LINX Reflux Management System in Subjects With GERD Who Have Previously Undergone a Laparoscopic Sleeve Gastrectomy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for LINX Reflux Management System in Subjects With GERD Who Have Previously Undergone a Laparoscopic Sleeve Gastrectomy (NCT02429830), a na na study. The primary outcome is Percentage of Participants Reporting Greater Than or Equal to (>=) 50 Percent (%) Reduction in Total Gastroesophageal Reflux Disease (GERD)- Health-Related Quality of Life (HRQL) Score Compared to Baseline (Off GERD Medications) at the 12-month Follow-up.

2. Clinical Question

The clinical question concerns symptom change after device treatment in a specific group: people with GERD after LSG. It is not a comparison of LINX with an untreated group or another intervention. The before-and-after framing can describe whether participants met the stated symptom-response threshold, but by itself it cannot separate change associated with treatment from other explanations for change over time. The record identifies safety and reflux symptoms as areas of study, but the endpoint definition alone does not establish how participants’ symptoms changed.

3. Trial Design

NCT02429830 is described as a prospective, multicenter study of the LINX system for GERD after LSG. The registry lists the study as completed, with enrollment of 30 participants. The recorded start date is 2017-04-05 and the primary completion date is 2021-06-08. The sponsor is Torax Medical Incorporated. The phase is listed as not applicable.

The design is single-group, with one arm in which participants who previously underwent LSG were treated with the LINX device and served as their own control. Allocation is listed as not applicable, and masking is listed as none. These design features mean that the primary question is framed as change from a participant’s baseline, rather than a randomized comparison between independent groups. The registry record does not report a separate control group.

The primary outcome is defined around the proportion of participants who achieved a specified reduction in total GERD-HRQL score at the 12-month follow-up, compared with baseline while off GERD medications. The record’s broader study description says that safety and reflux symptoms were monitored. It lists four outcome measures, but the other outcome definitions and their results are not reported in the registry record described for this study.

The stated analysis population, the Full Analysis Set, included participants meeting eligibility criteria who consented, completed baseline assessments, and underwent the LINX procedure. The record says the analyzed number included participants evaluable for the outcome. It does not report a detailed statistical analysis plan, the criteria for determining evaluability beyond that description, or how participants without an evaluable follow-up were handled.

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: The Full Analysis Set (FAS) consisted of participants who met all eligibility criteria, provided informed consent, completed baseline assessments, and underwent a LINX procedure. Here, 'N' (Number of participants analyzed) included all participants evaluable for this outcome measure.

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 Percentage of Participants Reporting Greater Than or Equal to (>=) 50 Percent (%) Reduction in Total Gastroesophageal Reflux Disease (GERD)- Health-Related Quality of Life (HRQL) Score Compared to Baseline (Off GERD Medications) at the 12-month Follow-up, measured over Up to 12 Months.

The primary endpoint is the percentage of participants reporting at least 50% reduction in total GERD-HRQL score at the 12-month follow-up compared with baseline measured off GERD medications. GERD-HRQL is a symptom questionnaire with 10 questions. Each question is scored from 0 to 5, from no symptoms through symptoms that incapacitate the participant. The total score is the sum of the individual question scores; higher totals indicate more severe disease.

Using a responder threshold turns the score change into a binary outcome: each evaluable participant either meets the stated reduction threshold or does not. The resulting percentage is intended to describe how common this defined level of symptom-score reduction was among participants assessed for the endpoint. A threshold can make a clinical response easier to communicate than a series of individual questionnaire scores, but it also compresses information. Participants with different score changes can fall into the same category, and a small difference around the threshold can determine whether someone is counted as a responder.

The baseline comparison gives each participant a reference point, but the endpoint remains a within-group measure. It does not, on its own, quantify what would have happened without the device. The registry record does not report the primary endpoint percentage, the number of participants contributing to that result, or an uncertainty interval. Therefore, the definition can be interpreted, but the observed frequency of response cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary endpoint summarize?

The primary outcome is a binary responder measure expressed as a percentage. A participant is classified according to whether their total GERD-HRQL score fell by at least 50% compared with their baseline score off GERD medications at the 12-month follow-up. The questionnaire score itself is based on 10 questions, each scored from 0 to 5, and the total is obtained by adding the responses. Higher total scores indicate more severe disease.

As a general statistical explanation, converting a score change into a responder category can make a result easier to communicate: it describes the share of participants who crossed a stated threshold. The tradeoff is that the category does not preserve the full amount of score change. A participant just meeting the threshold and one with a much larger change both count as responders, while participants close to the threshold on opposite sides are categorized differently. The registry record does not report the individual score changes or the primary responder percentage, so the extent of change cannot be evaluated from the registry entry.

How should the denominator be understood?

