Study of the Sensitivity of Manual vs Electric Aspiration to Detect Completed Early Abortion: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of the Sensitivity of Manual vs Electric Aspiration to Detect Completed Early Abortion (NCT01085825), a randomized na study. The primary outcome is Accurate Confirmation of Completed Abortion.

2. Clinical Question

The trial record describes a randomized comparison of manual vacuum aspiration (MVA) and electric vacuum aspiration (EVA) in early abortion. Its stated hypothesis concerns the sensitivity of gross inspection for identifying products of conception (POCs): the investigators expected a higher true-positive detection rate with MVA among patients subsequently shown to have completed abortions.

The posted primary outcome, however, is titled “Accurate Confirmation of Completed Abortion.” Its definition includes confirmation by urine pregnancy test, appropriately falling serum hCG levels, or patient report of returned menses. That endpoint is not the same as gross identification of POCs. The registry record does not report a primary outcome measure specifically counting positive POC identification among patients with completed abortions. This difference matters when interpreting what the posted result directly addresses.

The comparison is relevant statistically because the two procedures are assessed on a binary outcome: each participant is counted as having or not having accurate confirmation under the registry definition. The posted results record the outcome for each arm and an unadjusted comparison. They do not establish from the reported outcome alone whether one procedure is more sensitive for gross POC detection.

3. Trial Design

The registry describes a randomized, parallel-group trial with no masking. Participants were assigned to manual vacuum aspiration or electric vacuum aspiration. The enrollment listed is 500, and the condition is induced abortion. The study is marked completed. The registry lists the phase as not applicable.

The interventions are described as D & C abortion procedures. The arm descriptions identify MVA and EVA, but contain no further procedural detail. The registry record does not report how randomization was generated, whether allocation was concealed, or whether any steps were taken to keep outcome assessors unaware of assignment. With masking listed as none, the record indicates an unmasked trial; it does not provide further detail about who knew the assignment.

The registered study objective focuses on women with pregnancies of less than six weeks’ gestation and compares the sensitivity of MVA with EVA for detecting completed abortion. The brief description explains that the investigators were interested in identifying POCs by gross inspection and in the possibility that the two aspiration methods might differ in how much pregnancy tissue is visible after aspiration. These statements describe the rationale and hypothesis, not a reported finding.

The primary outcome is recorded over a timeframe of 2 weeks - 6 months. Its definition includes a urine pregnancy test, appropriately falling serum hCG levels, or a patient report of returned menses as means of accurately confirming completed abortion. The posted results give an outcome count and arm denominator for each group, plus a comparison between groups. The registry lists one outcome measure and one analysis. It does not report detailed procedures for follow-up, the analysis population, handling of missing observations, or the original sample-size assumptions. Those details should not be inferred from the enrollment or the posted planning illustrations.

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 Accurate Confirmation of Completed Abortion, measured over 2 weeks - 6 months.

The registered primary endpoint is titled “Accurate Confirmation of Completed Abortion.” It is measured in participants and recorded as a number. The registry definition says that accurate confirmation is determined by a urine pregnancy test, appropriately falling serum hCG levels, or patient report of returned menses. The stated timeframe is 2 weeks - 6 months.

This is a binary outcome in the posted results: a participant either has the recorded confirmation outcome or does not. A count of participants with the outcome can be compared across randomized arms, and a risk difference expresses the contrast between the proportions with the outcome. The endpoint is used to assess the recorded confirmation outcome rather than a continuous measurement.

There is an important distinction between this endpoint and the study’s stated central question. The brief description emphasizes positive gross identification of POCs among patients later shown to have completed abortions. The posted primary endpoint instead describes confirmation of completion using pregnancy testing, serum hCG levels, or reported return of menses. The registry record does not report a separate posted measure of positive gross POC identification. Accordingly, the primary result should be read as a comparison of accurate confirmation under the registered definition, not as a direct estimate of sensitivity for gross inspection.

In general, a binary endpoint can provide an interpretable arm-to-arm comparison when its definition and ascertainment are applied consistently. The registry record does not give further detail about the operational rules for combining the listed confirmation methods, or the handling of participants without an evaluable result.

