CoverEdge Algorithm Programming Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for CoverEdge Algorithm Programming Study (NCT02492880), a na na study. The primary outcome is Change in Paresthesia Distribution From Subject Completed Paresthesia Drawing Questionnaire.

2. Clinical Question

The question is descriptive: it concerns the distribution of paresthesia associated with programming features, not a comparison of those features against a control group. The primary endpoint is framed as a change, but the registry record does not define the scoring method, the reference point for determining change, or what magnitude or pattern of change would be considered important.

The record identifies chronic pain as the condition and describes the study as prospective, on-label, multi-center, exploratory, non-randomized, and single-arm. It does not report additional details about participant characteristics, the number or nature of programming settings assessed, or how participants’ drawings were evaluated. The endpoint results themselves are not reported in the registry record, so the question can be identified, but the observed change cannot be described from the record.

3. Trial Design

This was a prospective, on-label, multi-center, non-randomized, exploratory, single-arm study of programming features for the Precision Spectra™ spinal cord stimulator system using CoverEdge™ surgical leads. The registry lists a single group and an enrollment of 15. Allocation is recorded as NA, masking as none, and the study status as completed. The phase is listed as NA. Boston Scientific Corporation is identified as the sponsor.

The registry dates the study start to 2015-07-20 and primary completion to 2017-02-21. These dates describe the record’s study timeline; they do not establish when any particular participant completed an assessment. The primary endpoint’s timeframe is stated as minimum 25 days post IPG implant.

A single-arm design can describe observations in the enrolled group, but it does not directly compare the programming features with a separate control condition. In particular, changes observed over time in one group cannot by themselves distinguish effects associated with programming from other explanations, such as natural variation or changes in circumstances. The registry does not report a randomized allocation process or masking that could support a controlled contrast.

The registry record does not report the intended sample-size justification, detailed recruitment or eligibility criteria, the assessment schedule beyond the primary endpoint timeframe, or the statistical analysis plan. It also does not report results for the primary endpoint. The study’s completed status therefore should not be read as evidence that its outcome findings are available in the record. No conclusion about the endpoint’s observed direction, size, or precision can be drawn from the design details 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.

Before assignment: 15 subjects were enrolled in the study. 1 subject was enrolled in error who did not meet all inclusion criteria and was withdrawn and 1 subject was lost to follow-up prior to completing the Programming Visit. Statistically relevant conclusions cannot be made from this small sample size.

Overall Study

Reasons for not completing this period:

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 Change in Paresthesia Distribution From Subject Completed Paresthesia Drawing Questionnaire, measured over minimum 25 days post IPG implant.

The primary endpoint is titled “Change in Paresthesia Distribution From Subject Completed Paresthesia Drawing Questionnaire.” Its unit is participants, and it is described as a count of participants. The registry says the change is based on programming parameters and places assessment at a minimum of 25 days post IPG implant.

A drawing questionnaire offers a way to record where a participant experiences paresthesia. Describing its distribution may be relevant to characterizing the spatial pattern associated with programming features. This is a general explanation of the type of information such an endpoint can capture; the registry does not explain the questionnaire’s scoring or validation, or how a drawing was translated into a participant-level outcome.

The title uses the word “change,” but the record does not specify the baseline or other reference used to define change, the criteria for counting a participant, or how missing or ambiguous drawings were handled. It does not report the observed count or the number of participants with evaluable drawings. A clinically important threshold or an interpretation rule for the endpoint is also not reported in the registry record.

Because no primary endpoint result or analysis is recorded, the endpoint’s actual distribution of participant outcomes cannot be assessed. The description identifies what investigators intended to characterize, but not what was observed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

The endpoint is defined in participants and described as a count. For a count-based outcome, the central descriptive information would ordinarily include how many participants met the endpoint definition and the denominator assessed. Those details allow readers to understand the observed frequency and how much information the result contains. The registry record does not report the primary endpoint count or its denominator, so neither can be interpreted.

What would an estimate and confidence interval add?

In general, an estimate summarizes the observed result, while a confidence interval describes its statistical uncertainty under a specified analysis. A narrow interval indicates greater precision than a wide interval, though precision is not the same as clinical importance or freedom from bias. The registry does not report a primary endpoint estimate or confidence interval. No interval can be assessed, and none should be inferred from enrollment alone.

