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 Can Massage During One Year Improve Health in Health-care Providers Working in Hospital (NCT05555082), a na na study. The primary outcome is Symptoms of Stress.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05555082 |
| Phase | NA |
| Condition | Massage Therapy, Health-care Workers, Quality of Life |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 25 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University Hospital, Linkoeping |
| Results posted | Yes |
2. Clinical Question
Population
Health-care providers working in a hospital. The registry lists an enrollment of 25, but does not describe participant characteristics or clarify the number who completed the intervention and outcome assessments.
Intervention
Massage: 30 minutes of classical Swedish massage given by a certified masseur 10 times monthly during 12 months. The registry’s overall aim also includes examining feasibility and participants’ experiences of regular massage.
Comparator
There is no separate control group. The study is recorded as a single-group design, with the primary stress measure specified at baseline, described as the start of massage, and at 12 months, described as the end of massage.
Primary question
The primary outcome is symptoms of stress, measured with the Perceived Stress Scale-10 (PSS-10). The registry describes an investigation of health during the massage period, but does not report the resulting PSS-10 scores or a comparison of scores between the two timepoints.
In statistical terms, the question is whether stress scores measured in this group differed between the start and end of the intervention period, and how precisely any such difference was estimated. A baseline measure can describe participants before the intervention period, but it is not a concurrent control group. It therefore cannot by itself separate changes associated with massage from changes that might occur over time for other reasons.
The registry’s broader aims include mental and physical health, feasibility, experiences, layoffs, sick leave, reported patient safety risk cases, and health economics. The listed secondary outcomes include symptoms of anxiety, sleeping problems, symptoms of depression, and health-related quality of life. Results for these aims and outcomes are not reported in the registry record.
3. Trial Design
The registry records NCT05555082 as a completed study with a single-group model and an enrollment of 25. Allocation and phase are recorded as not applicable, and masking is listed as none. The sponsor is University Hospital, Linkoeping. The recorded study start is 2022-11-20 and primary completion is 2024-03-01.
All participants are described under one massage intervention, rather than being assigned to massage or a separate control condition. The intervention description is 30 minutes of classical Swedish massage given by a certified masseur 10 times monthly during 12 months. The primary outcome schedule specifies measurement at baseline, the start of massage, and 12 months, the end of massage.
This structure supports a description of outcomes over time within the study group, if measurements are available. It does not provide a randomized, like-for-like comparison between groups. The registry explicitly notes that this is not a randomized comparison. Consequently, any change between the recorded timepoints would not, on its own, establish that the intervention caused the change.
The registry lists five outcome measures and ten analyses. It does not describe the analysis methods, the analysis populations, or whether the planned measurement schedule was completed for all participants. Details of recruitment, participant characteristics, adherence, and departures from the intervention schedule are not reported in the registry record. The completed status indicates the recorded study status, not that every planned measure or analysis has a posted result.
The registry does not report a protocol rationale for the single-group structure, a control condition, or a sample-size justification for the trial. Planning illustrations based on a two-arm design should not be read as a description of the actual single-group study or its enrollment plan.
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 | Massage |
|---|---|
| STARTED | 25 |
| COMPLETED | 25 |
| NOT COMPLETED | 0 |
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 | Massage |
|---|---|---|
| Participants analysed | 25 | |
| Age, Continuous | years | 40 (SD 11) |
| Sex: Female, Male: Female | Participants | 25 |
| Sex: Female, Male: Male | Participants | 0 |
| Race and Ethnicity Not Collected | Participants | — |
| Number of smokers, ex-smokers and never smoked: Smokers | Number of participants | 4 |
| Number of smokers, ex-smokers and never smoked: Ex-smoker | Number of participants | 11 |
| Number of smokers, ex-smokers and never smoked: Never smoked | Number of participants | 10 |
6. Primary Endpoint
The registry lists the primary outcome as Symptoms of Stress, measured over Baseline (start of massage) and 12 months (end of massage).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is symptoms of stress measured with the Perceived Stress Scale-10 (PSS-10). The registry describes it as a 10-item self-report questionnaire about perceived stress during the past month. Total scores range from 0 to 40, and higher scores indicate greater perceived stress, which the registry characterizes as a worse outcome. The measurement is expressed in units on a scale.
