1 / 37

GLUCOWATCH ® G2™ BIOGRAPHER H. PETER CHASE, MD

GLUCOWATCH ® G2™ BIOGRAPHER H. PETER CHASE, MD. INTRODUCTION ACCURACY DATA HOME PILOT TRIAL DIRECNET STUDY GROUP SUMMARY. GlucoWatch ® G2™ Biographer. GlucoWatch ® G2 ™ Biographer (GW2B). Measures interstitial glucose extracted by reverse iontophoresis

elwyn
Download Presentation

GLUCOWATCH ® G2™ BIOGRAPHER H. PETER CHASE, MD

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. GLUCOWATCH® G2™ BIOGRAPHERH. PETER CHASE, MD • INTRODUCTION • ACCURACY DATA • HOME PILOT TRIAL • DIRECNET STUDY GROUP • SUMMARY

  2. GlucoWatch® G2™ Biographer

  3. GlucoWatch® G2™ Biographer (GW2B) • Measures interstitial glucose extracted by reverse iontophoresis • Requires a single calibration value following the 2-hour warm-up period • Glucose readings every 10 minutes for 13 hours • Values range from 40 to 400 mg/dL

  4. GlucoWatch G2 Biographer INTRODUCTION i) Second generation model (G2B) ii) Warm-up 2 hours  enter BG value iii) Reverse iontophoresis: AAA battery iv) Pulls interstitial fluid (including glucose) into gel discs in Auto Sensor v) Readings as often as every 10 min for up to 13 hrs (max = 76 readings; Ave = 55)

  5. INTRO: G2B vi) Numerous data integrity checks are performed that monitor environmental factors (temperature, sweating), sensor function, and performance. If the reading fails the data integrity checks, it is skipped because the value may be incorrect. vii) The G2 Biographer averages the reading obtained in the most recent cycle with the reading obtained in the previous 10 minute cycle.

  6. INTRO: G2B vii) Alarms for: • Hypo/hyper-glycemia (level set by user) • Pending low in next 10-20 minutes • Low or drop 30 minutes prior to detection of sweat viii) Up or down arrows with change of 9mg/dl

  7. INTRO: G2B: Major uses: i) Nocturnal hypoglycemia ii) Postprandial hyperglycemia iii) Hypoglycemic unawareness iv) Gestational diabetes v) Type 2 diabetes vi) Other (e.g. Glycogen Storage Dis.)

  8. G2B: Positives: • Detection of lows – particularly during the night • Making aware of post-prandial highs • “Watchdog” effect • Detecting “patterns” • e-mailing data to MD or RN

  9. INTRO: G2B:Negatives: • Skipped readings with sweating • Not always awakening for alarm • Not waterproof • Skin itching, blisters, (remove sensor with Unisolve®) (adults > youth) • Won’t take first calibration (6%) due to sweat, rapid BG change, weak signal • Other skipped readings

  10. Side Effects • No serious skin reactions • No other problems MildIrritation example ModerateIrritation example

  11. GlucoWatch Function • Sensor calibration • 1st attempt 94% • 2nd attempt 2% • Failed 4% • Sensor lifespan* • ≥14.5 hours (Full) 81% • 10.0 to 14.5 hours 3% • 6.0 to 10.0 hours 6% • <6.0 hours 10% • Of 14,232 possible GW2B measurements • 17% were skipped • Excludes sensors stopped early for logistical reasons. DirecNet Data

  12. Analyzer Features Analyzer alert settings may differ from Biographer settings Biographer DOWN alerts 220 mg/dL 160 mg/dL Trend arrows not shown on Analyzer screen

  13. Part II: ACCURACY STUDIES IN CHILDREN • Eastman RC, Chase HP, Buckingham B, et al. Pediatric Diabetes 3:127, 2002 • Clinic setting • 3 First GW Biographers/subject • Multiple wear sites • Compared to HemoCue® meter

  14. ACCURACY STUDIES IN CHILDREN • DirecNet Study Group • i) Inpatient • ii) 2 – 4 G2Bs/subject • iii) Upper and lower arm sites • iv) Compared to hospital lab BG

  15. ACCURACY STUDIES IN CHILDREN GWB G2B (Pediatric Diabetes) (DirecNet) Settings Clinic (14 Hr) Inpatient (26 Hr) No. Youth 66 (11.9 yrs) 89 (9.9 yrs) Sensors 198 285 Comparisons 1313 3,659 Skipped Readings: 14% 17%

  16. ACCURACY STUDIES IN CHILDREN • GWB G2B • (Pediatric Diabetes) (DirecNet) • Mean Difference* -17 mg/dl 2.1 mg/dl • Absolute Difference** 34 mg/dl 30.8 mg/dl • iii) MARD*** 21% 22% • *Mean Difference = Sensor value – Lab value • **Absolute Difference= Absolute value of difference • **MARD = Mean Absolute Relative Difference = • Sensor value – lab value x 100 • lab value

  17. ACCURACY STUDIES IN CHILDREN GWB G2B (Pediatric Diabetes) (DirecNet) iv) Correlation Coef. 0.82 0.86 v) Consensus Error 97% 97% Grid (A + B) vi) Paired Values 76% 74% within 20%

