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 Changes of Pain and Functional Parameters in Back Pain Patients Over Time (NCT03689400), a registered phase not stated study. The primary outcome is Changes in Visual Analog Scale Pain Scores.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03689400 |
| Phase | Phase not stated |
| Condition | Changes Over Time in Pain and Functional Parameters |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 19 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Applied Sciences and Arts of Southern Switzerland |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns patients with back pain, with the official title specifying patients with or without radiculopathy. The adverse-event record identifies a group of patients with lumbar disc herniation associated with radiculopathy. The registry reports enrollment of 19 participants. Four patients missed the six-month follow-up for the primary outcome.
Intervention
This was not a trial in which a treatment was assigned as an intervention. The registry describes attendance and documentation of patients over 6 months, including pre-operative, post-operative, and non-operated patients. Physiotherapy appears in the background as a recommended treatment, but the record does not state that all participants received it or specify a standardized treatment protocol.
Comparator
No randomized control group or like-for-like comparison is described. The study includes patients with different treatment histories, but the registry does not report group sizes or establish that those groups were comparable. Allocation is not stated, and the record cautions that the arms are not a like-for-like control comparison.
Primary question
The primary outcome asks how pain scores changed from baseline to 6 weeks and 6 months, as measured on a Visual Analogue Scale. The intended focus is change over time among the patients followed, rather than a controlled estimate of the effect of one treatment against another. Numerical scores and estimated changes are not reported in the registry record, so the size and precision of any observed change cannot be described.
The question is clinically recognizable but statistically descriptive: pain is measured repeatedly while participants have differing treatment pathways. Without reported treatment allocation, an appropriate comparison group, or numerical outcome results, changes over time cannot be attributed to a particular treatment. The registry’s stated aim to discuss different treatment options does not by itself establish a causal comparison between them.
3. Trial Design
The registry describes a completed study that enrolled 19 participants and followed pain and functional parameters over time. Its primary pain outcome was scheduled at baseline, 6 weeks, and 6 months. The study title and summary describe patients with back pain, including patients with or without radiculopathy, and the summary says that pre-operative, post-operative, and non-operated patients were included. The record does not give the number of participants in each treatment-history group.
The registry lists the study as completed. Its recorded start date is 2018-10-11, and its primary completion date is 2019-12-06. The sponsor is the University of Applied Sciences and Arts of Southern Switzerland. These administrative details establish the recorded scope and timing, but they do not supply details about recruitment methods, clinical sites, eligibility criteria, or the treatment received by each participant. Those details are not reported in the registry record.
This is not described as a randomized comparison. Allocation is not stated, and the record explicitly cautions that the arms are not a like-for-like control comparison. The inclusion of patients with differing treatment histories may allow their trajectories to be described, but those groups may differ in ways that influence both treatment choice and outcome. The registry does not report whether any adjustment or matching was planned to address such differences.
The registry lists 12 outcome measures and zero analyses. The primary outcome description identifies the scale and assessment times, but numerical outcome values, analysis methods, and estimates of change are not reported in the registry record. A detailed protocol, sample-size justification, and statistical analysis plan are also not reported in the registry record. As a result, the design can be characterized as longitudinal observation of pain and function, while the exact analysis strategy and basis for enrollment remain unclear.
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 | Patients With Lumbar Disc Herniation Associated With Radiculopathy |
|---|---|
| STARTED | 19 |
| COMPLETED | 15 |
| NOT COMPLETED | 4 |
Reasons for not completing this period:
| Reason | Patients With Lumbar Disc Herniation Associated With Radiculopathy |
|---|---|
| Lost to Follow-up | 4 |
Analysis population for the primary outcome, as defined in the registry: four patients missed the six-month follow-up
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 | Patients With Lumbar Disc Herniation Associated With Radiculopathy |
|---|---|---|
| Participants analysed | 19 | |
| Age, Continuous | years | 47.3 (SD 14.1) |
| Sex: Female, Male: Female | Participants | 4 |
| Sex: Female, Male: Male | Participants | 15 |
| Race and Ethnicity Not Collected | Participants | — |
| Level of lesion: first sacral vertebra (S1) | Participants | 5 |
| Level of lesion: fifth lumbar vertebra (L5) | Participants | 9 |
| Level of lesion: fourth lumbar vertebra (L4) | Participants | 2 |
| Level of lesion: third lumbar vertebra (L3) | Participants | 3 |
| Level of lesion: second lumbar vertebra (L2) | Participants | 0 |
| Side of lesion: Right | Participants | 9 |
| Side of lesion: Left | Participants | 10 |
| Type of treatment: Conservative only | Participants | 9 |
| Type of treatment: Surgery and Conservative | Participants | 10 |
6. Primary Endpoint
The registry lists the primary outcome as Changes in Visual Analog Scale Pain Scores, measured over Baseline, 6 weeks, 6 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in pain measured by a unidimensional 10-cm Visual Analogue Scale. Patients mark a point on a line whose endpoints represent “no pain” and “worst possible pain.” The distance from the low end of the scale to the patient’s mark is recorded in centimeters. Scores range from 0, indicating no pain, to 10, indicating worst possible pain; higher scores indicate more severe pain.
