This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Exercise Into Pain in Chronic Rotator Cuff Related Shoulder Pain: a Prospective Single-Group Feasibility Study (NCT04154345), a na na study. The primary outcome is Rate of Adherence (Physiotherapy Session).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04154345 |
| Phase | NA |
| Condition | Shoulder Impingement Syndrome |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Universiteit Antwerpen |
| Results posted | Yes |
2. Clinical Question
The study asks whether a program of exercise into pain can be delivered for people with chronic rotator cuff related shoulder pain, and whether clinical outcomes can be collected in a way that could inform a future randomized controlled trial. Its registered primary endpoint focuses on attendance, not on whether shoulder symptoms improve.
Population
People with shoulder impingement syndrome are listed as the study population. The title describes chronic rotator cuff related shoulder pain, and the brief summary refers to subacromial shoulder pain. Further eligibility details are not reported in the registry record.
Intervention
The intervention is exercise therapy that allows exercise into pain. The description says pain during exercise ranges from 4 to 7 on the Numeric Pain Rating Scale. The registry record does not report additional details about exercise selection or delivery.
Comparator
There is no comparator group. The study is registered as a single-group study, with allocation listed as not applicable. It therefore does not provide a randomized, like-for-like comparison with another treatment or a control condition.
Primary question
The primary endpoint counts participants meeting the study’s definition of good adherence: attendance at 7/9 (78%) of physiotherapist-led sessions. The registry specifies measurement every session, with a final measure at the end of 12 weeks. The observed count meeting that criterion is not reported in the registry record.
These features make the study’s central statistical question one of feasibility: can the painful exercise program be delivered, and can attendance and other clinical outcomes be collected? A feasibility result may describe whether procedures were workable in this study. Without a comparison group and reported outcome values, the record does not answer a comparative question about treatment effects.
3. Trial Design
The registry describes a prospective, single-group feasibility study titled “Exercise Into Pain in Chronic Rotator Cuff Related Shoulder Pain: a Prospective Single-Group Feasibility Study.” The study is registered as NCT04154345, sponsored by Universiteit Antwerpen, and marked completed. Its enrollment is 12. The recorded start date is 2019-11-28, and the primary completion date is 2020-05-14.
Allocation is listed as not applicable, masking as none, and the model as single group. The phase is listed as not applicable. These entries are consistent with a study that evaluates one exercise program without a randomized control arm. The listed intervention is exercise therapy involving exercising into pain. The description says pain allowed during exercises ranges from 4 to 7 on the Numeric Pain Rating Scale.
The stated purpose has two parts: evaluating the feasibility of applying a painful exercise program for subacromial shoulder pain, and assessing the time needed to collect clinical outcomes for a future randomized controlled trial. This is a different purpose from estimating a treatment contrast between groups. In a feasibility study, attendance, data collection, and the practicality of study procedures can be important outcomes in their own right.
The registry lists 19 outcome measures, including the adherence endpoint and secondary measures involving fear-avoidance beliefs, fear of pain, and passive and active range of motion. It lists zero analyses. The result for the primary adherence endpoint, the time needed to collect clinical outcomes, and numerical findings for the secondary measures are not reported in the registry record. A protocol, sample-size justification, interim analysis plan, and detailed statistical analysis plan are also not reported in the registry record.
Because there is only one study group, results can describe participants enrolled in this program, but they cannot establish what would have happened to a comparable group receiving another intervention. The record’s design and available result information should therefore guide interpretation: this is a feasibility study, and the posted information does not supply a reported estimate of comparative benefit or harm.