Why does the study design matter?

This is a single-group study, not a randomized comparison. Randomization in a controlled study is generally used to make comparison groups more comparable with respect to factors that could affect an outcome. Here, the record identifies no separate control group, so there is no between-group contrast to interpret. A single-arm study can still describe its participants and their measured outcomes, but it offers less support for attributing an observed change to the intervention than a suitable controlled comparison would.

The endpoint title describes a change in distribution, but the registry does not state the reference measurement or the rule used to classify a participant as having changed. It also does not specify whether the analysis would compare drawings within each participant, use a categorical classification, or apply another approach. These are not interchangeable methods: each defines the outcome and its uncertainty differently. The actual method is not reported in the registry record.

What can be inferred from the listed analysis information?

The registry lists zero analyses. This means no analysis result is recorded in the information available; it does not establish whether analyses were conducted outside the registry or whether a plan existed. The statistical plan, handling of repeated or incomplete measurements, and any adjustment for covariates are not reported in the registry record. No particular method should be attributed to the investigators.

The record includes a planning illustration based on a fraction of an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such calculations are planning exercises rather than results from this single-arm study. They are not observed power, do not show the study’s probability of detecting an effect, and do not substitute for a reported analysis. The registry does not report the trial’s own sample-size justification. A two-arm planning illustration also does not change the actual single-arm design.

Why can over-dispersion matter in general?

For count outcomes, a statistical model may assume a particular amount of variability. Over-dispersion means that the observed variability is greater than that assumed by a model. If it is ignored, uncertainty estimates can be too small and statistical evidence can appear stronger than warranted. This is a general consideration for count data, not a claim about this study: the registry does not report a model, a dispersion estimate, or an analysis that would allow over-dispersion to be assessed.

Similarly, a count can be informative only when its definition, observation window, denominator, and handling of missing data are clear. Here, the registry gives a timeframe for the endpoint but does not report the operational outcome definition, evaluable sample, or missing-data approach. Those omissions prevent a detailed assessment of the statistical methods or the reliability of any primary endpoint estimate.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and zero analyses. It does not report a multiplicity plan, such as whether multiple comparisons or outcome definitions were considered, or whether any adjustment was planned. With the analysis information absent, it is not possible to determine how multiplicity was handled. The single listed outcome measure alone does not establish that no additional analyses were conducted.

Missing-data methods are not reported in the registry record. The record does not state how many participants completed the paresthesia drawing questionnaire, whether any drawings were unusable, or how missing assessments were treated. Enrollment of 15 is not necessarily the number included in an endpoint analysis. Without these details, the completeness of endpoint data and the possibility of bias related to missing observations cannot be assessed.

The analysis population is also not reported. The record does not specify which participants would be included in the primary endpoint analysis or the rules for inclusion. It gives no account of deviations from the intended assessment schedule or how such deviations might affect inclusion.

These gaps do not establish that multiplicity or missing-data problems occurred. They mean the registry record does not document the methods needed to evaluate them. No assumptions about adjustment, imputation, exclusions, or analysis populations should be treated as study details.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists 15 participants at risk for serious adverse events and 0 affected. It also lists 15 at risk for other adverse events and 0 affected, with 0 deaths. No top serious adverse event terms are listed. These are the posted safety counts for the group named Precision Spectra™ SCS System Programming Features.

The counts describe what is recorded for this group; they do not provide a comparison with an untreated or alternative-treatment group. The registry does not report additional details about adverse event definitions, observation duration, severity grading beyond the serious-event category, or event collection methods. The safety counts therefore should not be extended beyond the information recorded.

Zero affected participants in the posted counts does not establish that no adverse events could occur, nor does it quantify risk beyond this study group and its recorded observation. It is also distinct from the missing primary endpoint result: safety counts do not indicate whether paresthesia distribution changed. The record gives no basis for comparing safety between groups because it describes only one group.

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

The record establishes that a completed, exploratory, single-arm study enrolled 15 participants and set out to characterize changes in paresthesia distribution based on programming parameters. It identifies a participant-completed drawing questionnaire and an endpoint timeframe of minimum 25 days post IPG implant. It also reports the group’s posted adverse event counts.

