The value of self-monitoring of blood glucose (SMBG) levels in patients with non-insulin-treated type 2 diabetes has been debated over the years.
A study was done to compare 3 approaches of SMBG for effects on hemoglobin A1c levels and health-related quality of life (HRQOL) among people with non-insulin-treated type 2 diabetes in primary care practice.
The Monitor Trial study was a pragmatic, open-label randomized trial conducted in 15 primary care practices in central North Carolina. Participants were randomized between January 2014 and July 2015. Eligible patients with type 2 non-insulin-treated diabetes were: older than 30 years, established with a primary care physician at a participating practice, had glycemic control (hemoglobin A1c) levels higher than 6.5% but lower than 9.5% within the 6 months preceding screening, as obtained from the electronic medical record, and willing to comply with the results of random assignment into a study group. Of the 1032 assessed for eligibility, 450 were randomized.
No SMBG, once-daily SMBG, and once-daily SMBG with enhanced patient feedback, including automatic tailored messages delivered via the meter.
Coprimary outcomes included hemoglobin A1c levels and HRQOL at 52 weeks. A total of 450 patients were randomized and 418 (92.9%) completed the final visit. There were no significant differences in hemoglobin A1c levels across all 3 groups. There were also no significant differences found in HRQOL. There were no notable differences in key adverse events, including hypoglycemia frequency, health care utilization, or insulin initiation.
From the results In patients with non-insulin-treated type 2 diabetes, they observed no clinically or statistically significant differences at 1 year in glycemic control or HRQOL between patients who performed SMBG compared with those who did not perform SMBG. The addition of this type of tailored feedback provided through messaging via a meter did not provide any advantage in glycemic control.
- No intensive education was included in the study.
- Patients with non–insulin treated type 2 diabetes receive no benefit from SMBG.
- The final conclusions are not valid if you do not educate the patients as what to do with the readings.
In another study to review in comparison with Young et al. is a 1-year evaluation of structured self-monitoring of blood glucose. In the Polonsky study, 483 patients with poorly controlled non–insulin-treated type 2 diabetes were randomly assigned to enhanced usual care vs enhanced usual care plus structured SMBG. The structured testing arm participants performed 7-point SMBG profiles on 3 days prior to each scheduled study visit, recording medications, food, and activity in relation to SMBG. More importantly, providers were trained to interpret the structured SMBG profiles and were provided with an algorithm of potential treatment strategies to use depending on the pattern identified. Baseline mean A1c was 8.9%. In the Polonsky study, both treatment arms improved over time, with 12-month A1c results favoring the structured testing group by 0.3% in the intention-to-treat analysis and 0.5% in the per-protocol analysis. Participants in the structured testing group had more medication changes made at their study visits.
Taking into account the balance of the evidence, routine daily SMBG in patients with non–insulin treated, reasonably well-controlled type 2 diabetes is probably a low-value activity on a population level. However, patients with less–well-controlled type 2 diabetes, or those who are using the information in a targeted fashion to gain behavioral insight or to make treatment decisions, probably do derive modest benefit in terms of overall glycemic control, especially when their care providers review and act on the information.
Publisher Comments: From my experience as a diabetes educator, I have found that first of all, 90%+ of these patients not on insulin are told to check their blood sugars once daily in the mornings before eating. I never understood why that is the case, so I ask my patients 3 questions, which are:
- When does diabetes cause the most damage? When your blood sugars are high or when they are normal?
- When are your blood sugars the highest? Before you eat or after you eat?
- After they answer I add, you just told me that your blood sugars cause the most damage when they are high and they are higher after meals, so why do you only check your blood sugars in the morning when they are usually the lowest prior to eating? Checking your blood sugars 1 1/2 to 2 hours after eating can teach you what different foods can do to your blood sugars. Then you can change your diet to foods that do not raise your blood sugars as much.
This gets patients to check their blood sugars after meals for different foods. So educating your patients can motivate them to check more often and take action. But, just to have them check their morning blood sugars when most likely no one even checks them may not be the best option.Most of the time their logs are blank or with very few readings.
JAMA Intern Med. 2017 Jun 10. doi: 10.1001/jamainternmed.2017.1233. [Epub ahead of print]
Polonsky WH, Fisher L, Schikman CH, et al. Structured self-monitoring of blood glucose significantly reduces A1C levels in poorly controlled, noninsulin-treated type 2 diabetes: results from the Structured Testing Program study. Diabetes Care. 2011;34(2):262-267. http://care.diabetesjournals.org/content/34/2/262