The "Use and Abuse of HOMA modeling" paper [Wallace TM, Levy JC, Matthews DR. Diabetes Care (2004); 27(6): 1487-95] addresses most HOMA issues. Additional HOMA related papers are listed in publications.
As HOMA is a steady state model, only clinically realistic values that would be seen in a fasting subject should be used. These are:
Outside the accepted range (see Q2) calculation is often impossible. The Excel version gives an answer wherever possible but answers outside the accepted input range should be treated with caution.
This problem is resolved in version 2.2 and above. Please download the latest version.
There are known IE problems associated with some web browsers. You can overcome these by following the instructions given below:
You must ensure that you have administrator rights on your computer. Please query this with your IT department. Typically you may see the following messages
The HOMA calculator is not running a simple equation to produce its answers. It is instead running very complex mathematical model of the human body. In order to produce the answers it chooses a starting point based upon the inputs value provided. It then iterates the model until it converges on the correct answer. Sometimes the model will not converge. Changing the inputs very very slightly will often change the starting parameters used for the model. This can lead to the model then being able to converge correctly and provide a working answer.
Our suggestion is to change the input values slightly below the actual value and then slightly above the actual value and check that the results returned are comparable.
The installation program for the HOMA Calculator installs a library in your Windows system. If this file is moved after installation then the Excel spreadsheet will stop working. Re-instalation of the the program should solve the problem. It is also worth pointing out that the software must be installed on each machine you are going to use the Excel workbook on. Although you cannot move the HOMACore.dll you may copy, move or rename the Excel workbook that is used to perform the calculations.