7. Results Posted in the Registry

• Electric Vacuum Aspiration: 66.4% (164/247) versus 72.5% (182/251) on control; risk difference -6.1 percentage points (95% CI -14.2 to 2.0), risk ratio 0.92 (0.81–1.03); unadjusted two-proportion z-test p = 0.139.

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports a chi-squared analysis for the comparison between the MVA and EVA groups. The posted outcome is binary, and the analysis compares the number of participants with accurate confirmation across the two arms. The posted results also support an unadjusted recalculation of the risk difference and its confidence interval from the arm-level counts. These are different descriptions of the same broad comparison, but the recalculation should not be mistaken for an additional sponsor analysis.

What does a risk difference express?

A risk difference contrasts the proportion with an outcome in one group against the proportion in another group. Here, the reported contrast is EVA compared with MVA. The estimate is -0.061. Its sign indicates that the observed outcome proportion was lower in EVA than in MVA under this direction of comparison. The estimate is a sample-based quantity; it is not a guarantee that the same difference would occur in another study or population.

In general, risk differences are expressed on an absolute scale, which can make them useful for understanding the size of an observed group contrast. They do not by themselves explain why an outcome differs, and their interpretation depends on the endpoint definition, follow-up, and analysis population. In this trial, the registered endpoint is accurate confirmation of completed abortion, not a directly posted gross-POC detection endpoint. The risk difference therefore pertains to the registered confirmation outcome.

What does the confidence interval add?

A confidence interval describes uncertainty around an estimate under the statistical method used. The interval reported for the risk difference runs from -0.142 to 0.020. Because it includes zero, the estimate is compatible with no arm difference under this interval procedure. The interval also includes values on either side of zero, so it does not settle the direction of the contrast. In general, a confidence interval is not a probability statement that the true effect lies within this particular interval, nor does it show the range of individual participant outcomes.

Confidence intervals are informative alongside p-values because they display a range of effect sizes compatible with the data and method, rather than reducing the finding to a threshold decision. A wide interval can signal limited precision. The interval leaves substantial uncertainty about the size and direction of the contrast. The registry record does not provide an adjusted confidence interval or a detailed account of the interval method.

What does the chi-squared test assess?

In general, a chi-squared test evaluates whether the distribution of a categorical outcome differs across groups, under assumptions appropriate to the data and test. For a binary endpoint, it compares the observed outcome counts with the counts expected under no association between group and outcome. The registry reports this method and a p-value of .13. The record does not identify a continuity correction, a stratification factor, or other refinements to the test.

A p-value describes how unusual data at least as discrepant as those observed would be under a specified null model and the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The registry p-value and the recalculated unadjusted p-value should be read in that limited sense. Neither value directly tests the trial’s stated gross-inspection sensitivity hypothesis as phrased, because the posted primary result is a different endpoint.

Why distinguish the study aim from the posted endpoint?

The brief description identifies positive POC detection on gross inspection among patients later shown to have completed abortions as the outcome of interest for the hypothesis. The posted primary endpoint instead counts accurate confirmation of completed abortion using urine pregnancy testing, appropriately falling serum hCG levels, or reported return of menses. These are related to completion status, but they are not interchangeable measurements. Sensitivity specifically concerns how often a test or assessment identifies a condition among those who truly have it. The registry record does not post the needed cross-classification of gross inspection results against completed-abortion status.

In general, endpoint alignment matters because an analysis can answer only the question represented by the measured outcome. The posted arm counts and risk difference address the registered confirmation outcome. They do not provide a direct sensitivity estimate for gross inspection or an estimate of how often POCs were visible in each arm.

What is not described?

The record does not report the randomization sequence method, allocation concealment, detailed outcome-assessment procedures, analysis population, missing-data method, or adjustment for covariates. It lists one analysis and one primary outcome measure, and no secondary outcomes are posted. It also does not report the trial’s original statistical analysis plan or a specific sample-size justification. These omissions do not prove that such procedures were absent; they mean they are not reported in the registry record.

In general, randomization aims to make comparison groups similar in expectation, while masking can reduce opportunities for knowledge of assignment to influence measurement or conduct. This trial is recorded as randomized and unmasked. The registry does not provide enough detail to assess the implementation of randomization or the possible consequences of the unmasked design. Such general considerations do not change the posted arithmetic, but they belong in the assessment of how confidently results can be interpreted.

