The Efficacy and Safety Study of Electro-acupuncture for Severe Chronic Functional Constipation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Efficacy and Safety Study of Electro-acupuncture for Severe Chronic Functional Constipation (NCT01726504), a randomized phase 2 study. The primary outcome is the Change in Mean Weekly CSBMs During Weeks 1-8 Since Treatment.

2. Clinical Question

This question is framed around a measured change rather than a single follow-up value. Each arm's reported result describes the change in weekly CSBMs during the treatment period compared with baseline; the between-arm estimate then contrasts those changes. This distinction matters because the primary result is not simply a comparison of the arms' final weekly CSBM levels.

The study also recorded outcomes related to bowel movements, stool consistency and straining, difficulty in defecation, constipation-related quality of life, rescue medicines and other defecation assistance, and adverse events. These broaden the clinical questions beyond the primary endpoint, but the registry does not post numerical results for every listed secondary outcome. The clinical question can therefore be answered most directly for the primary measure, while conclusions about other aspects of symptoms, quality of life, and safety depend on which results are actually posted.

3. Trial Design

The registry identifies this as a phase 2, randomized, parallel-group, triple-masked study and describes it as a multi-center randomized controlled trial. Enrollment is listed as 1075. The study compared electro-acupuncture with sham electro-acupuncture; sham was described in the study summary as placebo. The registry record lists Guang'anmen Hospital of China Academy of Chinese Medical Sciences as the sponsor.

The study start is recorded as 2012-10, and primary completion as 2014-10. Its status is completed. Those dates describe the registry record and do not, by themselves, establish when each participant entered or completed treatment. The treatment period relevant to the primary endpoint is weeks 1-8, with baseline used as the reference. A secondary CSBM outcome covers weeks 9-20.

Triple masking indicates that the registry classified the study as masked at three levels. Which people or roles were masked, how masking was maintained, and whether masking was assessed are not reported in the registry record. The record also does not report the allocation ratio, the random-sequence generation method, or allocation concealment. The sham arm is an active feature of the design: it gives the primary comparison a control condition intended to resemble the intervention, rather than a comparison with no procedure. The extent to which the sham procedure successfully maintained masking is not reported in the registry record.

The recorded enrollment and arm-specific outcome counts should be read as registry entries for the relevant results, not as a complete account of participant flow. Reasons for exclusions, withdrawals, missing outcome measurements, and the populations included in each analysis are not reported in the registry record. The record identifies a mixed models analysis for the primary comparison, but does not give enough detail to reconstruct its exact model specification or determine how it handled all missing observations.

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 the Change in Mean Weekly CSBMs During Weeks 1-8 Since Treatment, measured over Baseline and weeks 1-8.

The primary endpoint is the change in mean weekly CSBMs during weeks 1-8 since treatment, compared with baseline. CSBMs are the outcome as named in the registry; a fuller operational definition, including how an event qualified for this measure, is not reported in the registry record. The endpoint is continuous: it is summarized as a mean change, with standard errors reported for each arm.

Using change from baseline focuses the comparison on how the measured weekly frequency shifted during the treatment period, rather than on the follow-up value alone. The between-arm mean difference summarizes how far apart the average changes were. It is a group-level comparison and does not show the range of individual responses or establish that each participant changed by a similar amount.

A weekly measure is relevant to a condition involving bowel movement frequency because it expresses the outcome over a recurring time interval. The registry does not report a threshold for what would count as an important individual change or a clinically meaningful difference between groups. Consequently, the endpoint can describe the direction and precision of the average change, but the posted statistics alone do not establish how participants experienced the size of that change or whether it was important to them.

The primary time window is weeks 1-8. Later CSBM changes are listed separately for weeks 9-20, so they address a different period and are secondary rather than part of the primary endpoint.

7. Results Posted in the Registry

• Electro-acupuncture: mean 1.72 versus 0.82 on control; difference 0.90 (95% CI 0.55 to 1.25), standardized effect d = 0.31; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Changes in Mean Weekly CSBMs During Weeks 9-20

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Electro-acupuncture: mean 1.93 versus 0.82 on control; difference 1.11 (95% CI 0.72 to 1.50), standardized effect d = 0.34; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Electro-acupuncture than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Mean Weekly SBMs During Weeks 1-8

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Electro-acupuncture: mean 2.30 versus 1.28 on control; difference 1.02 (95% CI 0.74 to 1.30), standardized effect d = 0.44; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Electro-acupuncture than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Mean Scores for Stool Consistency and Straining During Weeks 1-8

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Electro-acupuncture: mean 0.87 versus 0.62 on control; difference 0.25 (95% CI 0.12 to 0.38), standardized effect d = 0.24; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Electro-acupuncture than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted numerical secondary results cover several distinct aspects of bowel function and symptoms, but the registry lists ten secondary outcomes and does not give numerical results for every one. Among the secondary outcomes with quantitative comparisons, the reported mean differences are positive. This indicates higher mean changes or scores in the electro-acupuncture arm on those measures, but the registry does not state the direction of clinical desirability for every scale. In particular, a positive score difference should not automatically be treated as favorable without knowing how the scale is coded.

