A score for predicting risk of death from cardiovascular disease in adults with raised blood pressure, based on individual patient data from randomised controlled trials
BMJ 2001; 323 doi: https://doi.org/10.1136/bmj.323.7304.75 (Published 14 July 2001) Cite this as: BMJ 2001;323:75
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Sir-The paper of Pocock et al (1)provides us detection of several
risk factors of death in adults with raised blood pressure by Cox
proportional hazards model. The relation of the created new risk score and
probability of dying was clearly shown in the development set.
However, their paper is flawed by the lack of validation in an independent
sample of patients- a basic methodological principle of any predictive
model(2).Therefore, it would be of outmost importance to test the
discrimination by ROC analysis and calibration (3) of this suggested new
risk model, especially when their calculations are based on older study
populations, as previously pointed out(4).Assessment of usefulness of the
model of Pocock et al. will be possible only after this mandatory
validation process.
1. A score for prediction risk of death from cardiovascular disease
in adults with raised blood pressure, based on individual patient data
from randomised controlled trials. BMJ 2001;323:75-81
2. Randolph AG, Guyatt GH, Calvin JE, Doig G, Richardson WS. Understanding
articles describing clinical prediction tools. Evidence Based Medicine in
Critical Care Group. Crit Care Med 1998;26:1603-1612
3. Ruttimann UE. Statistical approaches to development and validation of
predictive instruments. Crit Care Clin 1994;10:19-36
4. Vesti-Nielsen J. Independent cardiovascular risk cannot be predicted.
Electronic response.
Competing interests: No competing interests
Sir: After another careful review of the scoring method and responses
to the paper of Prof. Pocock and colleagues,permit me to voice the
following remarks: It is not clear what is meant by raised B P in adults.
Certain adults may have a temporary raised B P just by being monitored for
B P. Whereas, established raised B P has to be labelled as such, after 2-3
months of observed readings.
It is not clear that such a process was done to include adults with
"raised B P "
As has been mentioned in rapid responses, there are several risk factors
that were not included in the study that certainly may affect the outcome
of the scoring technique used making the limited risk factors in the study
incomplete and thus partially valid.Several responses were quite critical
and justifiably so. However, from a different perspective, it puts such
knowledge of risk factors within reach of general readers who would jump
on the occasion that such factors are the ultimate answer to risk of
death, especially when as one response suggested that combining it with
hyperlipemia and elevated homocysteine
would be of educative, informative value. Here again, though
elevated blood level of homcysteine is an independent risk
factor, any study that would include such a parameter in a study of risk
factors, needs to know an accurate dietary history the intake of the
essential amino acid methionine and folic acid, B6, and B12, from day
today in the adults being studied to ba able to say that truly
homocysteine levels are high.One should be precise before conducting such
research of risk factors, or cost effective medical practice would be
unreasonable, let alone Chiropractors assessing C-V Risk factors.
Munir E Nassar, M.D.
Competing interests: No competing interests
The article by Prof. Pocock et al. though potentially useful has
caused me some confusion. For some years doctors have been counselling
their hypertensive patients to loose weight. Now it would seem that
weight is not important as a predictor of future death. What do I tell my
patients now? Recent reviews on hypertension have stressed the importance
of pulse pressure in assessing future risks. This has also been considered
unimportant. Perhaps Prof Pocock would like to explain why weight(or
BMI),pulse pressure and diastolic pressure are unimportant predictors of
future risks.
Competing interests: No competing interests
"Lack of exercise" and "weight" are more important risk factors than
height. It is hard to imagine that these two factors were not assessed in
the primary trials. For a man who is 55 years old, non-smoker, whose
height is 175 cm with no other serious conditions, this patient according
to this score will be in a low risk category, whether he exercises
regularly and has an ideal weight or can hardly walk and is grossly
overweight.
Competing interests: No competing interests
Thanks for your work in putting together and publishing the
profile.1
I have found combining a general risk profile such as you
describe and individual risk factors usually brings a
greater involvement of patients in their vascular health.
Other factors I have found to have powerful educative value
are homocysteine, CRP, fibrinogen, glucose and the lipid and
apolipoprotein profiles along with changing fat:muscle
ratios. I've found the lifestyle changes resulting from this
combined approach are both effective and satisfying. And
while this more detailed approach takes more time the
maturing relationship that develops as factors are monitored
and (hopefully) change over time has well-documented
outcomes.2.
1.A score for predicting risk of death from cardiovascular
disease in adults with raised blood pressure, based on
individual patient data from randomised controlled trials
Stuart J Pocock, Valerie McCormack, François Gueyffier,
Florent Boutitie, Robert H Fagard, and Jean-Pierre Boissel
BMJ 2001; 323: 75-81
2. Love and Survival. Ornish,D. HarperCollins, NY, 1998
Competing interests: No competing interests
Sir: Permit me to add some important risk factors that impact on
morbidity and /or death from cardiovascular disease in adults. Obesity is
well recognized as an independent risk factor in the pathogenesis of
coronary artery disease (Ref. The Framingham Heart Study, Circ. 1983).
The finding of a carotid bruit on physical exam in an otherwise
asymptomatic adult correlates with likelyhood of presence of coronary
artery disease.
Sedentary life style with job related stress has been described to enhance
coronary artery disease, and thus are risk factors (Ref. Clinical Evidence
BMJ 4th and 5th editions)
Family history of heart disease,(Acute MI, compared to absence of AMI,
increases the likelyhood of CAD in siblings.
(ref. Heart Disease, White P.)
Undetected atrial septal defect or patent Foramen ovale in adults, with
potential paradoxical embolisation is a risk
factor for stroke.
The presence of atrial fibrillation of rheumatic origin or otherwise or
syphilitc aortitis are other risk factors.
