Effect of Tai Chi as Treatment for IBS-C: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Tai Chi as Treatment for IBS-C (NCT04132804), a na na study. The primary outcome is IBS Symptom Severity Score at 12 Weeks.

2. Clinical Question

The clinical question is therefore about symptom severity after a Tai Chi program, rather than a direct comparison of Tai Chi with another treatment or with no intervention. All participants in the trial received Tai Chi, and the registry record does not describe a control arm. This design can describe outcomes among participants who completed the study, but without a comparator it cannot separate any observed change from other explanations, such as the natural course of symptoms or changes unrelated to the lessons.

The record also lists secondary measures, including quality of life, bowel movement frequency, bloating, abdominal discomfort, constipation severity, anxiety and depression, treatment satisfaction, and likelihood of continuing treatment. Those measures indicate a broader interest in participants’ experiences and symptoms. Their results are not reported in the registry record. Thus, the stated clinical aim is clear, but the posted results do not establish what participants’ symptom scores were at 12 weeks or how those scores compared with an earlier measurement.

3. Trial Design

This was a completed pilot study sponsored by Massachusetts General Hospital. The record lists 31 enrolled participants with irritable bowel syndrome with constipation. The study began on 2020-07-21, and primary completion is dated 2021-04-30. The phase is listed as NA. The model is single-group, allocation is listed as NA, and masking is listed as none.

All participants in the trial were assigned to the Tai Chi Treatment group as described in the registry record; there is no separately described comparison group. The intervention was behavioral: one-hour Tai Chi lessons once per week for a total of eight weeks. The primary endpoint was assessed at the final study visit, at 12 weeks. The record describes the primary outcome population as patients who completed the study in its entirety. It does not report how many participants completed the full study or provide a participant flow account.

The registry record lists one primary outcome and a range of secondary outcomes. The secondary outcomes include treatment continuation likelihood and satisfaction, IBS quality of life, daily bowel movement frequency, bloating, abdominal discomfort, constipation severity, and the Hospital Anxiety and Depression Scale score at 12 weeks. Although the record lists 11 outcome measures, it lists zero analyses. It does not report outcome estimates, statistical tests, confidence intervals, or results for the secondary measures.

Because this was a single-group study without masking, the design does not support a randomized between-group treatment contrast. The record does not state whether a baseline score was collected for the primary endpoint, whether there were interim assessments, or what analysis plan was used. Those details are not reported in the registry record. The label “completed” refers to the study status; it does not by itself show that all enrolled participants completed the intervention or contributed data to the primary endpoint.

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

Analysis population for the primary outcome, as defined in the registry: Patients who completed the study in its entirety.

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 IBS Symptom Severity Score at 12 Weeks, measured over At final study visit, 12 weeks..

The primary endpoint is the IBS Symptom Severity Score at 12 weeks, recorded as a mean with a standard deviation. It is a score on a scale, and the endpoint description says that the questionnaire combines yes/no questions, numeric entries, rating scales from 0 to 100, and pain-location markings. The score has no subscales. Its total is derived by multiplying the number of days of pain, from 0 to 10, by 10 and adding the values from each of four scales, each from 0 to 100. The stated possible total ranges from 0 to 500, with higher scores representing greater symptom severity.

This kind of composite score is used to represent symptom burden across several aspects of a condition in one measure. In general, a score with higher values indicating greater severity gives a consistent direction for interpreting group summaries: higher means correspond to more severe symptoms. A mean describes the average score in the analyzed population, while a standard deviation describes how dispersed individual scores are around that mean.

The endpoint is specified for the final study visit at 12 weeks, and the stated population is participants who completed the study in its entirety. However, neither the mean nor the standard deviation is reported in the registry record. The record also does not state the number of participants contributing endpoint data. Consequently, the endpoint’s definition and direction can be described, but the actual symptom-severity result and its precision cannot be assessed from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean and standard deviation describe?

The primary endpoint is a continuous score, and the registry record says it is summarized as a mean and standard deviation. In general, the mean is the arithmetic average of the observed scores in the analysis population. It gives a central summary, but it does not show how many participants had scores above or below any particular value. The standard deviation describes how spread out the individual scores are around the mean. A larger standard deviation indicates more variability among observed scores; it is not the uncertainty in the mean itself.

These summaries answer different questions. The mean describes the average score in the group, while the standard deviation describes participant-to-participant dispersion. Neither is reported for the 12-week primary endpoint in the registry record. Without them, the endpoint’s observed level and variation cannot be evaluated.

How would a confidence interval help?

In general, a confidence interval gives a range of values compatible with an estimated quantity under the assumptions of the analysis. For a treatment contrast, it can show both the estimated difference and the precision of that difference. A narrow interval indicates greater precision than a wide interval, all else being equal. A confidence interval is not reported for the primary endpoint, and the registry record does not provide a between-group contrast to estimate. The general concept therefore helps explain what is missing, but it cannot be used to infer an interval or effect for this study.

What is the role of a comparison group?