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
| Stage | Painful Exercises |
|---|---|
| STARTED | 12 |
| COMPLETED | 8 |
| NOT COMPLETED | 4 |
Reasons for not completing this period:
| Reason | Painful Exercises |
|---|---|
| Covid-19 pandemic | 4 |
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.
| Characteristic | Unit | Painful Exercises |
|---|---|---|
| Participants analysed | 12 | |
| Age, Continuous | years | 50.5 (37 to 53.5) |
| Sex: Female, Male: Female | Participants | 7 |
| Sex: Female, Male: Male | Participants | 5 |
| Race and Ethnicity Not Collected | Participants | — |
| Body Mass Index | kg/m^2 | 23.2 (21.3 to 24.8) |
| duration of symptoms | months | 6.5 (4 to 15.3) |
| dominant side affected | Participants | 7 |
| previous treatment | Participants | 8 |
6. Primary Endpoint
The registry lists the primary outcome as Rate of Adherence (Physiotherapy Session), measured over measurement every session, final measure at the end of 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the rate of adherence to physiotherapy sessions, expressed as a count of participants. The registry defines good adherence as attendance at 7/9 (78%) of physiotherapist-led sessions. Measurement is specified for every session, with a final measure at the end of 12 weeks. Thus, the endpoint is intended to summarize whether participants reached a prespecified attendance threshold during the program.
Attendance is useful in a feasibility study because it describes engagement with the study intervention. If participants attend the planned sessions, that can inform whether the program and its delivery schedule appear workable for a later study. It does not, by itself, measure improvement in shoulder pain, function, or range of motion. Nor does meeting the attendance threshold establish that the exercise program caused a clinical change.
The registry record does not report the number of participants who met the threshold, the distribution of session attendance, or how attendance was handled when a session was missed or its status was unknown. It also does not report a confidence interval for the adherence result. Consequently, the endpoint’s definition is available, but its observed value and statistical precision cannot be assessed from the registry record.
A count endpoint can be presented as a count of participants meeting a criterion, while a proportion with an uncertainty interval can help show how precisely the underlying adherence rate is estimated. The record does not provide the numerator or an interval, so neither should be inferred from the enrollment figure alone.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry gives the study’s design and the definition of its primary endpoint, but it does not report the observed adherence count. The record lists zero analyses. As a result, the central feasibility outcome cannot be interpreted numerically: there is no reported number of participants meeting the good-adherence criterion, no reported attendance distribution, and no reported uncertainty interval for that outcome.
The endpoint threshold is attendance at 7/9 (78%) of physiotherapist-led sessions, with measurement every session and a final measure at the end of 12 weeks. That definition tells readers how good adherence was intended to be classified; it does not reveal whether participants reached the threshold. Enrollment of 12 identifies the number recorded as enrolled, but it does not establish how many had complete attendance data or how many met the endpoint.
For a binary endpoint, a count and a proportion describe the observed frequency of participants meeting the criterion. A confidence interval would convey how uncertain that estimated frequency is, especially when based on a small study group. These are general statistical points; the registry record does not provide the values needed to assess the observed frequency or its precision. No confidence interval, test result, or model estimate for adherence is reported.
The single-group design also limits what can be concluded. Attendance can be described for this group, but there is no concurrent comparator to distinguish the experience under this program from what might occur under another approach. In general, a between-group treatment effect requires a valid comparison; a single-group feasibility study does not estimate that contrast. The absence of a control arm is not a flaw relative to every feasibility objective, but it does restrict conclusions about comparative effectiveness.
The stated purpose also includes assessing the time needed to collect clinical outcomes for a future randomized controlled trial. No time-to-collection result is reported in the registry record. The secondary outcomes include fear-avoidance beliefs, fear of pain, and passive and active range-of-motion measures, but their numerical results are not reported. The record therefore does not support conclusions about changes in those measures.
The serious adverse event entries list zero serious events and zero deaths among 12 at risk in the painful exercises group. The other adverse-event entries list zero events among 12 at risk. These are registry counts, not estimates that establish absence of risk. Event definitions, ascertainment details, and completeness of follow-up are not reported, so the figures should be read as the events recorded in the registry rather than as proof that no events occurred.
Overall, the available record supports a description of the research question, intervention, endpoint definition, and design. It does not give a reported primary outcome result or the secondary outcome findings. Interpretation should stay at that level and should not turn the study’s feasibility aims into claims about clinical benefit or comparative safety.
9. Statistical Methods Explained
Statistical methods help distinguish the question a study is designed to answer from the conclusions its data can support. In this study, the design is single group and the primary endpoint is a count of participants classified by an attendance threshold. The registry record lists zero analyses, so there is no reported statistical result to interpret for that endpoint. The explanations below describe general methods relevant to this kind of outcome and design, not analyses reported for this study.
