Safety & Efficacy Study of the Adiana System for Women Who Desire Permanent Birth Control (Sterilization): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety & Efficacy Study of the Adiana System for Women Who Desire Permanent Birth Control (Sterilization) (NCT00737061), a na na study. The primary outcome is 1 Year Pregnancy Rate.

2. Clinical Question

3. Trial Design

The EASE Trial is described as a multicenter, prospective evaluation of transcervical sterilization using the Adiana System. The registry lists a single-group model and one treatment arm. Allocation is recorded as NA, and masking is listed as none. This is therefore a single-arm study, not a randomized comparison with a concurrent control group. The study phase is recorded as NA.

The registry enrollment entry is 770. Separately, the primary-outcome description states that treatment was attempted for 645 participants in the intent-to-treat population. It says that 570 participants were able to rely on the device and were used to evaluate the one-year endpoint. These figures describe different aspects of the record; the enrollment entry should not be treated as the number assessed for the primary endpoint.

The device was intended to produce tubal occlusion for permanent birth control. The endpoint description ties assessment of pregnancy prevention to successful bilateral treatment and demonstration of occlusion by hysterosalpingogram at the end of a waiting period. The record does not give further detail about the waiting-period duration or the full sequence of eligibility and follow-up assessments.

The study status is terminated. The registry record lists a start of 2002-11 and primary completion of 2005-12. It does not report a reason for termination in the information available for this account. The listed secondary outcomes concern device placement, patient satisfaction, and comfort. The registry lists 11 outcome measures and 4 analyses, but does not describe how those analyses map to the individual outcomes.

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: 770 subjects were enrolled: 75 withdrew consent and 50 were excluded for pathology/procedural criteria. All subjects were enrolled on an intent to treat (ITT) basis. The ITT population included all patients who were enrolled in the study and had device placement attempted. 645 subjects had treatment attempted. No comparative assessment was made.

Waiting Period

Reasons for not completing this period:

1 Year Wearing Period

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: 645 participants had treatment attempted; Intent to Treat population. Of these 645, 570 were able to rely on the device and are used to evaluate the pregnancy prevention rate for the 1-year endpoint. During the 1-year follow-up period, there were 6 pregnancies, of which 3 were attributable to physician error, i.e., misinterpretation of HSG results.

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 1 Year Pregnancy Rate, measured over 1 year.

The primary endpoint is titled “1 Year Pregnancy Rate.” It measures the cumulative percentage of pregnancies occurring within the one-year timeframe. The stated primary objective was to assess pregnancy prevention after one year of reliance on the Adiana System. Pregnancy is the event of interest: the endpoint is intended to quantify how often pregnancy occurred in the defined assessment population during the specified period.

The endpoint definition limits the assessment to participants who underwent successful bilateral treatment and demonstrated tubal occlusion by hysterosalpingogram at the end of the waiting period. The registry describes 645 participants with treatment attempted in the intent-to-treat population, and says 570 were able to rely on the device and were used for the one-year endpoint. These populations should not be conflated: the endpoint description identifies reliance and confirmed occlusion as relevant to its assessment, while the intent-to-treat description includes those whose treatment was attempted.

A one-year pregnancy endpoint is a direct measure of the event the device was intended to prevent over a stated follow-up period. Its interpretation depends on the definition of the analysis population, how pregnancies and follow-up were ascertained, and how incomplete follow-up was handled. The numerical pregnancy rate, uncertainty interval, and analysis details are not reported in the registry record. The description notes 6 pregnancies during the one-year follow-up period, but does not give a numerical endpoint estimate or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study design determines which statistical conclusions can be drawn. This trial is identified as prospective and single-group, with allocation recorded as NA and masking listed as none. In a prospective study, outcomes are followed after study entry according to the study’s assessment process. In a single-group study, however, there is no concurrent comparison group in the record. That design can describe outcomes in the enrolled study population, but it does not produce a randomized between-group estimate of treatment effect.

The primary outcome is binary at the participant level: a participant either experienced the event of interest, pregnancy, during the defined follow-up period or did not. A percentage of participants with an event is a proportion, and its interpretation depends on both the event count and the denominator used. Here, the record distinguishes 645 participants for whom treatment was attempted from 570 who were able to rely on the device and were used to evaluate the one-year endpoint. The endpoint definition additionally refers to successful bilateral treatment and documented tubal occlusion by hysterosalpingogram. Because the registry does not report the endpoint percentage or its confidence interval, the result’s numerical magnitude and precision cannot be assessed from the record.

A confidence interval is a statistical range around an estimate that communicates uncertainty due to sampling variation under the assumptions of the method. A narrower interval generally indicates greater precision, while a wider interval indicates less precision. It is not a guarantee that the true value lies within that particular interval, and it does not resolve potential bias from missing follow-up, selection into the endpoint population, or outcome classification. No confidence interval for the primary endpoint is reported in the registry record.

