Diabetes Care 28: , 2005

Transcription

1 Emerging Treatments and Technologies O R I G I N A L A R T I C L E Youth and Parent Satisfaction With Clinical Use of the GlucoWatch G2 Biographer in the Management of Pediatric Type 1 Diabetes THE DIABETES RESEARCH IN CHILDREN NETWORK (DIRECNET) STUDY GROUP* OBJECTIVE A continuous glucose monitor satisfaction scale (CGM-SAT) was evaluated during a 6-month randomized controlled trial of the GlucoWatch G2 Biographer (GW2B) in youths with type 1 diabetes. RESEARCH DESIGN AND METHODS At the end of the 6-month trial, 97 parents and 66 older children who had been randomized to the GW2B group completed the CGM-SAT, which assesses satisfaction on 37 items using a five-point Likert scale. Descriptive analysis, calculation of several reliability estimates, and assessment of concurrent validity were performed. RESULTS The CGM-SAT demonstrated high internal reliability (Cronbach s 0.95 for parents and 0.94 for youths aged 11 years), split-half reliability ( 0.91 for parents and 0.93 for youths), and parent-adolescent agreement ( 0.68, P 0.001). Convergent validity was supported by marginally significant associations with treatment adherence and frequency of GW2B use. CGM-SAT scores did not correlate significantly with changes in treatment adherence, quality of life, or diabetes-related anxiety from baseline to 6 months. Mean scores on CGM-SAT items indicated that 81% of parental responses and 73% of youths responses were less favorable than neutral. Descriptive analysis indicated the GW2B requires substantial improvement before it can achieve widespread clinical utility and acceptance. CONCLUSIONS The results supported the psychometric properties of the CGM-SAT. The CGM-SAT warrants further research use and cross-validation with other continuous glucose monitors. This study provides a benchmark for comparison with new glucose sensors. The Diabetes Control and Complications Trial (1) elevated the importance of achieving tight glycemic control without increasing severe hypoglycemia (2,3). Pursuit of these difficult competing goals has stimulated development of continuous glucose monitoring Diabetes Care 28: , 2005 (CGM) devices to supplement conventional self-monitoring of blood glucose (SMBG) in the management of type 1 diabetes. Several CGM devices have received Food and Drug Administration (FDA) approval for such applications (4,5). These devices read blood glucose From the DirecNet Coordinating Center, Jaeb Center for Health Research, Tampa, Florida. Address correspondence and reprint requests to Tim Wysocki, PhD, ABPP, c/o DirecNet Coordinating Center, Jaeb Center for Health Research, Amberly Dr., Suite 350, Tampa, FL direcnet@jaeb.org. Received for publication 23 February 2005 and accepted in revised form 4 May *A complete list of DirecNet Study Group members can be found in the APPENDIX. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances. Abbreviations: CGMS, continuous glucose monitoring system; CGM-SAT, continuous glucose monitor satisfaction scale; FDA, Food and Drug Administration; GW2B, GlucoWatch G2 Biographer; SMBG, selfmonitoring of blood glucose by the American Diabetes Association. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. levels frequently and automatically, providing a near-continuous glucose profile that can augment conventional SMBG. Two CGM devices, the GlucoWatch G2 Biographer (GW2B; Cygnus, Redwood City, CA) and the continuous glucose monitoring system (CGMS; Medtronic Minimed, Northridge, CA), are FDAapproved for use as supplements to SMBG. The technology may eventually replace conventional SMBG. Future CGM devices may be sufficiently accurate and reliable to permit automatic continuous adjustment of insulin administration via an insulin pump. Accuracy of current CGM devices is lower than that of available home glucose meters (6,7), but they could still yield clinical benefits. Regardless, it is likely that existing CGM devices will be refined and improved (8 11). Evaluation of satisfaction with CGM use would be valuable at this early point in the emergence of this technology, but no validated measures exist. CGM could change diabetes care greatly, with increased breadth and amount of blood glucose data and increased feedback about glycemic effects of treatment events. There are many