August 26, 2013
Reasons Behind Varying Blood Glucose Readings
We should be happy that Joslin has highlighted some of the less talked about variables in our blood glucose readings. When they have a blog that many people read, I am concerned that they are not including information that many bloggers do cover and complain about incessantly. Surely, Joslin has a larger reading base and could reach more people, but time after time, much information is totally ignored. Back to why blood glucose readings can vary dramatically even eating the same meal day after day.
#1. Food consumption can be a large component of blood glucose reading variability. Then when we remember that food labels, meaning carbohydrate count, can vary by 20 percent and sometimes more. And, we wonder why we get readings that vary.
#2. Meter accuracy can be a factor. With the exception of a few meters that are accurate within 15 percent on the low side in their test strips, all meters are supposed to be within 20 percent of actual blood glucose. Now we are learning that many test strips, once they have received FDA approval, do not meet that requirement in their test strips and yet the FDA is doing nothing about it. There is even greater questions about the test strips being brought into the US from other countries by CMS.
#3. Exercise and physical activity is another variable. The amount of exercise or other physical activity can draw glucose from our liver and put it to work in our bodies, shorting us later when we take our readings. Being sedentary can also affect our blood glucose levels when we are normally physically active and they can affect our readings.
#4. Insulin is also a variable. Yes, even our insulins are not that dependable. I quote what Joslin wrote. “One of these is the insulins we have available. NPH insulin is notorious for having large intra-individual variability (meaning you can get widely different results each time you use it), but even the newer insulins, Lantus® and Levemir®, are not anywhere near 100 percent reproducible every time. One study by Heise et al published in Diabetes found that the serum concentrations of insulin Lantus® and insulin Levemir® varied by 24 percent and 18 percent when participants received four same- quantity doses of the medication.” This is even more dramatic than I had thought.
#5. Liver output of glucose is a variable. Our liver puts out glucose when it is called upon by our bodies. When we have lost some of our pancreas capability, this can become a larger variable than we realize. This is especially true for those of us with type 2 diabetes.
#6. Emotions and stress are variables. Some people try to ignore this, but these are factors in our blood glucose production. It also can become a larger variable if you become stressed before taking a reading.
#7. Illness and injury is a variable. When you are on the verge of an illness, your liver can be called upon to supply more blood glucose to help in the battle of an illness. A severe injury can affect blood glucose readings as well, while a minor injury will have a smaller effect.
#8. Hormones are variables. In addition to a woman's normal monthly cycle, other things in our daily lives can increase or decrease our level of hormone activity and this will affect our blood glucose readings.
#9. Food consumed at other meals and snacks are variables. People are forgetful and often do not remember the extra carbohydrates they consumed the previous meal. It is that second small serving they had or the small 15-gram carbohydrate snack that turned into 25 grams of carbohydrates. Or maybe you had less to eat that anticipated. It is little things like this that can cause variances in our blood glucose readings.
If you think about it, whether you are a type 1 or a type 2 on insulin, calculating a dosage is a crap shoot. It is surprising that we are as close as we are most of the time. Knowing this also confirms why doctors are so nervous about hypoglycemia. Is it any wonder that when people forget to inject insulin or take their oral medication, we sometimes have very high spikes in blood glucose? Or when we take our medicine and then don't eat what we anticipated that we can have hypoglycemia.
Doctors will very seldom remind patients to not take a medication if they are not feeling like eating unless there is a blood glucose reading above a certain level. Doctors also forget to review the correction ratio for insulin to assist people for injections when they are ill or don't feel they can eat.
The above are not intended to be all inclusive of all variables, but should point out why people with diabetes have burnout from all the calculations and variables to keep track of on a daily basis. Our diabetes health is dependent on these considerations and our calculations. Sorry folks, the doctor can't do this for you.