Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38
BMJ 1998; 317 doi: https://doi.org/10.1136/bmj.317.7160.703 (Published 12 September 1998) Cite this as: BMJ 1998;317:703
All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
Editor- We were very interested to learn of the results from the UK
Prospective Diabetes Study Group regarding tight blood pressure control
and type 2 diabetes.1 Many of our patients share similar characteristics
as the study population, and this information is highly applicable to our
practice.
In utilizing an evidence-based medicine approach, we attempted to
calculate the numbers needed to treat based upon the data presented. We
are concerned that there is a discrepancy between the numbers needed to
treat which are stated in the article, and those that can be calculated.
The study states that the number needed to treat over 10 years to prevent
any complication is 6.1 and to prevent death from a diabetes related cause
is 15.0. In calculating the numbers needed to treat by using the values
in figure 4 (based upon a median follow up of 8.4 years), we conclude that
the number needed to treat to prevent any complication is 11, and to
prevent death is 20. The following table describes our method:
clinical end point tight control
absolute risk less tight control
absolute risk absolute risk reduction number needed to treat
any diabetes related end point 259/758= 34.2% 170/390=43.6% 9.4% 1/0.094~
11
death related to diabetes 82/758= 10.8% 62/390=15.9% 5.1% 1/0.051~20
Again, we appreciate the quality of the patient-oriented research
conducted in this study. However, we would have found it more useful if an
explanation were included that described the authors' derivation of the
numbers needed to treat.
Stefan M Groetsch, MD Resident
Joseph T LaVan, MD Resident
John W Epling, MD Family Physician
Department of Family Practice
Naval Hospital Jacksonville
2080 Child Street
Jacksonville, Florida 32214 USA
Fax Number : 904-777-7988
e-mail: jak0sxg@jak10.med.navy.mil
1. UK Prospective Diabetes Study Group. Tight blood pressure control
and risk of macrovascular and microvascular complications in type 2
diabetes: UKPDS 38. BMJ 1998;317: 703-713. (12 September.)
Competing interests: No competing interests
The findings of the UK Prospective Diabetes Study Group have been
eagely awaited by interested clinicians in Primary Care for some time. All
through the summer we said to one another at audit meetings: "The issues
will be clarified when the UKPDSG's latest research is published."
Consequently I was very surprised to discover that some papers were
published in the BMJ, some in The Lancet. Why was this done?
The Lancet is not as available to clinicians in Primary Care as the BMJ (I
have only met one colleague who subscribes, whilst many receive the BMJ)
and is not available electronically to non-subscribers. Our Audit Group is
collating and summarising the findings from both journals knowing that the
Lancet papers are not as accessible for critical appraisal.
Who chose which journal each paper would appear in? How will the
correspondence generated by the papers be integrated? Who will critically
evaluate the effects of the decision to publish in this way?
Yours sincerely, Jonathan Richards
Competing interests: No competing interests
Sir-
The United Kingdom Prospective Diabetes Study (UKPDS) has shown over 10
years of follow-up that persons with newly diagnosed type 2 diabetes can
maintain excellent glycemic control (HbA1c of 7.0%), and that such
control can significantly reduce microvascular complications.1 The study
has also shown that strict blood pressure control can significantly reduce
mortality as well as microvascular and macrovascular complications among
these persons.2 Thus, the UKPDS successfully answered its primary research
questions. The design of the study was such that several secondary
questions could not be answered convincingly.3 However, several important
lessons in ethics and public health can be learned from the UKPDS.
The fact that the comparison group maintained a relatively low HbA1c
level (7.9%) over 10 years of follow-up suggests that the researchers
were ethical to the point of risking a null finding. This is refreshing
because in their enthusiasm to establish the efficacy of specific
treatment(s) some investigators replace standard drug therapy with an
inactive placebo.4 Another remarkable aspect of the UKPDS is that the
researchers continuously adapted the intervention to changes in scientific
knowledge and clinical practice, adaptations that are reasonable and
justifiable in a 20-year trial which chooses to adhere to sound ethical
principles.
The UKPDS was conducted in primary health care settings rather than
specialist centers or university hospitals, and thus, the results are
likely to be closer to what would be found in clinical practice than would
those from other large clinical trials. 5 By simulating clinical practice
as closely as possible, the UKPDS has given data on effectiveness that are
more suitable for translating into public health practice than are
efficacy data collected in highly controlled and ideal environments. In
including a blood pressure control trial,2 the investigators acknowledged
that diabetes complications are multifactorial in aetiology; glycemic
control is but one aspect. The vast population burden of diabetes
complications can be effectively and efficiently tackled only if risk
factors like high blood pressure, dyslipidaemia, and smoking receive at
least as much attention as glycemic control. The biggest impact of the
UKPDS results may be toward better management of blood pressure among
people with type 2 diabetes.2 Finally, the fact that conventional
glycemic treatment for persons in the comparison group of the UKPDS
resulted in a relatively low HbA1c level suggests that some attributes
(e.g., universal health-care, emphasis on primary care, relationship
between primary and specialist care, patient education) of the U.K. model
of health-care may be particularly suitable for managing chronic diseases.
Countries like the United States may benefit from examining some of these
attributes, and modifying their approaches to chronic disease management
accordingly.
Sincerely,
K. M. Venkat Narayan, M.R.C.P.
Gloria L.A. Beckles, M.B.B.S.