A continuous score retains gradations in reported stress rather than reducing participants to a category. The mean can describe the group’s average score at a measurement timepoint, while the standard deviation describes the spread of individual scores around that mean. The registry identifies the endpoint parameter as a mean and the dispersion measure as a standard deviation.
Measuring the same endpoint at baseline and at 12 months can describe how scores in the study group compare across the intervention period. The endpoint is relevant to the stated aim of examining mental health because it directly assesses perceived stress. The questionnaire’s reference to stress during the past month also defines the period participants are asked to consider when answering.
No baseline or 12-month mean, standard deviation, change estimate, confidence interval, or statistical test result is reported in the registry record. Therefore, the endpoint definition explains what was intended to be measured, but the record does not establish the observed stress level or its change during the study.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary outcome and its measurement schedule, but does not post the outcome values. In particular, it does not report the PSS-10 mean or standard deviation at baseline or at 12 months, nor a change estimate, confidence interval, or p-value. The direction, size, and precision of any observed change in stress therefore cannot be evaluated from the posted results.
The study is completed and lists an enrollment of 25, but the enrollment figure does not establish how many participants contributed to each outcome measurement. The number with complete baseline and end-of-intervention assessments, and the handling of any missing scores, are not reported in the registry record. This matters because a comparison over time depends on which participants contribute measurements at each timepoint.
Even if a within-group difference were reported, this design would describe change in the massage group rather than a treatment effect relative to a control group. General statistical interpretation: a before-and-after change can reflect the intervention, but can also reflect other influences over the same period, such as changes in participants’ circumstances or the way outcomes are measured. Without a concurrent comparator, those explanations cannot be distinguished by the study design alone.
Precision is also important. A mean difference is an estimate, and a confidence interval, when reported, conveys the range of values compatible with the data under the method used. The registry does not post such an interval for the primary endpoint. No conclusion about whether a possible change is small or large, or estimated precisely or imprecisely, can be drawn without the outcome statistics.
The registry lists secondary outcomes that include anxiety symptoms, sleeping problems, depression symptoms, and health-related quality of life. It also describes broader aims concerning feasibility, experiences, layoffs, sick leave, patient safety risk cases, and health economics. The results for these outcomes and aims are not reported in the registry record, so the primary endpoint description should not be mistaken for evidence about them.
The record reports no serious adverse events, other adverse events, or deaths in the massage group, with 25 listed at risk for each category. These are the posted safety figures; the record does not provide additional detail about event collection, follow-up completeness, or how events were classified. They should be read as registry counts, not as a complete account of all possible safety information.
9. Statistical Methods Explained
What a mean and standard deviation describe
The registry specifies a mean as the summary parameter for the PSS-10 and a standard deviation as its measure of dispersion. General statistical explanation: a mean summarizes the central level of a set of scores, while a standard deviation describes how much scores vary around that mean. They answer different questions. Two groups or timepoints can have similar means but different variability, or differing means with substantial variation among individual scores.
For this endpoint, a mean at baseline would describe average reported stress at the start of massage, and a mean at 12 months would describe average reported stress at the end of massage. A comparison of those averages can summarize change in the group, but interpreting it requires the actual estimates and a clear account of who contributed data. Those estimates are not reported in the registry record.
Within-person measurements
General statistical explanation: when the same participants are measured at two timepoints, their scores are related. A method that compares paired observations can account for this relationship; treating the two sets of measurements as if they came from unrelated people may misrepresent uncertainty. The registry gives two timepoints for the primary outcome, but does not report which statistical test or model was used, whether the analysis used paired observations, or how incomplete pairs were handled. No particular method should be assumed.
A within-group comparison has a distinct interpretation from a comparison between randomized groups. It can describe whether the observed scores changed over time among participants with measurements. It cannot, without a separate comparison group, distinguish intervention-related change from time trends or other influences. This is a limitation of the design, not something a statistical adjustment can automatically resolve.
Uncertainty and confidence intervals
General statistical explanation: a confidence interval communicates uncertainty around an estimated quantity, such as a mean or a change in means. A narrower interval indicates greater precision under the analysis assumptions; a wider interval indicates less precision. The interval does not remove bias from a nonrandomized design, and it does not substitute for a comparator when the question is whether the intervention caused a change.
The registry record does not report a confidence interval, standard error, or p-value for the primary outcome. It is therefore not possible to assess the precision of the PSS-10 estimates or to determine whether a statistical test was used. The absence of a posted result is not itself evidence that scores stayed the same or changed.
