Mobile Communication Technology for Adolescents With Diabetes: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Mobile Communication Technology for Adolescents With Diabetes (NCT00605839), a randomized na study. The primary outcome is Quality of Parent-child Relationship.

2. Clinical Question

The study rationale describes tensions that can arise when adolescents seek greater independence while managing diabetes, and when parents remain closely involved in treatment. It proposes that communication between adolescents and health professionals might alter family interactions. That rationale explains why a parent-child relationship measure was selected, but it is not itself evidence that the technology changed relationships or diabetes management.

The registry record reports a randomized, parallel-group comparison. It does not report a posted statistical comparison between groups for the primary outcome, so the group-level changes should be read as descriptive results rather than as a demonstrated difference between approaches.

3. Trial Design

This was a randomized, parallel-group trial marked as single-masked in the registry record. The record does not identify who was masked or describe how masking was maintained. It lists an enrollment of 105 and indicates that the study is completed. The listed start is 2008-01, and primary completion is 2008-12. The phase is recorded as NA, and Indiana University is listed as the sponsor.

The three trial groups were Glucopak cell phone and intensive monitoring, cell phone only, and usual care. The Glucopak group received the experimental device and was placed in close communication with the clinic. The cell-phone-only group received phones and was encouraged to communicate more closely with the clinic without using Glucopak. The usual-care group did not receive a cell phone or Glucopak. These descriptions define the intended contrast; the registry record does not provide details about the frequency or content of communications, adherence to device use, or differences in clinical care beyond the group descriptions.

The primary outcome was reported for participants who completed the study. The posted group counts for this outcome are 39 for Glucopak care, 37 for cell-phone-only care, and 28 for usual care. These are endpoint group counts, not a description of everyone originally enrolled. The record does not explain the flow from enrollment to the endpoint population or give reasons for non-completion.

Random allocation can support a fair comparison when allocation and follow-up are adequately implemented, but the record does not give the randomization procedure, allocation concealment method, masking details, or protocol. It also does not describe intervention fidelity. Those omissions limit what can be concluded about the conduct of the trial from the registry record alone.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Everyone who completed the study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Quality of Parent-child Relationship, measured over Change from baseline to 6 months. Please see above for a description of how the change score should be interpreted..

The primary endpoint is the change from baseline to 6 months in the total score on the Cornell Parent Behavior Description Scale. The instrument measures antecedents and consequences of children’s perceptions of their parents’ behavior toward them. The posted outcome is expressed as a mean change in units on a scale, with a 95% confidence interval for each group.

The scale has 14 subscales, each scored from 0-10. The total score is the sum of those subscales, with a potential range from 0 (fewest behaviors) to 140 (most behaviors). The registry’s stated interpretation is important: a change of zero indicates no change, a positive change indicates worsening, and a negative change indicates improvement. This direction is specific to the scale’s stated interpretation; it should not be reversed based on the usual intuition that higher scores are better.

A parent-child relationship outcome is relevant to the trial’s rationale because the study proposed that mobile communication might affect how parents and adolescents share responsibility for diabetes management. The scale is not described as measuring glycemic control, device use, or clinical events. It therefore addresses a family relationship aspect of the intervention rather than all of the outcomes that might matter in diabetes care.

The registry record identifies the endpoint population as everyone who completed the study. It does not report how missing scale responses were handled, whether a minimum number of completed scale items was required, or whether the score was analyzed in a different population.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it is a mean change score on a summed questionnaire scale. A mean describes the average change within a group, while individual participants may have changes above or below that value. The reported mean is not a count of participants who improved, and it does not reveal how uniformly participants changed.

What does the confidence interval express?

A confidence interval communicates uncertainty around an estimate. In general, a 95% confidence interval is produced by a method that, under its assumptions, would cover the underlying value in a specified proportion of repeated applications. It is not a range that guarantees where every participant’s score falls, and it is not a statement that there is a 95% probability that a fixed true value lies inside this particular interval.

For the Glucopak group, the interval runs from -2.11 to 2.54; for the cell-phone-only group, it runs from -6.12 to -0.36; and for usual care, it runs from -5.41 to 4.23. The registry identifies these as 95% confidence intervals but does not report the calculation method or model. Consequently, the interval widths can be read as a guide to uncertainty, but the registry record does not permit a detailed audit of how they were obtained.

How does the score direction affect interpretation?

The outcome description defines negative change as improvement, positive change as worsening, and zero as no change. This direction applies to the total-score change, not necessarily to every item or subscale considered separately. A mean near zero does not imply that every participant’s score stayed constant: individual changes in opposite directions can average out. The registry does not post participant-level data or the spread of individual changes, so that pattern cannot be examined.