potential benefits of CGM augmentation of diabetes care (12,13). CGM could enhance the capacity to achieve tight glycemic control while minimizing severe hypoglycemia. These potential benefits may also yield psychological benefits, such as improved treatment adherence, reinforcement of concepts taught in diabetes education, reduced anxiety about hypoglycemia, and improvement of diabetes self-efficacy (12,13). CGM also carries the potential for adverse psychological effects such as increasing the diabetes treatment burden, overwhelming patients or parents with the amount of resultant data, invading patients privacy and intruding into their social lives, and aggravation of family conflict surrounding glycemic control. Among those who experience these pit- DIABETES CARE, VOLUME 28, NUMBER 8, AUGUST

2 Continuous glucose monitoring in diabetes falls, CGM use would likely be dissatisfying and of limited benefit. Recently, DirecNet (Diabetes Research in Children Network), which is a National Institutes of Health funded research consortium, completed a 6-month randomized trial of 200 youths aged 7 17 years with type 1 diabetes comparing management of type 1 diabetes based on conventional SMBG alone versus conventional SMBG supplemented with use of the GW2B. Since there were no available measures of satisfaction with use of CGM devices, the investigators constructed the CGM satisfaction scale (CGM-SAT) for that trial. This is a five-choice Likert scale that seeks respondents ratings of 37 aspects of CGM satisfaction and therapeutic impact. The instrument was designed as a research tool to be useful in evaluations of current and future CGM devices that provide direct glucose feedback and alarms that warn of glycemic extremes. Parents and youths aged 11 years in the GW2B group completed the scale at the conclusion of the 6-month trial. The objectives of this report were to evaluate the psychometric properties of the CGM-SAT and to analyze patient and parent satisfaction with use of a near real-time CGM device. RESEARCH DESIGN AND METHODS The study was conducted by a network of five clinical centers, a coordinating center, and a central laboratory. An external data and safety monitoring board and the institutional review board at each center approved the study protocol, informed consent form, and assent form. A parent or guardian gave written consent and children gave written assent before any study procedures were performed. The protocol described in a separate publication (14) is summarized below. Participants and randomization To be eligible, a subject had to be between 7 and 18 years old, have type 1 diabetes with use of insulin for at least 1 year, have an HbA 1c (A1C) level between 7.0 and 11.0% inclusive, and be on a stable insulin regimen (either insulin pump or two or more daily injections) for the prior 2 months with no plans to switch modality of insulin administration during the next 6 months. Exclusion criteria included prior home use of a GW2B, use of corticosteroids within the last 6 months, or presence of another chronic illness. The sample size for the trial was based on the desire to detect a difference in A1C of 0.5% between the GW2B or usual care groups after 6 months in their respective treatments. Between July 2003 and January 2004, 200 subjects entered the trial (40 at each of the five clinical centers), with 99 randomized to the GW2B group and 101 to the usual care group. Since families were selected for enrollment by the participating physicians, virtually all who were approached agreed to enroll. The average age of youths in the GW2B group was years, 45% were female and 85% were Caucasian, 6% were African American, 2% were Asian, 2% Hispanic, 4% multiple races, and 1% unknown race. Educational attainment for fathers and mothers was 24 and 16% postgraduate degrees, 35 and 35% bachelors degrees, 16 and 17% associates, 23 and 31% high school diploma, and 1 and 1% less than high school, respectively. Mean diabetes duration was years. Insulin modality was multiple daily injections for 54% and insulin pump for 46%. Mean baseline A1C was 8.0%, with 41% 8.0%. Procedures Subjects in the GW2B group were provided with a GW2B and an unlimited number of sensors. The GW2B resembles a large wristwatch that adheres to the skin via a sensor that draws interstitial