What does a count endpoint represent?
A count of participants meeting a criterion records how many satisfy a defined classification. Here, the classification is good adherence, defined as attendance at 7/9 (78%) of physiotherapist-led sessions. A count is easy to interpret when the underlying attendance records are complete and the classification rules are applied consistently. Its meaning depends on what qualifies as an attended session, how missed or rescheduled sessions are handled, and how incomplete records are treated. Those operational details are not reported in the registry record.
A proportion places such a count in relation to the group being evaluated. A confidence interval around a proportion gives a range of values compatible with the data and the chosen statistical method; it conveys precision rather than guaranteeing that the true value lies in that particular interval. General interval methods can behave differently with small samples, especially when the observed proportion is near either boundary. The registry does not report the adherence count or an interval, so no specific estimate or precision statement can be made.
Why does the study design matter?
A single-group study can describe what happened among the enrolled participants, including attendance and the feasibility of data collection. It cannot, on its own, estimate a treatment difference against a control group. In general, outcomes may change for reasons other than the intervention, and a comparison group helps assess those alternative explanations. This design is consistent with the stated feasibility purpose, but it does not answer a randomized comparative-effectiveness question.
Masking is listed as none. Masking concerns whether participants, clinicians, or outcome assessors know which intervention is being delivered or assessed. Its relevance depends on the outcome: attendance is a recorded behavior, while some clinical measures may involve assessment procedures. The registry does not report further masking details or an assessor-specific plan, so no more specific assessment of bias control is possible.
What do the planning assumptions mean?
The record’s planning description refers to illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also states that the effect to detect is a specified fraction of the observed effect. These are planning assumptions, not evidence that the feasibility study itself had two arms, used randomized allocation, or conducted a test under those conditions. In a single-group feasibility study, such an illustration would describe a hypothetical future comparison rather than the design actually registered.
Planning sample sizes are not observed power. They describe how many participants might be needed under stated assumptions for a future study to detect a target effect with a chosen statistical procedure. Their interpretation depends on the target effect, outcome variability or event rate, allocation, significance level, and analysis method. If any assumption differs from the future study, the planning result may not apply. The registry record does not report the study’s own sample-size justification, and no planning result should be read as an observed finding from this feasibility study.
For planning, the record distinguishes participant counts per arm for outcomes other than time-to-event outcomes from total event counts for time-to-event outcomes. This is a general distinction in the planning description, not a statement that a time-to-event endpoint was used as the primary outcome. The primary endpoint is registered as a participant count based on session attendance.
Why can over-dispersion matter?
For some count outcomes, a simple statistical model assumes the variation is tied closely to the mean count. Over-dispersion means the observed counts vary more than that model expects. If ignored, uncertainty can be understated and intervals or tests can appear more precise than they should. This is a general issue for count data; the registered adherence endpoint is a count of participants meeting a binary threshold, and no model-based analysis or over-dispersion assessment is reported in the registry record.
What can be inferred from no reported analysis?
Zero analyses in the registry record means there is no posted analytical result to summarize for the registered outcomes. It does not reveal why analyses are absent, whether data were collected, or whether an analysis was conducted outside the record. Those reasons are not reported in the registry record. Statistical interpretation must therefore separate the endpoint definition from an outcome estimate: the former is recorded, while the latter is not available in the registry record.
For the same reason, no p-value, confidence interval, adjusted estimate, or conclusion about statistical significance can be stated for adherence or the secondary measures. Statistical significance, if it were reported, would not by itself establish clinical importance or causation. In this study, the registry record does not report an outcome analysis on which to base either kind of conclusion.
