Type 2 diabetes: Value of home blood sugar monitoring unclear

Robert H. Shmerling, MD
Robert H. Shmerling, MD, Faculty Editor, Harvard Health Publishing

Follow me on Twitter @RobShmerling

It’s a central tenet of diabetes treatment: monitor the blood sugar closely, then adjust your diet, exercise, and medications to keep it in a good range. And that makes sense. Poorly controlled blood sugar is a major risk factor for diabetic complications, including kidney disease, vision loss, and nerve damage.

While efforts to carefully monitor and control the blood sugar in diabetes are worthwhile, “tight control” is not always helpful — and it may even cause harm. For example, in studies of people with longstanding type 2 diabetes, the type that usually begins in adulthood and is highly linked with obesity, those with the tightest control either had no benefit or had higher rates of cardiovascular disease and death. Meanwhile, studies of people with type 1 diabetes — the type that tends to start during childhood due to an immune attack against the insulin-producing cells in the pancreas — suggest that tight control may help protect against cardiovascular disease. So, it seems the benefits and risks of tight control depend on the situation.

Home blood sugar monitoring for type 2 diabetes

People with diabetes are often advised to check their blood sugar levels at home by pricking a finger and testing the blood with a glucose meter. They can review the results with their doctors over the phone, online, or at the next office appointment. The value of this for people with type 2 diabetes is uncertain.

In a study published in JAMA Internal Medicine, researchers enrolled 450 people with Type 2 diabetes, none of whom were taking insulin. They were randomly assigned to one of three groups:

  • no self-monitoring of blood sugar
  • once daily self-monitoring of blood sugar
  • once-daily self-monitoring of blood sugar with “enhanced feedback” from their blood glucose meters with messages intended to educate and motivate the study volunteers.

After one year these researchers found that, compared with those not self-monitoring blood sugar, those who self-monitored had no improvement in the control of their blood sugar, and had no improvement in measures of quality of life.

So what?

The impact of this study could be enormous. Of the enrolled study subjects, three-quarters routinely checked blood sugar at home. If that’s typical of people with type 2 diabetes, these findings could allow thousands of people to stop sticking themselves and save money on monitoring equipment, with no ill effects on their health.

But even if these findings are confirmed, there may be situations when home monitoring is still useful and important. For example, home monitoring might be a good idea when people like those in this study:

  • develop an infection
  • change the dose of their diabetes medications
  • add or stop taking one of their medications
  • gain or lose a significant amount of weight
  • begin taking insulin.

This study did not examine these situations and so could not draw conclusions about them. It’s also worth noting this study lasted only one year. It may take longer to see a benefit from home monitoring. Finally, this study did not include individuals with type 1 diabetes, so the results do not apply to them.

The bottom line

This new study suggests that doctors treating people with type 2 diabetes may not need to recommend routine self-monitoring of blood sugar. However, while that may be true for the average person with type 2 diabetes who is not taking insulin, we’ll need more studies and longer-term studies to identify which people with type 2 diabetes will benefit most from home monitoring and when it’s just not worth the effort.

Comments:

  1. Eva

    I was in the exact situation as you are right now. I have been suffering from Diabetic pains for a long while now.

  2. martin

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  3. Janet Mennies

    How about those of us with pre-diabetes (A1C 5.6-6.4% range)? Insurance will not cover the cost of monitoring supplies unless we get the diagnosis of diabetes. My doctor asked me to monitor, and although it took me 3 years, I was able to get it down from 5.9 to 5.4% thanks to the feedback I got from fasting and 2 hour post-meal blood measurements at home. There are just too many unanswered questions in the study described above to write off the importance of home glucose monitoring.

    • Kathy Vannoy, MS, RDN, LD

      Absolutely–I agree, it’s not time to quit testing.

      Congratulations on getting your A1C down.

      I have type 2 diabetes and found an off brand meter (with suggestion from my diabetes educator), Prodigy Pocket. There are a number of others.

      The meter is about $12 and 50 strips are about $10.