10. Confidence Intervals and Precision

The risk difference for EVA compared with MVA is -0.061, with a 95% confidence interval from -0.142 to 0.020. The point estimate is negative, but the interval crosses zero. Thus, the posted data do not precisely establish the direction of the difference. The interval is compatible with an effect favoring EVA, no difference, or an effect favoring MVA under the contrast’s stated direction.

In general, a confidence interval gives a range of estimates compatible with the observed data and the method’s assumptions. A narrower interval indicates greater precision about the effect estimate; a wider interval indicates more uncertainty. Precision is not the same as validity: an interval can be narrow around an estimate even if the outcome was poorly measured or the analysis was biased. Conversely, an interval spanning zero does not establish that groups are equivalent.

The interval’s width matters because it leaves room for differences on both sides of no effect. The reported p-value of .13 and the unadjusted recalculated p-value of 0.139 are consistent with uncertainty rather than a clear separation under conventional significance testing. They do not state the probability that there is no difference, and they do not quantify the probability that one procedure is better.

Precision should also be considered in light of endpoint alignment. The estimate describes accurate confirmation of completed abortion as defined in the registry. It does not directly quantify the sensitivity of gross inspection for POCs, the study’s stated hypothesis. The registry record does not report a confidence interval for that gross-inspection sensitivity comparison. Consequently, the posted interval should not be transferred to that unreported outcome.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total events. They are illustrations based on the observed effect, rather than the trial’s original design assumptions. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each planning scenario uses the stated fraction of the observed effect. The registry record does not report the trial’s own original sample-size assumptions or justification.

The 80% power column gives the planned number of participants per arm for a future study to have an 80% chance of detecting the effect specified in that row, if the planning assumptions and effect are appropriate. The 90% power column gives the corresponding per-arm planning number for a 90% chance under those assumptions. These are design targets for a hypothetical future study, not descriptions of the number enrolled in this trial or evidence that this trial had a particular power.

The listed scenarios use 100%, 75%, and 50% of the observed effect. The figures rise as the assumed effect becomes smaller: detecting a smaller difference generally requires more participants, all else equal. For example, the planning illustration for 100% of the observed effect gives 890 participants per arm for 80% power and 1,191 participants per arm for 90% power; for 50% of the observed effect, it gives 3,460 and 4,631 participants per arm, respectively.

These are planning illustrations, not observed power. Their usefulness depends on the observed effect being a reasonable basis for planning, as well as on the listed statistical assumptions. The estimate in this trial has uncertainty, so planning solely around its point estimate may not represent the effect a future study should target. The posted figures do not establish the original rationale for the trial’s enrollment.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.725; treatment proportion p₁ = 0.664; average p̄ = 0.695.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6514 = 1.2767.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6500 = 0.5470.
4. n = (1.2767 + 0.5470)² / (-0.0611)² = 890.0, rounded up to 890 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.725099601593626                          # control proportion
p1 <- 0.663967611336032                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1085825)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 890 (80% power), 1,191 (90% power)
 75% of observed effect: n per arm = 1,561 (80% power), 2,089 (90% power)
 50% of observed effect: n per arm = 3,460 (80% power), 4,631 (90% power)
power.prop.test: 890 
Simulated power at n = 890 per arm: 0.802 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Analyses Reported by the Sponsor

The registry reports the sponsor’s own analysis as a chi-squared comparison with p = .13. The unadjusted recalculation from the posted arm summaries gives p = 0.139. The two p-values are close but not identical. The record does not provide enough detail to identify the specific reason for the difference, such as the exact test implementation or any rounding used in the reported analysis.

The recalculated estimate and confidence interval are simple unadjusted comparisons from the posted summary statistics. They are useful for describing the arm-level contrast, but they do not replace the registry’s own analysis. Because the record does not flag a discrepancy, there is no stated discrepancy requiring a different interpretation. The sponsor’s reported chi-squared result remains the registry’s own analysis, while the recalculation offers a complementary unadjusted view.

Both p-values are above conventional significance thresholds, but neither proves that the arms are equivalent or that there is no effect. The p-values also concern the posted accurate-confirmation endpoint. They should not be described as a direct statistical test of gross-inspection sensitivity, which is not separately reported in the primary results.

