Is Intensive Monitoring Useful in Well-Controlled Diabetes?

Norra MacReady

June 11, 2013

New data suggest that patients whose diabetes is already relatively well-controlled may benefit further from intensive self-monitoring of blood glucose (SMBG).

The latter has been associated with improved blood glucose values, reduction in metabolic risk factors, and improved quality of life, as well as faster medication changes when needed in people with poorly controlled type 2 diabetes, explain Emanuele Bosi, MD, from the Diabetes Research Institute, San Raffaele Hospital and Scientific Institute, Milan, Italy, and colleagues in their article in Diabetes Care, published online June 4, 2013.

So they set out to see whether a similarly intensive regimen would be advantageous for well-controlled diabetics. They found there were benefits, but these were minimal, and experts not involved with this research told Medscape Medical News that while the study was well done, they were not convinced the extra cost of SMBG was worth the marginal added benefit. Also, this approach may not be generalizable outside of a clinical-trial setting, they said, noting that patients tend to tire of such self-monitoring in the long run.

Study Conducted Throughout Italy in Patients Not on Insulin

Dr. Bosi and colleagues conducted their 12-month, prospective, open-label trial, called PRISMA, in 39 diabetes clinics throughout Italy. Patients were eligible if they were 35 to 75 years of age, had type 2 diabetes not treated with insulin, and HbA1c levels between 7% and 9%. The study was supported by Roche Diagnostics Diabetes Care.

Patients were randomly assigned to 1 of 2 groups. Those in the intensive structured monitoring (ISM) group followed an SMBG protocol in which they measured their blood glucose before breakfast and lunch, 2 hours after lunch, and 5 hours after lunch but before dinner, 3 days a week for the duration of the study.

They were taught how to interpret the findings and given suggestions for reaching target glucose levels. In addition, their physicians were able to review and discuss these data with the participants at follow-up visits at 3, 6, 9, and 12 months and recommend changes in medication and lifestyle as needed. Patients in the active control (AC) group followed the SMBG protocol for just 1 week before the visits at 6 and 12 months.

Both groups were assigned a target HbA1c level of  less than 7%. The primary study end points were change in HbA1c from baseline to 12 months, and the percentage of patients reaching a low blood glucose target index (LGBI) no greater than 2.5 or a high index (HGBI) of no more than 5.0.

"LBGI and HBGI are summary statistics computed from SMBG data shown to predict the risk of hypoglycemia and hyperglycemia, respectively," the authors explain.

There were 501 patients in the ISM group and 523 in the AC group, all of whom were included in an intention-to-treat (ITT) analysis. Of those, 14% and 13.6%, respectively, did not complete the study.

In the ITT analysis, HbA1c declined by a mean of 0.39% among patients in the ISM group, compared with a mean reduction of 0.27% in the AC group ( P = .013). The percentage of patients reaching or maintaining the glucose risk targets were 74.6% and 70.1% in the ISM and AC groups, respectively (P = .131). Medication changes were prescribed to 38.7% of patients in the ISM group at follow-up visits 2, 3, or 4, vs 28% of the AC patients ( P < .001). The ISM group also had more detected episodes of mild hypoglycemia (1.32 vs 0.42 events per patient-year; P < .0001). There were no significant differences between groups in changes in body mass index or psychosocial measures.

These findings confirm "the clinical usefulness and overall safety of using structured SMBG to provide guidance in the prescription of diabetes medications and lifestyle changes in noninsulin-treated type 2 diabetic patients, ultimately improving glycemic control," the authors conclude.

But Is the Extra Effort Worth the Cost and Inconvenience?

Prior articles have questioned the value of intensive self-monitoring of blood glucose in type 2 diabetes patients who do not use insulin, and although clinical-practice guidelines advise this regimen, the evidence cited to back it up has not been robust, say critics.

This new study "was well designed and well done," said John E. Anderson, MD, president, medicine and science, of the American Diabetes Association. SBMG "did seem to spur the healthcare providers to make earlier decisions, and I think it was interesting that the SBMG patients also seemed to make more lifestyle decisions based upon the feedback of seeing their glucose pattern after various meals and activities."

But, said Dr. Anderson, who was not involved in this study, "after 12 months of intensive monitoring, you had only a 0.12% difference in HbA1c. This is a very small separation, even if it was statistically significant, and it was within a very controlled clinical trial conducted at diabetes clinics. It may be difficult to generalize these findings to patients treated in primary-care practices or whose diabetes is not as well controlled," he told Medscape Medical News.

"The question is, is it worth the extra cost and the extra monitoring to achieve that 0.12% difference in HbA1c?"

"These subjects were already in pretty good control, so the amount the HbA1c­ could be lowered was limited,” added Daniel Einhorn, MD, president of the American College of Endocrinology. He noted that patients often tire of frequent self-monitoring, "although it was encouraging that subjects in the structured group showed no worsening of quality-of-life parameters. As with blood pressure and cholesterol, any lowering of glucose has long-term benefit in a population, but this may be difficult to prove in an individual, and frequent monitoring is not inexpensive."

This study was supported by Roche Diagnostics Diabetes Care. Dr. Bosi served on the PRISMA study advisory board and serves on advisory boards for Roche and Abbott. Disclosures for the coauthors are listed in the article. Dr. Anderson and Dr. Einhorn have reported no relevant financial relationships.

Diabetes Care. Published online June 4, 2013. Abstract


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