Evaluation of an Ascensia Lancing System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of an Ascensia Lancing System (NCT02606838), a na na study. The primary outcome is Number of Subjects With Numeric Meter Results When Users Obtain Fingerstick Capillary Blood Using the Styx Lancing Device ( 28 Gauge Lancets).

2. Clinical Question

The study’s stated purpose was to determine whether untrained people with diabetes could perform basic tasks with the device and obtain adequate blood volume for blood glucose meter testing from fingerstick and palm lancings. The primary outcome captures one specific part of that purpose: whether a numeric meter result was obtained after fingerstick collection with the specified lancet. It is not, by itself, a measure of every step in operating the device or of the accuracy of a numeric glucose value.

3. Trial Design

The registry describes a completed, single-group device study titled “Evaluation of an Ascensia Lancing System,” with the official title “User Performance of the Styx Lancing System.” The sponsor is Ascensia Diabetes Care. The listed condition is diabetes, and the intervention is the Styx Lancing Device. Enrollment is 119. The record lists the start as 2015-11 and primary completion as 2015-12.

Participants were people with diabetes described as untrained. They used the Styx Lancing Device System to obtain fingerstick and alternate-site palm capillary blood. For the primary outcome, participants used 28 Gauge lancets for fingerstick collection. The registry describes study staff testing the collected blood with Contour NEXT Blood Glucose Meters. The primary timeframe is 1 hour.

The registry lists allocation as NA, masking as NONE, and the study model as SINGLE GROUP. It explicitly identifies the study as not being a randomized comparison and notes that its arms are not a like-for-like control comparison. Consequently, the design can describe task performance within the studied group, but it does not estimate a randomized difference between the device and a control. No phase is specified beyond NA.

The record lists five outcome measures: the primary fingerstick outcome with 28 Gauge lancets and four secondary outcomes. These secondary measures concern numeric meter results for palm sampling with 28 Gauge lancets, fingerstick sampling with 30 Gauge lancets, and palm sampling with 30 Gauge lancets, as well as questionnaire responses about the device. The record does not report the observed outcome values or a statistical analysis for these measures. It also does not report a protocol-level sample-size justification or details of participant flow in the information available for this analysis.

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

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 Number of Subjects With Numeric Meter Results When Users Obtain Fingerstick Capillary Blood Using the Styx Lancing Device ( 28 Gauge Lancets), measured over 1 hour.

The primary endpoint is the number of participants with numeric blood glucose meter results after they use the Styx Lancing Device with 28 Gauge lancets to obtain fingerstick capillary blood. The registry describes three possible recording outcomes: a numeric result, a non-numeric result such as an error message, or no result obtained. The endpoint counts participants in the numeric-result category; it does not combine all three categories into a reported distribution in the information.

This measure is relevant to the study’s stated task-performance question because a numeric meter reading indicates that the sampling and testing process reached a usable output for that attempt. It is a practical outcome, distinct from the blood glucose value itself. The registry does not define this endpoint as a measure of glucose accuracy, successful device operation at every step, participant preference, or clinical benefit.

The record gives the primary timeframe as 1 hour and says study staff tested the collected blood using Contour NEXT Blood Glucose Meters and recorded the results. It does not report the number of participants who had numeric results, the number with non-numeric results, or the number for whom no result was obtained. Those outcome values are not reported in the registry record, so the observed rate of obtaining a numeric result cannot be described from the available information.

As a general statistical point, a count can describe how many participants met an endpoint, but interpretation usually also depends on the denominator and on how missing or unusable observations are handled. The registry’s primary outcome is stated as a participant count, and the outcome description distinguishes non-numeric results from results not obtained. No additional endpoint-analysis details are reported.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods help distinguish what an outcome measures from how uncertain its estimate may be. In this study, the primary outcome is a count of participants with numeric meter results after a specified fingerstick procedure. A count is descriptive: it states how many participants met the outcome definition. To understand its frequency, a reader would also need the denominator used for analysis and the handling of participants with non-numeric or unobtained results. The primary outcome value and those analysis details are not reported in the registry record.

What would a confidence interval communicate?

As a general statistical explanation, a confidence interval describes uncertainty around an estimated quantity, such as a proportion derived from a count and an appropriate denominator. A narrower interval indicates greater precision under the method’s assumptions; a wider interval indicates greater uncertainty. An interval does not guarantee that the true value lies within its limits, and it does not by itself establish whether a result is important. No confidence interval for the primary endpoint is reported in the registry record, so its precision cannot be assessed from the available information.

Why do outcome categories and denominators matter?

The endpoint description separates numeric meter results, non-numeric results such as error messages, and results not obtained. Keeping these categories distinct can help explain how task performance was recorded. If only the count of numeric results is reported, the interpretation still depends on knowing which participants were included in the denominator and what happened to observations without a numeric result. For example, excluding an observation and classifying it as not successful answer different descriptive questions. The registry record does not report a rule for handling missing or unobtained results in an analysis.

What does the design allow?