The registry does not report whether the sponsor’s analysis adjusted for other variables, how missing observations were handled, or whether the chi-squared test included a correction. No additional analysis is posted that would resolve those questions. The most defensible reading is to report the registry’s result as recorded and identify the recalculation explicitly as an unadjusted re-analysis of the arm summaries.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure and one analysis, with no secondary outcomes posted. It does not report whether multiple endpoints, subgroup comparisons, interim analyses, or other repeated tests were planned or conducted. A multiplicity adjustment or strategy is not reported in the registry record. It would therefore be inappropriate to assume that one was used or that none was used in the full study documentation.

In general, testing multiple outcomes or comparisons can increase the chance of finding at least one apparently unusual result by chance. Statistical plans often address this through prespecified primary outcomes, hierarchical testing, or adjustment methods. Those are general concepts; the record does not say whether any such approach was part of this trial’s original plan. The posted primary comparison can be interpreted as recorded, while acknowledging that the broader testing context is not reported.

The registry record does not describe missing-data handling, exclusions after randomization, or the analysis population. It does not state whether the reported arm denominators include all randomized participants, all participants with follow-up, or another defined set. The posted arm counts are 251 for MVA and 247 for EVA, while the adverse-event record lists different at-risk counts. The registry does not explain the denominator differences. These values should be kept tied to their respective result records rather than treated as interchangeable.

In general, missing outcome data can affect a comparison if the likelihood of missingness differs between groups or relates to the outcome. The effect depends on how much information is missing and why; those details are not reported, so the direction or size of any effect cannot be assessed. The record also does not identify an intention-to-treat, per-protocol, or other analysis population. This limits assessment of how assignment and outcome data were carried through the analysis.

The registry reports a randomized trial, but it does not provide sufficient analysis-plan details to assess prespecification, deviations, or the treatment of incomplete follow-up. The absence of these details is a reporting limitation, not evidence that a particular method was or was not used.

15. 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.

The adverse-event record lists 252 participants at risk in the MVA group and 248 in the EVA group. It records 0 serious adverse events and 0 other adverse events in each group. These are the figures in the registry’s adverse-event results; they are separate from the denominators in the primary outcome results.

The deaths field is not populated for either group, so deaths are not reported in the registry record. No serious adverse-event terms are listed. A recorded zero means that the registry reports no events in that category for the stated at-risk group; it does not, by itself, provide detail about surveillance, definitions, reporting completeness, or the duration of safety follow-up.

In general, adverse-event counts are best interpreted together with the number of people assessed, the event definitions, and the period over which events were monitored. The registry record does not give further detail about those procedures or explain why adverse-event at-risk counts differ from the denominators in the primary outcome results. The posted figures should therefore be read narrowly as the recorded adverse-event counts, not as a complete account of every possible harm or as evidence about comparative safety beyond the information recorded.

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

The posted primary outcome shows accurate confirmation of completed abortion in 182 of 251 participants assigned to MVA and 164 of 247 assigned to EVA. The unadjusted risk difference for EVA compared with MVA is -0.061, and its 95% confidence interval ranges from -0.142 to 0.020. This is an uncertain estimate: the interval includes zero and extends to values on either side of no difference. The registry’s chi-squared analysis reports p = .13.

These results describe the registered confirmation endpoint, which uses urine pregnancy testing, appropriately falling serum hCG levels, or patient report of returned menses. They do not directly report how often gross inspection identified POCs among patients later shown to have completed abortions. The trial’s stated hypothesis concerns that narrower sensitivity question, but the posted primary outcome does not provide a direct estimate of it.

The findings do not establish equivalence between MVA and EVA. A non-significant result does not prove that the procedures have identical outcome rates; the confidence interval shows that uncertainty remains. Nor do the results establish that one method is superior on the gross-inspection question. The posted endpoint is not the same as that question, and the record does not report a separate result for gross POC identification.

In general, an estimate from a randomized trial describes the comparison in its enrolled population, under the trial’s procedures and outcome definition. Applying it elsewhere requires considering whether populations, follow-up, measurement, and conduct are comparable. The registry record does not provide enough information to assess all of those factors. The results should be read as evidence about the recorded outcome and comparison, not as medical advice or a recommendation about treatment.