A visual analog measure is used to represent a subjective experience as a continuous numerical score. Repeating the measure can describe how reported pain changes over time within the people assessed. The registry specifies assessments at baseline, 6 weeks, and 6 months, and describes the outcome parameter as a mean with standard deviation. The mean gives a group-level summary, while the standard deviation describes variation in scores among participants. Neither statistic reveals whether all participants changed in the same direction.
Repeated assessment is useful for describing the course of symptoms, but an endpoint’s measurement schedule does not establish that a treatment caused a change. In this study, treatment histories differ and a randomized comparison is not described. The registry also notes that four patients missed the six-month follow-up. Numerical means, standard deviations, and change estimates for the scheduled assessments are not reported in the registry record. Consequently, the endpoint definition is clear, but the amount of pain change and its precision cannot be assessed from the recorded results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies pain change as the primary outcome and gives a clear measurement scale and schedule. It does not, however, report the actual pain scores at baseline, 6 weeks, or 6 months, nor does it provide numerical estimates of change. Although the outcome is specified as a mean with standard deviation, those values are not reported in the registry record. There is therefore no numerical basis in the record for describing the direction, size, or variability of the observed pain trajectory.
The registry lists zero analyses. No confidence interval, test statistic, p-value, or adjusted estimate is reported. Without an estimate and a measure of its uncertainty, it is not possible to assess how precisely the study characterizes change. A point estimate alone would describe the sample; an uncertainty interval would indicate the range of effects reasonably compatible with the data under the analysis assumptions. Neither is available in the registry record.
Interpretation is also constrained by the study’s observational structure. The summary says that pre-operative, post-operative, and non-operated patients were included, but allocation is not stated and the record cautions that the arms are not a like-for-like control comparison. Differences between treatment-history groups could reflect factors related to the patients’ condition, clinical decisions, or other circumstances. Because group counts, baseline characteristics, and adjusted comparisons are not reported in the registry record, the record cannot establish that observed trajectories would be comparable across groups even if numerical results were available.
Four patients missed the six-month follow-up for the primary outcome. The record does not explain why those assessments were missed or how missing outcome values were handled. This matters because a summary based only on participants with an observed follow-up may differ from one that uses a suitable method to account for missing data. The available record does not indicate which approach, if any, was used.
The study is described as completed, and the primary endpoint and follow-up times are specified. Those features describe the intended longitudinal question, not the results. The registry record does not report numerical findings that would support a conclusion about whether pain scores changed, how large any change was, or whether changes differed by treatment history. The most defensible reading is therefore that the registry documents a study designed to observe pain and function over time, while leaving its primary numerical outcome and analysis unavailable.
9. Statistical Methods Explained
What does the mean describe?
For a continuous outcome such as a visual analog pain score, the mean is the arithmetic average across the participants included in a particular summary. It can provide a compact description of the group’s typical score at an assessment time. The mean does not describe every participant’s experience, and it can be influenced by scores at either end of the scale. The registry identifies the mean as the summary parameter for the primary outcome, but reports no means at baseline, 6 weeks, or 6 months.
A change in a group mean is not the same as the set of individual changes. Some participants may have higher scores over time, others lower scores, and some little change; a group average can conceal this variation. When the same people are assessed repeatedly, the measurements are also related within each person. A sound analysis of repeated measures generally needs to account for that within-person dependence rather than treating every measurement as unrelated. The registry’s analysis method is not reported in the registry record, so it is not possible to tell how repeated observations were handled.
What does the standard deviation describe?
The standard deviation describes how spread out individual scores are around the mean. It is a description of variability in the measured scores, not a measure of the precision of the mean itself. A standard deviation may help readers understand whether participants’ scores cluster closely together or vary widely. It does not show the full distribution, and it does not indicate whether the mean is estimated precisely without considering the amount of information available. The registry names the standard deviation but does not provide its values.
It is useful to distinguish variability among participants from uncertainty about a group estimate. A confidence interval is a general statistical tool for expressing uncertainty around an estimate under specified assumptions. A narrow interval indicates greater precision than a wide interval, but interpretation depends on the analysis and assumptions used. No confidence intervals for pain scores or changes are reported in the registry record. General statistical explanations of these measures do not fill in the missing study results.
Why does the repeated schedule matter?