As a general principle, a single-group study can describe observed performance in the participants studied, but it cannot provide a randomized between-group treatment contrast when there is no control group. Here, the registry identifies a SINGLE GROUP model, allocation as NA, and no randomized comparison. The registry also lists masking as NONE. These details define the design context; they do not supply a substitute comparison or allow an effect relative to another method to be calculated.

What can be said about hypothesis testing?

A hypothesis test evaluates data against a specified statistical model and null hypothesis. Its interpretation depends on the prespecified question, analysis method, and assumptions, as well as the observed data. The registry lists n analyses as 0 and does not report a test, p-value, or inferential analysis for the primary endpoint. That does not show whether analyses were performed outside the registry; such analyses are not reported in the registry record. Without a stated test and result, there is no basis to describe statistical significance.

How should planning illustrations be read?

General sample-size planning asks how many participants may be needed under assumed design conditions to detect a specified effect with a chosen significance level and power. The record’s planning description uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect defined as a stated fraction of an observed effect. These assumptions describe planning illustrations, not the actual single-group design described for this study. The record says that non-time-to-event illustrations are expressed as participants per arm, while time-to-event illustrations use a total number of events. No calculated planning values are included in the information available for this analysis.

Such planning values are not observed power. Observed power is not a useful replacement for reporting the estimated effect and its uncertainty: after a study, the data and the uncertainty around the estimate are the relevant evidence. A planning illustration based on an observed effect is conditional on its assumptions and should not be interpreted as a probability that this completed study detected a real effect. Since no primary outcome estimate is reported in the registry record, the result itself cannot be judged against any planning illustration.

Why can over-dispersion matter?

As a general explanation, over-dispersion occurs when observed variability is greater than a statistical model expects. If a count model assumes less variability than the data contain, uncertainty estimates can be too small and tests can appear more decisive than warranted. The record does not report a count model, a dispersion estimate, or an analysis for this endpoint. This general issue therefore cannot be used to infer that over-dispersion occurred in the study; it is a consideration only if a suitable model is used for count data.

Finally, the outcome description specifies a short, task-based measurement setting: study staff tested collected blood with Contour NEXT Blood Glucose Meters, and the primary timeframe is 1 hour. The registry does not report additional measurement occasions, a longer-term outcome, or the statistical procedures used to combine repeated observations, if any. No repeated-measures or adjusted analysis should be assumed from the endpoint description alone.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Persons With Diabetes")
n      <- c(119)
events <- c(119)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Persons With Diabetes  119  119  100.0  96.9  100.0  96.9  100.0  97.0  100.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures: one primary measure and four secondary measures. The secondary outcomes cover numeric meter results for palm blood with 28 Gauge lancets, fingerstick blood with 30 Gauge lancets, palm blood with 30 Gauge lancets, and questionnaire responses concerning the Styx Lancing Device. The presence of several outcomes creates a general multiplicity consideration: when multiple outcomes are tested, the chance of at least one apparently unusual result can increase if each is assessed separately. The registry record does not report a multiplicity adjustment, a hierarchy for secondary outcomes, or a statistical analysis plan. It is not possible to determine whether or how multiplicity was addressed.

Missing-data handling is also not reported in the registry record. The primary outcome description distinguishes numeric results, non-numeric results, and results not obtained, but does not state how participants in the latter categories were handled in any analysis. The record does not report the number of observations missing for the primary or secondary outcomes, reasons for missingness, or an imputation method. Accordingly, no assumption about missing outcomes should be made.

The analysis populations are not described. The registry does not state whether the primary outcome was analyzed in all enrolled participants, only those who attempted the task, or another defined group. It does not report exclusions, protocol deviations, or participant flow relevant to an analysis population. Although the record lists enrollment as 119, it does not report an analyzed denominator for the primary endpoint. The registry lists n analyses as 0; no analysis population or multiplicity procedure can be reconstructed from the information reported.

12. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The safety figures in the registry record list 119 people with diabetes at risk for serious adverse events and 0 affected by a serious adverse event. For other adverse events, the record lists 119 at risk and 1 affected. These are separate categories in the registry and should not be conflated: the record reports no serious adverse events and one other adverse event among the participants listed at risk.

The registry does not give further details about the other adverse event, such as its nature, timing, severity, or relationship to the device. The serious adverse event terms list is empty. Deaths are not reported in the registry record. These figures describe the safety information entered in the registry; they do not establish that no unrecorded events occurred or provide a comparison with another device, because the study had no randomized control group.

As a general statistical point, counts from a single group describe what was recorded in that group, while comparisons require a suitable comparator and consistent event ascertainment. The registry does not report additional safety analyses or uncertainty estimates. The figures should therefore be read as registry-reported counts, not as a comparative risk estimate or proof of absence of risk.

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

The study addresses whether untrained people with diabetes could perform basic tasks with the Styx Lancing Device to obtain blood for meter testing. Its primary endpoint is narrowly defined: the number with numeric meter results after fingerstick collection using 28 Gauge lancets. The registry describes how the blood was tested and distinguishes numeric results from error messages and results not obtained.