Sample-size planning illustrations
The registry record describes planning illustrations based on an observed effect and assumptions of a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These assumptions describe a planning exercise, not the actual single-group trial design. The illustrations are not observed power and do not establish that the trial was designed to detect a particular effect. The trial’s own sample-size justification is not reported in the registry record.
General statistical explanation: sample-size planning estimates how much information a proposed study might need under specified assumptions. Such an estimate depends on the effect used for planning and on the design and analysis assumptions. A planning illustration cannot show how much power a completed study actually had, and it does not replace the observed estimates or their uncertainty. No planning values or observed effect for the primary endpoint are reported in the registry record.
Outcome scale and interpretation
The PSS-10 is a continuous self-report measure whose total score is described as ranging from 0 to 40; higher values represent greater perceived stress. This direction is essential when interpreting a reported estimate: higher and lower scores do not mean the same thing. Since the registry does not post the scores, there is no basis for stating whether the group’s measured stress increased, decreased, or remained similar.
The standard deviation would help describe how much participants’ reported scores differ from one another, but it is not itself a measure of uncertainty in the mean. General statistical explanation: uncertainty in an estimate also depends on the amount and structure of the data and on the analysis method. The registry does not provide enough outcome detail to evaluate those elements for this endpoint.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists five outcome measures and ten analyses. The named secondary outcomes include symptoms of anxiety, sleeping problems, symptoms of depression, and health-related quality of life, alongside the primary stress outcome. The record does not describe how the analyses map to the outcomes, which analyses were prespecified as primary or secondary beyond the named endpoint, or whether any multiplicity adjustment was planned or applied.
General statistical explanation: when researchers test several outcomes or make several comparisons, the chance of at least one apparently notable result can increase. Methods for handling multiple tests can address that issue, but the appropriate approach depends on the analysis plan and the questions being asked. Since the registry does not report a multiplicity procedure, one should not assume that the posted analyses were adjusted or that they were not adjusted.
Missing-data methods are not reported in the registry record. The record does not state how many participants had usable baseline and 12-month PSS-10 scores, whether incomplete questionnaires occurred, or whether any missing values were imputed or otherwise handled. It also does not describe reasons for missing measurements or differences between participants with and without follow-up data.
The analysis populations are not reported. It is therefore unclear which participants were included in each outcome analysis or whether analyses were restricted to those who completed the massage schedule. No analysis population should be inferred from the enrollment figure alone. These omissions limit assessment of the representativeness and completeness of the results, in addition to the absence of posted endpoint statistics.
11. 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 |
|---|---|---|---|
| Massage | 0 | 25 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Massage | 0 of 25 |
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 |
|---|---|
| Massage | 0 of 25 |
The registry lists the massage group with 25 participants at risk for serious adverse events and 0 affected. For other adverse events, it also lists 25 at risk and 0 affected. Deaths are recorded as 0. These are the safety figures posted for the group.
A count of 0 affected means that the registry lists no events in that category for the stated group; it does not establish that every possible event was assessed or that no event could occur outside the recorded observation. The record does not provide further detail about event definitions, the method or frequency of safety checks, the duration of safety follow-up, or whether the at-risk count reflects all participants who received massage.
General statistical explanation: a zero count is an observed count, not proof that an event is impossible. How informative it is depends on the number of people observed, the completeness of follow-up, and the way events were sought and classified. The registry figures should therefore be read narrowly as the adverse-event counts recorded, rather than as a comprehensive estimate of safety risk.
The record does not identify any serious adverse-event terms or provide narrative descriptions of events. This is consistent with the listed zero counts, but does not supply additional information about how safety was monitored.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed, single-group study of massage among health-care providers working in a hospital was registered, with an enrollment of 25. It specifies an intervention and a primary stress measure, the PSS-10, scheduled at baseline and at 12 months. It also records zero serious adverse events, zero other adverse events, and zero deaths in the massage group, with 25 listed at risk for each adverse-event category.
The record does not report the PSS-10 scores or other outcome results. It consequently does not show whether participants’ stress scores changed, how large any change was, or how precisely it was estimated. It also does not report results for the listed secondary outcomes or the broader aims concerning feasibility, experiences, work absence, patient safety risk cases, and health economics.
