KEYSTONE, COLO. – When it comes to self-monitoring of blood glucose, it’s not the quantity that matters, it’s the quality of the testing.
This was the central lesson of the Structured Testing Program (STeP) study, a 12-month, randomized, multicenter trial conducted in poorly controlled, non–insulin-treated type 2 diabetes patients. STeP showed that self-monitoring of blood glucose (SMBG) has clinical value in such patients, provided the testing is done in a structured way that facilitates timely treatment decisions by their primary care physician.
Dr. William Polonsky
Patients assigned to the structured SMBG intervention showed a significantly greater reduction in their mean glycosylated hemoglobin at 12 months than did active controls. They also evidenced significantly more shrinkage in their mean amplitude of glycemic excursions and greater quality of life improvement as reflected in depression and diabetes-related emotional distress scores, William H. Polonsky, Ph.D., reported at a conference on the management of diabetes in youth.
"The most interesting thing is how the study impacted physicians," said Dr. Polonsky at the conference sponsored by the University of Colorado and the Children’s Diabetes Foundation at Denver. "Use of the testing form to create a blood glucose snapshot for quarterly review contributes to more aggressive treatment intensification."
The various salutary changes documented in the STeP study were achieved using a relatively modest but carefully considered intervention: that is, patients randomized to structured SMBG were asked to measure their blood glucose seven times per day on 3 consecutive days within 2 weeks prior to the quarterly diabetes-focused visit with their primary care physician.
Patients recorded and graphed these 21 blood glucose readings using the Roche Diagnostics Accu-Chek 360 View analysis system. They brought the form with them to the quarterly office visit.
Patients could do as much or as little testing as they wanted during the rest of each 3-month period. It was only those 21 measurements obtained on 3 consecutive days once every 3 months that served as the basis for physician/patient discussion and treatment modifications. In fact, patients in the intervention arm achieved greater improvement in HbA1c than did controls while using significantly fewer blood glucose test strips, said Dr. Polonsky, founder and CEO of the Behavioral Diabetes Institute and a psychologist at the University of California, San Diego.
"This points to perhaps the most important outcome of this study: It’s not the blood glucose testing quantity that we should be thinking about, it’s the quality," he said "The goal here is to reconsider what blood glucose monitoring can be. It really can and should be a powerful motivational tool. It hasn’t typically ever been used in that way. Too often it’s a demotivational tool."
The STeP study involved 483 poorly controlled patients with type 2 diabetes in 34 primary care practices. Their mean baseline hemoglobin A1c was 8.9%, with a body mass index of 35.1 kg/m2 and a 7.6-year disease duration. Patients in the intervention and active control/usual care arms received a free blood glucose meter and test strips and were instructed in their use at the baseline visit.
Primary care physicians in practices assigned to the intervention received 2 hours of training in how to interpret and make lifestyle and/or medication changes based on their patients’ structured SMBG charts; the patients themselves got a DVD explaining their task. All STeP participants met with their physician in a diabetes-focused visit at months 1, 3, 6, 9, and 12.
Mean HbA1c fell from 8.9% to 8.0% over the course of 12 months in controls and dropped significantly more, to 7.7%, in the structured SMBG group. Moreover, among the 130 patients in the intervention arm who adhered to the intervention protocol by completing at least 80% of their quarterly forms, the mean HbA1c at 12 months was 7.6%, while in nonadherent patients, the final HbA1c was the same as that of control patients. A significant drop from months 1 to 12 was seen in preprandial to postprandial glucose excursions at all meals in the structured SMBG group.
At the 1-month visit, 76% of patients in the intervention arm received a medication and/or lifestyle change recommendation from their primary care physician, compared with 28% of controls. Over the course of 12 months, patients in the structured SMBG group received a treatment change during a mean of 2.7 out of their 5 office visits, while those in the usual care arm received a treatment change at a mean of 1.1 visits.
Scores on the Patient Health Questionnaire depression screening instrument (PHQ-8) dropped significantly in both study arms over the 12 months, but the reduction was significantly greater in the structured SMBG arm. Moreover, when the analysis was restricted to subjects having an elevated baseline depression score of greater than 10 on the PHQ-8, the intervention group showed a dramatic, nearly 6-point reduction over the study period, a 2.4-point greater drop in depressive mood and symptoms than that seen in controls.