Why are within-group results not a group comparison?

Each posted mean describes change in one group. The clinical question about comparative effects requires an analysis that directly contrasts change between randomized groups, with an estimate and uncertainty for that contrast. An apparent difference between point estimates is not itself a test or estimate of the treatment contrast. Likewise, checking whether each group’s interval includes zero does not test whether the groups differ. The registry record does not post a two-arm comparison for this continuous endpoint, so no comparative effect estimate or uncertainty interval is available in the record.

What can the group counts tell us?

The reported endpoint counts indicate the number included in each group’s outcome results: 39 in Glucopak care, 37 in cell-phone-only care, and 28 in usual care. They do not explain why those participants were included, whether all randomized participants contributed, or how missing measurements were treated. The registry states that the endpoint concerns study completers, but does not give an analysis-population definition beyond that description.

How should the planning illustration be read?

The sample-size illustrations are based on the observed effect, use a two-sided significance level of 0.05, assume equal allocation between the two arms, and use a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. For non-time-to-event outcomes, the illustrations refer to participants per arm. These are planning illustrations, not results from the completed trial and not observed power. The registry record does not report that these assumptions were the trial’s original design assumptions or that the trial was planned around the posted estimates.

In general, a planning calculation explores how many participants might be needed under specified assumptions about the target effect, variability, significance level, and power. Its output depends on those assumptions. Because the posted information does not establish the original sample-size rationale or provide a reported statistical plan, the illustration should not be treated as a reconstruction of the sponsor’s design process.

What other analytical details are unavailable?

The registry record does not report the statistical model, any adjustment for baseline score, the method used to calculate confidence intervals, handling of protocol deviations, or an interim-analysis plan. It does not report an adjustment for multiple outcome testing. Without those details, the reported group summaries can be described, but the analysis cannot be independently assessed in depth. General statistical principles about confidence intervals and comparisons do not fill in those trial-specific omissions.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and posts no secondary outcomes. That does not establish that the study measured only one outcome or that no other analyses were conducted; it means that no secondary outcome results are posted in this record. The record does not report whether multiple comparisons were planned, whether any adjustment for multiplicity was used, or how the primary outcome was selected from any broader set of measures.

Missing-data information is limited. The primary outcome population is described as everyone who completed the study, and the arm-level endpoint counts are 39, 37, and 28. The registry record does not report how many randomized participants lacked a score, reasons for missingness, or the approach used for incomplete questionnaires or missing follow-up measurements. It also does not report whether any imputation or sensitivity analysis was performed.

Restricting an outcome analysis to study completers can affect interpretation if participants with missing outcomes differ from those with observed outcomes. This is a general concern, not evidence that such a difference occurred in this trial. Randomization does not by itself resolve the consequences of incomplete outcome data when the posted analysis population is limited to completers.

The registry does not report a detailed analysis-population definition, such as whether the primary analysis included all randomized participants or followed another prespecified rule. It does not post a statistical analysis plan or a sponsor analysis for the primary outcome. These omissions mean that the endpoint summaries cannot be fully evaluated for missing-data handling, multiplicity, or fidelity to a prespecified analysis.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

The registry posts zero serious adverse events affected in the Glucopak group, zero in the cell-phone-only group, and zero in usual care. The corresponding numbers at risk are 39, 37, and 28. It also posts zero other adverse events affected in each group, with the same group-specific numbers at risk.

These entries describe the adverse-event counts recorded in the registry for the stated groups. A zero count means that no affected participants were entered for that category in the posted results; it is not proof that no event could occur or that the intervention has no safety risks. The registry record does not provide event definitions, collection procedures, surveillance duration, or narrative details that would allow broader assessment of safety reporting.

The deaths fields are null for the groups. A null entry is not a reported zero and should not be interpreted as confirmation that no deaths occurred. The record also lists no serious adverse-event terms. Without more detail, the safety information is limited to the posted affected-participant counts and at-risk group counts.

12. What the Result Does, and Does Not, Mean

The results describe average change in a parent-child behavior score among participants identified as study completers. The cell-phone-only group’s posted mean change was -3.24, with a 95% confidence interval from -6.12 to -0.36. The Glucopak group’s mean was 0.22, with an interval from -2.11 to 2.54; usual care had a mean of -0.59, with an interval from -5.41 to 4.23. The scale description interprets negative changes as improvement and positive changes as worsening.