Baseline, 6-week, and 6-month assessments allow a longitudinal description of pain. The choice of summary affects the question answered. Comparing group means at each scheduled time describes average scores at those times; summarizing within-person change focuses on how each participant’s score differs from their own baseline. A model using all available repeated measurements may answer a related question while making assumptions about the pattern of missing data. The registry does not state which of these approaches was planned or performed.
Repeated measurement alone does not control for other events or differences that may occur over time. In an observational study, a change after treatment does not establish that treatment caused the change. A controlled causal estimate requires an appropriate comparison and assumptions about how the groups were formed and how they differ. Here, the registry says that pre-operative, post-operative, and non-operated patients were included, while also warning that the arms are not a like-for-like control comparison. The record does not report an approach for addressing confounding.
What can sample-size planning illustrations tell readers?
A sample-size calculation is a planning exercise that describes how many participants might be needed under assumptions about the effect to detect, variability, significance level, allocation, and statistical model. The assumptions described for the planning illustrations use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects expressed as stated fractions of the observed effect. These are assumptions for illustrations, not evidence that the trial was designed with those parameters. The record does not report the trial’s own sample-size justification.
Such planning values must not be read as observed power or as proof that a study can detect a clinically important effect. They are conditional on the assumptions used, and an assumed effect size may not reflect the true effect. The study enrolled 19 participants, but the record does not provide a trial-specific design justification or the numerical estimates needed to assess the illustrations’ inputs. It also cautions that the arms do not form a like-for-like control comparison, which limits the interpretation of planning calculations that posit equal allocation between two arms.
What remains unknown about the analysis?
The registry lists zero analyses. It does not report the statistical model, the handling of repeated observations, covariate adjustment, hypothesis tests, confidence intervals, or a prespecified analysis plan. It also does not report whether interim analyses were planned or performed. Those details are important because analytic choices influence the estimate and uncertainty, especially when observations are repeated and some follow-ups are missing.
The primary endpoint is described as a continuous outcome summarized by a mean and standard deviation. That description is not enough to reconstruct an analysis. In particular, it does not say whether the main estimand was an average score at each time, average change from baseline, or a contrast between treatment-history groups. The registry record therefore supports explanation of the measurement and general statistical principles, but not a reconstruction or independent evaluation of the study’s statistical findings.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 12 outcome measures, but it does not report how many were treated as primary or secondary for statistical testing, nor does it describe a procedure for handling multiplicity. When several outcomes or time points are tested, the chance of at least one apparently notable result can increase. Statistical plans may address this through a prespecified hierarchy, adjustment, or a clearly descriptive interpretation. Which approach, if any, was used is not reported in the registry record. The primary outcome’s scheduled assessments are stated, but the record does not say whether a single time point or an overall longitudinal test was the main inferential target.
Four patients missed the six-month follow-up for the primary outcome. The record does not report the reasons for missing assessments, whether missingness differed by treatment history, or how the missing values were handled. In general, missingness can affect both the number of observations contributing to an estimate and the conclusions drawn from it. Complete-case summaries, imputation, and repeated-measures models rely on different assumptions; none can be attributed to this study based on the registry record.
The analysis population is not reported in the registry record. It is therefore unclear which participants were included in each outcome summary or whether any exclusions occurred. The registry reports enrollment of 19 participants, but that number alone does not identify the denominator used for each assessment or analysis. These omissions limit evaluation of possible selection effects and make it difficult to reproduce the analysis. A protocol or statistical analysis plan could clarify these matters, but such details are not reported in the registry record.
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 |
|---|---|---|---|
| Patients With Lumbar Disc Herniation Associated With Radiculopathy | 0 | 19 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Patients With Lumbar Disc Herniation Associated With Radiculopathy | 0 of 19 |
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 |
|---|---|
| Patients With Lumbar Disc Herniation Associated With Radiculopathy | 0 of 19 |
The registry reports a safety group titled “Patients With Lumbar Disc Herniation Associated With Radiculopathy.” It lists 19 patients at risk for serious adverse events and 0 affected by serious adverse events. For other adverse events, it likewise lists 19 at risk and 0 affected. The recorded number of deaths is 0. These are counts in the registry record; they are not estimates of comparative risk between randomized treatment groups.
A count of zero reported events means that no events in that category are recorded for the listed group in the registry. It does not establish that the risk is absent, particularly when the group is small or follow-up and event-collection details are not available. The registry record does not report the adverse-event collection period, event definitions, attribution procedures, or a comparison with a control group. No serious adverse-event terms are listed.
Safety counts should be interpreted alongside the study’s design and reporting scope. The record does not describe randomized treatment assignment, and the broader study includes patients with different treatment histories. The figures therefore cannot be used to compare treatment safety or to determine whether an event was caused by a particular treatment. They describe only the reported counts for the listed group.
