TMS for Smoking Cessation in PLWHA Cessation in People Living With HIV/AIDS (PLWHA): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for TMS for Smoking Cessation in PLWHA Cessation in People Living With HIV/AIDS (PLWHA) (NCT04936594), a na na study. The primary outcome is Change in Attentional Bias iTBS (Intermittent Theta Burst Stimulation) Smoking.

2. Clinical Question

3. Trial Design

The registry record identifies this as a completed, single-group study with enrollment of 9. Allocation is listed as not applicable and masking as none. The study is described as a pilot. Its stated intervention names are iTBS and TMS, both classified as devices. The arm description says participants who smoke and live with HIV/AIDS receive iTBS and a sham comparator identified as TMS.

There is an important distinction between that arm description and the recorded design fields. The registry identifies a single-group model and explicitly notes that this is not a randomized comparison and that the arms are not a like-for-like control comparison. The description of a sham comparator does not by itself establish how participants were assigned, whether the observations were paired, or what comparison was planned. Those details are not reported in the registry record.

The study summary describes a proposal to modulate craving and attentional bias in 40 people, with 20 subjects in each arm. It also describes cognitive tasks and neuroimaging before and after TMS, and a point-of-contact urine drug screen before study initiation. The registry enrollment is 9; the record does not explain the difference between that enrollment and the proposed recruitment target. Nor does it report how many participants completed each assessment or contributed data to the primary outcome.

The primary outcome timeframe is baseline and immediately after intervention, approximately 4 hours. The record also lists change in Tobacco Craving Questionnaire Short Form scores for iTBS and sham as secondary outcomes. Eight outcome measures are recorded, but no analysis entries are listed. The protocol details, analysis plan, and explanation of the single-group structure are not reported in 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: A total of 9 participants were enrolled; however, 1 participant dropped out before the experimental sessions began.

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 Change in Attentional Bias iTBS (Intermittent Theta Burst Stimulation) Smoking, measured over baseline and immediately after intervention, approximately 4 hours.

The primary endpoint is change in attentional bias toward smoking cues after iTBS. It is defined using fixation time on cigarette and neutral cues, measured in milliseconds with an eye tracker. The visual probe task presents smoking images alongside matched neutral images; after the image pair disappears, a visual probe appears where one of the images had been. The task is adapted for smoking images and is administered on a computer.

In general, attentional-bias tasks are intended to quantify how visual attention is distributed across cue types. Fixation time offers a behavioral measure of looking at the displayed cues; it is not itself a measure of smoking cessation. The stated endpoint focuses on cue-related attention immediately after the intervention, with baseline serving as the earlier assessment. The registry describes the timeframe as baseline and immediately after intervention, approximately 4 hours.

The endpoint is a continuous measure, summarized in the record as a mean with standard error. In general, a mean describes the average measurement in the analyzed group, while a standard error describes uncertainty in an estimated mean. The registry record does not report the observed means, the change estimate, its standard error, or a confidence interval. It therefore does not show the magnitude or precision of the primary endpoint result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the endpoint summarize?

The registry identifies the primary measure as a mean of a continuous outcome, with standard error as its dispersion measure. In general, a mean combines individual measurements into an average on the outcome’s scale. Here that scale is milliseconds of fixation time on cigarette and neutral cues. A standard error describes the precision of an estimated mean, rather than the spread of individual participants’ measurements. The registry record does not report the mean or standard error values for the outcome.

The endpoint is described as change from baseline to immediately after intervention, approximately 4 hours. In general, change scores compare measurements taken at different times. Their interpretation depends on the exact analysis: investigators might analyze individual change scores or model repeated measurements, for example. Those are general approaches, not methods established for this study. The analysis method is not reported in the registry record.

How should uncertainty be understood?

In general, a confidence interval expresses a range of values compatible with an estimate under the assumptions of the analysis. A narrower interval indicates greater precision; a wider interval indicates more uncertainty. A p-value, when reported, describes how unusual data at least as incompatible with a specified null hypothesis would be under that hypothesis and the model assumptions. Neither measure alone describes clinical importance, and neither replaces the estimate itself. The registry record does not report a confidence interval, p-value, or other inferential result for the primary endpoint.

The distinction between variability and precision matters. Individual fixation times can vary substantially, while the standard error concerns uncertainty in the group mean. In general, the precision of a mean depends on the data and the number of usable observations. Although enrollment is 9, the number contributing to the endpoint is not reported in the registry record, so the precision cannot be reconstructed.

What does the study structure allow?