      Because my blood sugars were fairly stable, I started the new meter and know the meter runs lower than my previous name brand meter.

      Although you can’t make direct correlations with results from other meter, it’s still very helpful.

      I know what my new “normals” are and when it’s running high.

      I encourage people to talk to their doctor and/or diabetes educator to find a meter that will work best for them., not just for finances, but for the more “accurate results” when needed.

      If I was on insulin or other medication that could cause low blood sugars, I would stick to the original name brand meter because the numbers are a little more exact.

      Keep up the good work.

    • Kathy Vannoy, MS, RDN, LD

      I hear ya. Strips are so expensive. There are “main line” meters that have a tighter range for readings. Those are essential if you’re on insulin or medication that can cause low blood sugars.

      Other “off brand” meters sometimes have a wider range of readings.

      I checked with my diabetes educator and she suggested trying an off brand. My pharmacy was selling Prodigy Pocket–$12 for meter and $10 for 50 strips. Readings run lower than the name brand meter I was using before but I know what my new “normal range” is so I shouldn’t get any surprises when my A1C is tested again.

      Good luck!

  4. cheryl perkins

    Eat to your meter. In other word, cut your carbs according to how high your reading is. If you just take your blood sugar – and don’t change your behavior to bring the next number down, yes, it would be useless.
    I could not have my low 5 A1c without my meter.
    Also, it would help a lot if meters were more accurate. The allowed 20 percent away from true value is ridiculous at this point.

  5. glenbarrington

    I’m pretty sure that monitoring my blood glucose levels hasn’t really been all that effective in controlling my “Sugar”, except in the sense that it helped prove to me that diet and exercise could work to keep me healthy.

    I don’t know that researchers fully understand the despair and uncertainty a newly diagnosed Type 2 diabetic goes through. Being able to see how variations in my new regimen affected my blood glucose levels was a real help in finding my path, and kept me from giving up in frustration.

  6. Karim Miteff

    This article is insane. Once a day glucose monitoring is not sufficient to determine trends or adjust diet properly in any sort of diabetic patient. When you continuous glucose monitoring becomes non-invasive and I expensive, as simple as a fitnit reading let’s say, type 2 diabetes will reduce in incidence dramatically, along with the end of the fast food and sugary beverage industries.

    The the individual above who saw his readings jump to 140, if he was measuring only once a day, he missed out on managing his disease more aggressively, only accelerating his adoption of insulin. I am wondering if his fasting insulin level was ever checked and did it ever go back to normal? Type 2 diabetes is simply not treated or managed properly in the majority of patients, especially here in the U.S. It is a travesty.

    • Kathy Vannoy MS, RDN, LD

      I agree with Karim.

      This “treatment” has “No effect” because it is ineffective from the start.

      With no insulin treatment, it’s helpful to test twice a day to look for patterns with usual foods, testing before and after meals to see what’s happening. On insulin, of course, you need to test more frequently.

      This study would be very interesting to repeat with different parameters. I worked 12 years as dietitian and diabetes educator. The past 18 months I have lived with type 2 diabetes.

      Self-monitoring was invaluable to my clients and now for me.

      Why not repeat the experiment, but have people test different times of day or number of tests (at least twice a day). That would be interesting.

      Maybe for people NOT on insulin, Twice a day is enough vs 4-6 times per day.

      I can’t imagine NOT testing my blood sugar. Who wants a big bad surprise on their A1C the next time they go for a check up.

  7. Mik Sohn

    Whoever reached this conclusion must be out of his mind. Anyone who has diabetes type 2 knows that self-monitoring at least once a day in the early stages under oral medication and twice a day under insulin is a must to keep track of one’s body’s reaction to diet and medication. When my morning measurements started creeping up into the 140’s – 160’s at maximum oral dosages, I knew that it was time for insulin, and my doctor agreed with me. Had I not done the daily measurements and waited another three months for my next doctor’s visit, the excess glucose would’ve done irreparable harm to my system.