Performance of a New Glucose Meter System in Children and Young Adults: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Performance of a New Glucose Meter System in Children and Young Adults (NCT00985257), a na na study. The primary outcome is Percent of Blood Glucose (BG) Results Within +/-15mg/dL or +/-20% of Laboratory Glucose Method.

2. Clinical Question

In plain terms, the study asks how closely readings from the new meter system corresponded to laboratory reference measurements in the described study setting. The stated tolerance depends on the reference glucose value: the description uses an absolute difference of +/-15mg/dL for reference results below 75mg/dL and a relative difference of +/- 20% for reference values at or above 75mg/dL. Duplicate blood glucose results were used for the outcome calculation.

This is a measurement-performance question rather than a comparison of clinical outcomes between assigned treatments. The registry describes one group and does not identify a randomized control arm. It also does not report the primary outcome estimate, an uncertainty interval, or an analysis of how performance varied across participants or glucose ranges. The clinical question can therefore be identified from the protocol description, but the posted record does not establish the observed degree of agreement or its precision.

3. Trial Design

The record describes a completed, single-group device study sponsored by Ascensia Diabetes Care. It lists enrollment of 123 and gives the study period as 2009-09 to 2009-10. The listed condition is diabetes, and the intervention is the DIDGET investigational blood glucose monitoring system. The arm description identifies subjects with type 1 and type 2 diabetes who were 4 to 24 years of age; subjects, parents or guardians where applicable, and healthcare professionals used the system.

Allocation is listed as NA, masking as NONE, and the model as SINGLE GROUP. Thus, the registered design does not describe random assignment or a masked comparison between treatment arms. Meter readings were compared with a laboratory method, the YSI Analyzer. That reference method supplies a basis for evaluating measurement agreement; it is not a separately randomized group of participants.

The primary outcome is described as the percent of blood glucose results within specified tolerances of laboratory results, with a timeframe of 1-2 hours. To obtain glucose concentrations across the meter test range, 47 blood samples were modified. The described glucose distribution included 121 natural capillary samples plus the modified samples and ranged from 25.7 to 563.5mg/dL. The record says two sets of subject results were not analyzed because sufficient sample was not obtained.

The registry marks the study completed, but it does not report the primary outcome value or any analyses; the analysis count is 0. Details such as the number of participants with evaluable primary outcome data, the exact analysis population, and the statistical analysis plan are not reported in the registry record. Enrollment should not be treated as the number contributing to every outcome.

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

Analysis population for the primary outcome, as defined in the registry: To achieve glucose concentrations across the meter test range, 47 blood samples were modified. The total glucose distribution (total 121 natural capillary samples plus 47 modified) ranged from 25.7 to 563.5mg/dL. Two sets of subject results were not analyzed because sufficient sample was not obtained for the YSI reference test.

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 Percent of Blood Glucose (BG) Results Within +/-15mg/dL or +/-20% of Laboratory Glucose Method, measured over 1-2 hours.

The primary endpoint is described as the percent of blood glucose results that fall within a specified tolerance of the YSI laboratory glucose method. For reference results below 75mg/dL, the stated tolerance is +/-15mg/dL. For reference values at or above 75mg/dL, it is +/- 20%. Duplicate blood glucose results were used in calculating the outcome. The registry lists the timeframe as 1-2 hours.

This kind of endpoint is used to describe how often a device’s readings meet a predefined agreement criterion against a reference measurement. The threshold changes with the reference concentration: one rule is an absolute difference and the other a relative difference. In general, reporting a percentage meeting the criterion can make a device comparison easier to interpret than reporting only an average difference, because it directly describes the proportion of readings within the specified tolerance. It does not, by itself, describe the size or direction of errors outside that tolerance, or how results vary among people and glucose concentrations.

The registry record does not report the measured percentage, the number of results meeting the criterion, or an uncertainty interval. It therefore documents the intended endpoint and its calculation rule, but not the observed result or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome uses a tolerance-based agreement rule. For each reference result, the rule identifies whether the corresponding blood glucose result is within the permitted distance. The permitted distance is expressed differently across the reference range: an absolute difference of +/-15mg/dL below 75mg/dL, and a relative difference of +/- 20% at or above 75mg/dL. The outcome is described as the percent of results that satisfy the relevant rule. The registry says duplicate results were used, but does not report the exact calculation procedure, how duplicates were handled, or the resulting percentage.

What does an agreement percentage tell a reader?

In general, an agreement percentage describes the frequency with which measurements meet a stated criterion. It depends on the criterion chosen, so it should be read together with the tolerance definition. A percentage alone does not convey the size of discrepancies among readings that fail the rule. It also does not show whether errors tend to be above or below the reference, or whether performance differs at particular concentrations. Those questions require additional summaries or analyses, which are not reported in the registry record.