  18. ACCURACY STUDIES IN CHILDREN:HYPOGLYCEMIA Overnight Hypoglycemia (<70mg/dl) • 18 episodes by G2B (DirecNet) • 2) 10 episodes = Lab glucose matched • 8 episodes = not confirmed

  19. 4/7 4/8 4/9 4/10 0534 BG-54 0405 BG-44 True lows detected by alarm 13 yo on CSII Basal rates had been erased Accidentally put in rates 12 hours off

  20. 4/13 4/12 BG 177 13 yo on CSII with correct/new basal rates in place HbA1c = 7.4%

  21. Part III: HOME PILOT STUDY Use of the GlucoWatch Biographer (GWB) in Children with Type 1 Diabetes (T1DM) Chase HP, Roberts MD, Wightman C, Klingensmith G, Garg SK, et al. Pediatrics 111:790-794,2003. Objective: To determine the usefulness of the GWB for: 1) detection of hypoglycemia 2) improving glucose control in children and adolescents with T1DM in a home environment

  22. 40 Randomized Study Subjects • Age 7-17 years; mean = 12.4 yrs • Type 1 diabetes 1 yr (mean = 6.3 yrs) • HbA1c >8% on 2 occasions during prior 6 months • Absence of clinically significant disease or condition that would interfere with participation in the trial • No history of severe hypoglycemia for 6 months preceding entry into the trial (many had prior history of severe hypoglycemia >6 months before study) • Willingness to be randomly assigned to standard care or standard care with Biographer monitoring 4 times/week

  23. Study Plan • Randomization to two treatment groups • standard care in the home environment • standard care in the home environment with GlucoWatch Biographer monitoring • Biographer alerts set to 70 and 300 mg/dL • Confirmation of alerts by conventional blood glucose monitoring • Both groups: weekly review of SMBG data (±GWB data) and a phone call from HPC

  24. Outcome Measures • HbA1c measured at baseline, and at 1 and 3 months (DCA-2000) • Hypoglycemia events determined - Biographer alert = 70 mg/dl - Hypoglycemic event = SMBG <70 mg/dl • Surveys • Fear of Hypoglycemia • Quality of Life (DCCT)

  25. GWB: HOME USE Week 1-45-89-13 #Uses/wk 4.1 3.7 3.0 %Hi BG* 4.7 2.5 3.1 %Lo BG* 14.2 16.6 16.5 *GWB readings

  26. Frequency of Hypoglycemia Home Meter Blood Glucose < 70 mg/dL * * * * * * * p<0.05versuscontrol

  27. Median HbA1c by Group vs. Time * * p<0.05 versus control group

  28. Summary and Conclusions • Biographer use was well tolerated in the home environment • HbA1c was significantly lower (p<0.05) in the Biographer treatment group compared to the control group after 3 months of treatment • Biographer users detected significantly more hypoglycemia during the day and night than non-users • The Biographer is useful for improving glucose control and detecting hypoglycemia in children and adolescents with type 1 diabetes

  29. Reduction in Complications:Eastman RC, Chase HP and Leptien AD Pediatric Diabetes 4:82-86, 2003 • Using DCCT data, a decline in HbA1c from 9.0 to 8.4 for 100 subjects for a lifetime would: • Prevent severe eye disease in 20 people • Prevent blindness in 6 people • Prevent gross kidney damage in 20 people (8 needing transplants) • Prevent 6 cases of neuropathy

  30. Slept through alarms 4/15 4/19 0805 BG 305 4/18 1059 BG 259 0733 BG 138 2008 BG 56 Picked up low at calibration 2 GWB tracings Pre-teen girl IDDM x 5yrs Patient at slumber party

  31. 4/25 5/2 1736 bg350 0908 bg245 1759 bg215 1357 bg175 Went to office No snack given 1009 bg45 1151 bg80 Low alarm at same time as last week (1530) No bg test 1511 Piano teacher gave candy but did not test Pre-teen girl IDDM x 5yrs

  32. Part IV: DIRECNET STUDY GROUP DIabetes REsearch in Children NETwork • NIH funded collaborative study group (NICHD and NIDDK) • 5 Centers: Denver, Iowa, Nemours (FL), Stanford and Yale. • + Coordinating Center: = Jaeb Center for Health Research, Tampa, FL

  33. DIRECNET STUDY GROUP • Objective = to critically evaluate the clinical usefulness of current and future glucose sensors in youth with T1DM. • Initial inpatient study= accuracy of G2B and of CGMS. Abstracts #156 OR, • #432-P and #387-P . • v) Next study: Similar to the GWB Pilot Trial done in Denver, but with 200 children x 6 months.

  34. Part V: SUMMARY Purpose of the GlucoWatch Biographer: To detect trends and to track patterns in glucose levels as a supplement to SMBG (not to replace SMBG). Conclusion: The level of accuracy is sufficient for detecting trends. Pilot data shows the GWB is useful for improving glycemic control and detecting hypoglycemia in children and adolescents with T1DM.

More Related