I really was not comfortable with waiting 3 months to see if my plan to combat diabetes was effective. I also needed some tool to keep me motivated on a daily basis. What I was looking for was a way to predict what my blood numbers were going to be in the future if I stuck with my plan. I also wanted to know ahead of time if I needed to adjust my plan based on an unfavorable prediction.
In my reading I ran across an article on the “5% Club” (http://www.tudiabetes.org/group/the5club). This is a forum for diabetics who have managed to get their HbA1C numbers down below 6%. That sounded exactly like my goal. While reading the 5% Club members forum I stumbled upon a link to an Excel spreadsheet (http://www.loanuniverse.com/Diabetes/) That could be used to predict/estimate HbA1C numbers. The spreadsheet uses the Nathan formula to perform the HbA1C calculation.
In my reading, I discovered that there are a lot of HbA1C / Blood Glucose equations in use. The Nathan formula is one. It appears that most labs use the DCCT formula. There is also some literature that suggests that the new ADAG formula may give a better indication of average glucose levels based on HbA1C values. So, not knowing which methodology was best I decided to modify the spreadsheet to use them all. I also wanted to use only 1 Excel workbook to do all of my diabetes-related tracking.
The following is a link to my version of the workbook.
Here is a list of the modifications I made:
- Added a daily calorie and carb log
- Added a few more columns on the glucose log for more glucose data entry (calculation accuracy increases as you increase the number of data points)
- Expanded the glucose log from 120 days to 360 ( HbA1C values are still base on 120 days of data. Each month (30-day period) the HbA1C calculation uses the previous 120 days of data.)
- Added both the DCCT & ADAG formulae calculations in addition to the Nathan formula calculation
- Added the ability to change the glucose concentration units (mmole/mL = mg.dL / 18.05)
- Added the ability to select between Whole Blood Glucose or Plasma Glucose (PG = 1.11 * WBG)
- Added the ability to set high alarm values for calories, carbs, glucose concentration and HbA1C values (cell background and font color change if the alarm value is exceeded)
- Daily calorie and carb numbers are imported onto the Glucose / HbA1c sheet to facilitate side-by-side comparison of food intake vs glucose levels
- Added a worksheet for recording calorie and carb values for food one might routinely eat.
If you have any questions or comments about this workbook you can contact me at