Acupuncture Using Yamamoto's Method for the Treatment of Acute Nonspecific Low Back Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Acupuncture Using Yamamoto's Method for the Treatment of Acute Nonspecific Low Back Pain (NCT01124955), a randomized na study. The primary outcome is Pain Assessed on a 10-point Numeric Pain Scale.

2. Clinical Question

The central comparison is therefore between real YNSA acupuncture and a non-penetrating YNSA procedure in patients with acute nonspecific low back pain. The study was randomized and parallel-group, according to the registry record. The trial aimed to assess pain as well as functional capacity, quality of life and the number of sodium diclofenac pills taken per day. Secondary outcomes listed in the record include the Roland-Morris Disability Questionnaire, SF-36 quality of life, a Likert improvement scale and the number of anti-inflammatory tablets taken. The registry description does not report comparative numerical results for those outcomes. The clinical question is identifiable, but the record does not provide enough outcome information to determine the size or precision of a treatment-group difference.

3. Trial Design

The registry record describes a randomized, double-blind, parallel-group trial. Enrollment was 80. The listed groups were acupuncture and non-penetrating acupuncture; the intervention descriptions say that each group received 5 sessions, with real YNSA in the intervention group and non-penetrating YNSA in the placebo group. The sponsor was the Federal University of São Paulo. The record lists the trial as completed, with a start of 2009-11 and primary completion of 2010-06.

Randomization assigns participants to study groups using a chance-based process. In general, this can reduce systematic differences between groups at the point of assignment, although it does not guarantee that groups are identical. The registry calls the study double-blind, but does not specify which participants, clinicians, outcome assessors or analysts were masked. It also does not report the randomization sequence method, allocation concealment procedures, or details of how the placebo procedure was intended to maintain masking.

The primary outcome is described as pain measured with a visual analog scale graded from 0 to 10, with scores recorded in centimeters. The timeframe lists days 0, 3, 7, 14, 21 and 28; the outcome description also says pain was assessed before and after an acupuncture session. How these descriptions map onto each other is not reported in the registry record. The record names intention-to-treat analysis for the primary outcome, but does not describe its implementation. Further information about adherence, treatment fidelity, withdrawals and follow-up completion is not reported in the registry record.

The registry lists functional capacity, quality of life, improvement assessment and anti-inflammatory tablet use as secondary outcomes. The posted record does not state a sample-size justification, analysis plan, or specific primary between-group contrast. Without those details and numerical outcome results, the design can be described, but the comparative effect cannot be assessed from the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: 80 patients were randomized during the study.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Intention to treat analysis (ITT)

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 Pain Assessed on a 10-point Numeric Pain Scale, measured over days 0, 3, 7, 14, 21 and 28.

The primary endpoint is pain assessed on a 10-point numeric pain scale, reported as a mean in centimeters. The scale is described as ranging from 0, meaning no pain, to 10, meaning worst imaginable pain. The registry lists assessments on days 0, 3, 7, 14, 21 and 28, and describes measurements before and after an acupuncture session. It does not make clear how the session-based measurement description corresponds to each listed day.

Pain is a patient-reported symptom, so a rating scale can represent how participants experience and communicate symptom intensity. A mean summarizes the average scores in a group; the standard deviation describes how spread out individual scores are around that average. In general, these summaries can help describe both the group-level result and the variability between participants. They do not, by themselves, show how many participants experienced a meaningful change, nor do they establish that a difference is important to patients.

The registry lists mean and standard deviation as the endpoint summary and identifies an intention-to-treat population. However, it does not report the group means, standard deviations, changes from baseline, between-group estimates or confidence intervals. Because the listed primary outcome includes multiple assessment times and the registry does not reduce them to one comparison, the primary endpoint’s schedule is described, but a single primary treatment-effect estimate is not available in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with identifying the comparison, outcome, population and time point. In this trial, the comparison is real acupuncture using YNSA versus non-penetrating acupuncture using YNSA. The primary outcome is a continuous pain score summarized as a mean with standard deviation, and the named analysis population is intention to treat. The registry lists multiple assessment days, but does not report a single primary contrast. Without a defined contrast and its results, the trial’s primary treatment effect cannot be reconstructed from the posted record.

What does a mean represent?

In general, a mean is the arithmetic average of observed measurements in a group. For a continuous outcome such as pain on a numeric scale, it provides a concise description of the group’s central level. A group mean does not show the full distribution of scores. Two groups can have similar means while differing in how variable their participants’ scores are, and means can conceal differing patterns among individuals. The registry specifies standard deviation as the measure of dispersion, but does not report the actual means or standard deviations.

When evaluating a randomized comparison, the main quantity of interest is often a between-group difference in outcome, such as a difference in mean pain score at a prespecified time. A change from baseline can also be analyzed, but it answers a related, not identical, question. The registry record does not say whether the intended comparison was a difference at a particular assessment, a difference in change, or a repeated-measures analysis combining observations across time. These analysis choices are not interchangeable, and the record does not provide enough detail to identify which one governed the sponsor’s analysis.