Hence for the sake of better accuracy in assessing the score of risk
factors implicated in morbidity and mortality
of coronary artery disease, the physician may have to be more inclusive of
CAD risk factors.
Munir E Nassar, M.D.
Competing interests: No competing interests
The article is an interesting experiment in maths but the authors
cannot be serious when they suggest using this experiment for giving
advice in the real world. If the rates for heart disease had been constant
it would be useful in the real world instead of in the closed system of
the article only, but they are not so. The authors mention the differing
rates in different countries and do admit it would be difficult to predict
a risk in for instance France based, as the calculations are, mainly on
old American and English studies. But they forget the even larger
variations over time in many parts of the world. The cardiovascular
mortality rates have been falling constantly at least since 1980, in most
countries (except in the former Eastern bloc) by 2-7 % yearly. (for
example UK Glasgow 2.6% and UK Belfast by 6% per year, Sweden 3.8-8% in
different centres per year, and so on). A third of this reduction is
caused by decreasing incidence rates for coronary heart disease.(1)
People simply are getting healthier.
The calculations in the article have a built-in blemish in that they
are based on older studies in populations with substantially higher basic
rates for cardiovascular disease. The logic in itself is flawless but the
arguments do not hold. It is impossible, based on old studies, to predict
in figures the absolute risk of cardiovascular death for a person living
today, since the rates in the future are unknown, and whatever drives the
changing rates is unknown as well. Perhaps the relative risks are the
same, which I seriously doubt, but the absolute risks, necessary to advise
a patient, have changed substantially.
1. Tunstall-Pedoe H, Kuulasmaa K, Mähönen M, Tolonen H, Ruokoski
E,Amouyl P. Contribution of trends in survival and coronary-event rates to
changes in coronary heart disease mortality: 10-year results from 37 WHO
MONICA Project populations. The Lancet 1999; 353:1547-57
Competing interests: No competing interests
Dear Editor
The 1.article is a challenge to current practice. We are very busy in
General Practice but often this activity is poorly focussed and of very
questionable benefit. Like many practices we run a hypertension clinic and
try to follow the latest 2.Hypertension guidelines ( currently moving to
multiple drug treatments in resistant cases – which is generally all of
them if we use current targets )
The advent of the computer based Cardiovascular Risk calculators
allows us for the first time graphically to give the patient a sense of
their individual risk and what happens when the risks are modified. The
average BP drop seen the trial data of ( 12.8 mmHg Systolic and 5.8 mmHg
), which anecdotally is more than I see in practice, is frankly of
virtually no value when compared to other risk factor modification like
smoking and cholesterol for which we do have effective interventions.
Height is a different issue perhaps we should bring back the rack !
This is a call to arms that in we stop talking about the
“Hypertension Clinic”, stop making people tired and impotent with our
medication, give our patients a truly “informed Choice” about the benefits
of treatment, stop the publication of the “ ABC of Hypertension” ! , and
stop filling our surgeries with patients with borderline Hypertension with
no other risk factors ( which only makes them anxious and miserable anyway
).
Lets have a nurse lead “Cardiovascular Risk Clinic” and see our
patients on an annual basis when we spend time looking at all the risk
factors
Dr Des Spence
GP Glasgow
1. “A score for predicting risk of death from cardiovascular disease
in adults with raised blood pressure, based on individual patient data
from randomised controlled trials”. BMJ 2001;323:75-81 ( 14 July )
2. British Hypertension Society guidelines for hypertension management
1999: summary. BMJ 1999;319:630-635 ( 4 September )
Competing interests: No competing interests
How can height, not weight be a risk factor? AND how can BMI or some
such be ignored as a risk factor?
Competing interests: No competing interests
Which blood pressure, cholesterol, and creatinine measurements are the most appropriate
Dear Editor
I would like to predict the risk score for all patients in my
practice aged 35 years or older as so clearly described in this article.
My enthusiasm invariably turns to disappointment when using risk
scores, for the following reasons:
1. Age: most of these studies stop at the age of 74. As a
significant proportion of my patients are aged 75 and over, I feel
cheated. Is there any possibility of extrapolating the risk scores to an
older age?
2. Tobacco: should I include ex-cigarette smokers who have only
recently stopped smoking, recent being, for example, during the last year.
3. Blood pressure: which measurement do I use?
The most recent measurement,
The average of the last three measurements
The highest recorded measurement
The average of the three highest recorded measurements
Seated, standing, ambulatory, or the patient’s own measurement
4. Which cholesterol measurement is the most appropriate?
The most recent measurement,
The average of the last three measurements
The highest recorded measurement
The average of the three highest recorded measurements
5. Which creatinine measurement is the most appropriate?
The most recent measurement,
The average of the last three measurements
The highest recorded measurement
The average of the three highest recorded measurements
6. Left ventricular hypertrophy: how should it be defined?
Echocardiogram evidence only
ECG evidence
Ideally I would like to be able to discuss with a patient their
current risk score, and be able to compare with their previous risk
scores, since when they have stopped smoking, blood pressure has been
reduced and their hypercholesterolaemia has been treated.
Likewise on a practice basis, I would like to be able to produce a
“before and after” risk score to assess the effectiveness of the various
treatments, which my practice has implemented often at great expense,
time, and energy.
I am disappointed that the above points are not specifically
addressed in this and other similar risk score assessments as to which are
the most appropriate blood pressure, cholesterol and creatinine
measurements to use for the purpose of risk score assessment.
Yours faithfully
Michael J White MB BS MRCGP DCH DRCOG
General Practitioner
Stakes Lodge Surgery,
3a Lavender Road,
Waterlooville
PO7 8NS
No competing interests
Competing interests: No competing interests