10. Exact Estimates for Each Arm
No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.
| Arm | Participants | Events | Observed % | Clopper-Pearson 95% CI | Wilson 95% CI | Bayesian 95% credible interval |
|---|---|---|---|---|---|---|
| Painful Exercises | 8 | 7 | 87.5% | 47.3% to 99.7% | 52.9% to 97.8% | 51.8% to 97.2% |
R code and output
arm <- c("Painful Exercises")
n <- c(8)
events <- c(7)
for (i in seq_along(n)) {
ci <- binom.test(events[i], n[i])$conf.int # Clopper-Pearson exact interval
cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i]) # Bayesian, uniform Beta(1,1) prior
wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}
ARM Painful Exercises 8 7 87.5 47.3 99.7 52.9 97.8 51.8 97.211. Multiplicity, Missing Data and Analysis Populations
The registry lists 19 outcome measures, including the primary adherence endpoint and secondary measures of fear-avoidance beliefs, fear of pain, and passive and active range of motion. When a study evaluates multiple outcomes, the chance of at least one apparently unusual result can increase if each is tested separately without accounting for the number of comparisons. General approaches include identifying a primary outcome in advance, adjusting inference across outcomes, or treating secondary findings as exploratory. The registry record does not report a multiplicity strategy or indicate which analyses, if any, were intended to be confirmatory.
The record identifies the adherence measure as primary, but lists zero analyses and does not report numerical findings for the primary or secondary outcomes. Therefore, there are no posted outcome tests to interpret as a family of results, and no multiplicity adjustment can be assessed. The protocol and detailed statistical analysis plan are not reported in the registry record.
Missing data can affect both the count meeting the adherence threshold and the interpretation of other clinical measures. For example, a session with no recorded attendance status is not automatically equivalent to an attended or missed session. General analysis plans may specify how incomplete measurements are handled and whether a participant must have complete records to be included. The registry record does not report missing-data amounts, reasons for missingness, imputation methods, or rules for incomplete attendance records.
The analysis populations are also not reported in the registry record. It is therefore unclear which enrolled participants would have been included in any analysis, whether all enrolled participants were expected to contribute data, or how deviations from the exercise program were to be handled. These omissions prevent assessment of the relationship between enrollment, follow-up, and any possible analysis. They do not justify assumptions about whether data were missing or whether participants were excluded.
12. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Painful Exercises | 0 | 12 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Painful Exercises | 0 of 12 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Painful Exercises | 0 of 12 |
For the painful exercises group, the registry lists 12 participants at risk for serious adverse events and zero serious adverse events. It also lists zero deaths. The other adverse-event entries list 12 participants at risk and zero events. These are the counts recorded in the registry, not a comparison with another group.
A zero count means no event of the relevant type is listed in the record for this group. It does not demonstrate that the intervention has no risk, and it does not show that all possible harms were assessed or captured. The registry record does not report event definitions, the method or timing of safety monitoring, completeness of follow-up, or additional details about the other adverse-event category.
Safety counts are most informative when readers know how events were defined, how actively they were sought, how long participants were followed, and how missing safety information was handled. Those details are not reported in the registry record. The figures should therefore be read narrowly as registry-reported counts among those listed as at risk, rather than as a definitive safety conclusion or evidence of comparative safety.
13. What the Result Does, and Does Not, Mean
This study’s statistical meaning is primarily about feasibility. It was designed to evaluate applying a painful exercise program and the time needed to collect clinical outcomes for a future randomized controlled trial. Its primary endpoint measures attendance, using a stated threshold for good adherence. Those aims differ from demonstrating that one treatment is better than another.
The registry record does not report the observed adherence count, the attendance distribution, or the time needed to collect clinical outcomes. It also lists zero analyses and does not report numerical findings for the secondary measures. Consequently, the record does not establish how many participants met the adherence definition, whether the program was feasible according to that endpoint, or how the measured clinical outcomes changed.
Even if an attendance result were available, attendance would describe participation rather than clinical effectiveness. A participant could attend sessions without a particular clinical change, or have a clinical change for reasons not attributable to the program. A single-group study lacks a concurrent comparator for evaluating such alternatives. This is a general limitation of single-group designs, not a finding about what happened to participants in this study.
The zero serious adverse event and death counts are also limited to what the registry lists. They do not prove that risks were absent or permit a comparative safety judgment. Follow-up and ascertainment details are not reported in the registry record.