fluid through the skin and displays the estimated glucose level every 10 min for up to 13 h. Audible alarms signal high, low, and rapidly falling glucose levels. The data are stored in memory for computer analysis. Subjects were encouraged to use sensors as often as desired, using a minimum of four sensors during the 1st week and then at least two sensors weekly thereafter (with use of at least one sensor weekly during sleep). Subjects were given a personal computer for home use to download SMBG and GW2B data and view glucose results weekly. All subjects were asked to complete a weekly computerized hypoglycemia questionnaire. The GW2B group was also asked to report problems with using the device. Phone contacts were made after 1, 2, and 4 weeks and then monthly through 6 months to review diabetes management. Follow-up visits occurred at 3 and 6 months. At each visit, measures included A1C, frequency of GW2B use, problems encountered with its use, and episodes of hypoglycemia. A standardized assessment of skin reactions attributable to GW2B use was performed. CGM-SAT An initial pool of 34 items was compiled by one of the authors (T.W.) after consultation with other psychologists who were familiar with pediatric diabetes and its management regarding possible affective, behavioral, or cognitive effects of CGM use. The intent in designing the scale was to create a measure of satisfaction and perceived therapeutic impact of current and future CGM devices. The scale is relevant to CGM devices that provide frequent and immediate glucose information and alarms to signal unwanted glucose fluctuations. Based upon the researchers collective knowledge of the technology in development, it was the group consensus that these features would characterize most future CGM devices. The initial scale items were drafted and then reviewed for content, format, and wording by the entire DirecNet research group, which includes 11 physicians, 10 registered nurses, a psychologist, and 4 other research professionals. Following several iterations of this review and editing process, a CGM-SAT scale consisting of 37 items was finalized, with a Flesch-Kincaid grade level of 5.3, as calculated by Microsoft Office 2000 (Microsoft, Redmond, WA). At 6 months, the CGM-SAT was completed. The CGM-SAT consists of 37 statements about CGM use, and respondents rate their agreement or disagreement with each statement on a five-point Likert scale. Among the 37 items, 19 are negatively worded (e.g., the CGM is uncomfortable or painful ) and 18 are positively worded (e.g., the CGM makes adjusting insulin easier ). For the latter 18 items, responses were reverse scored such that higher scores indicate more favorable satisfaction or greater benefit. Positively and negatively worded items were distributed nonsystematically throughout the sequence of questions. CGM-SAT scores could range from 37 to 185. The questionnaire was completed independently using a tablet personal computer by parents and youths aged 11 years on the coordinating center s secure website. Based on prior experience with similar measures, the researchers felt that many children aged 11 years would 1930 DIABETES CARE, VOLUME 28, NUMBER 8, AUGUST 2005

3 The DirecNet Study Group have difficulty interpreting certain CGM- SAT items, and so it was administered only to older children. The computerized administration of the CGM-SAT required entry of a response to every item before submission. Among GW2B participants completing the trial, 97 of 98 parents and 66 of 67 youths aged 11 years completed the CGM-SAT at the 6-month visit. Other questionnaires At baseline and 6 months, parents and youths aged 11 years also completed the Diabetes Worry Scale (15) and the age-appropriate form of the PedsQL diabetes module (16), a diabetes-specific quality-of-life scale. Finally, parents and older youths were interviewed by telephone at baseline and 6 months with the Diabetes Self-Management Profile (17), a structured interview about diabetes selfmanagement. Previous studies (15 17) have demonstrated that each of these measures has adequate psychometric properties. Statistical analyses CGM-SAT scores were summarized with means SD. The Kolmogorov-Smirnov test was used to verify normality of distributions. We calculated internal consistency (Cronbach s ), average interitem correlation, and split-half reliability (Pearson correlation between the evennumbered and odd-numbered items) separately for parents and youths. Associations between CGM-SAT scores and other continuous variables were calculated using Pearson correlation. Since multiple comparisons were performed, only P values 0.01 were considered statistically significant. With regard to associations between CGM-SAT scores and the other psychological measures that were obtained, we anticipated that higher CGM-SAT scores (greater satisfaction) would be associated with more favorable quality of life (PedsQL), better overall treatment adherence (Diabetes Self- Management Profile), and lower diabetesrelated anxiety (Diabetes Worry Scale). Finally, change in the PedsQL, Diabetes Self-Management Profile, and Diabetes Worry Scale scores during the 6-month study were examined as correlates of CGM-SAT scores. RESULTS Summary of clinical trial results As described elsewhere (14), 98 (99%) of 99 subjects in the GW2B group completed the 6-month trial. Mean A1C was 8.0% at baseline and 8.1% at 6 months (P NS). During the 1st month, the number of sensors used averaged weekly, while the number of sensors with 8 h of use averaged weekly. Only 16% of the subjects averaged at least 2.0 uses of 8 h per week, and none averaged 4.0 per week. By the 3rd month, 7 (7%) of 99 subjects stopped using the GW2B, and by the 6th month, 26 (27%) of 98 subjects had done so. Skin irritation from the GW2B was reported at least once during the 6 months by all 99 subjects. At the 6-month visit, 54 (55%) subjects were considered to have acute GW2B-related changes (mild in 36%, moderate in 19%, and severe in 0). Nonacute changes (e.g., scabbing, dry skin, hypopigmentation, hyperpigmentation, or scarring) occurred in 50 (51%) children. Reasons given for declining use included skin irritation (76%), frequent skips (periods of varying duration in which no glucose estimate is displayed) (56%), excessive alarms (47%), and inaccurate readings (33%). Descriptive analyses Means SD total scores on the CGM-SAT (maximum possible score 185) were for parents and for youths. Total scores ranged from 44 to 154 for parents and 54 to 154 for youths. Total scores were normally distributed for parents and youths according to the Kolmogorov-Smirnov test. Table 1 presents means and SD scores (after reverse scoring) for each CGM-SAT item for youths and parents, as well as the correlation coefficient for each item with the total score. Parents mean responses were 3.0 (neutral) for 30 of 37 items (81%), and for youths, 27 of 37 mean responses (73%) met this criterion. The items that obtained the three lowest mean scores (lower satisfaction) and the three highest mean scores (higher satisfaction) were identified to further describe the CGM-SAT findings. The three lowest mean scores (1.9 in each case) for parents, indicating low satisfaction with the GW2B, were on item 33 (interferes a lot with sports, playing outside, etc.), item 16 (is uncomfortable or painful), and item 32 (shows more glitches and bugs than it should). The three lowest mean scores for youths were for item 16 (is uncomfortable or painful; mean 1.8), item 22 (allows more freedom in daily life; mean 2.0), item 18 (is more trouble than it is worth; mean 2.2), item 19 (has helped my family to get along better about diabetes; mean 2.2), item 33 (interferes a lot with sports, playing outside, etc.; mean 2.2), and item 36 (causes too many interruptions during the day; mean 2.2). The items with the three highest mean scores for parents, indicating the aspects of CGM use that were less dissatisfying, were item 1 (causes me to be more worried about controlling blood sugars; mean 3.6), item 29 (causes our family to talk about blood sugars too much; mean 3.5), item 14 (sometimes gives too much information to work with; mean 3.5), and item 5 (makes me think about diabetes too much; mean 3.5). The items with the three highest mean scores for youths, indicating the aspects of CGM use that they found less dissatisfying, were item 29 (causes our family to talk about blood sugars too much; mean 3.5), item 25 (has caused more family arguments; mean 3.4), and item 1 (causes me to be more worried about controlling blood sugars; mean 3.4). Internal consistency Cronbach s was 