The record does not report the primary endpoint result or a statistical analysis. It therefore does not show how many participants had a change, what direction any change took, how large it was, or how precisely it was estimated. No conclusion that the programming features did or did not produce a particular outcome can be drawn from the registry information alone.

The single-arm design also limits what any descriptive change could establish. Without a concurrent control group, a change observed among participants could not be separated reliably from other influences using a between-group comparison. This design limitation is separate from the absence of reported results: even a numerical result would need interpretation in light of the lack of a control group.

The safety entries show 0 participants affected by serious adverse events among 15 at risk, 0 affected by other adverse events among 15 at risk, and 0 deaths. These are recorded counts, not a comparative safety estimate. They do not establish that risks are absent outside the recorded study experience.

In short, the record is informative about the research question and design, but not about the primary outcome’s findings. The endpoint definition, analysis population, missing-data approach, and statistical analysis are not reported in enough detail to evaluate a primary result, and the result itself is not reported in the registry record.

13. Why This Trial Matters Statistically

This study raises a statistical question that is distinct from a conventional treatment-versus-control question: how to describe a participant-level change in paresthesia distribution when the outcome is based on drawings and the study has one group. The registry identifies the endpoint and its timing, but does not describe how drawings were scored or how a change was defined. Those operational details matter because they determine what the count represents and whether different participants’ assessments are comparable.

The single-arm design makes it especially important to distinguish description from causal comparison. A study may document what happened among enrolled participants, but without a control group it cannot use a direct randomized contrast to isolate the contribution of the programming features. Clear reporting of the endpoint definition, denominator, estimate, and uncertainty would be needed even for a careful descriptive interpretation.

The record also illustrates why study completion and outcome reporting are separate matters. Although status is completed, the primary endpoint result and analyses are not reported in the registry record. The listed enrollment and safety counts cannot fill that gap. Without an outcome count and its analysis, readers cannot judge the observed pattern or its precision.

For statisticians and clinical researchers, the record therefore highlights the value of transparent outcome definitions, analysis populations, missing-data procedures, and results reporting. Those elements are necessary to understand what a participant-level change means and how far the evidence can be interpreted. In this case, the registry supports a description of the intended question and study structure, while leaving the central outcome findings 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 primary limitation for interpreting this specific study is that the registry record does not report the primary endpoint result, despite listing the study as completed. It also lists zero analyses. There is no reported count of participants meeting the endpoint definition, no endpoint denominator, and no estimate or uncertainty interval.

The endpoint description leaves important measurement details unspecified. The record does not define the reference point for “change,” the criteria for classifying a participant, the process for evaluating the drawings, or any threshold for an important change. It does not report the number of questionnaires completed or how incomplete or unclear drawings were handled. This prevents assessment of the measurement and analysis in detail.

The study is non-randomized and single-arm, with no like-for-like control comparison. Any descriptive observations from such a design would have limited ability to separate changes associated with programming from other influences. The registry does not report further participant characteristics, eligibility details, the full assessment schedule, or the statistical analysis plan.

Finally, the posted safety counts are limited to the one group and do not provide a comparator. Details on adverse-event collection and observation are not reported in the registry record. These limitations concern what can be learned from the registry information; they do not establish that the study was conducted incorrectly or that unreported results had any particular direction.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: CoverEdge Algorithm Programming Study — NCT02492880.
• Registry record last updated 2022-11-04; status last verified 2022-11.
• Results first posted 2018-08-07.
• 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

NCT02492880 is a completed, prospective, on-label, multi-center, non-randomized, exploratory, single-arm study titled “CoverEdge Algorithm Programming Study.” The official title describes characterization of programming features of the Boston Scientific Precision Spectra™ Spinal Cord Stimulator System using CoverEdge™ surgical leads. Boston Scientific Corporation is listed as sponsor.

The registry lists chronic pain as the condition, enrollment of 15, and a study start date of 2015-07-20 with primary completion on 2017-02-21. The primary endpoint concerns change in paresthesia distribution from a participant-completed drawing questionnaire, assessed at minimum 25 days post IPG implant.

The registry record does not report the primary endpoint result or an analysis. Safety entries list 0 serious adverse events among 15 at risk, 0 other adverse events among 15 at risk, and 0 deaths.