Improving Metabolic Control and Reducing Hypoglycemic Risk in Type 1 Diabetes Mellitus With Biological and Behavioral Feedback

Subjects were randomized into group A or group B matched by gender, age, and baseline HbA1c. Group A began with routine self-monitored blood glucose (SMBG) alone (level 1), followed sequentially by IBMF-1 (level 2) and IBMF-2 (level 3). Group B began with level 2, followed by level 3 and then level 1.

Each level continued for 3 months and proceeded as follows: level 1 was routine SMBG. Subjects were given LifeScan OneTouch UltraSmart meters (LifeScan Inc., Milpitas, CA) and free strips, and asked to perform SMBG four to five times per day. No additional instructions about the timing of SMBG or the interpretation of the data were given. No changes to treatment were recommended. At each visit, the subject was only asked about any health concerns or any new medications or change in insulin. This information was recorded but not used for feedback. Thus, level 1 should be regarded as a control condition, which was different from routine SMBG only because subjects were enrolled in a study and given free test strips.

IBMF-1 (level 2) retained level 1, but an HHC (hand-held computer) was given to the subjects, programmed to estimate HbA1c, risk for hypoglycemia (Low BG Index, LBGI), and glucose variability (Average Daily Risk Range, ADRR) using previously published algorithms. The subjects were asked to carry the HHC and enter all their glucose readings when per- forming SMBG. The estimates of HbA1c were updated weekly, and the estimates of risk for hypoglycemia and glucose variability were updated at each SMBG entry. Detailed instructions were provided on the meaning of these different types of glucose feedback; the study staff was available to answer any questions.

IBMF-2 (level 3) retained level 2, but the HHC asked subjects to provide symptom ratings when BG (blood glucose) was low and at an equal number of matching euglycemic readings. From these data, the HHC estimated a set of potentially significant symptoms of hypoglycemia for each individual, using an iterative algorithm following a previously published symptom significance estimation procedure. The patient manual for the HHC program is provided in supplementary data of published manuscript.