The later CSBM measure concerns weeks 9-20, whereas the primary CSBM measure concerns weeks 1-8. The presence of a secondary measure over a later period provides a separate view of timing, but it does not replace the primary comparison or establish persistence beyond the assessed period. Other secondary outcomes address different constructs, so their mean differences should not be treated as interchangeable evidence for the primary endpoint.

The overall pattern can be considered alongside the primary result: the numerical secondary comparisons point in the same direction in terms of larger reported values in the electro-acupuncture arm, while the record leaves other secondary results without posted numerical detail. The relationship between those outcomes and the primary finding is therefore supportive only in a descriptive sense. It does not establish that every aspect of symptoms, function, or quality of life changed in a clinically beneficial direction.

Secondary findings usually carry less inferential weight when many outcomes are assessed, particularly if no multiplicity strategy is specified. Repeated statistical testing can raise the chance that some results appear notable by chance. The registry does not report whether secondary analyses were adjusted for multiplicity or identify a prespecified hierarchy for interpreting them. The primary result is consequently the clearest focal comparison, while secondary results are best treated as additional, less definitive evidence rather than independent confirmation of the primary finding.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• the Percentage of Participants With Three or More Weekly CSBMs
• Changes in Mean Weekly CSBMs During Weeks 9-20
• Mean Weekly SBMs During Weeks 1-8
• Mean Scores for Stool Consistency and Straining During Weeks 1-8
• Change of Average Weekly Degree of Difficulty in Defecation From Baseline
• Then Change Score of Health-related Quality of Life Via Patient-Assessment of Constipation Quality Of Life (PAC-QOL)
• Number of Participants With Adverse Events Related to Acupuncture
• Mean of Weekly Frequency of Rescue Medicine and Other Defecation Assistances Used

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous and is summarized with a mean. The registry reports arm-specific mean changes and standard errors, then a mean difference between electro-acupuncture and sham electro-acupuncture. A mean gives a group-level average on the outcome's scale. It is useful for comparing average changes, but it does not describe how observations are distributed or how many participants had a particular response.

What does the standard error describe?

A standard error describes the estimated uncertainty in a sample mean, rather than the spread of individual observations. General statistical explanation: a smaller standard error usually indicates a more precisely estimated mean, all else being equal. It should not be read as though most individual participants had values within one standard error of the mean. The arm standard errors in the primary results are 0.12 and 0.13. The registry does not report standard deviations for the primary endpoint in the arm summaries.

What is the mean difference?

The mean difference compares the average change in one arm with the average change in the other. For the primary endpoint, the recalculated difference is 0.9. Its positive direction reflects the higher reported mean change in the electro-acupuncture arm. This contrast is expressed on the original outcome scale, which makes it directly interpretable in the measure's units, but the clinical importance of a difference of this size is not defined in the registry record.

What does the p-value add?

The registry's mixed models analysis reports p <0.001. The recalculated unadjusted comparison also reports p <0.001. General statistical explanation: a p-value describes how incompatible the observed data are with a specified null model, under 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 a difference. The registry does not report the full model specification, so the sponsor's p-value cannot be independently reconstructed from the registry description alone.

The recalculated p-value is unadjusted. It assesses the primary arm comparison without an adjustment for the presence of other outcomes or analyses. Whether and how multiplicity was handled in the sponsor's analysis is not reported in the registry record. The distinction matters because several outcomes were planned or recorded, and repeated testing can increase the chance of finding an apparently unusual result by chance if no suitable strategy is used.

Why can over-dispersion matter?

General statistical explanation: count outcomes can have variability that exceeds what a simple statistical model assumes. When that happens, uncertainty may be understated unless the analysis accounts for the extra variability; this is often called over-dispersion. The registry describes CSBM outcomes as means but does not report the individual-level distribution or enough model detail to assess whether over-dispersion was relevant or how it was handled. It would therefore be inappropriate to claim that the primary analysis did or did not address it.

What is the role of the mixed models analysis?