The stated Full Analysis Set consists of participants who met all eligibility criteria, gave informed consent, completed baseline assessments, and underwent the LINX procedure. For this outcome, the registry says the number analyzed included participants evaluable for the measure. That description matters because the enrolled group and the endpoint denominator need not be the same if some participants lack an evaluable follow-up. The registry record does not state how many participants were evaluable for the primary endpoint, whether any participants were excluded from its denominator, or how missing follow-up information was handled.

In general, a percentage is interpreted in relation to its denominator. Without the endpoint count and denominator, the primary result cannot be reconstructed or its precision assessed. A confidence interval, if reported, would describe the range of estimates reasonably compatible with the data under the interval’s assumptions. No such interval for the primary endpoint is reported in the registry record.

What can a before-and-after design establish?

The single-group design uses participants’ baseline values as a reference and describes their later status. In general, paired measurements can account for stable differences between participants because each participant is compared with their own baseline. However, the comparison does not include a separate group experiencing the same period without the intervention. Thus a change in the outcome over time cannot automatically be attributed to the intervention. Other influences and ordinary measurement variation may also contribute to a before-and-after difference.

Allocation is listed as not applicable and masking as none. The record characterizes participants as serving as their own control, but this does not turn the design into a randomized trial. The statistical analysis plan, including any method used to adjust for potential influences or to estimate uncertainty, is not reported in the registry record. No analyses are listed in the registry record.

What do the safety counts represent?

The adverse-event summary gives participants at risk and participants affected in the LINX Device group, separately for serious and other adverse events, and also gives the death count. These are descriptive counts. Serious adverse event terms include dysphagia and pain, each reported at 3.3%. The terms should not be added together or treated as distinct participants unless the registry establishes that they do not overlap; it does not report that information. In general, safety counts describe events observed and recorded under the study’s definitions. They do not, by themselves, establish causation or provide a comparison with another treatment group.

How should planning illustrations be read?

General sample-size calculations translate assumptions about an effect, significance level, allocation, and statistical method into a planning quantity. The stated planning assumptions for this study’s illustrations are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. These are planning illustrations based on the observed effect, not evidence that the trial was designed or powered that way. The registry record does not report the trial’s own sample-size justification. Such calculations are not observed power and do not remedy the absence of a reported primary endpoint result. A planning quantity is not the number of participants observed to respond and should not be interpreted as a treatment finding.

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("LINX Device")
n      <- c(26)
events <- c(21)
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  LINX Device  26  21  80.8  60.6  93.4  62.1  91.5  61.9  91.4

11. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures, but the primary outcome is the one defined in detail in the available record. The other outcome definitions and their results are not reported in the registry record. It is therefore not possible to assess how the outcomes relate to one another, which were designated as secondary, or whether their analyses were intended to support confirmatory claims.

When several outcomes or several statistical tests are examined, the chance of at least one apparently unusual result can increase. As a general statistical matter, multiplicity procedures can address that issue by adjusting inference or by defining a hierarchy of outcomes. The registry record does not report a multiplicity strategy, a testing hierarchy, or whether any adjustment was planned. It also does not provide primary endpoint test statistics or p-values to interpret.

The stated analysis population required eligibility, consent, baseline assessments, and a LINX procedure, with the analyzed number including participants evaluable for the outcome. That is not enough information to determine whether all enrolled participants contributed to the primary analysis. The registry record does not report the number evaluable at the 12-month follow-up, the amount or pattern of missing data, reasons for missingness, or any imputation or sensitivity analysis. In general, missing outcome data can affect a responder percentage if participants with and without observed follow-up differ in their outcomes. Without the handling rules and denominator, the scale and direction of any such effect cannot be assessed.

No analyses are listed in the registry record. This absence means there is no reported inferential analysis to review for the primary endpoint, including any model, uncertainty estimate, or analysis of sensitivity to assumptions. It should not be taken as evidence that no analysis was conducted outside the registry; the record simply does not report one.

12. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: dysphagia (3.3%), pain (3.3%).

The registry reports safety counts for the LINX Device group. Serious adverse events affected 2 of 30 participants, and other adverse events affected 15 of 30 participants. No deaths were recorded. Dysphagia and pain are listed among the serious adverse event terms, each reported at 3.3%.

These figures are descriptive. They count participants affected in this study group and do not show how the same events would compare with another treatment or with no device. The record does not report a randomized control group, so these counts cannot be used as comparative risk estimates. The serious-event terms are listed with percentages, but the registry does not clarify whether a participant could have contributed to more than one term. The terms should therefore be read individually rather than combined into a total.

Seriousness is a classification of adverse events, not a statement about causation. The registry record does not report whether the events were judged related to the device, when they occurred, how long they lasted, or whether they resolved. The counts describe what was recorded in the study; they do not establish that the device caused or did not cause any event.