Even a reported difference between baseline and 12 months would describe change over time in this group. Because there is no separate control group, the design cannot by itself establish that massage caused such a difference. Other influences during the study period could also contribute to a change. This distinction between observed change and causal effect is central to interpreting a single-group study.
The absence of posted outcome statistics should not be interpreted as evidence of no effect, an improvement, or a worsening. It means that the registry record does not allow those conclusions to be assessed. Likewise, the adverse-event counts are limited to what the record lists and do not provide a complete account of monitoring or follow-up.
The study therefore contributes information about the registered question, intervention, outcome schedule, design, and recorded safety counts. The outcome results, missing-data handling, analysis methods, and sample-size justification are not reported in the registry record, so conclusions about effectiveness, precision, and the broader aims remain unavailable from the posted information.
13. Why This Trial Matters Statistically
This study is statistically notable because it asks about change over time in a health-care workforce using a continuous self-report measure. Repeated measurement can be useful for describing how the same group’s reported stress compares between the start and end of an intervention period. The registry identifies the PSS-10 and defines the direction of its scale, which are important details for interpreting any eventual estimate.
At the same time, the single-group design makes the distinction between description and causal inference especially important. A baseline measurement is a reference point, not a concurrent control. If scores change, the design alone cannot determine how much of that change is attributable to massage rather than to other changes over time. This limitation remains even if an estimate is precise.
The record also illustrates why outcome reporting matters. Naming a measure and its schedule does not reveal the observed scores, the size of a change, or the uncertainty around it. Without those results, readers cannot assess the primary stress outcome or compare it with the study’s broader aims concerning mental and physical health, feasibility, and work-related outcomes.
Finally, planning illustrations need to be kept separate from the completed study’s evidence. The described illustrations use assumptions for a two-arm design, whereas this trial is recorded as a single group. They are planning exercises, not observed power and not a substitute for trial-specific outcome estimates. The registry’s missing analysis and sample-size details further limit statistical appraisal.
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.
A central limitation is that the registry does not report the primary outcome results. Baseline and 12-month PSS-10 means and standard deviations, a change estimate, and measures of uncertainty are not reported in the registry record. The same absence of posted results applies to the listed secondary outcomes and broader aims.
The study has a single-group design and no separate control condition. Consequently, any change over time would not provide a randomized comparison and could not, by itself, identify a causal effect of massage. The registry records no masking, and does not describe any procedures to limit the influence of expectations on self-reported stress scores.
The registry lists enrollment of 25 but does not report the number contributing data at each timepoint, completion of the intervention, adherence, or reasons for any missing assessments. Missing-data methods and analysis populations are also not reported. These gaps prevent assessment of whether outcome estimates, if available elsewhere, represent all enrolled participants or a subset.
Statistical methods are not described in the registry record. It does not state how the two timepoints were analyzed, whether estimates were adjusted, how uncertainty was calculated, or whether multiplicity was addressed across outcomes and analyses. The trial’s own sample-size justification is not reported. Planning illustrations based on a two-arm design do not resolve these trial-specific omissions.
Finally, the safety record provides counts but not detailed event ascertainment, classification, or follow-up information. The listed zeros should be interpreted in that limited reporting context. Participant characteristics and details of the study setting beyond health-care providers working in a hospital are not reported in the registry record, limiting assessment of how broadly the findings might apply even if results were available.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Can Massage During One Year Improve Health in Health-care Providers Working in Hospital — NCT05555082.
- Registry record last updated 2025-12-18; status last verified 2025-12.
- Results first posted 2025-12-18.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT05555082 is recorded as a completed, single-group study sponsored by University Hospital, Linkoeping, with enrollment of 25. The registry lists no masking and no randomized comparison. The intervention is 30 minutes of classical Swedish massage given by a certified masseur 10 times monthly during 12 months.
The primary outcome is symptoms of stress measured with the PSS-10 at baseline and 12 months. The registry describes the scale as ranging from 0 to 40, with higher scores indicating greater perceived stress. It lists five outcome measures and ten analyses, but does not report primary or secondary outcome results, statistical methods, missing-data handling, analysis populations, or the trial’s sample-size justification.
The massage group is listed with 25 at risk and 0 affected for serious adverse events, 25 at risk and 0 affected for other adverse events, and 0 deaths. The record does not provide additional detail about event monitoring or follow-up.