0.95 for parents and 0.94 for youths, and average interitem correlations were 0.33 for parents and 0.30 for youths. Split-half reliability was r 0.91 for parents and 0.93 for youths. Table 1 also presents correlation coefficients for parents and adolescents for each item with the CGM-SAT total score. The average item-total correlation was 0.59 for parents and 0.57 for adolescents, and the range across items was for parents and 0.03 to 0.77 for adolescents. Items with extremely high itemtotal correlation coefficients could be considered for deletion in subsequent studies using this instrument. Comparison of parent-youth dyads For the 66 cases where both parent and youth (aged 11 years) completed the CGM-SAT, the correlation between their scores was 0.68 (P 0.001). DIABETES CARE, VOLUME 28, NUMBER 8, AUGUST

4 Continuous glucose monitoring in diabetes Table 1 Mean scores on each CGM-SAT item for parents and youths, proportion of respondents endorsing each response alternative Using the continuous monitor Mean score Item-total correlation Youths (n 66) Agree strongly Agree Neutral Disagree Disagree strongly 1. Causes me to be more worried about controlling blood % 20% 27% 30% 18% sugars 2. Makes adjusting insulin easier* % 23% 30% 15% 27% 3. Helps me to be sure about making diabetes decisions* % 20% 29% 23% 23% 4. Causes others to ask too many questions about diabetes % 26% 24% 23% 8% 5. Makes me think about diabetes too much % 21% 29% 27% 14% 6. Helps to keep low blood sugars from happening* % 27% 20% 24% 18% 7. Has taught me new things about diabetes that I didn t % 18% 27% 29% 20% know before 8. Causes too many hassles in daily life % 33% 18% 23% 5% 9. Teaches me how eating affects blood sugar % 32% 26% 27% 12% 10. Helps me to relax, knowing that unwanted changes in % 21% 27% 30% 14% blood sugar will be detected quickly* 11. Has helped me to learn about the right amount of % 9% 21% 45% 20% exercise* 12. Helps with keeping diabetes under control on sick % 18% 33% 21% 20% days* 13. Has convinced me that blood sugar is predictable and % 14% 30% 35% 20% orderly* 14. Sometimes gives too much information to work with % 17% 33% 33% 12% 15. Has made it easier to accept doing blood sugar tests* % 20% 33% 27% 15% 16. Is uncomfortable or painful % 21% 12% 9% 3% 17. Has helped me to learn how to treat low sugars better* % 20% 27% 35% 15% 18. Is more trouble than it is worth % 29% 12% 20% 2% 19. Has helped my family to get along better about % 5% 33% 38% 23% diabetes* 20. Shows patterns in blood sugars that we didn t see % 35% 21% 23% 11% before* 21. Helps prevent problems rather than fixing them after % 23% 33% 26% 14% they ve happened* 22. Allows more freedom in daily life* % 8% 9% 45% 33% 23. Makes it clearer how some everyday habits affect % 23% 42% 17% 15% blood sugar levels* 24. Makes it easier to complete other diabetes self care % 12% 38% 30% 15% duties* 25. Has caused more family arguments % 15% 26% 24% 26% 26. Is too hard to get working right* % 27% 14% 20% 8% 27. Has been harder or more complicated than expected % 26% 23% 21% 5% 28. Has helped to control diabetes better even when not % 8% 32% 36% 18% wearing it* 29. Causes our family to talk about blood sugars too much % 11% 21% 45% 15% 30. Makes it harder to sleep % 33% 9% 15% 14% 31. Causes more embarrassment about feeling different % 12% 26% 29% 17% from others 32. Shows more glitches and bugs than it should % 18% 24% 24% 3% 33. Interferes a lot with sports, playing outside, etc % 26% 12% 15% 6% 34. Skips too many readings to be useful % 27% 23% 12% 5% 35. Gives a lot of results that don t make sense % 30% 27% 21% 2% 36. Causes too many interruptions during the day % 38% 23% 14% Alarms too often for no good reason % 26% 24% 20% 5% *Indicates that items were reverse scored so that higher scores always indicate more satisfaction DIABETES CARE, VOLUME 28, NUMBER 8, AUGUST 2005