12. What the Result Does, and Does Not, Mean
The registry record defines a longitudinal question about pain and functional parameters in patients with back pain, and specifies a primary pain measure and assessment times. It also records enrollment of 19 participants and notes that four patients missed the six-month follow-up for the primary outcome. These details help describe the study’s scope and the completeness issue that may matter for interpreting the primary outcome.
The record does not report the numerical pain scores or changes at baseline, 6 weeks, or 6 months. It provides no confidence intervals, p-values, or analysis estimates, and lists zero analyses. As a result, the posted registry information cannot establish the direction or magnitude of pain change, how variable the scores were, or how precisely any change was estimated. It also cannot support a conclusion about differences among pre-operative, post-operative, and non-operated patients.
Even with numerical changes, a change over time in an observational study would not by itself show that treatment caused the change. The registry says allocation is not stated and warns that the arms are not a like-for-like control comparison. Differences in patient characteristics or clinical circumstances could influence treatment history and outcomes. The record does not report an adjustment strategy that would address those concerns.
The study’s purpose and endpoint are therefore identifiable, but its primary result is not available in the registry record. The safety counts are reported separately and describe zero serious adverse events, zero other adverse events, and zero deaths in the listed group of 19 at risk. Those counts do not substitute for efficacy results or establish a comparative safety profile. The record supports a description of what was measured and what was registered, not a judgment about treatment benefit or harm.
13. Why This Trial Matters Statistically
This study raises a common statistical challenge in clinical research: describing symptom trajectories when participants have different treatment histories. Repeated pain measurement can show how scores evolve over time, but treatment decisions and outcomes may both reflect underlying clinical differences. Without randomization or a clearly comparable control group, an apparent difference between groups may combine treatment effects with those pre-existing differences.
The endpoint also illustrates the importance of separating measurement from inference. A visual analog scale converts a subjective experience into a continuous score that can be summarized and followed over time. The mean and standard deviation offer useful descriptions, but they do not by themselves provide an estimate of treatment effect, its uncertainty, or the distribution of individual responses. An analysis plan must specify the target comparison and account for repeated observations.
Missing follow-up is another practical issue. Four patients missed the six-month assessment, and the registry does not report why or how the missing values were handled. The appropriate interpretation of longitudinal results can depend on those details. Clear reporting of analysis populations, missing-data assumptions, estimates, and uncertainty is essential for readers to assess how much the findings rely on complete observations.
The registry record is informative about the study’s aim, primary measurement, schedule, and enrollment, but it lists zero analyses and does not include numerical primary-outcome findings. This distinction matters: a registered question is not a reported result. The record illustrates why transparent posting of estimates and analysis methods is needed before readers can evaluate the statistical evidence, rather than relying on study aims or outcome definitions alone.
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 primary limitation of the registry record is that it does not report numerical results for the primary pain outcome. The outcome definition and scheduled assessment times are stated, but group means, standard deviations, changes, and uncertainty estimates are absent. The record lists zero analyses, so the statistical evidence for the primary question cannot be evaluated from the recorded information.
The study enrolled 19 participants, and four patients missed the six-month follow-up for the primary outcome. The record does not state why follow-up was missed, how missing observations were handled, or how many participants contributed data at each earlier assessment. The analysis population and denominators for the outcome summaries are not reported in the registry record.
The study includes pre-operative, post-operative, and non-operated patients, but group sizes and relevant baseline characteristics are not reported. Allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. Accordingly, even if group-level results were available, causal interpretation would be limited without details on group comparability and adjustment for confounding.
Other important design and analysis details are not reported in the registry record, including eligibility criteria, treatment protocols, the statistical analysis plan, the trial’s sample-size justification, handling of repeated measures, and any multiplicity strategy. The registry lists 12 outcome measures, but their inferential hierarchy is unclear. These reporting gaps prevent a full appraisal of how the study was conducted and analyzed. They do not establish that a particular method was or was not used; they mean that the registry record does not document it.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Changes of Pain and Functional Parameters in Back Pain Patients Over Time — NCT03689400.
- Registry record last updated 2025-12-17; status last verified 2025-12.
- Results first posted 2025-12-17.
- 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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18. Record Summary
The registry describes a completed longitudinal study of pain and functional parameters in patients with back pain, including patients with or without radiculopathy and differing treatment histories. It reports enrollment of 19 participants and identifies pain on a Visual Analogue Scale as the primary outcome, assessed at baseline, 6 weeks, and 6 months. Four patients missed the six-month follow-up for that outcome.
The record lists 12 outcome measures and zero analyses. Numerical primary-outcome results and the statistical analysis plan are not reported in the registry record. Allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. Safety reporting lists 0 serious adverse events, 0 other adverse events, and 0 deaths among 19 patients at risk in the identified group. These details describe what the registry records, but the absence of outcome estimates prevents assessment of the magnitude or precision of pain change.