General measurement analysis may also examine paired differences between a device and its reference, their distribution, and whether the differences change across the measurement range. Such approaches can add detail beyond a pass-within-tolerance percentage. They should not be attributed to this study: the registry lists no analyses, and it does not report these summaries.

Why does the laboratory method matter?

The YSI Analyzer is identified as the laboratory glucose reference. A device-to-reference assessment depends on the reference measurements and the procedures used to obtain paired readings. The registry description states that subject blood was used and that duplicate results entered the calculation. It does not provide further details about laboratory procedures, calibration, handling of repeated readings, or quality-control methods. Those details are not reported in the registry record.

The description says samples were modified to achieve glucose concentrations across the meter test range. It records 47 modified samples and 121 natural capillary samples, with the total glucose distribution ranging from 25.7 to 563.5mg/dL. In general, deliberately broadening a tested measurement range can help examine performance across concentrations that may not be represented as often in naturally collected samples. However, the registry does not report results separately for modified and natural samples, or explain how each contributed to the primary estimate. No conclusion about their relative influence can be drawn.

How should uncertainty be assessed?

In general, a confidence interval expresses the uncertainty around an estimated quantity under the analysis assumptions. For a percentage, it helps show how much the estimate might vary because only a finite set of measurements was observed. The registry does not report a confidence interval or another uncertainty measure for the primary outcome. The precision of the intended agreement percentage is therefore not available.

Measurements from the same person or from repeated use of a device may be related rather than independent. In general, accounting for such clustering can matter because treating related observations as independent may understate uncertainty. The description notes duplicate results and subject results, but the record does not explain the dependence structure or analysis method. It is not possible to tell whether or how repeated measurements were accounted for.

Over-dispersion is a general concern when variability in count or percentage data exceeds what a simple model assumes. If present, it can make standard errors too small unless the analysis allows for the extra variability. This is a general statistical consideration, not a reported feature of this study. The registry does not identify a model, dispersion assessment, or variance adjustment.

Finally, sample-size calculations are planning tools, not findings. The listed planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. The registered study is listed as single-group, and the record does not report numerical planning results. Any such sample-size illustration should be interpreted as a hypothetical planning exercise, never as observed power or as evidence about the study’s result.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure and zero analyses. It does not report a statistical analysis plan, hypothesis tests, confidence intervals, or secondary outcome analyses. Multiplicity refers, in general, to the increased chance of a misleading positive finding when multiple hypotheses or outcomes are tested. With no reported analyses or inferential results, the record does not allow an assessment of whether multiplicity was relevant or how it would have been handled. A protocol for multiplicity control is not reported in the registry record.

Missing data also require careful interpretation. The record states that two sets of subject results were not analyzed because sufficient sample was not obtained. It does not describe how many individual measurements were unavailable, why sufficient sample was lacking, whether the missing results were included in any denominator, or whether sensitivity analyses were performed. It also does not report a participant flow account for the primary endpoint. The effect of these exclusions on the posted outcome cannot be evaluated because the outcome itself is not reported.

The registry enrollment is 123, but enrollment is not necessarily the same as the number with usable primary outcome data. The record does not specify the analysis population, the number contributing readings, or the handling of participants with incomplete measurements. Those details are not reported in the registry record.

In general, a complete account of missingness identifies what was missing, why it was missing, and how the analysis treated it. Without that information, readers cannot determine whether the analyzed observations adequately represent the enrolled participants or whether missingness could affect the estimated agreement percentage.

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 5% reporting threshold.

The registry lists 123 subjects with diabetes at risk for serious adverse events and 0 subjects affected. It also lists 123 at risk for other adverse events and 0 affected. These are the counts recorded for the listed group; they are not a comparison between randomized groups. The deaths field is null, which is not the same as a reported count of zero. No top serious adverse-event terms are listed.

These figures should be read as registry entries, not as proof that no adverse events could occur. The record does not report a safety observation period, detailed event definitions, collection procedures, or a breakdown of adverse events by type. It also does not explain whether the safety counts cover the same period as the primary outcome timeframe of 1-2 hours. The number at risk does not establish that every participant had complete safety follow-up.

Because the primary outcome value and analysis are not reported, the safety entries do not fill the gap in the device-performance results. They describe the adverse-event counts recorded in the registry, with the limits noted above.

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

The record documents a single-group evaluation of the DIDGET blood glucose monitoring system in people with diabetes, with readings compared against the YSI laboratory glucose method. It specifies a tolerance-based primary outcome and describes the sample range used. Those details establish what performance question was intended and how a result was to be classified.