Why does the assessment schedule matter?

Repeated measurements can describe how an outcome evolves over time. In general, an analysis of repeated observations can account for the fact that measurements from the same participant are related to one another. Treating every observation as independent would ignore that relationship. The registry lists days 0, 3, 7, 14, 21 and 28 and also describes measurements before and after an acupuncture session. The link between those descriptions, the planned model and the primary comparison is not reported in the registry record.

Multiple time points also create choices about which result is primary. If each time point is tested separately, the chance of finding at least one apparently notable result can increase when many tests are considered. In general, multiplicity procedures can control that risk, or a prespecified primary time point can focus the main inference. The registry does not report a multiplicity adjustment, a hierarchy of time points, or a prespecified single-time-point analysis. It would be inappropriate to assume that any particular approach was used.

How should uncertainty be assessed?

A standard deviation describes variation among individual observations; a standard error describes uncertainty in an estimated quantity, such as a mean. A confidence interval generally combines an estimate with its uncertainty to show a range of values compatible with the data and assumptions. These concepts are related but not interchangeable. The posted results contain no primary estimate or confidence interval, so the precision of the group comparison cannot be assessed.

A p-value, in general, evaluates how unusual data at least as extreme as those observed would be under a specified null model. 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 does not report a primary comparison p-value. No inference about statistical significance can therefore be drawn from the information available in the registry record.

What does intention to treat mean?

In general, intention-to-treat analysis compares participants according to their randomized assignment, regardless of subsequent adherence, because this preserves the randomized comparison as far as possible. The registry names an intention-to-treat analysis for the primary outcome. It does not describe how missing measurements, withdrawals, treatment deviations or incomplete follow-up were handled, or define which participants were included in that analysis. The label alone does not resolve those practical details.

The registry also describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such planning calculations illustrate how a hypothetical future study might be sized to detect a stated fraction of an effect under assumptions. They are not observed power, do not provide a substitute for an estimate with uncertainty, and do not establish the adequacy of this trial’s enrollment. The registry does not report the trial’s own sample-size justification. Any numerical planning values should be interpreted as illustrations rather than as evidence about the trial’s outcome.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is listed across days 0, 3, 7, 14, 21 and 28. Repeated time points can be useful for describing the course of pain, but they create an analysis choice: a study may focus on a prespecified time point, analyze the pattern over time, or report separate comparisons at multiple times. The registry record does not specify which approach was used. It notes that the primary outcome has several categories or time points and was not reduced to one comparison.

In general, multiplicity refers to the increased chance of a misleading positive finding when multiple hypotheses or outcomes are tested. A prespecified testing hierarchy, an adjustment procedure, or a clearly designated primary contrast can help readers interpret results. Whether any such method was planned or used is not reported in the registry record. This uncertainty does not show that an inappropriate method was used; it means the posted record does not permit evaluation of the issue.

The registry identifies an intention-to-treat analysis for the primary outcome. It does not report the number of participants with observed measurements at each time point, how missing outcome data were handled, whether any imputation was used, or how withdrawals were treated in the analysis. These details matter because missing observations can affect the estimate and its uncertainty, particularly if missingness differs between groups or relates to participants’ pain scores. The reasons and patterns of missing data are not reported in the registry record.

The handling of secondary outcomes and any adjustment across those outcomes is also not reported in the registry record. The listed secondary measures include functional capacity, quality of life, improvement assessment and tablet use, but the record does not describe a testing hierarchy or multiplicity strategy. Readers therefore cannot determine which findings, if any, were designated confirmatory and which were exploratory.

11. 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 0,001% reporting threshold.

The adverse-event figures list 0 serious events among 40 at risk in the acupuncture group and 0 among 40 at risk in the placebo group. The figures also list 0 other adverse events among 40 at risk in each group. These are the event counts recorded for the displayed categories. They should not be read as proof that no adverse experiences of any kind occurred, or that the treatments have no risks.

A zero count can be reassuring as a description of what was recorded, but it provides limited information about the range of possible event rates, particularly when the number of people at risk is limited. In general, the precision of a safety estimate depends on both the observed event count and the amount of follow-up information. The registry does not report an exposure-adjusted analysis, detailed event definitions, duration of follow-up for safety, or a fuller description of how events were collected.

Deaths are listed as null for both groups. That is not the same as a reported count of zero; the death counts are not reported in the registry record. The record lists no serious-event terms, but it does not provide additional details about event ascertainment or whether events were actively solicited. The figures therefore describe the posted safety entries, not a comprehensive assessment of all potential harms.

