high-risk groups; among women without such contact, the prevalence of infection may be even lower than 0.01 percent.
MEANING OF POSITIVE TESTS
Test sensitivity is not the issue here, and to emphasize our concern with the false positive rate, our analysis makes the best-case assumption that the combination of enzyme immunoassay and Western blot testing for HIV is 100 percent sensitive, identifying all persons who are infected. The meaning of positive tests will depend on the joint false positive rate. Because we lack a gold standard, we do not know what that rate is now. We cannot know what it will be in a large-scale screening program. However, we can be fairly sure that without careful quality control, it will rise.
Bayes' rule allows us to calculate the probability that a person with positive tests is infected.29<http://www.nejm.org/doi/full/10.1056/NEJM198707233170410#ref29>Imagine testing 100,000 people, among whom the prevalence of disease is 0.01 percent. Of the 100,000, 10 are infected; 99,990 are not. A combination of tests that is 100 percent sensitive will correctly identify all 10 who are infected. If the joint false positive rate is 0.005 percent, the tests will yield false positive results in 5 of the 99,990 people who are not infected. Thus, of the 15 positive results, 10 will come from people who are infected and 5 from people who are not infected, and the probability that infection is present in a patient with positive tests will be 67 percent.
From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Simon Hatcher
Sent: Wednesday, February 09, 2011 6:22 PM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Question about screening and denominators
I had this discussion with a friend over a beer last night and we couldn't agree on the answer. Here's the scenario:
The incidence of a disease in a population is 1:1000
There is a test which correctly detects the disease 95%of the time
If I test positive with the test what is my risk of having the disease?
Be interested in any thoughts on the "correct" answer.
Cheers
Simon
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