The primary outcome value is not reported in the registry record. As a result, the available information does not establish how often participants obtained numeric readings or how often the other recorded outcomes occurred. The registry also does not report the secondary outcome results for alternate-site palm sampling, fingerstick sampling with 30 Gauge lancets, or questionnaire responses. No conclusion about the observed level of task performance can be drawn from the endpoint definitions alone.

Even if a numeric-result count were available, it would not by itself establish the accuracy of the glucose values, the amount of blood collected, or clinical benefit. The record does not describe a numeric accuracy endpoint or report a direct measurement of blood volume. The primary measure indicates whether a numeric meter result was obtained under the described procedure; interpretation should not extend beyond that measure.

The study’s single-group design also limits what can be concluded comparatively. There is no randomized control group or like-for-like comparison in the registry record. Thus, the design cannot estimate how outcomes differ from another device or collection procedure. The record reports no inferential analysis or precision estimate, so statistical uncertainty around the primary outcome is also unavailable.

These limits do not erase the study’s descriptive purpose. A task-based outcome can be useful for characterizing a device-use question, provided the observed results and their denominators are reported. In this registry record, the endpoint definition and study design are available, but the outcome values and analysis details needed to judge the observed performance are not reported.

14. Why This Trial Matters Statistically

This study illustrates why an endpoint’s operational definition matters. “Numeric meter result” is more specific than a broad claim that a device was usable: the record defines a result category, names the collection method and lancet gauge, and describes the meter testing process. That specificity helps identify what the primary outcome represents and what it does not represent. In particular, the endpoint is not itself a measure of glucose accuracy or a direct measure of blood volume.

The record also illustrates the importance of reporting outcome counts together with denominators and handling rules. The primary outcome is a participant count, while its description acknowledges non-numeric results and results not obtained. Without the observed count, analyzed denominator, and treatment of those categories, readers cannot estimate the frequency or judge its precision. Clear reporting of each outcome category would make the task-performance evidence easier to interpret.

Design context is equally important. Because the study is single-group and not a randomized comparison, it can address a descriptive performance question but not a comparative effect against a control. Stating that distinction prevents a within-group observation from being mistaken for evidence that one device outperforms another. The absence of reported inferential analyses, confidence intervals, and analysis populations further limits conclusions about uncertainty.

Finally, the record lists multiple outcome measures, including different sampling sites, lancet gauges, and questionnaire responses. This raises general questions about which outcome is primary, how secondary outcomes are interpreted, and whether multiplicity was considered. The registry does not report those analysis details. Together, these features make the study a useful example of how endpoint definition, design, denominators, missing-data rules, and analysis reporting shape the conclusions that can be drawn from a clinical device study.

15. 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 most immediate limitation is that the registry record does not report the observed value for the primary endpoint. It also does not report the values for the secondary outcomes. Without these results, the study’s observed task performance cannot be quantified, and no estimate of uncertainty can be assessed.

The single-group design provides no randomized control comparison. The registry identifies no like-for-like control group, and masking is listed as NONE. These design features mean that any descriptive observation would not establish a difference relative to another device or sampling method. The record does not provide a basis for a comparative effect estimate.

The endpoint is limited to whether a numeric meter result was recorded after a specified fingerstick procedure. The registry does not report a direct measurement of blood volume or a numerical accuracy outcome. Its stated purpose refers to adequate blood volume, but the reported endpoint definition alone does not show how much blood was obtained or whether a glucose reading was accurate. The timeframe for the primary outcome is 1 hour, and longer-term performance is not described in the registry record.

Several reporting details are also absent: the analyzed denominator, the number of non-numeric results, the number of results not obtained, missing-data handling, analysis populations, inferential methods, and multiplicity procedures. The record does not report participant characteristics beyond the description of untrained people with diabetes, nor does it provide further eligibility criteria or participant flow. These gaps restrict assessment of the outcome and of how well the findings might apply beyond the study group.

The safety information is limited to the recorded event counts. Details of the one other adverse event are not reported in the registry record, and deaths are not reported. The record does not describe event definitions or additional safety analyses. These limitations concern what can be concluded from the registry record; they do not imply that unreported information was never collected.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of an Ascensia Lancing System — NCT02606838.
• Registry record last updated 2017-05-12; status last verified 2016-12.
• Results first posted 2017-05-12.
• 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.

19. Record Summary

The registry record describes a completed, single-group study of the Styx Lancing Device in untrained people with diabetes, with enrollment of 119. The study’s primary question concerns the number of participants with numeric meter results after fingerstick blood collection using 28 Gauge lancets. The primary timeframe is 1 hour.

The record lists four secondary outcomes covering other lancet and sampling-site combinations and questionnaire responses. It reports no randomized comparison, lists masking as NONE, and does not list statistical analyses. The observed primary and secondary outcome values, confidence intervals, analysis populations, missing-data procedures, and multiplicity methods are not reported in the registry record.

The safety record lists 0 participants with serious adverse events and 1 with another adverse event, with 119 at risk in each category. Further details about the other adverse event and deaths are not reported in the registry record. The available record supports a description of the study question and design, but not a quantitative interpretation of its task-performance outcomes.