These summaries do not establish that a technology approach caused a change. They also do not show whether cell-phone-only care differed from Glucopak care or usual care. The registry record does not post a direct comparison for the continuous endpoint, and it does not provide an adjusted or unadjusted contrast between groups. A reader should not create such a comparison by subtracting the means or by treating overlap or non-overlap of separate confidence intervals as a formal test.

The endpoint addresses perceived parent behavior and the parent-child relationship as measured by the Cornell scale. It does not directly measure glucose control, diabetes complications, adherence, or the quality of clinical communication. The study rationale links family interactions and self-management, but the primary result alone cannot establish effects on those other domains.

The completer population, unavailable details about missing outcomes, and absence of a reported analysis method constrain interpretation. The posted means and confidence intervals provide useful descriptive information about the measured outcome, but do not resolve these design and analysis questions. The record also does not state the minimally important difference for the scale, so it is not possible to judge the clinical importance of the observed point estimates from the registry information alone.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it separates technology-supported communication into distinct approaches: a cell phone with Glucopak and intensive monitoring, a cell phone without Glucopak, and usual care. That arrangement could help distinguish the role of the device from the role of closer communication with the clinic, if the study’s analysis directly compared the groups. The registry record does not post such a comparison for the primary continuous outcome, so this potential distinction remains unanswered by the posted results.

The endpoint also illustrates why outcome direction and definition matter. A negative change is labeled improvement and a positive change worsening. Reading the sign without consulting that definition could reverse the interpretation. The scale concerns parent-child behavior as perceived by children, making it a family-interaction measure rather than a direct clinical measure of diabetes control.

The posted within-group estimates show why confidence intervals should accompany point estimates. The cell-phone-only interval lies below zero, whereas the Glucopak and usual-care intervals include zero and span both directions. These statements describe the estimates and their reported uncertainty, not proof of a causal effect or evidence that one approach outperformed another.

Finally, the study highlights the distinction between a completed randomized trial and a complete registry report. A randomized design is informative for comparative questions, but readers need the direct contrast, analysis methods, missing-data handling, and analysis-population details to judge the primary question fully. Those items are not reported in the registry record. The available results therefore support careful description of the outcome, while leaving important comparative and methodological questions unresolved.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The posted primary outcome is restricted to participants who completed the study. The registry record does not explain how many participants did not contribute to that outcome, why outcome data were missing, or whether the completer group differed from those without measurements. This limits assessment of selection effects and of how well the reported summaries represent everyone randomized.

The record provides group means and confidence intervals but no direct between-group estimates for the primary outcome. It explicitly indicates that values were missing or not estimable for a two-arm comparison of the continuous endpoint. As a result, the central comparative question cannot be answered from these posted results alone.

Important design and analysis details are also absent. The registry does not identify who was masked, describe the randomization procedure or allocation concealment, report a statistical model, explain the confidence-interval method, or provide a statistical analysis plan. It does not describe the amount of intervention use, communication frequency, or adherence. These gaps make it difficult to assess implementation and to evaluate whether the analyses followed a prespecified approach.

The scale measures perceived parent behavior, not glycemic control or other clinical outcomes. The registry does not report a minimally important difference, so the practical importance of the estimated changes cannot be assessed using a stated threshold. It also does not post secondary outcome results, despite a study rationale that refers to diabetes self-management.

Finally, the safety entries provide affected-participant counts but little context about collection and definitions. Deaths are recorded as null rather than as a reported count. These limitations are specific to what the registry record reports and should not be taken as evidence that unreported procedures or outcomes did not exist.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Mobile Communication Technology for Adolescents With Diabetes — NCT00605839.
• Registry record last updated 2017-10-11; status last verified 2017-09.
• Results first posted 2013-11-20.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes a completed randomized, single-masked, parallel-group trial sponsored by Indiana University. It lists enrollment of 105, with a start date of 2008-01 and primary completion in 2008-12. The study concerns adolescents with type 1 diabetes and compares Glucopak cell-phone monitoring with intensive clinic communication, cell-phone communication without Glucopak, and usual care.

The primary outcome is change from baseline to 6 months in the Cornell Parent Behavior Description Scale total score among study completers. Negative change is defined as improvement and positive change as worsening. The posted mean changes are 0.22 for Glucopak care, -3.24 for cell-phone-only care, and -0.59 for usual care, each with a 95% confidence interval. The registry record does not post a direct two-arm comparison for this continuous outcome.

Serious and other adverse-event affected counts are posted as zero for each group; death counts are null. The record does not report detailed missing-data methods, a statistical analysis plan, or secondary outcome results.