Frequency of Blood Glucose Monitoring in Relation to Glycemic Control in Patients With Type 2 Diabetes
We were disappointed with the conclusions of Harris (1) and the accompanying editorial (2) on self-monitoring of blood glucose (SMBG). The article is based on outdated data and reflects an era with much less SMBG capability and convenience, reimbursement, therapeutic modalities, and evidence for the benefits of improved glycemic control. Moreover, the study itself was uncontrolled, self-reported, and did not indicate whether the patients were taught about data usage. It would be unfortunate if this article and editorial were used to justify denial of appropriate reimbursement for SMBG in type 2 diabetes.
Optimal modern therapy of type 2 diabetes uses a “treat-to-target” approach, expeditiously moving patients along a sequence of therapies to achieve better diabetes control (3,4). However, to make effective and efficient decisions about therapy, patients and health care professionals should rely on appropriate data, of which SMBG is a key component (4).
The ISIS group recently (October 1996 to September 1999) assessed data from >3,000 clinic visits of 228 patients with type 2 diabetes (aged 35–65 years) who were seen by 65 doctors (assorted specialties) in four Adventist Health clinics. During this period, the average HbA1c decreased by 0.8. Patients were placed into two groups based on diabetes control (HbA1c ≤8 for >95% of measurements during the 3-year period or HbA1c >8) (5). We then examined the consistency with which a health care professional documented discussing glucose monitoring and recorded the frequency of SMBG. We created “diabetes care intervals,” or periods from one visit in which the primary focus was diabetes care to the next visit with the same focus. Patients were categorized as “regular SMBG performer” if, throughout the 3-year period, almost all visits documented frequency of SMBG and results. A patient was labeled “irregular SMBG performer” if there were few mentions of SMBG documented and/or if documentation did not contain the frequency of SMBG. Finally, patients were labeled “not monitored” if there was no mention of SMBG or if documentation noted that that patient was not monitoring.
Almost 21% of patients were regular SMBG performers, and 70% of these patients had HbA1c ≤8. For the 42% of patients who were irregular SMBG performers and the 37% of patients not monitoring, only 18 and 22%, respectively, had HbA1c ≤8 (P < 0.0001). Regularly monitoring and consistently discussing blood glucose appeared to be positively associated with a better glycemic control.
In summary, we should recognize the limitations of the Harris (1) study, not give it undo prominence or extend the data beyond its limited historical value, and consider the important and growing case for studies utilizing a treat-to-target approach. We believe that it is not the collection of blood glucose data but rather the effective use of blood glucose information for making clinical decisions that leads to improvements in diabetes control. Finally, we agree with Kennedy (2) that better studies are needed, but we believe that the studies should be large-scale observational studies of the usage of blood glucose data in normal clinical settings and stratified by therapy.
Address correspondence to Dr. Barry Ginsberg, VP of Medical Affairs, \E BD CHC, 1 Becton Dr., Franklin Lakes, NJ 07417. E-mail:.