Improving the accuracy of predicting cardiovascular risk
BMJ 2010; 340 doi: https://doi.org/10.1136/bmj.c2334 (Published 13 May 2010) Cite this as: BMJ 2010;340:c2334
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Ever since Cicero wrote his De Divinatione, people in all walks
of life have been trying to predict the future as the future is where
human kind is headed. Bob Dole, in his 1996 campaign speeches did say that
accurately: “This is about the future.” “That’s where this country is
headed.” Modern medical science has been in the forefront of future
predictions, following on the astrologers of yore, about their patients
which, incidentally, can never be done accurately, though.
BMJ published that beautiful paper by Professor Firth in 1991 with
the title: Predicting the unpredictable, but nothing much seems to have
changed in the science of mathematical future predictions unless one knows
all about the initial state of the organism, which is impossible with our
present knowledge in medicine. (1) We still make every effort to try and
show that our new method is much better than the existing ones to “screen”
the populace for future disease predictions.
Of course, the motivation to refine the methods of predictability
comes from the fact that the routine screening of the apparently healthy
population is a much more lucrative business than treating the sick. The
whole world population would be our potential clients. One could only
imagine the financial returns, not to speak of the trillions coming from
drugging the hapless “healthy” people in the fond hope of keeping them
here for ever, based on our predictions in the health scare system that we
have so ingeniously devised in the last half a century inside the once
noble medical profession. (2, 3)
Writing in this week’s Nature about the accuracy of future
predictions using mathematics, scientists, led by Martin A Novak from the
Harvard mathematics department, have a nice quote to show how inaccurate
future predictions would be: "Now may be your last chance to be a 'newly
wed'," they quip in the Nature paper. "The married couples of the future
can only hope for 'wedded' bliss." (4)
“According to quantum mechanics, it is not possible to ever have
accurate enough data. Without even needing to invoke quantum mechanics, it
is simply not practically possible to get data accurate enough, even in an
entirely deterministic, Newtonian universe. Weather forecasts are a
perfect example of this. Chaos theory doesn't put any accuracy on
measurements or predictions: what it says is that measurement errors for
chaotic systems (which human system is) will produce errors in predictions
that grow exponentially over time, making it difficult to forecast
accurately far into the future. But if you can measure precisely enough
(and chaos theory puts no limits on measurements) then there's no
theoretical limit to how accurate your predictions can be.”
“I think the weakest way to solve a problem is just to solve it;
that's what they teach in elementary school. Marvin Minsky said, "You
don't understand something until you understand it more than one way." I
think that what we're going to have to learn is the notion that we have to
have multiple points of view. It was based on a few things from the past
like how smart you had to be in Roman times to multiply two numbers
together; only geniuses did it. We haven't gotten any smarter, we've just
changed our representation system. We think better generally by inventing
better representations.” (5)
None of the risk factor measurers that we have to date, including the
ones in this paper, are good enough to have the total knowledge of the
initial state of the organism to be able to predict its future. (6) The
whole exercise is futile unless we are able to size up the human
consciousness which plays the key role in all future happenings to human
kind, more so the cardiovascular mortality and morbidities. The best way
to predict the future is to invent it. Let us then put all our heads
together to invent a healthy future for human kind by teaching them to
live well to remain healthy as long as they live. I call this as the
“wellness concept”. (7) Catch them young before they get converted to the
wily ways of the present world order. Change of mode of living,
tranquility of mind and universal compassion devoid of greed, hatred,
anger and pride are the best insurance to future good health-
cardiovascular health included.
Rigorous analysis of anything in science also needs a very rigorous
analysis of its tall claims and success rates. “No man, no author, not
even the greatest, ever provide the last word on anything. Men (women) are
vain authorities who can resolve nothing.” -Michel de Montaigne.
Yours ever,
bmhegde
References:
1) Firth WJ. Chaos-doctors predicting the unpredictable. BMJ 1991: 303;
1565-1568
2) Smith R. The screening industry. BMJ 2003; 326: 893.
3) Hegde BM. Chaos-a new science in the making. JAPI 1996; 44: 167.
4) Science Codex June 12th, Harvard University.
5) Key Allan C. Predicting the future. Stanford Engineering 1989; 1: 1-6.
6) Scott I. Improving the accuracy of predicting cardiovascular risk. BMJ
2010; 340: c2334.
7) Hegde BM: Wellness - a new concept ; editorial J.Indian Med Assoc.
1996; 94:286-288
Competing interests:
None declared
Competing interests: No competing interests
Dear Editor,
In response to the editorial “Improving the accuracy of predicting
cardiovascular risk”, the author had high praise for the QRISK2 risk
prediction score for cardiovascular disease. He argued that it was more
accurate as it took into consideration variables not included in the
Framingham score which was previously recommended by the National
Institute for Health and Clinical Excellence (NICE) and QRISK1, and gave
his endorsement. As I read the article, I wondered if we really needed
another risk assessment tool, and was there a more cost effective way to
predict cardiovascular risk?