General statistical considerations also distinguish an estimate from a test. A hypothesis test evaluates data against a specified null hypothesis and model; a p-value is not a measure of the size or clinical importance of an effect. Neither a primary-endpoint p-value nor a hypothesis-testing procedure is reported in the registry record. Without a comparator, the central result would ordinarily be a one-group event estimate rather than a randomized treatment contrast, but the record does not give the method used to calculate that estimate.

The registry’s planning illustration is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It is described as targeting a stated fraction of the observed effect. These are planning assumptions, not evidence that the trial itself used a two-arm design: the actual study is listed as single-group. Sample-size planning calculations are illustrative and do not measure observed power. Observed power is not a substitute for a confidence interval and cannot repair an absent or imprecise result. The numerical planning outputs and the observed effect used for that illustration are not reported in the registry record included for this account.

For binary outcomes, the analysis also depends on how participants with unknown or incomplete outcomes are handled. Treating every person without a recorded pregnancy as event-free could misstate a rate if some participants had inadequate follow-up; excluding those participants changes the analysis population and may introduce bias if follow-up is related to outcome. General methods include clearly defined analysis populations and explicit missing-data approaches. The registry record does not report the extent of missing primary-outcome data or the method used to handle it.

Over-dispersion is a general issue when data vary more than a chosen model expects. It can lead a model to understate uncertainty if the extra variation is ignored. Its relevance depends on the data structure and statistical model; it is not possible to determine from the registry information whether an over-dispersion adjustment was needed or used. The registry record does not report a model for the primary endpoint.

Finally, planned analyses and multiplicity are important when a study assesses many outcomes or performs multiple comparisons. Repeated testing can increase the chance of finding a nominally significant result by chance, while adjustment methods change how evidence is evaluated across a family of tests. The registry lists 11 outcome measures and 4 analyses, but does not report which analyses were confirmatory, whether there were multiple primary comparisons, or whether any multiplicity adjustment was used. Those details should not be inferred from the count of outcomes or analyses 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("Adiana Permanent Contraception System")
n      <- c(570)
events <- c(6)
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  Adiana Permanent Contraception System  570  6  1.1  0.4  2.3  0.5  2.3  0.5  2.3

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 11 outcome measures and 4 analyses. Its listed secondary outcomes include device placement rate, satisfaction with placement and device wearing, and comfort with placement and device wearing. Some outcome descriptions appear more than once in the list. The record does not specify which outcomes were assessed in each analysis, which analyses were prespecified, or whether the one-year pregnancy endpoint was the only confirmatory endpoint.

Multiplicity arises when several outcomes, time points, subgroups, or statistical tests are examined. If multiple tests are treated as independent opportunities to claim a finding, the chance of at least one false-positive result can increase. Statistical strategies can define a primary family of tests or adjust significance thresholds, but the appropriate approach depends on the prespecified questions and analysis plan. The registry record does not report whether an adjustment was made, so the listed outcomes should not be read as if multiplicity had been addressed.

Missing outcome data can also affect interpretation. The record gives the treatment-attempt and device-reliance populations, but does not report how many participants had complete one-year follow-up, whether follow-up differed across participants, or how missing pregnancy status was handled. The result could depend on the analysis population and assumptions about participants whose outcome status was unknown. Those assumptions are not reported in the registry record.

The record describes an intent-to-treat population for treatment attempted, while also identifying participants able to rely on the device for the one-year endpoint. It does not explain the full analysis-population rules or how participants with unsuccessful treatment, unconfirmed occlusion, or incomplete follow-up were handled in each analysis. These omissions limit assessment of potential selection and missing-data bias.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: uterine leiomyoma (0.6%), pneumonia (0.5%), pelvic pain (0.5%), gastric bypass (0.5%), surgery (0.5%).

The adverse-event record lists the Adiana Permanent Contraception System group with 645 participants at risk for serious adverse events and 60 affected in that category. It also lists 645 at risk for other adverse events and 642 affected in that category. These are separate event categories; the counts should not be added together to infer a number of participants with any adverse event, because the record does not say whether people could appear in both categories.

The listed serious-event terms include uterine leiomyoma at 0.6%, pneumonia at 0.5%, pelvic pain at 0.5%, gastric bypass at 0.5%, surgery at 0.5%, and benign breast neoplasm at 0.3%. The registry record does not provide the denominator or additional calculation details for these term-specific percentages in the information. The terms and percentages do not establish that the device caused the events. They are event listings, not evidence of a causal relationship.

The death count is null in the registry data. A null entry is not the same as a reported count of zero; deaths are therefore not reported in the registry record. The adverse-event information also does not, by itself, show how event timing, severity classification, or relatedness to the device was adjudicated.

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

The study addresses a specific statistical question: what pregnancy outcomes were observed during one year of reliance on the Adiana System among participants meeting the stated endpoint criteria? The registry describes a prospective, multicenter, single-group evaluation. It reports 6 pregnancies during the one-year follow-up period and identifies 570 participants as able to rely on the device and used to evaluate the endpoint. These details describe the study population and events, but the numerical pregnancy rate and its uncertainty are not reported in the registry record.

