Detailed answers to most UKPDS Risk Engine queries can be found in the
associated methodology papers which are listed under publications. Brief
answers to many frequently asked questions are as follows:
1. Is the UKPDS risk engine validated in patients on statin therapy, or
must untreated total cholesterol and HDL-C values be used?
Given that most statin trials have delivered CV risk reductions commensurate with that expected from the observational relationship between LDL cholesterol levels and CV outcomes it is to be expected that the UKPDS Risk Engine will give reliable CV risk estimates from statin-modified LDL values. Although we are not aware of any formal validation of the UKPDS Risk Engine in a statin-taking population, it successfully estimated CV outcomes for the PROactive trial (Lancet 2006:367;25).
2. How can I use the UKPDS Risk Engine to compare cardiovascular disease risk to a 20% threshold, as recommended by NICE?
Summing the coronary heart disease (CHD) and stroke risk estimates from the Risk Engine is not recommended: it gives only an approximate estimate of cardiovascular disease (CVD) risk, due to double-counting of people who have both CHD and stroke. Instead, treat the 20% threshold of CVD risk as approximately equivalent to a 15% threshold for CHD risk. [Williams B, Poulter NR, Brown, MJ, Davis M, McInnes GT, Potter JF, Sever PS, Thom S. British Hypertension Society guidelines for hypertension management 2004 (BHSIV): summary BMJ 2004;328,634-640]
3. For what populations is it valid to use the UKPDS Risk Engine?
The Risk Engine is intended for use in adults who have:
- Type 2 (adult-onset or NIDDM) diabetes
- No previous heart disease or stroke
- White, Afro-Caribbean or Asian-Indian ethnic background
- No serious life-threatening illness such as cancer
The Risk Engine is likely to be most accurate when used with patients
similar to those in the UKPDS cohort, that is, aged between 25 and 65
at diagnosis of diabetes and with a duration of diabetes less than 20
4. Can the UKPDS Risk Engine be used for individuals who do not have
No. To calculate coronary or stroke risk in individuals without diabetes,
other models such as the Framingham risk equations should be used (See
Anderson et al, Cardiovascular disease risk profiles, American Heart Journal
1990; 121: 293-8). A computer implementation of the Framingham equations
is available from the British Hypertension Society (www.hyp.ac.uk/bhs/managemt.html)
or the Joint British Guidelines (www.bnf.org/calculatorrisk.htm)
5. Can the UKPDS Risk Engine be used for diabetic individuals with
established cardiovascular disease?
Not at present. The Risk Engine requires that there be no history of
coronary heart disease or a stroke. Work is in progress to develop a model
that predicts risks for individuals who already have coronary heart disease
or have had a stroke.
6. Can the UKPDS Risk Engine be used in populations with impaired glucose
tolerance (IGT) or impaired fasting glucose (IFG)?
The performance of the Risk Engine in these "pre-diabetic"
populations has not been assessed. Results obtained for any individuals
with IGT or IFG should be interpreted with caution.
7. In what ethnic groups can the Risk Engine be used?
The Risk Engine utilises data from self-reported White Caucasian, Afro-Caribbean
and Asian-Indian individuals and takes account of these ethnic groups
as necessary. Whilst South Asians are recognised generally to be at greater
risk of heart disease, we did not find South-Asian ethnicity to be an
independent risk factor once all of the traditional risk factors were
included in a a multivariate model. Results obtained for individuals from
any other ethnic groups should be interpreted with caution.
8. Why are the risks not different for non-smokers and ex-smokers?
No significant differences were found in coronary heart disease or stroke
risk between non-smokers and ex-smokers but the "ex-smoking"
category has been maintained as it is likely to be required in future
versions of the UKPDS Risk Engine which address other diabetic complications.
This ex-smoking effect, however, may be time-dependent with an elevated
risk in the first few years after giving up smoking with no difference
in later years. In the case of a very recent ex-smoker we recommend treating
results obtained as potential underestimates of risk.
9. Why is there an option to specify the number of measurements for
Where HbA1c, systolic blood pressure or lipid levels are entered as a
mean of several values, this option permits a regression dilution adjustment
to be made that takes account of the biological and measurement variation
seen in these variables.
10. Why do the UKPDS Risk Engine results not match the tables in the
The Windows version of the Risk Engine automatically adjusts for regression
dilution (see question 7) whereas the published tables are unadjusted.
Setting the option "Number of values" to "2" for HbA1c,
"6" for blood pressure and "2" for cholesterol will
give identical results for the same input values and the message "Adjusted
for regression dilution" will no longer appear below the output boxes.
11. Why do results in the Windows version of the UKPDS Risk Engine
not match results in the Excel version of the Risk Engine?
The Windows implementation adjusts for regression dilution (see
questions 7 & 8) by default and uses "Age now". The Excel
implementation does not automatically adjust for regression dilution and
uses "Age at diagnosis of diabetes". This is because the Windows
version has been designed for use in clinical practice whereas the Excel
version is intended primarily for use by researchers and by health planners.
The two implementations will give identical results if equivalent settings
12. Does it matter how the input variables are measured?
For maximum accuracy, input variables should be measured in a similar
fashion to the UKPDS. Specifically, HbA1c should be measured on a DCCT/UKPDS-aligned
assay, total cholesterol and HDL cholesterol measured on CDC-aligned assays
and blood pressure measured as the mean of three measurements taken over
a few minutes.