5 The DirecNet Study Group Table 1 Continued Mean score Item-total correlation Parents (n 97) Agree strongly Agree Neutral Disagree Disagree strongly % 15% 32% 30% 22% % 26% 27% 30% 14% % 31% 25% 29% 12% % 21% 23% 33% 18% % 11% 29% 37% 18% % 35% 20% 26% 14% % 35% 18% 27% 16% % 31% 25% 12% 6% % 33% 36% 21% 9% % 22% 25% 29% 20% % 8% 38% 38% 14% % 20% 43% 24% 10% % 9% 15% 37% 37% % 18% 25% 44% 11% % 12% 39% 30% 16% % 39% 16% 5% 1% % 33% 41% 12% % 20% 21% 18% 3% % 33% 37% 20% % 49% 20% 16% 6% % 33% 27% 26% 10% % 30% 35% 24% % 32% 18% 8% % 40% 30% 13% % 24% 26% 22% 20% % 28% 21% 15% 4% % 36% 9% 19% 4% % 16% 24% 41% 16% % 12% 27% 49% 8% % 29% 15% 23% 2% % 20% 31% 34% 10% % 36% 16% 4% 1% % 26% 16% 9% 2% % 30% 25% 8% % 36% 24% 14% 2% % 33% 31% 11% 2% % 35% 19% 13% 5% Associations between CGM-SAT scores and other measures For parent CGM-SAT responses, a suggestive trend that did not meet the P 0.01 level for significance was observed with frequency of GW2B use (94 24 vs vs among patients averaging 1.0, 1.0 to 2.0, and 2.0 weekly GW2B uses, respectively; 0.23, P 0.02). Neither CGM-SAT total or subscale scores correlated significantly with patient age or change in A1C from baseline to 6 months. CGM-SAT total scores did not correlate significantly with either 6 months or change in total scores from baseline on either the PedsQL or Diabetes Worry Scale among parents or adolescents. CONCLUSIONS A 6-month randomized trial comparing the glycemic effects of current diabetes management with and without supplemental use of an FDA-approved CGM device (GW2B) provided the context for initial validation of a measure of satisfaction with and perceived therapeutic impact of CGM devices such as the GW2B and similar devices as they become available. The results of the study supported the psychometric properties of the CGM- SAT. The reliability of the instrument was supported by high coefficients from parents ( 0.95) and youths aged 11 years ( 0.94). Modest average interitem correlations and estimates of strong split-half reliability were also obtained with parents and youths responses. Also, parent and adolescent scores were strongly correlated (r 0.68, P 0.001). The high internal consistency coefficients suggest that the scale may contain redundant items. Table 1 presents the item-total correlations for each item for parents and adolescents separately. Those items with very high item-total correlation coefficients may be candidates for deletion in subsequent iterations of the CGM-SAT. However, item deletion is probably inappropriate until the performance of the CGM-SAT can be evaluated with other CGM devices. The convergent validity of the instrument was supported weakly by marginal associations between parent scores and frequency of GW2B use and adolescent scores with overall diabetes treatment adherence. CGM-SAT scores were not associated with scores on a measure of diabetes-related anxiety (Diabetes Worry DIABETES CARE, VOLUME 28, NUMBER 8, AUGUST

6 Continuous glucose monitoring in diabetes Scale) or diabetes-specific quality of life (PedsQL diabetes module) following 6 months of GW2B use or with changes in scores on those measures over 6 months. In the trial, use of the GW2B did not improve metabolic control. The failure to observe a significant effect of the GW2B on diabetes control may be because subjects used the sensor too infrequently to affect glycemic control. At the start of the study, participants were given the device and offered an unlimited free supply of sensors, and they were encouraged during telephone contacts to use the GW2B frequently. However, GW2B use was considerably less than we had hoped. The CGM-SAT provides important insights into why this occurred. The data presented in this report yielded a detailed description of parents and older youths satisfaction with use of the device and provided substantial descriptive data that can serve as a standard for comparison in future evaluations of other CGM devices. Mean total scores on the CGM-SAT were 98.5 for parents and 98.3 for youths, yielding mean item scores of 2.7 for both. For most items (81% for parents and 73% for youths), the mean satisfaction rating was 3.0, indicating less than favorable reactions to GW2B use. These data suggest that the sample, in aggregate, was mildly dissatisfied with use of the GW2B. The absence of glycemic benefit from using the GW2B and the occurrence of skin irritation, frequent skips, excessive alarms, and inaccurate readings reported by study participants all probably contributed to the declining frequency of GW2B use to a mean of 1.5 times weekly during the last month. Glycemic benefit from use of a CGM device may require that it be used more continuously than occurred here. CGM-SAT items reflecting the least