The cautious conclusion is that the registry documents a feasibility study, its exercise intervention, and its planned adherence criterion, but does not report the outcome information needed to judge the observed feasibility results. It cannot support claims that the exercise program did or did not improve shoulder symptoms, nor can it establish treatment effects relative to another approach. Those questions would require reported outcome data and, for comparative effects, an appropriate comparison design.
14. Why This Trial Matters Statistically
Feasibility studies address practical questions that can determine whether a larger clinical study can be conducted. Attendance, intervention delivery, and the time required to collect outcome measures can help identify issues for future study planning. In this record, those aims are explicit: evaluating a painful exercise program and assessing the time needed to collect clinical outcomes for a future randomized controlled trial.
The primary endpoint illustrates why an operational definition matters. Good adherence is defined as attendance at 7/9 (78%) of physiotherapist-led sessions, with measurement every session and a final measure at the end of 12 weeks. A threshold makes the intended classification understandable, while also making the details of attendance recording and incomplete data important. Those details and the observed count are not reported in the registry record.
The single-group design is also statistically informative because it sets a boundary on interpretation. It can be used to describe feasibility within the enrolled group, but it cannot provide a randomized estimate of how outcomes compare with another intervention. Recognizing that boundary prevents an attendance outcome or a future clinical measure from being mistaken for evidence of comparative effectiveness.
Finally, the record lists 19 outcome measures but zero analyses. This highlights the distinction between registering outcomes and reporting results. Without numerical findings and a documented analysis approach, readers cannot assess the precision of adherence estimates, the pattern of secondary outcomes, or how missing data and multiplicity were handled. Those are important considerations when moving from feasibility work to a definitive comparative study.
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.
The main trial-specific limitation for interpretation is that the registry record does not report the observed primary endpoint result. Although it defines good adherence as attendance at 7/9 (78%) of physiotherapist-led sessions, it does not state how many participants met that threshold or describe the distribution of attendance. The stated final measurement time is the end of 12 weeks, but results at that point are not reported in the registry record.
The study has a single-group design, with allocation listed as not applicable and masking as none. There is no comparator for estimating a relative treatment effect. This means the design can address feasibility questions descriptively, but it cannot separate changes associated with the intervention from other explanations for changes in clinical measures.
The registry lists 19 outcome measures and zero analyses. Numerical results for the secondary measures, the time needed to collect clinical outcomes, and the statistical methods used to analyze outcomes are not reported in the registry record. The protocol, detailed statistical analysis plan, multiplicity strategy, analysis populations, missing-data approach, and sample-size justification are also not reported. These omissions prevent evaluation of prespecification, analysis choices, and the completeness of outcome reporting.
The enrollment is 12, but that figure alone does not show how many participants posted complete attendance or clinical outcome data. The registry record does not report follow-up completeness or missingness. Likewise, the safety entries list zero events but do not include the event definitions or ascertainment details needed for a broader safety assessment. These limitations restrict what can be concluded from the record; they do not establish that data collection or analyses were absent outside the registry.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Exercise Into Pain in Chronic Rotator Cuff Related Shoulder Pain: a Prospective Single-Group Feasibility Study — NCT04154345.
- Registry record last updated 2025-06-24; status last verified 2025-06.
- Results first posted 2025-06-24.
- 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.
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19. Record Summary
NCT04154345 is registered as a completed, prospective, single-group feasibility study sponsored by Universiteit Antwerpen. The title is “Exercise Into Pain in Chronic Rotator Cuff Related Shoulder Pain: a Prospective Single-Group Feasibility Study.” Enrollment is 12; the recorded start date is 2019-11-28, and the primary completion date is 2020-05-14.
The intervention is exercise therapy involving exercise into pain, with pain allowed during exercise described as ranging from 4 to 7 on the Numeric Pain Rating Scale. The primary endpoint is adherence to physiotherapist-led sessions, with good adherence defined as attendance at 7/9 (78%) of sessions. The record lists 19 outcome measures and zero analyses. It does not report the observed primary endpoint result, numerical secondary outcome findings, or the time needed to collect clinical outcomes.
The registry lists zero serious adverse events and zero deaths in the painful exercises group. The study’s stated aim is feasibility and preparation for a future randomized controlled trial, not a randomized comparison in this study.