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

The registry record describes a prospective, multicenter, single-group study of the LINX device in participants with GERD after LSG. It defines a primary symptom-response outcome based on a reduction in GERD-HRQL score at the 12-month follow-up and reports selected safety counts. It does not report the primary endpoint percentage or its numerator and denominator. Consequently, the posted record does not establish how often participants met the symptom-response threshold.

The endpoint definition clarifies what a response would mean within the study: a participant’s total score at follow-up met the specified reduction relative to their baseline score off GERD medications. It does not by itself establish that the device caused a change. Because the study has one group and no reported randomized comparator, a before-and-after result would not separate the intervention’s contribution from other influences on symptoms over time.

The safety information is also limited to observed counts in the study group. Serious adverse events affected 2 of 30 participants, other adverse events affected 15 of 30, and no deaths were recorded. Those counts do not provide a comparative assessment and do not determine whether events were caused by the device. The registry does not report event-level details that would support a fuller assessment.

These limitations do not imply that the intervention was beneficial or ineffective, nor that safety events were or were not related to it. The appropriate statistical reading is narrower: the registry identifies the study population, design, endpoint definition, and selected safety observations, while leaving the primary symptom-response result and important analysis details unreported. Any interpretation of efficacy beyond that would require results not reported in the registry record.

14. Why This Trial Matters Statistically

This study illustrates why a clear endpoint definition and a reported endpoint estimate are both necessary for statistical interpretation. The registry specifies a clinically oriented symptom-score threshold and a follow-up time, so the intended outcome is understandable. But without the proportion meeting that threshold, the number analyzed, and an uncertainty estimate, readers cannot determine the observed response frequency or its precision.

The single-group design also highlights the distinction between describing change and estimating a comparative treatment effect. Participants serving as their own control can provide a within-person reference, but they do not supply a concurrent randomized comparison. In general, this distinction matters because a change from baseline is not automatically the same as a difference caused by treatment. The design must be considered alongside the endpoint rather than treating the response definition as causal evidence.

The record’s analysis-population description raises another central issue: enrolled participants and participants evaluable for an outcome may differ. Knowing the primary endpoint denominator and the handling of missing follow-up would help readers understand which participants contributed to the estimate. The record does not report those details for this outcome.

Finally, the safety counts show why event categories and denominators must be stated precisely. Serious and other adverse events are reported separately, while event-term percentages are listed without detail on overlap or attribution. These data can be described, but not turned into comparative safety estimates in a single-group study. Together, these features make the record useful for understanding the intended question and design, while placing clear boundaries on what its posted results support.

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.

Several limitations are specific to this study record. The study is single-group, with participants described as serving as their own control. There is no randomized comparator group reported, so the design does not provide a concurrent estimate of what would have happened without the LINX device. The before-and-after framing may describe change, but cannot by itself establish its cause.

The primary endpoint result is not reported in the registry record. The record therefore does not show the proportion of participants meeting the response threshold, the number contributing to the endpoint analysis, or an uncertainty interval. Although enrollment is listed as 30, that does not establish how many participants had an evaluable 12-month outcome.

The Full Analysis Set definition is stated, but outcome-specific details are limited. Missing-data methods, reasons for missing follow-up, and sensitivity analyses are not reported. The registry also lists four outcome measures without reporting the other outcome definitions or results in the record. A statistical analysis plan, multiplicity approach, and trial sample-size justification are not reported in the registry record.

The safety summary provides counts and selected serious event terms, but not timing, duration, attribution, or participant-level overlap among terms. These missing details limit the interpretation of both symptom outcomes and safety. The limitations concern what can be concluded from the registry record; they do not establish that unreported analyses or information do not exist elsewhere.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: LINX Reflux Management System in Subjects With GERD Who Have Previously Undergone a Laparoscopic Sleeve Gastrectomy — NCT02429830.
• Registry record last updated 2022-08-10; status last verified 2022-08.
• Results first posted 2022-07-05.
• 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

NCT02429830 is a completed, prospective, multicenter, single-group study of the LINX device in participants with GERD after LSG. Enrollment was 30. The registry lists allocation as not applicable and masking as none; participants were described as serving as their own control.

The primary endpoint was the percentage of participants with at least 50% reduction in total GERD-HRQL score at the 12-month follow-up compared with baseline off GERD medications. Its result is not reported in the registry record. The record lists four outcome measures and no analyses.

In the LINX Device group, serious adverse events affected 2 of 30 participants, other adverse events affected 15 of 30, and no deaths were reported. Dysphagia and pain are listed as serious adverse event terms, each at 3.3%. The record does not report a randomized comparator, detailed missing-data methods, or a trial sample-size justification.