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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

Query regarding numbers needed to treat

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

15 October 1998
Stefan M Groetsch