13. Does it matter that patients may have had diabetes for several
years before diabetes is diagnosed?
The UKPDS Risk Engine provides the best risk estimates available for
people with newly diagnosed type 2 diabetes reflecting a mix of individuals
who will have had their diabetes diagnosed with varying degrees of delay.
As the risk of diabetic complications increase with duration of disease
the UKPDS Risk Engine, like all risk calculators, will tend to underestimate
the actual risk for any individual who has had unrecognised diabetes for
more years than most. Conversely, screening programmes for diabetes may
detect people at an earlier stage than usual when their risk may be overestimated.
14. How are cholesterol and HDL cholesterol values converted from conventional
units (mg/dl) to SI units (mmol/l), and vice versa?
We use the conversion factor one mmol/l = 0.02586 mg/dl. as listed in
the Diabetes Care SI Conversion Table.
15. Why does changing the measurement units for cholesterol alter predicted
risk for some patients?
Rounding of converted values can make a slight difference to the predicted
16. Why are confidence intervals not symmetric in version 1.1 onwards?
Version 1.1 calculates confidence intervals on a logistic scale to avoid
them exceeding 100% or becoming negative. The intervals calculated will
be similar to those in Version 1.0 but may be asymmetric, rather than
17. I've just installed a new Windows' version of the Risk Engine and
every time I try to use it I get an error message 'Invalid value for Time',
what does this mean?
This can occur when a new version is not installed successfully. To solve
the problem, uninstall the Risk Engine and then re-run the new version
installer as follows:
- Select 'Settings', 'Control Panel' from the start menu.
- Double-click the 'Add/Remove Programs' icon.
- Select 'UKPDS Risk Engine' from the list.
- Click on the 'Change/Remove' button.
- Click the 'Yes' button when prompted 'Are you sure you want to completely
remove UKPDS Risk Engine 1.x and all it's components?'
- Click the 'OK' button when the 'Application Removal' dialog appears.
- Re-install the new version of the UKPDS Risk Engine.
18. I've downloaded the UKPDS Risk Engine for Windows, how do I install it?
The program you download is a self installing application. It is not
itself the application that calculates the risks. Installation is as follows:
- Download the file from the DTU website.
- Double click the RiskEngine icon.
- You will see the copywrite message, click the OK button.
- The screen will change a few times.
- You may be told that your system files are out of date.
- If you are you must allow the installer to update them for you.
You must then restart the computer and re-run the installer.
- You will see the UKPDS Risk Engine Setup screen. Click the OK button.
- The second dialog will appear, Click on the Computer icon to install
the software. You may change the folder to which the software is installed
but it is not recomend.
- Choose a program group that the software should install into.
- Again select the default option by clicking the Continue button.
- You may see a 'Version conflict' dialog box, if you do click the 'No
to All' button.
- Installation should now be complete. Click OK.
You can run the software by choosing 'UKPDS Risk Engine' from the 'UKPDS
Risk Engine' section of the 'Programs' part of the 'Start' menu.
For this procedure to work under Windows NT, 2000 or XP you will need
to be logged in with administrative rights to the computer.
19. Do new versions of the Risk Engine give the same answers as older versions?
The estimated risk for CHD and stroke risk are the same in all versions.
The confidence intervals may vary slightly between versions 1.0 and later
releases, as the confidence interval method was improved in version 1.1
20. Does the Risk Engine take microalbuminuria into acount?
The current version of the UKPDS Risk Engine does not include the presence of microalbuminuria as a risk factor. A new version is being prepared which looks at the risk of cardiovascular disease in people with new or established diabetes in which the presence or absence of microalbuminuria will be included.
21. Does the Risk Engine take obesity into acount?
We have examined in detail all available measures of size and obesity but they do not contribute independently to estimated risk in the presence of the other more informative risk factors used currently by the UKPDS Risk Engine. The only time we have found this to be the case is when estimating the risk of congestive heart failure as reported in UKPDS Paper 68 (Diabetologia 2004; 47: 10: 1747-1759) describing the UKPDS Outcomes Model
22. I am having problems downloading the UKPDS Risk Engine
There are known IE problems associated with some web browsers. You can overcome these by following the instructions given below:
- Go to our website http://www.dtu.ox.ac.uk/RiskEngine/download.php
- Right click and let go on the 'Windows' link under the ‘Download the UKPDS Risk Engine’ heading.
- Select 'Save target as...' from the menu that pops up.
- Select a location for the file - use desktop for now to keep things simple – and save.
- Close Internet Explorer and all other applications.
- There should be an Icon on the desktop called 'RiskEngineSetup' or 'RiskEngineSetup.exe'. It should have a yellow warning triangle icon.
- Double click this icon.
After that it should all work as described in the FAQ question "I've downloaded the UKPDS Risk Engine for Windows, how do I install it?"
23. I have downloaded and installed the UKPDS Risk Engine but it will not work
You must ensure that you have administrator rights on your computer. Please query this with your IT department. Typically you may see any of the following messages:-
- -2147024770 automation error
- Code: 429 active X component can’t create object
- Setup fatal error: unable to generate installation log file
24. Mac OS X 10.7, Lion support?
A new version of the UKPDS Risk Engine is being prepared that will be compatible with Mac OS X 10.7, Lion.