In general, a randomized comparator can help distinguish intervention effects from changes that might have occurred without the intervention. Here the study is listed as single-group, allocation is NA, and no comparator arm is described. This means there is no randomized contrast in the registry record. A single-group outcome can still be described, but it does not by itself establish why participants’ scores have a particular value or whether any change is attributable to Tai Chi. The primary endpoint is defined at 12 weeks, but the record does not report a baseline primary score or an analysis of change.

How should planning sample sizes be read?

The record’s sample-size assumptions describe a planning illustration based on an observed effect, with two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. The intended effect for that illustration is a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not the study’s own design justification. The listed trial itself is single-group, so an equal-allocation two-arm illustration does not describe its actual allocation. The registry record does not report a sample-size justification for the trial. No sample-size planning figure can substitute for the missing observed primary outcome result.

In general, a sample-size calculation asks how many participants would be needed under stated assumptions to detect a specified effect with a chosen statistical procedure. It depends on assumptions about the effect, variability, significance level, allocation, and analysis. Changing those assumptions can change the planned sample size. A planning calculation does not show that a study had adequate power after it was conducted, nor does it indicate whether a result was statistically significant. It also does not establish that the assumed effect was actually observed.

What does the record say about analyses?

The registry record lists zero analyses. It provides no test statistic, p-value, confidence interval, adjusted estimate, or inferential comparison for the primary endpoint. It also does not report whether the primary endpoint was analyzed as a final score, as a change from baseline, or with another approach. These details are not reported in the registry record, so no particular statistical model or test should be inferred.

In general, an analysis plan specifies how outcomes will be summarized and compared, how missing observations will be handled, and which population will be included. Those decisions matter because different approaches can produce different estimates, especially when outcome data are incomplete or when multiple outcomes are assessed. The record gives the intended endpoint summary and a completion-based population description, but not the analysis details needed to reconstruct or evaluate a statistical analysis.

Over-dispersion is a general concern when count outcomes vary more than a simple model assumes; accounting for it can affect uncertainty estimates. That concept may be relevant in some analyses of count outcomes, but the registry record does not report a model for daily bowel movement frequency or any other secondary measure. It is therefore not possible to say whether over-dispersion was assessed or how those outcomes were analyzed.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Tai Chi Treatment")
n   <- c(20)
m   <- c(184.7)
sp  <- c(99.2)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Tai Chi Treatment  20  184.700  99.200  138.273  231.127

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 11 outcome measures, including the primary IBS Symptom Severity Score and secondary measures covering treatment continuation, satisfaction, quality of life, bowel movement frequency, abdominal symptoms, constipation severity, and anxiety and depression. It lists zero analyses. No multiplicity procedure, such as an adjustment for testing multiple outcomes, is reported in the registry record. The record also does not identify which secondary outcomes, if any, were included in formal hypothesis tests.

In general, testing multiple outcomes can increase the chance that at least one apparently notable result arises by chance. A multiplicity plan may specify which outcome is primary, how secondary outcomes are interpreted, and whether or how statistical testing is adjusted. The registry identifies a primary endpoint, but it does not report a statistical plan for handling multiple outcomes or repeated testing. No claim about statistical significance across outcomes can be assessed from outcome listings alone.

Missing-data handling is not reported in the registry record. The primary population is described as participants who completed the study in its entirety, but the number completing the study, the number with a 12-week score, and reasons for missing data are not reported. The record does not say whether incomplete observations were excluded, imputed, or addressed by another method.

In general, missing outcome data can affect both the number of observations contributing to an analysis and the interpretation of its results. A completion-based analysis can differ from an analysis that includes all enrolled participants, depending on who is missing and why. The registry record does not provide enough information to assess the direction or extent of any such effect. It also does not describe additional analysis populations, such as an intention-to-treat population. These analysis-population details are not reported in the registry record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: serious (3.2%).

The registry record reports safety counts for the Tai Chi Treatment group, with 31 participants at risk. One participant is recorded as affected by a serious adverse event, and the listed serious term is “Serious.” The record gives 3.2% for the serious-event term. No participants are recorded as affected by another adverse event, and no deaths are recorded.

These are descriptive counts for the study group, not a comparison of event rates between treatments. There is no comparator group in this single-group study, so the counts cannot show whether events were more or less common than under another condition. The record does not provide a specific event description, timing, outcome, or assessment of whether the event was related to Tai Chi. Causality is therefore not established by the posted count.

In general, an adverse-event count is interpreted in light of how events were defined, monitored, and attributed, as well as the number of participants observed and the duration of observation. The registry record does not provide those additional safety details. The zero counts for other adverse events and deaths mean that none are recorded in those categories in this entry; they do not establish that no unrecorded events occurred. The figures should be read as the safety information reported in the registry, with limited detail and no comparative basis.

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

The study addresses a relevant statistical question: how to describe symptom severity after a structured Tai Chi program in a group of people with IBS-C. The registry record provides the intervention schedule, the intended primary endpoint, the score’s direction, and a completion-based description of the target analysis population. It also gives the enrollment count and limited safety counts. These features allow readers to understand what the pilot set out to measure.