The record lists a single-group model, allocation as not applicable and no masking, and explicitly warns that this is not a randomized comparison with like-for-like control arms. In general, randomized comparisons can help separate intervention effects from other differences between groups, provided the design and analysis are appropriate. A within-person comparison can account for stable differences between participants, but it does not automatically rule out changes over time, task practice, or other influences. These are general considerations; the registry record does not specify whether the primary analysis was within-person or how the two intervention descriptions were handled.

The record says the primary outcome is measured at baseline and immediately after intervention. In general, paired measurements require an analysis that recognizes the relationship between observations from the same participant. Treating such measurements as independent can misrepresent uncertainty. Whether pairing was used, and how missing paired measurements were handled, are not reported in the registry record.

How should planning illustrations be read?

Any sample-size illustrations use the stated assumptions of a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. The record notes that these are planning illustrations computed from an observed effect, not the trial’s own design. No numerical observed effect or resulting planning counts are reported in the registry record. In general, such calculations describe sample sizes under chosen assumptions; they are not observed power and do not establish the precision or significance of the completed study.

For continuous outcomes, the record’s planning note distinguishes participants per arm from event totals used for time-to-event calculations. The primary outcome in this study is continuous, so the relevant concept is participants per arm. However, the recorded study is single-group and not a randomized comparison, making it especially important not to treat a two-arm planning illustration as evidence that the completed study had a valid two-arm contrast. Sample-size assumptions and the actual design serve different purposes.

Over-dispersion is a general concern when observed variation exceeds what a statistical model assumes. If a model understates variability, its uncertainty estimates can be too small. The registry record does not report a model for the primary endpoint or information sufficient to assess dispersion. No claim about over-dispersion or any model adjustment can therefore be made for this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists eight outcome measures and identifies change in attentional bias after iTBS as the primary outcome. It also lists changes in Tobacco Craving Questionnaire Short Form scores for iTBS and sham as secondary outcomes. No analysis entries are listed. The statistical plan, including whether outcomes were tested separately or how multiple comparisons were handled, is not reported in the registry record.

In general, when several outcomes or statistical tests are considered, the chance of at least one apparently notable result can increase. Multiplicity procedures can address that issue, but the appropriate approach depends on the prespecified questions and analysis plan. Because the plan is not reported, it is not possible to determine whether multiplicity was addressed or how any results should be interpreted in light of the outcome set. No numerical outcome results are reported in the registry record from the registry record.

The record does not report a missing-data method, the number of missing measurements, or how participants with incomplete assessments were handled. It also does not identify the analysis population—for example, which enrolled participants were included in the primary outcome analysis. These details are important because the endpoint requires measurements over time and the reported enrollment is 9, while the primary-outcome denominator is not given.

In general, missingness can affect both the amount of information available and the interpretation of an estimate, especially if the likelihood of missing data is related to participants’ measurements or characteristics. The registry record does not provide information to assess that possibility. The number of outcome measures alone does not establish which were analyzed, and the absence of analysis entries should not be interpreted as a particular missing-data or multiplicity strategy.

11. 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.

The registry safety group is titled People Living With HIV/AIDS (PLWHA) Who Smoke. It reports 8 participants at risk for serious adverse events and 0 serious adverse events. For other adverse events, it reports 8 at risk and 0 events. Deaths are reported as 0. No serious-event terms are listed.

These counts describe the safety entries in the registry record; they do not establish that no events occurred outside the recorded scope or period. The record does not provide event narratives, observation duration, or additional detail on how events were collected. The enrollment field reports 9, while the safety group reports 8 at risk for each event category. The reason for the difference is not reported in the registry record, and the enrollment total should not be substituted for the safety denominator.

In general, a zero count in a small group is not proof that an event is impossible or that an intervention is safe. The count is also not a comparative estimate: the registry identifies a single-group design, not a randomized, like-for-like safety comparison. The posted figures should therefore be read as recorded event counts among the stated at-risk group, with limited information about their precision and context.

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

This record identifies a completed pilot study of TMS in people living with HIV/AIDS who smoke. Its primary endpoint concerns short-term change in attentional bias toward smoking cues, measured in milliseconds with a visual probe task and eye tracker. That definition clarifies the outcome the study intended to examine. It does not show the observed change: numerical results for the endpoint are not reported in the registry record.

The same distinction applies to the listed craving outcomes. The record names changes in Tobacco Craving Questionnaire Short Form scores for iTBS and sham, but it does not report their values or analyses. The registry lists eight outcome measures and no analysis entries. Without results and uncertainty estimates, the size, direction and precision of any outcome cannot be assessed.