17. Why This Trial Matters Statistically

This trial raises a useful statistical distinction between a study’s motivating question and the endpoint recorded in its results. The brief description centers on sensitivity of gross inspection for detecting POCs among patients whose abortions are subsequently confirmed as complete. The posted primary outcome instead records accurate confirmation of completed abortion using pregnancy testing, serum hCG levels, or reported return of menses. Recognizing that distinction prevents a result for one measurement from being presented as if it directly answered another.

The randomized, parallel-group design provides a framework for comparing the two aspiration approaches on the posted binary endpoint. The risk difference communicates the absolute contrast, and its confidence interval makes uncertainty visible. The interval crosses zero and includes effects in either direction, illustrating why the point estimate alone is not an adequate summary. The p-value likewise cannot determine whether the approaches are equivalent or resolve the separate gross-inspection question.

The record also shows why outcome denominators and result contexts must be kept distinct. The primary outcome results and adverse-event record use different at-risk counts, and the registry does not explain the difference. A careful interpretation preserves the source and meaning of each count rather than combining them. More broadly, transparent reporting of endpoint definitions, follow-up, analysis populations, and missing-data methods supports reproducible interpretation.

Finally, the planning illustrations make the relationship between assumed effect size and required study size explicit: smaller target effects require more participants under the listed assumptions. They are useful for thinking about future design, but they are not evidence of the trial’s original planning rationale or its observed power. Together, these points make the record a case study in endpoint alignment, uncertainty, and disciplined reading of trial results.

18. 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 trial-specific limitation in interpreting the posted result is the mismatch between the study’s stated hypothesis and its recorded primary endpoint. The hypothesis concerns positive gross identification of POCs among patients later shown to have completed abortions. The posted primary outcome concerns accurate confirmation of completed abortion using specified follow-up evidence. The registry does not post a separate gross-inspection sensitivity result, so the central hypothesis cannot be directly evaluated from the reported primary outcome counts.

The record gives limited procedural information. It identifies a randomized, parallel design and no masking, but does not describe the randomization method, allocation concealment, who assessed outcomes, or how the listed confirmation methods were combined. The arm descriptions provide no further procedural detail. These omissions restrict assessment of trial conduct and measurement, without establishing that any particular safeguard or procedure was absent.

The registry does not report the analysis population, missing-data approach, exclusions, or the original statistical analysis plan. It also does not report the trial’s original sample-size justification or assumptions. The planning figures are based on the observed effect and cannot fill that gap. No secondary outcomes are posted, and the record does not describe multiplicity handling or interim analyses.

The primary outcome and adverse-event result records list different participant denominators, with no explanation in the registry. The adverse-event record reports zero serious and zero other events in each group, but the deaths field is not populated. The record provides no further detail about event ascertainment or safety follow-up. These reporting limits mean the safety figures should be interpreted as recorded counts rather than a comprehensive safety assessment.

The confidence interval for the unadjusted risk difference includes zero and spans effects in both directions. This limits precision about the size and direction of the confirmation-outcome contrast. The result should not be generalized beyond its endpoint or treated as a direct result for gross POC detection.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Study of the Sensitivity of Manual vs Electric Aspiration to Detect Completed Early Abortion — NCT01085825.
• Registry record last updated 2017-02-01; status last verified 2016-12.
• Results first posted 2015-06-08.
• 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.

22. Record Summary

NCT01085825 is a completed randomized, parallel-group trial comparing manual vacuum aspiration with electric vacuum aspiration for early abortion. The registry lists enrollment of 500 and records no masking. The study description focuses on sensitivity for gross detection of POCs, while the posted primary outcome measures accurate confirmation of completed abortion using a urine pregnancy test, appropriately falling serum hCG levels, or patient report of returned menses.

The primary outcome results record 182 of 251 participants in the MVA arm and 164 of 247 in the EVA arm. The risk difference for EVA compared with MVA is -0.061, with a 95% confidence interval from -0.142 to 0.020. The registry reports a chi-squared p-value of .13; an unadjusted recalculation gives p = 0.139.

The interval includes zero, and the posted outcome is not a direct measure of gross-inspection sensitivity. No secondary outcomes are posted. Details about missing data, analysis populations, original sample-size assumptions, and several trial procedures are not reported in the registry record.