The registry names mixed models as the method for the sponsor's primary analysis and reports its p-value. In general, mixed models can account for structured observations, such as measurements repeated over time or grouped within participants, when the model is specified for that design. The registry record does not specify the repeated-measure structure, fixed or random effects, covariance assumptions, covariate adjustment, or missing-data assumptions. The presence of a method label alone is not enough to infer those details or establish exactly how the estimate was obtained.

The arm-level re-calculation is intentionally more limited. It uses the posted summary results to describe an unadjusted difference, its confidence interval, and a p-value. It does not reproduce a participant-level model, make covariate adjustments, or resolve missing-data questions. Since the registry reports no discrepancy between its result and the recalculation, both convey a positive difference with p <0.001, but their estimates arise from different analytic descriptions. The sponsor's own analysis remains the appropriate source for its model-based inferential result.

11. Confidence Intervals and Precision

The recalculated primary mean difference is 0.9, with a 95% confidence interval from 0.553 to 1.247. The interval gives a range of estimates compatible with the posted summary data under the assumptions of the recalculation. It communicates uncertainty around the estimated average contrast; it is not a range containing 95% of individual participant outcomes and does not mean there is a 95% probability that the true difference lies in this particular interval.

The interval lies above zero, consistent with the positive mean difference and the recalculated p-value of p <0.001. Its lower and upper bounds show that the estimate is not perfectly precise: a range of positive differences is compatible with the data and analysis. The registry's mixed models result reports p <0.001 but does not include a model-based estimate or confidence interval, so the posted record does not allow a direct comparison of the precision of the sponsor's adjusted or model-based estimate with the recalculated interval.

Precision is distinct from clinical importance. The confidence interval describes statistical uncertainty on the measured outcome scale, while the registry does not identify a threshold for a meaningful difference. It also does not provide individual-level outcome distributions or the proportion of participants who crossed a meaningful response threshold. The standard errors of 0.12 for electro-acupuncture and 0.13 for sham electro-acupuncture describe uncertainty in the respective arm means, not individual variability.

The interval is based on the posted summary statistics and an unadjusted re-calculation. It should therefore be interpreted alongside the registry's mixed models analysis, not as a replacement for it. The exact confidence-interval method for the sponsor's analysis is not reported in the registry record.

12. 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 expressed as participants per arm, not as total events. They are illustrative calculations based on the observed effect, rather than the trial's original design assumptions. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is the stated fraction of the observed effect. The trial's own original sample-size assumptions are not reported in the registry record.

The 80% power column describes the planned number of participants per arm for an analysis to have an 80% chance of detecting the specified effect under the planning assumptions, if that effect is the true one and the assumptions hold. The 90% column gives the corresponding planning target for a higher chance of detection. These are design targets, not guarantees that a study with those numbers will find a statistically significant result.

The scenarios scale the effect used for planning. For the primary result, planning for 100% of the observed effect gives 164 participants per arm for 80% power and 219 participants per arm for 90% power. Planning for 50% of the observed effect gives 653 participants per arm for 80% power and 874 participants per arm for 90% power. The larger requirements for a smaller effect illustrate a general principle: smaller effects are harder to distinguish from random variation and therefore need more participants, all else being equal.

These figures are not observed power. They are prospective planning illustrations derived from the observed effect, not a measure of the probability that this completed trial detected an effect. They also do not show that the original trial was designed using these assumptions. Any interpretation depends on the stated planning model and assumptions, which may differ from the sponsor's unreported original design choices.

13. 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, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.900; pooled standard deviation σ = 2.901.
2. n = 2 × (1.96 + 0.842)² × 2.901² / 0.900² = 163.1, rounded up to 164 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
delta <- 0.9                      # observed difference in means
sigma <- 2.90098158019167                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^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 (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1726504)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 164 (80% power), 219 (90% power)
 75% of observed effect: n per arm = 290 (80% power), 389 (90% power)
 50% of observed effect: n per arm = 653 (80% power), 874 (90% power)
power.t.test: 164.1 
Simulated power at n = 164 per arm: 0.797 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-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.

14. Analyses Reported by the Sponsor

The registry's own primary analysis is labeled a mixed models analysis. For the comparison between electro-acupuncture and sham electro-acupuncture, it reports p <0.001. The registry does not post the model-based mean difference, confidence interval, or additional model details. The result therefore establishes the reported statistical evidence but does not provide the full numerical estimate from the sponsor's analysis.

The recalculated unadjusted comparison uses the arm-level mean changes and standard errors posted in the registry. It gives a mean difference of 0.9, a 95% confidence interval from 0.553 to 1.247, and p <0.001. This is a straightforward summary-statistic comparison, not a reconstruction of the mixed model. It does not incorporate any model adjustments that may have been used in the sponsor's analysis.

