The effect of preapplication of corticosteroids on skin irritation and performance of the GlucoWatch G2 Biographer.

Skin irritation due to iontophoresis may limit the frequency of use of devices for drug delivery or transdermal extraction of analytes of clinical interest. This study examined whether preapplication of corticosteroid preparations could reduce skin irritation from iontophoresis used by the GlucoWatch G2 Biographer (Cygnus, Inc., Redwood City, CA) in monitoring interstitial glucose levels frequently and automatically. Numerous corticosteroid preparations were screened to identify formulations that did not interfere with adhesion of the Biographer to the skin or glucose sensing. Kenalog (Westwood-Squibb Pharmaceuticals, Inc., Buffalo, NY) (triamcinolone acetonide) and Cortizone-10 Quick Shot (Pfizer, Inc., New York, NY) (hydrocortisone) sprays were selected and, in a double-masked, randomized, controlled trial, were applied to the forearms of 66 subjects with diabetes and allowed to dry. Biographers were applied and worn for 15 h, and home blood glucose measurements were taken every 30 min to assess accuracy. Irritation was assessed periodically by trained observers and study subjects. Skin irritation was reduced by both corticosteroid sprays, with the fraction of subjects who experienced moderate irritation reduced by 57% and 43% for the Kenalog and Cortizone-10 Quick Shot sprays, respectively. The treatment effect persisted at the 1-week assessment. Preapplication of these preparations did not affect the clinical utility of interstitial glucose readings. Preapplication of Kenalog or Cortizone-10 Quick Shot sprays significantly reduced skin irritation due to iontophoresis, and did not interfere with glucose measurements. This approach may enable the minority of users who experience moderate to severe skin irritation to use the Biographer more frequently for diabetes management.

Cost-effectiveness of use of the GlucoWatch Biographer in children and adolescents with type 1 diabetes: a preliminary analysis based on a randomized controlled trial.

OBJECTIVE: To conduct a preliminary analysis of the cost-effectiveness of the use of the GlucoWatch Biographer in the management of type 1 diabetes in children and adolescents. METHODS: The computer model used to analyze the cost-effectiveness of intensive diabetes treatment in the Diabetes Control and Complications Trial (DCCT) was modified to simulate cohorts of patients who participated in a small clinical trial at one center comparing standard and Biographer-assisted standard care. The model is a Monte Carlo simulation model that simulates the lives of individual patients. Cohorts of 10,000 patients are simulated to accumulate statistics on average treatment costs and complications. Complication and treatment costs were updated to 2002 dollars. Future costs and benefits are discounted using a rate of 3%. The perspective of the analysis is from a single payer of health care costs. RESULTS: The model predicts that use of the Biographer, if sustained for the life of the cohort, would delay the development of the first serious diabetes complication by 4.1 yr. Treating 18 subjects would prevent one case of blindness and 1.4 cases of renal failure. The intervention costs $91,059/years-of-life (YOL), $61,326/quality-adjusted life-years (QALYs), and $9930/yr free of a major complication. If the biographer ceased to be effective after age 17, the cost per QALY would increase to $103,178/QALY gained. CONCLUSIONS: Preliminary analysis of the cost-effectiveness of use of the GlucoWatch Biographer in diabetes management is encouraging. Definitive analysis will require confirmation in other studies and populations.

Use of the Cygnus GlucoWatch biographer at a diabetes camp.

BACKGROUND: Detection and prevention of nocturnal hypoglycemia is a major medical concern at diabetes camps. OBJECTIVE: We conducted an open-label trial of the Cygnus GlucoWatch biographer to detect nocturnal hypoglycemia in a diabetes camp, a nonclinical environment with multiple activities. METHODS: Forty-five campers (7-17 years old) wore a biographer. The biographer was placed on the arm at 6:00 PM, with the low alarm set to 85 mg/dL (4.7 mmol/L). Overnight glucose monitoring occurred per usual camp protocol. Counselors were to check and record blood glucose values if the biographer alarmed. RESULTS: Biographers were worn for 154 nights by 45 campers. After a 3-hour warm-up period, 67% of biographers were calibrated, of which 28% were worn the entire night (12 hours). Thirty-four percent of readings were skipped because of: "data errors" (65%), sweat (20%), and temperature change (16%). Reported biographer values correlated with meter glucose values measured 11 to 20 minutes later (r = 0.90). Of 20 low-glucose alarms with corresponding meter values measured within 20 minutes, there were 10 true-positive alarms, 10 false-positive alarms, and no false-negative alarms. Campers reported sleep disruption 32% of the nights, and 74% found the biographer helpful. Campers reported they would wear the biographer 4 to 5 nights each week. CONCLUSIONS: Half of the biographer low-glucose alarms that had corresponding blood meter values were true-positive alarms, and the remaining were false-positive alarms. There was close correlation between the biographer and meter glucose values. The majority of campers found the biographer helpful and would use it at home.