Edward. W. Gregg, Ph.D
David. F. Williamson, Ph.D
J. Saaddine, M.D.
Michael M. Engelgau, M.D.
Frank Vinicor, M.D.
Division of Diabetes Translation, National Center for Chronic Disease
Prevention and Health Promotion, Centers for Disease Control and
Prevention, Atlanta, Georgia, USA.
REFERENCES
1. UK Prospective Diabetes Study Group. Intensive blood-glucose
control with sulphonylureas or insulin compared with conventional
treatment and risk of complications in patients with type 2 diabetes
(UKPDS 33). Lancet 1998;352:837-53.
2. UK Prospective Diabetes Study Group. Tight blood pressure control
and risk of macrovascular and microvascular complications in type 2
diabetes:UKPDS 38. Br Med J 1998; 317:703-13.
3. Nathan DM. Some answers, more controversy, from UKPDS
(Editorial). Lancet 1998;352:832-33.
4. Maggs DG, Buchanan TA, Burant CF, et al. Metabolic effects of
troglitazone monotherapy in type 2 diabetes mellitus: a randomized, double
-blind, placebo-controlled trial. Ann Intern Med 1998;128:176-85.
5. DCCT Research Group. The effect of intensive diabetes treatment
on the development and progression of long-term complications in insulin-
dependent diabetes mellitus: The Diabetes Control and Complications Trial.
N Engl J Med 1993; 329: 978-86
Competing interests: No competing interests
As a layman who makes the effort both to understand my
diabetes and to control it effectively, I read with interest the
UKPDS study results in the 12/9/98 edition of the BMJ.
All cost-effective efforts to reduce blood pressure to
acceptable levels for Type 2 diabetics (and enhance control of blood
glucose levels at the same time) are greatly
appreciated, as is improving understanding of the relationship between the
two. My own experience tells me that tight control of blood pressure for a
Type 2 diabetic can be achieved whilst reducing medication - and lead to
improved control of diabetes, so long as it is combined with a programme
of regular, vigorous exercise and a strictly healthy diet of adequate
energy and nutritional balance to support the exercise.
A brief historical summary to begin with ; I was diagnosed with Type
2 diabetes in August 1993. By November `96, I had a peak blood pressure
reading of 172/104, my fasting blood glucose results were levelling off at
6.3 - and I was on daily glibenclamide (1.25 mg/day) for diabetes and on
ramipril (5 mg/day) for the blood pressure.
Almost 2 years down the road, the situation has improved
dramatically, thanks to 3 - 5 sessions per week of vigorous exercise (road
running, aerobic endurance & weight training) and a rigorously
implemented healthy diet (with energy-source targets of complex
carbohydrates 55%, fats 28% and protein 17%). I began this programme in
June 1997 ; by early September `97, I was taken off glibenclamide and the
following November, the ramipril was reduced to 1.25mg/day.
Over the 15 months that I have enjoyed this programme, my BMI is down
to 22.5 (from 28.9) , blood pressure has stabilised at 122/72, blood
glucose is down by 12.5%, serum cholesterol is down to 4.3 and my HDL/LDL
ratio is 1.3. A resting heart rate of 62- 65 (cf 85 in mid `97) and
improved aerobic fitness ("comfortable energy use" in aerobic workouts is
11kcal/min) + greater muscular strength emphasis the improvements I have
achieved.
The lessons to be learnt are:-
- Relatively intense vigorous exercise (using interval training is a
useful way for Type 2 diabetics to lose weight
- Backing up regular exercise with a healthy diet is essential
- Most Type 2 diabetics lack motivation to enjoy vigorous exercise
and use "cooking-from-scratch" skills (though some older diabetics may be
incapable of intense exercise)
The BDA estimate that only 20% of Type 2 diabetics are on
diet and exercise control suggests that there is a long way to go in
improving this situation. It would be interesting to make a cost-
effectiveness comparison between the sort of programme that I am on
(including exercise costs) and the control of diabetes through medication
+ general health & fitness regimes.
Mike Coulson
Competing interests: No competing interests
Deficiencies of UKPDS
I read with interest the results the reports from UKPDS.My person
interest is in Epidemiology and its relevance to coal face General
Practitioners, whose task is to decide what is relevant for the patient in
front of them.
There is one glaring omission from the reports. I have not seen any
reference to the side effects of medication, no mention of metformin
diarrhoea, no mention of ACEI cough, no mention of atenolol tiredness.
Similarly there is no mention of patient satisfaction with insulin
injection nor the guilt syndrome imposed on patients whose "diabetic
numbers" do not meet the Guidelines set by specific disease issue
crusaders.
The primary care clinician must decide whether the morbidity induced
( fear of the label, cost/pain of tests, multiple visits to the doctor,
side effects of medication) is worth the morbidity that only MIGHT be
prevented.
In the BP arm of this trial with tight control there were 42
cardiovascular events per 1000 patient years and 59 per 1000 in the less
tight group. This is a difference of only 17 per 1000 treatment years. How
many per 1000 had side effects? and how many patients would object if they
knew that the effort of optimising the BP only benefited 1.7% per annum?.
It is no wonder many GP's do not seem to reach the Guidelines set by
"Experts" as many of us intuitively sense that the effort is not worth the
benefit for the individual.
Lastly it is a great same that such a large GP based trial has lost
total objectivity by not looking at the other side of the equation.
Competing interests: No competing interests