I do not doubt the QRISK2’s relevance or reliability in predicting
cardiovascular risk, but what about the many individuals who are
disadvantaged, have limited access to healthcare, and who will not seek
medical care because of a lack of health insurance. How will they benefit
from this new development in cardiovascular risk assessment?
De Koning et al (2007) meta-analysis showed that waist circumference
and waist-to-hip ratio is significantly associated with cardiovascular
disease. This offers a straight forward, low cost way to provide this
important assessment to those who while being at high risk for
cardiovascular disease are often the ones who can least afford assessment.
We need to get information about cardiovascular risk to at risk
populations and to train healthcare providers to accurately take waist
circumference and waist-to-hip ratios. Let us do something to offer
practical, cost effective ways to assess cardiovascular risk to segments
of our populations that are at the greatest disadvantage and who can least
afford to bear the burden of cardiovascular illness and all that it
entails.
Reference:
De Koning, L., Merchant, A. T. Pogue, J., & Anand, S.S. (2007) Waist
circumferences and waist-to-hip ratio as predictor of cardiovascular
events: meta-regression analysis of prospective studies. European Heart
Journal. Vol.28 Issue 7 Pp.850-856
Competing interests:
None declared
Competing interests: No competing interests
Use of cardiovascular risk scores to communicate with patients
The focus of the editorial (BMJ 2010;340:c2334) is on the clinician
as decision
maker using cardiovascular risk scores. However, I and many of my
General
Practice colleagues use the risk scores (Framingham and QRISK), not only
to
decide on the need for primary prevention and but also in an attempt to
communicate risk to patients, and persuade them to take potentially
unpleasant drugs or change their lifestyle to reduce their risk when they
do
not have symptoms.
Adherence rates for medication are typically about 50% and even well
validated physician orientated decision-making tools may not be
consistently
used by clinicians (McDonald et al 2002). Calculating percent risk of
CVD
over 10 year does not automatically equate with increased patient
compliance although training in communicating risk and using visual
illustrations can improve rates of preventative therapy and compliance
(Benner et al 2008).
Dr Ian Scott, (BMJ 2010;340:c2334) in his editorial, states that the
cardiovascular risk tools may not be readily accessible in busy practice
settings and cites a 15 year old paper to support his thesis (Wyatt,
& Altman
1995). Primary Care has moved on in those 15 years and all General
Practitioners in the UK have ready and routine access to these risk
scores through integration of risk calculators with clinical computer
systems.
Other practitioners can use internet based scores a paper version e.g. in
the
BNF. Lack of access to these tools, in modern primary care in the
developed
world, is not a reasonable excuse for guessing risk (of CVD) and
prescribing
potent preventative drugs.
Researchers are keen to develop the next risk assessment tool but
more
effort needs to made to get these tools into practical use both by
clinicians and to develop better and more effective ways of communicating
those risks to patients with meaningful outcomes in terms of health
improvement. Some methods of communicating risk using ‘heart age’ or
comparisons with ‘normal risk’ have been mathematically modelled but not
researched in the real world of primary care (D'Agostino et al 2008).
There is
a pressing need to find ways of translating validated risk scoring into
user-
friendly, patient friendly, understandable and effective communication
tools
with real benefit.
Bibliography
Benner, J.S., Erhardt, L., Flammer, M., Moller, R.A., Rajicic, N.,
Changela, K.,
Yunis, C., Cherry, S.B., Gaciong, Z., Johnson, E.S. & others, 2008, A
novel
programme to evaluate and communicate 10-year risk of CHD reduces
predicted risk and improves patients' modifiable risk factor profile,
International journal of clinical practice, 62(10), pp. 1484-98.
D'Agostino, R.B., Vasan, R.S., Pencina, M.J., Wolf, P.A., Cobain, M.,
Massaro,
J.M. & Kannel, W.B., 2008, General cardiovascular risk profile for use
in
primary care: the Framingham Heart Study, Circulation, 117(6), pp. 743-53.
McDonald, H.P., Garg, A.X. & Haynes, R.B., 2002, Interventions to
enhance
patient adherence to medication prescriptions: scientific review, JAMA :
the
journal of the American Medical Association, 288(22), p. 2868.
Wyatt, J.C. & Altman, D.G., 1995, Commentary: Prognostic models:
clinically
useful or quickly forgotten? British Medical Journal, 311(7019), p. 1539.
Competing interests:
None declared
Competing interests: No competing interests