The record does not report the percentage of results within tolerance, an uncertainty interval, or any analysis. It therefore does not establish the observed level or precision of agreement between the meter and laboratory reference. The registry description of the threshold must not be mistaken for a result, and the reported glucose range must not be interpreted as an accuracy range.

The study is listed as single-group, with allocation NA and masking NONE. Its laboratory comparator is a measurement reference, not a randomized control arm. The registry does not provide a between-group comparison or outcome results that would support a treatment-effect interpretation. It also does not report results across age groups, diabetes types, users, sample types, or glucose levels.

In general, a device agreement outcome is specific to the measurement method, the reference, the tested samples, the tolerance rule, and the analysis used. The registry identifies some of these elements but does not report the full analysis details or the numerical endpoint. The result therefore cannot be used to quantify performance, compare subgroups, or assess the uncertainty of an estimate from this record alone.

The appropriate conclusion is narrow: the registry describes a planned assessment of meter readings against a laboratory method, but the posted record does not report the primary result. The safety counts are also limited to the entries recorded and do not substitute for detailed safety reporting.

13. Why This Trial Matters Statistically

This study raises a useful statistical distinction between evaluating a measurement device and comparing clinical treatments. The registered question concerns agreement between meter readings and a laboratory reference. It is not a randomized comparison of treatment assignments. Recognizing that distinction helps prevent a device-performance endpoint from being interpreted as a treatment effect.

The tolerance rule is also central to interpretation. A reading is classified relative to a threshold that uses an absolute difference below 75mg/dL and a relative difference at or above 75mg/dL. An agreement percentage is meaningful only alongside that rule, and it may not reveal the pattern or magnitude of readings outside the tolerance. The registry gives the rule but not the observed percentage or the distribution of discrepancies.

The described sample set was assembled to cover the meter test range, including modified blood samples. This makes the scope of tested measurements relevant to understanding what the outcome represents. The registry reports the range and sample composition but does not provide performance results by sample type or glucose concentration.

From a reporting perspective, the missing outcome estimate, uncertainty measure, analysis population, and analysis details prevent readers from judging the size and precision of the primary result. The registry does include limited safety counts, but lacks details about the safety observation period and event collection. This record therefore illustrates why a clearly specified endpoint is not enough on its own: readers also need the result, its uncertainty, and enough analysis information to understand how it was obtained.

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 main limitation for interpreting this record is that the primary outcome result is not reported. There is no percentage within tolerance, count of qualifying readings, confidence interval, or analysis listed. The intended endpoint can be described, but its observed value and precision cannot be assessed.

The study is registered as single-group, with no masking and no randomized allocation. The YSI Analyzer is a laboratory reference for measurement comparison, not a control arm. The record therefore does not support a randomized between-group interpretation. It also does not report results by age, diabetes type, user, or glucose range.

The registry describes a sample distribution that included 121 natural capillary samples and 47 modified samples, spanning 25.7 to 563.5mg/dL. It does not report how results were distributed across these samples, whether results differed between natural and modified samples, or how the sample sets contributed to the primary estimate. Two sets of subject results were excluded because sufficient sample was not obtained, but the effect of this exclusion is not reported.

Further details needed to evaluate the analysis are not reported in the registry record. These include the number contributing primary outcome data, the analysis population, the treatment of duplicate readings, methods for uncertainty estimation, and any sensitivity analyses. The record also does not report a statistical analysis plan or a prespecified decision criterion.

The adverse-event entries lack a reported observation period and event details. The null deaths field cannot be interpreted as a recorded zero. Together, these limitations mean that the record gives useful design and endpoint definitions but insufficient results and analysis detail for a full statistical assessment.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Performance of a New Glucose Meter System in Children and Young Adults — NCT00985257.
• Registry record last updated 2016-02-29; status last verified 2016-01.
• Results first posted 2010-11-02.
• 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

This completed, single-group device study evaluated the DIDGET blood glucose monitoring system in subjects with diabetes. The record lists enrollment of 123, study dates of 2009-09 to 2009-10, no masking, and allocation NA. Subjects, parents or guardians where applicable, and healthcare professionals used the system.

The primary outcome was the percent of blood glucose results within a specified tolerance of YSI laboratory results, using thresholds of +/-15mg/dL below 75mg/dL and +/- 20% at or above 75mg/dL. The record describes natural and modified samples across a glucose distribution from 25.7 to 563.5mg/dL, and notes that two sets of subject results were not analyzed because sufficient sample was not obtained.

The primary result and analyses are not reported in the registry record. Serious and other adverse-event entries each list 0 affected subjects among 123 at risk; the deaths field is null.