The registry record does not flag a discrepancy between its result and the recalculation. Both results indicate a positive difference in mean change and report p <0.001. Their agreement in direction and reported p-value does not make the methods interchangeable: the sponsor's analysis is the trial's stated primary analysis, while the recalculation is a separate unadjusted comparison. When a discrepancy is flagged, the sponsor's own analysis takes precedence; no discrepancy is flagged for this primary result.

More detailed assessment of the sponsor's estimate would require information not reported in the registry record, including the exact model specification, analysis population, and handling of missing observations. The registry-reported analysis should be cited as the sponsor's result; the recalculated interval can be used to understand the scale and precision of the summary-statistic contrast, with its unadjusted nature made explicit.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists eleven outcome measures, including the primary endpoint and ten secondary outcomes. A multiplicity strategy matters when several outcomes or comparisons are tested because repeated testing can increase the chance of at least one result appearing statistically notable even when there is no underlying difference. The registry record does not report whether the sponsor adjusted for multiple testing, used a hierarchy of endpoints, or designated which secondary outcomes were confirmatory and which were exploratory.

The posted primary analysis reports a mixed models p-value of p <0.001. The recalculated primary comparison is explicitly unadjusted. These registry entries do not establish how multiplicity was handled in the sponsor's full analysis. Numerical secondary results should therefore be read with caution, particularly because the record does not describe a correction or decision framework for interpreting the set of outcomes together.

Missing-data handling is also not reported in the registry record. The record does not state how missing weekly measurements were treated in the mixed models analysis, what assumptions were made about missingness, or whether sensitivity analyses were conducted. It does not provide a participant-flow account that would explain how many people were eligible for each analysis or why measurements might be absent. Arm-level outcome counts alone cannot establish the extent or pattern of missing data.

The analysis populations are not reported in the registry record. It is not possible to determine from the posted description whether the primary analysis used all randomized participants, a modified analysis population, or another defined set. The exact randomization and masking implementation, covariate adjustments, and full model specification are also not reported. These gaps do not negate the posted result, but they constrain reproducibility and make it difficult to assess the robustness of the analysis or the consequences of exclusions and missing observations.

Details about interim analyses, stopping rules, and the original statistical analysis plan are not reported in the registry record. Their absence from the record should not be taken as evidence that any particular procedure was or was not used. A complete account would be needed to assess prespecification, multiplicity control, and analysis choices across the full set of outcomes.

16. Safety Results

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

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The registry records serious adverse events affecting 0 participants among 534 at risk in the electro-acupuncture arm and 0 among 538 at risk in the sham electro-acupuncture arm. These are the posted counts for the serious adverse event category. They do not establish that no adverse events of any kind occurred, and they do not describe the full experience of every participant.

The record lists 31 other adverse events in the electro-acupuncture arm among 534 at risk and 24 in the sham electro-acupuncture arm among 538 at risk. These counts are separate from the serious-event counts. The registry does not provide further detail in the posted safety fields about event types, severity beyond the serious classification, duration, or clinical consequences. Specific serious-event terms are not reported in the registry record, and deaths are not reported in the registry record.

Zero recorded serious events in each arm should be interpreted as a count observed and entered in the registry, not as proof that serious harms are impossible or that the two safety profiles are equivalent. The record does not provide enough information about safety follow-up duration, event ascertainment, or analysis populations to quantify how confidently the absence of recorded serious events characterizes risk. The listed adverse-event counts are descriptive registry results and should be considered separately from the primary efficacy comparison.

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

The posted primary result shows a larger mean change in weekly CSBMs in the electro-acupuncture arm than in the sham electro-acupuncture arm during weeks 1-8. The recalculated unadjusted mean difference is 0.9, with a 95% confidence interval from 0.553 to 1.247 and p <0.001. The registry's mixed models analysis also reports p <0.001. Together, these results describe a positive between-arm difference on the registered primary measure.

This finding does not mean that every participant experienced a change, that all participants changed by the group average, or that the observed difference has the same importance for everyone. Group means conceal individual variation. The registry does not report an individual response threshold or a minimum difference considered clinically important, so statistical evidence cannot by itself establish the practical importance of the average contrast.

The primary outcome addresses one measurement over weeks 1-8. It does not alone establish what happened to every secondary outcome, how participants rated their quality of life, how often rescue treatments were used, or whether any effect persisted after that interval. The registry contains a secondary CSBM outcome for weeks 9-20, but this is a separate result and should not be confused with the primary treatment-period endpoint. Numerical findings are not posted for every listed secondary outcome.