satisfaction among parents and youths concerned functional aspects of the instrument (skin problems, skipped readings, false alarms, inaccuracy). In contrast, those items that yielded mean ratings conveying less dissatisfaction related to psychological or behavioral effects of CGM use (e.g., anxiety, intrusiveness, family conflict, and information overload). Participants in the study were therefore more dissatisfied with the technical functioning of the device than they were about the psychological ramifications of using it. Psychological effects of CGM use may become more apparent as new devices are introduced and the existing devices are refined. Limitations of the report include the fact that it was based on data obtained from a sample of patients and parents who may not have been representative of all such families in terms of parental education, socioeconomic status, and motivation to optimize glycemic control. Further studies of the CGM-SAT with a more broadly representative sample of patients and parents will be needed to verify that the present findings apply more generally. The results point to aspects of the GW2B in particular, and perhaps CGM devices in general, that should be targeted for improvement in order for the technology to be clinically acceptable and effective. These include reducing skin irritation consequent to use of the device, decreasing the frequency of skips, reducing false alarms that alert the patient to erroneous glucose fluctuations, and improving the overall accuracy of the device. Since the GW2B is among the first such devices to have received FDA approval for clinical use, it is likely that future iterations of this technology will be designed in an effort to overcome these initial obstacles. APPENDIX Writing committee: Tim Wysocki, PhD, ABPP; Roy W. Beck, MD, PhD; William V. Tamborlane, MD; Rosanna Fiallo-Scharer, MD; Michael J. Tansey, MD; Stuart A. Weinzimer, MD; Craig Kollman, PhD; Katrina J. Ruedy, MSPH; and Dongyuan Xing, MPH. The DirecNet Study Group Clinical centers: listed in alphabetical order with clinical center name, city, and state. Personnel are listed as (PI) for principal investigator, (I) for coinvestigator, and (C) for coordinators. 1) Barbara Davis Center for Childhood Diabetes, University of Colorado, Denver, CO: H. Peter Chase, MD (PI); Rosanna Fiallo-Scharer, MD (I); Jennifer H. Fisher, ND, RN (C); Barbara Tallant, RN, MA (C). 2) Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA: Eva Tsalikian, MD (PI); Michael J. Tansey, MD (I); Linda F. Larson, RN (C); Julie Coffey, MSN (C). 3) Nemours Children s Clinic, Jacksonville, FL: Tim Wysocki, PhD, ABPP (PI); Nelly Mauras, MD (I); Larry A. Fox, MD (I); Keisha Bird, MSN (C); Kelly L. Lofton, RN (C). 4) Division of Pediatric Endocrinology and Diabetes, Stanford University, Stanford, CA: Bruce A. Buckingham, MD (PI); Darrell M. Wilson, MD (I); Jennifer M. Block, RN, CDE (C); Paula Clinton, RD, CDE (C). 5) Department of Pediatrics, Yale University School of Medicine, New Haven, CT: Stuart A. Weinzimer, MD (PI); William V. Tamborlane, MD (I); Elizabeth A. Doyle, MSN (C); Kristin Sikes, MSN (C). Coordinating center. Jaeb Center for Health Research, Tampa, FL: Roy W. Beck, MD, PhD; Katrina J. Ruedy, MSPH; Craig Kollman, PhD; Dongyuan Xing, MPH; Andrea Kalajian, MS; Cynthia R. Stockdale. National Institutes of Health. Gilman D. Grave, MD; Barbara Linder MD, PhD; Karen K. Winer, MD. University of Minnesota Central Laboratory. Michael W. Steffes, MD, PhD; Jean M. Bucksa, CLS; Maren L. Nowicki, CLS; Carol A. Van Hale, CLS. Data and safety monitoring board. Dorothy M. Becker, MBBCh; Christopher Cox, PhD; Christopher M. Ryan, PhD; Neil H. White, MD, CDE; Perrin C. White, MD. Acknowledgments Support provided by National Institutes of Health/National Institute of Child Health and Human Development Grants HD , HD , HD041890, HD , HD , and HD and by Nemours Research Programs. GlucoWatch G2 Biographers were purchased from Cygnus at a discounted price. References 1. Diabetes Control and Complications Trial Research Group: Effect of intensive diabetes treatment on the development and progression of long-term complications in adolescents with insulin-dependent diabetes mellitus: Diabetes Control and Complications Trial. 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