The purposes of this paper were to identify plausible elements of the psychological context of CGM use that may influence its incorporation into T1DM therapy and to illustrate the interactions among these variables during a recently completed randomized trial of one CGM device, the GlucoWatch G2 Biographer. The results of the randomized trial, as summarized in separate publications (19
), revealed little glycemic benefit from use of the GW2B, declining use of the GW2B over time and modest satisfaction ratings. In an effort to explore the psychological context of CGM use, selected psychosocial measures were obtained during the trial and their associations with other study measures were evaluated.
In general, the study revealed little evidence that GW2B use resulted in either beneficial or adverse psychological effects on either parents or older youths. None of the changes in scores on the DSMP, DWS, or PedsQL differed significantly between the UC and GW2B groups at the end of the study. As reported elsewhere (manuscript under review), CGM-SAT scores generally indicated minimal benefit from GW2B use, although there was a marginal positive correlation between overall satisfaction and frequency of GW2B use during the study. The absence of adverse psychological effects of GW2B use is also noteworthy, suggesting that the additional treatment burden entailed in its use was not a substantial source of distress among parents or youths.
The study was designed with the assumption that GW2B use would be relatively stable over the 6-mo study period. This was not the case as GW2B use declined steadily during the study. It is possible that psychological effects of GW2B use might have been more discernible earlier in the study had measures been collected at more frequent intervals. Regardless, it is clear that no such effects persisted for 6 months.
Additional analyses were performed to examine psychosocial predictors of GW2B use. Better treatment adherence (DSMP) and quality of life (PedsQL) as reported by parents at baseline was associated with more frequent GW2B use during the study. Patients' reports of these same variables were not associated with frequency of GW2B use. Also, change in HbA1c was not correlated significantly with change in any of the psychosocial measures for either parents or adolescents.
The clinical importance of the present work rests on two points. First no adverse effects of GW2B use on the psychological measures obtained in this study were evident despite the absence of glycemic benefit from its use. Second, the majority of participants (73%) continued using the GW2B throughout the study, although less often. These observations suggest that GW2B use was not unduly burdensome to most patients and families, although presumably those who found it intolerable simply stopped using it.
It should be noted that, relative to recent study samples in which the same psychological measures were obtained, the average characteristics of the enrolled sample indicated rather favorable status at baseline in terms of diabetic control (Mean HbA1c = 8.0%), treatment adherence (Mean DSMP score = 63) and quality of life (Mean PedsQL = 30 for adolescents, 36 for parents). This profile suggests that the study participants tended to be overall in better diabetic control, and to report better adherence and diabetes-related quality of life than might be true of a randomly selected sample of diabetes clinic patients. Given this observation, it is possible that use of the GW2B could not drastically improve these outcomes in this particular sample. Enrollment of a more broadly representative sample of patients could perhaps provide a more sensitive evaluation of the glycemic and psychological effects of CGM use.
The present study illustrates the empirical evaluation of selected psychological variables that were potential predictors of outcomes of GW2B use as well as psychological variables that could conceivably be affected by GW2B use. Additional similar studies could enhance our understanding of how patients and families adapt to this technological advance, assess the degree to which this technology is burdensome or generates adverse psychological effects, and identify variables that differentiate effective from ineffective use of such technology. The present study did not systematically assess how patients and parents used and responded to GW2B data, and investigation of those behaviors may be critical to optimizing the therapeutic benefits of this technology.
Given that the GW2B yielded little discernible therapeutic benefit and that patients tended to use it infrequently, it is not particularly surprising that its use was not associated with pronounced positive or negative psychological effects. Nonetheless, the present report can serve as a basis for comparison for analyses of the psychological context of new CGM devices as they become available and are incorporated into clinical care.