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

The registry record makes the study’s comparison understandable: randomized participants with acute nonspecific low back pain were assigned to real YNSA acupuncture or non-penetrating YNSA, and pain was designated as the primary outcome. The intervention descriptions state that both groups received 5 sessions. The record also lists measures of function, quality of life, improvement and anti-inflammatory tablet use.

What the record does not establish is the comparative result. It does not report group scores, a between-group estimate, a confidence interval or a primary-outcome p-value. The listed pain assessments span days 0, 3, 7, 14, 21 and 28, and the primary outcome was not reduced to one comparison. Without a reported estimate, it is not possible to say how large a difference was observed, in which direction it went, or how precisely it was estimated.

This absence should not be interpreted as evidence of no effect, evidence of equivalence, or proof that the study failed to find a difference. Those interpretations require results and an analysis that directly addresses the comparison. Nor can an estimate be inferred from the trial’s design, enrollment, or planning assumptions. A planning calculation based on an observed effect is not a substitute for reported results and is not observed power.

The safety entries show zero serious and other adverse events recorded in the displayed categories for both groups, with 40 at risk per group in each category. They do not establish that all potential harms were absent. The death fields are not reported in the registry record. Overall, the available information supports a description of the question, design, endpoint schedule and recorded safety counts, but leaves the primary clinical and statistical result unresolved.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it compares a treatment procedure with a non-penetrating procedure while identifying both as YNSA-based approaches. The randomized, double-blind, parallel-group design signals an effort to structure a controlled comparison. The registry record, however, does not specify who was masked or how masking was maintained, so the implications of the double-blind label cannot be evaluated in detail.

The outcome schedule also illustrates why a clearly defined estimand matters. Pain was to be measured repeatedly, and the record describes both assessment days and before-and-after session measurements. A reader needs to know which population, time point, outcome summary and group contrast form the primary question. Here, the registry does not report a single primary comparison or explain the relationship between the two descriptions of measurement timing.

In general, repeated measurements can add information about the timing and persistence of change, but they also require careful modeling and transparent reporting. A single mean difference at a defined time answers a different question from an overall pattern across time. Similarly, an intention-to-treat label is informative but does not explain how missing measurements were addressed. The record illustrates the difference between naming an analysis concept and reporting enough detail to reproduce or evaluate its implementation.

The trial therefore matters as an example of why design descriptions and outcome results need to be read together. Randomization and masking labels do not substitute for an effect estimate and its uncertainty. Conversely, the lack of a reported estimate in the registry cannot be converted into a null finding. Statistical interpretation requires a prespecified contrast, transparent handling of repeated and missing data, and numerical results that allow readers to assess magnitude and precision.

14. 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 most consequential limitation for interpreting this trial from the registry record is that a single primary-outcome comparison is not reported. The outcome has multiple listed assessment days, and no numerical group results, treatment-effect estimate, confidence interval or primary p-value appears in the record. The size, direction and precision of a comparative pain effect therefore cannot be evaluated.

The outcome description refers to a scale measured before and after an acupuncture session, while the timeframe lists days 0, 3, 7, 14, 21 and 28. The registry does not explain how these descriptions align or which measurement entered the primary analysis. The statistical model and handling of repeated observations are also not reported. This limits assessment of whether the analysis matched the intended question.

Although the record names intention-to-treat analysis, it does not describe missing-data procedures, withdrawals, adherence, or the number of observations available at each time point. It calls the trial double-blind without specifying who was masked or how masking was maintained. Randomization methods and allocation concealment details are not reported in the registry record. These omissions make it difficult to assess possible bias or reproduce the analysis.

The registry lists enrollment of 80, but does not report a trial-specific sample-size justification or the assumptions behind the original design. The planning illustration described in the record is not a substitute for that justification. Secondary-outcome estimates and a multiplicity strategy are not reported either. These are limitations of what can be concluded from the registry information; they do not establish that the trial itself failed to collect or analyze those data.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Acupuncture Using Yamamoto's Method for the Treatment of Acute Nonspecific Low Back Pain — NCT01124955.
• Registry record last updated 2011-06-15; status last verified 2009-11.
• Results first posted 2011-06-13.
• 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.

18. Record Summary

The registry record describes NCT01124955, a completed randomized, double-blind, parallel-group trial sponsored by the Federal University of São Paulo. Enrollment was 80. The study compared real YNSA acupuncture with non-penetrating YNSA for acute nonspecific low back pain; both group descriptions specify 5 sessions.

The primary outcome was pain on a 10-point numeric scale reported in centimeters, with assessments listed on days 0, 3, 7, 14, 21 and 28. The registry names an intention-to-treat analysis but does not report one primary comparison or numerical comparative outcome results. Secondary measures included function, quality of life, improvement and anti-inflammatory tablet use.

The posted adverse-event figures record 0 serious and 0 other events in each group, with 40 at risk per group for each category. Death counts are not reported in the registry record. Important analysis details, including missing-data handling, the repeated-measures approach and the multiplicity plan, are not reported in the registry record.