The outcome does not answer every question about permanent birth control. It does not, in the information recorded here, compare Adiana with another device or method. There is no randomized control group, and no comparative effect estimate is reported. Consequently, the event count cannot be used on its own to state how outcomes would differ under another approach or to attribute observed outcomes to the device.

The endpoint is specific to pregnancy during the stated one-year period and to the population able to rely on the device after specified treatment and occlusion criteria. It does not by itself summarize all aspects of the procedure or longer-term outcomes. The registry lists secondary measures concerning placement, satisfaction, and comfort, but detailed results for those measures are not included in the registry record for this account. Longer-term follow-up results are likewise not reported in the registry record.

Statistical precision remains an essential part of interpreting a rate. A confidence interval and a clearly specified denominator would help readers assess the range of values compatible with the data under the chosen analysis. Neither is reported for the primary result in this account. The number of events should therefore be read as a descriptive statement, not as a complete estimate with known precision.

In short, the record establishes the trial’s single-group design, its one-year pregnancy endpoint, the stated assessment populations, and the reported event count. It does not establish a comparative treatment effect, a causal effect, or the precision of the primary endpoint estimate. Those conclusions would require details and results that are not reported in the registry record.

14. Why This Trial Matters Statistically

This trial illustrates why a clear definition of the analysis population is central to interpreting a clinical endpoint. The record distinguishes participants whose treatment was attempted from those who were able to rely on the device for evaluation of the one-year outcome. The endpoint description further specifies successful bilateral treatment and documented tubal occlusion. Those distinctions affect the question answered by an event rate: a rate among participants who meet post-treatment conditions is not automatically interchangeable with a rate among everyone whose treatment was attempted.

The study also highlights the limits of single-group evidence. A prospective design can make the outcome and follow-up question explicit, but a single arm does not provide the concurrent comparison needed to estimate a randomized difference between strategies. The reported pregnancies are meaningful descriptive information, yet without a comparator they cannot isolate the device’s contribution from other factors that might affect observed outcomes.

Statistical reporting is as important as the outcome definition. An event count is not a complete result without the denominator, an estimate, and a measure of uncertainty. The registry record identifies the endpoint and populations but does not report the numerical one-year rate or its confidence interval. Readers therefore cannot evaluate precision from the registry information alone.

Finally, multiple outcomes and incomplete follow-up can complicate interpretation even when the primary question appears straightforward. The record lists several secondary measures and does not report the multiplicity strategy or missing-data handling. This example reinforces the value of transparent reporting of endpoint populations, analysis methods, uncertainty, and the status of outcomes not fully described.

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 registry information has several trial-specific limitations for statistical interpretation. Most importantly, the numerical one-year pregnancy rate, confidence interval, and primary-endpoint test are not reported in the registry record. Although the record states that 6 pregnancies occurred during the one-year follow-up period, it does not provide enough information to determine the reported rate or its precision.

The descriptions identify 645 participants with treatment attempted and 570 participants able to rely on the device for the endpoint. They do not fully explain the relationship between these populations and every endpoint eligibility rule, including successful bilateral treatment and confirmed occlusion. The full analysis-population definitions are not reported in the registry record. Details about follow-up completeness, missing pregnancy status, and the handling of incomplete follow-up are also not reported.

The description of pregnancy attribution is incomplete: it ends after stating that 3 pregnancies were attributable to “physic.” The complete attribution and the classification of the other pregnancies are not reported in the registry record. The timing of events and the methods used to ascertain or adjudicate pregnancies are also not reported in the information available for this account.

The single-group design and absence of a listed comparator limit causal and comparative conclusions. The registry does not report a full statistical analysis plan, adjustment methods, or the relation between the 4 analyses and the 11 outcome measures. It also does not report whether multiplicity was addressed. Termination status is listed, but the reason for termination is not reported in the registry record. These limitations constrain interpretation of both efficacy-related outcomes and safety listings.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety & Efficacy Study of the Adiana System for Women Who Desire Permanent Birth Control (Sterilization) — NCT00737061.
• Registry record last updated 2017-09-08; status last verified 2017-08.
• Results first posted 2013-01-25.
• 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 EASE Trial is listed as a multicenter, prospective, single-group evaluation of the Adiana Transcervical Sterilization System for women aged 18–45 seeking permanent birth control. The study phase is NA, allocation is NA, and masking is listed as none. Enrollment is 770, and the study status is terminated.

The primary endpoint was the cumulative pregnancy rate during one year of reliance, with assessment tied to successful bilateral treatment and demonstrated tubal occlusion by hysterosalpingogram. The registry states that treatment was attempted for 645 participants and that 570 were able to rely on the device for endpoint evaluation. It reports 6 pregnancies during one-year follow-up, but the numerical endpoint rate and its precision are not reported in the registry record.

The adverse-event listing reports serious and other adverse-event counts, along with selected serious-event terms and percentages. Deaths are not reported. The record does not provide a comparator, complete analysis details, missing-data methods, or multiplicity procedures.