The comparison is against sham electro-acupuncture, not against no treatment or every possible alternative. The registry classifies the study as randomized and triple-masked, but does not report which roles were masked, whether masking was successful, or key details of the randomization and analysis procedures. The results therefore need to be understood within this specific study design and the information available in the registry record.

The safety results list zero serious adverse events in each arm, alongside other recorded adverse events. Those counts do not prove that serious harms cannot occur or demonstrate equivalence in safety. The findings describe the posted results; they are not medical advice and do not settle treatment decisions for an individual.

18. Why This Trial Matters Statistically

This trial illustrates why a controlled comparison is more informative than reading a treatment-arm change in isolation. The sham electro-acupuncture arm also had a reported mean change in the primary outcome. The between-arm mean difference addresses whether the average change differed across the randomized groups, rather than attributing every observed change in the intervention arm to the intervention itself.

It also shows the complementary roles of an effect estimate, a confidence interval, and a p-value. The mean difference of 0.9 describes the estimated separation on the endpoint scale. The 95% confidence interval from 0.553 to 1.247 conveys uncertainty around that estimate, while p <0.001 indicates strong statistical evidence against the tested null model under the analysis assumptions. None of these quantities alone determines clinical importance.

The registry offers both a sponsor-reported model-based analysis and enough arm-level summary data for an unadjusted recalculation. Comparing those forms of evidence makes the importance of transparent reporting visible. The sponsor's mixed models p-value is available, but the model estimate and specification are not. As a result, the recalculation helps describe the scale of the summary contrast, while it cannot reproduce every element of the sponsor's analysis.

Finally, the trial has multiple secondary outcomes, but the registry does not report a multiplicity strategy or numerical findings for all of them. This is a useful reminder that a list of outcomes and a collection of p-values should not be interpreted as a set of equally strong, independent confirmations. Prespecified priorities, complete results, and clear analysis details are central to evaluating a clinical trial statistically.

19. 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 record leaves important details of the study population and conduct unspecified. Eligibility criteria and a fuller description of participants are not reported in the registry record, so the precise population represented by the results cannot be assessed from the posted information alone. Although the study is identified as randomized, the sequence-generation method, allocation concealment, allocation ratio, and masking roles are not reported. The registry calls the study triple-masked but does not report whether masking was successful.

The primary sponsor analysis is identified as mixed models, but its model specification, covariates, assumptions, and handling of missing data are not reported. The analysis population is also not reported. The sponsor's result includes a p-value but not a model-based estimate or confidence interval. The recalculation offers an unadjusted estimate and interval from posted summary data, but cannot resolve these omissions or substitute for participant-level analysis.

There are eleven outcome measures, and the registry lists ten as secondary. A multiplicity procedure or endpoint hierarchy is not reported. Numerical results are not posted for every listed secondary outcome, limiting a full assessment of the breadth of outcomes. The record also does not define a clinically meaningful threshold for the primary measure or provide a responder analysis, so the clinical importance and distribution of individual changes cannot be determined from the mean comparison alone.

The safety record gives adverse-event counts but does not provide detailed event descriptions, follow-up duration, or deaths. These omissions limit interpretation of the completeness and scope of safety ascertainment. The registry's brief sham-arm description is incomplete, and the record does not report how well the sham matched the intervention in participant experience. These limitations qualify interpretation of both the primary comparison and the wider clinical picture, without changing what the posted primary statistics report.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: The Efficacy and Safety Study of Electro-acupuncture for Severe Chronic Functional Constipation — NCT01726504.
• Registry record last updated 2016-02-22; status last verified 2016-01.
• Results first posted 2015-11-23.
• 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.

23. Record Summary

NCT01726504 is a completed phase 2, randomized, parallel, triple-masked, multi-center trial sponsored by Guang'anmen Hospital of China Academy of Chinese Medical Sciences. The registry lists enrollment as 1075 and records study start as 2012-10 and primary completion as 2014-10. It compared electro-acupuncture with sham electro-acupuncture for severe chronic functional constipation.

The primary endpoint was change in mean weekly CSBMs during weeks 1-8 compared with baseline. The arm means were 1.72 and 0.82, respectively. The recalculated unadjusted mean difference was 0.9, with a 95% confidence interval from 0.553 to 1.247 and p <0.001. The registry's mixed models analysis reports p <0.001, without posting its model-based estimate or confidence interval.

The registry lists ten secondary outcomes, but numerical results are not posted for all of them. Serious adverse events affected 0 participants in each arm, while other adverse-event counts were 31 and 24. Important details about missing data, analysis populations, multiplicity, and the full statistical model are not reported in the registry record.