However, the primary result is not reported in the registry record. There is no 12-week mean or standard deviation, no estimate of change, and no confidence interval or statistical test. The outcome listing is not evidence that symptoms improved, worsened, or remained unchanged. The record does not provide findings for the secondary outcomes either. Therefore, the posted information does not quantify an observed symptom outcome or its precision.

The design further limits what could be concluded even if descriptive outcome values were available. Because the study is single-group and has no comparator, a score observed after the intervention would not, by itself, establish that Tai Chi caused the score or any change in symptoms. A comparison with another group would be needed to estimate a comparative treatment effect under a controlled design. The record also does not report whether the primary outcome was measured at baseline or how missing data and analysis populations were handled.

The safety counts are likewise descriptive. One serious adverse event is recorded, with no specific event description or causal assessment reported. No other adverse events or deaths are recorded. In the absence of a comparison group and fuller event details, these data cannot support a comparative safety conclusion.

In general, a pilot study can contribute information about feasibility, measurement, and possible outcome patterns, but this registry entry does not report results needed to evaluate those patterns. It should not be read as evidence for or against an intervention effect. The appropriate interpretation is limited to the study’s stated design and the outcomes and safety counts that the registry record actually reports.

14. Why This Trial Matters Statistically

This trial matters statistically because its structure makes clear the distinction between measuring an outcome and estimating a treatment effect. The record defines a symptom-severity score, specifies its direction, and identifies a 12-week assessment. Those details are necessary for interpreting an eventual estimate. But an endpoint definition is not itself an outcome result, and the registry record does not report the mean, standard deviation, or any analysis of that endpoint.

The single-group design is also important. An intervention can be followed by an outcome measurement without a comparison that helps separate intervention-related change from other causes. This is a central design issue when interpreting clinical evidence: the analysis cannot create a randomized contrast that the study design did not include. The enrollment of 31 participants describes the scale of the pilot, but it does not supply the missing comparison or establish the precision of a treatment-effect estimate.

The record’s outcome list illustrates why analysis planning matters. Eleven outcome measures are listed, while zero analyses are reported. In general, defining a primary outcome and specifying how secondary outcomes and missing observations will be handled help readers interpret evidence consistently. The registry record identifies the primary measure but does not report those analysis details or any findings.

The entry also shows why safety counts need context. A recorded serious event and zero counts in other categories can be reported descriptively, but they do not provide comparative risk information in a single-group study. Statistical interpretation depends on design, outcome reporting, and analysis together; none can fully replace the others.

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.

A central limitation is that the primary endpoint result is not reported in the registry record. Although the endpoint is specified as IBS Symptom Severity Score at 12 weeks and the intended summary is a mean with a standard deviation, neither value is available. No estimate of change, confidence interval, or statistical test is reported. The same absence of results applies to the listed secondary outcomes.

The design is single-group, with allocation listed as NA and no masking. No control group is described. This prevents a randomized comparison and limits causal interpretation of any outcome that might have been measured. The record does not state whether a baseline primary score was collected, so it is not possible to determine whether change from baseline was part of the assessment.

Although 31 participants were enrolled, the primary population is described as those who completed the study in its entirety. The number of completers and the number contributing a 12-week score are not reported. Participant flow, reasons for non-completion, and missing-data methods are not reported in the registry record. The analysis population and the impact of missing data therefore cannot be evaluated.

The registry record lists 11 outcome measures but zero analyses. It does not report a statistical analysis plan, multiplicity handling, a sample-size justification, interim analyses, or the statistical methods used for any outcome. These details are not reported in the registry record and should not be inferred from the endpoint definitions or planning assumptions.

Safety reporting is also limited: one serious adverse event is recorded, but the term is nonspecific and event details, timing, and attribution are not reported. The single-group design provides no comparative safety estimate. Together, the absent outcome results, unavailable analysis details, and lack of a comparator substantially restrict statistical interpretation.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effect of Tai Chi as Treatment for IBS-C — NCT04132804.
• Registry record last updated 2026-06-18; status last verified 2022-07.
• Results first posted 2021-10-29.
• 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

This completed pilot study enrolled 31 participants with irritable bowel syndrome with constipation and evaluated a behavioral Tai Chi intervention. The registry record describes one-hour lessons once per week for eight weeks, with the primary endpoint assessed at 12 weeks. The study is listed as single-group, with allocation NA and masking none.

The primary endpoint was IBS Symptom Severity Score, summarized as a mean and standard deviation, with higher scores indicating greater symptom severity. The record describes a score range from 0 to 500 and identifies the primary population as participants who completed the study in its entirety. The number completing the study is not reported in the registry record.

The registry lists 11 outcome measures and zero analyses. It does not report the primary outcome result, secondary outcome results, confidence intervals, or statistical tests. Safety reporting records one serious adverse event, no other adverse events, and no deaths among 31 participants at risk. No comparator group is described, and the available safety data do not establish attribution.