The design description also matters. The registry lists a single-group model, no masking and allocation as not applicable, and flags that the study is not a randomized comparison with like-for-like control arms. A treatment contrast should not be inferred simply from the description of a sham comparator. In general, an observed change over time is not by itself proof that an intervention caused it; the record does not provide a reported analysis that resolves this issue.

The record’s enrollment is 9, while its study summary describes a proposed total of 40 participants, with 20 in each arm. It does not explain the difference or report the number contributing to each outcome. As a result, the available record cannot establish how complete the endpoint data were or how precisely any result was estimated.

The meaning is therefore limited but useful: the registry records the study’s population, intervention descriptions, endpoint definition, timeframe and safety counts. It does not provide a basis for claiming a measured change, a treatment effect, or a definitive comparison. The absence of numerical results in this record should not be mistaken for a finding of no effect.

13. Why This Trial Matters Statistically

The study illustrates why a clearly defined endpoint and a clearly described design are both needed for statistical interpretation. The primary endpoint is specified as fixation time on cigarette and neutral cues, in milliseconds, assessed at baseline and immediately after intervention, approximately 4 hours. This gives a reader a concrete sense of what was measured and when. At the same time, the registry’s single-group model and warning about the lack of a like-for-like control comparison constrain what a change could establish.

The record also shows why enrollment, analysis denominators and safety denominators should be distinguished. It reports enrollment of 9, a proposed recruitment target of 40 in the study summary, and 8 at risk in each safety category. It does not explain these differences or report the primary endpoint denominator. Without that context, the amount of information supporting an outcome estimate is unclear.

From a statistical education perspective, the record is a reminder that a named outcome is not the same as a reported result. A continuous mean and standard error would help describe the endpoint and its precision, while an analysis plan would clarify how repeated measurements and multiple outcomes were handled. Neither numerical estimates nor analysis entries are reported. The stated planning assumptions are not a substitute for results from the completed study.

The record also makes the limits of pilot evidence relevant. In general, a pilot can be useful for examining procedures and generating estimates for later research, but its interpretation depends on how it was designed and reported. No claims about the study’s feasibility findings or observed effects can be made from the information in this registry record. Its statistical importance lies in the questions it defines and in the reporting details still needed to evaluate the answers.

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 main limitation for interpretation is that numerical results for the primary outcome are not reported in the registry record. The record gives the endpoint definition, unit, summary measure and timeframe, but no observed mean, change estimate, standard error, confidence interval or test result. The craving outcomes are named but their results are likewise not reported. This prevents assessment of effect size, direction and precision.

The design information is limited and includes a tension between the single-group model and the arm description of iTBS plus a sham comparator. The record explicitly says this is not a randomized comparison and that the arms are not a like-for-like control comparison. It does not explain the assignment or analysis structure. The planned recruitment description of 40 participants, with 20 in each arm, also differs from the recorded enrollment of 9, without an explanation in the registry record.

The number analyzed for the primary endpoint is not reported, nor are the missing-data approach, analysis population, multiplicity strategy or statistical plan. The record lists eight outcome measures but no analysis entries. These omissions limit interpretation of both precision and the role of secondary outcomes.

Safety reporting is also limited to counts: 8 at risk and 0 events in each of the serious and other adverse-event categories, with 0 deaths. The reason the safety denominator differs from the enrollment field is not reported. Event collection details and observation duration are not reported in the registry record. These limitations mean the safety figures should be read as recorded counts, not as a comprehensive or comparative assessment.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: TMS for Smoking Cessation in PLWHA Cessation in People Living With HIV/AIDS (PLWHA) — NCT04936594.
• Registry record last updated 2023-07-13; status last verified 2023-06.
• Results first posted 2023-07-13.
• 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 a completed pilot study of TMS for smoking cessation in people living with HIV/AIDS who smoke. It lists enrollment of 9 and identifies iTBS and TMS as device interventions. The study summary describes a proposed total of 40 participants, with 20 in each arm, but the difference from recorded enrollment is not explained.

The primary outcome is change in attentional bias after iTBS, measured as fixation time on cigarette and neutral cues in milliseconds at baseline and immediately after intervention, approximately 4 hours. The record identifies a single-group model, no masking and allocation as not applicable, and notes that this is not a randomized comparison with like-for-like control arms.

Eight outcome measures are listed, including secondary craving outcomes. No analysis entries or numerical primary-outcome results are reported in the registry record. The safety group reports 8 at risk and 0 serious adverse events, 8 at risk and 0 other adverse events, and 0 deaths. The reason for the difference between enrollment and safety denominators is not reported.