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 Manual Therapy and Strengthening for the Hip in Older Adults With Chronic Low Back Pain (NCT04009837), a randomized na study. The primary outcome is Quebec Back Pain Disability Scale.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04009837 |
| Phase | NA |
| Condition | Chronic Low-back Pain, Hip Impairments, Hip-spine Syndrome |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 184 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Delaware |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns older adults with chronic low back pain and a vulnerable subgroup described as having hip and low back pain. The registry record identifies hip impairments and hip-spine syndrome among the conditions of interest. More detailed eligibility criteria are not reported in the registry record.
Intervention
One randomized arm received a hip-focused rehabilitation intervention. The study title describes manual therapy and strengthening for the hip, but the registry record does not give further detail about treatment content, dose, or delivery.
Comparator
The other randomized arm received a spine-focused rehabilitation intervention. The record does not report additional details about its treatment components or how the two interventions were matched in duration or contact.
Primary question
The primary measure was the Quebec Back Pain Disability Scale, assessed from baseline to the 8-week post-intervention assessment. The clinical question is whether the two rehabilitation approaches differ in back-pain-related limitations in daily activities over that period. A numerical between-arm estimate for this comparison is not reported in the registry record.
The registry describes the study as a randomized clinical trial with parallel arms and double masking. It records an enrollment of 184, but this does not establish how many participants contributed to each outcome analysis. The primary measure can describe disability, but the posted record does not give enough outcome statistics to determine the magnitude or precision of any difference between the interventions.
3. Trial Design
The registry record describes a randomized, double-masked, parallel-group trial comparing hip-focused rehabilitation with spine-focused rehabilitation. Both interventions are classified as behavioral. The recorded enrollment is 184. The study status is completed; the recorded start date is 2019-11-01, and the primary completion date is 2022-10-03.
The primary outcome was the Quebec Back Pain Disability Scale, assessed from baseline to the 8-week post-intervention assessment. Other recorded outcomes include the Quebec scale, walking speed at the 6-month final assessment, fast-speed walking, Timed Up-and-Go, Six-Minute Walk Test, 30 Second Chair Stand Test, movement-evoked pain, and the Patient Health Questionnaire-9. The registry lists 16 outcome measures in total.
The record establishes random assignment to two parallel interventions, but it does not report the randomization procedure, allocation concealment, the masking roles, or whether masking was maintained. It also does not report the planned allocation ratio. Equal allocation appears as an assumption for a planning illustration, not as a documented description of the trial’s actual allocation.
The record does not give detailed treatment protocols, adherence information, the number randomized to each arm, or the number analyzed for every outcome. It notes that some participants withdrew over time, so the number analyzed in one or more outcome rows differs from the overall number analyzed. The specific analysis populations and methods used to handle those withdrawals 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.
Overall Study
| Stage | Hip-focused | Spine-focused |
|---|---|---|
| STARTED | 91 | 93 |
| 8-Weeks (Post-intervention) | 83 | 82 |
| COMPLETED | 83 | 82 |
| NOT COMPLETED | 8 | 11 |
Reasons for not completing this period:
| Reason | Hip-focused | Spine-focused |
|---|---|---|
| Withdrawal by Subject | 5 | 4 |
| Did not complete any aspect of of 8-week assessment | 3 | 7 |
Analysis population for the primary outcome, as defined in the registry: The number analyzed in one or more rows differs from the overall number analyzed because some participants withdrew from the study over time.
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 | Hip-focused | Spine-focused | Total |
|---|---|---|---|---|
| Participants analysed | 91 | 93 | 184 | |
| Age, Continuous | years | 70.8 (SD 6.0) | 70.6 (SD 6.4) | 70.71 (SD 6.19) |
| Sex: Female, Male: Female | Participants | 61 | 60 | 121 |
| Sex: Female, Male: Male | Participants | 30 | 33 | 63 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 | 1 | 2 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 90 | 92 | 182 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Asian | Participants | 0 | 1 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 17 | 15 | 32 |
| Race (NIH/OMB): White | Participants | 72 | 77 | 149 |
| Race (NIH/OMB): More than one race | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 91 | 93 | 184 |
| Low Back Pain duration (years) | years | 15.7 (SD 14.6) | 14.0 (SD 12.0) | 14.8 (SD 13.4) |
6. Primary Endpoint
The registry lists the primary outcome as Quebec Back Pain Disability Scale, measured over Baseline to 8-week assessment (i.e. post-intervention).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the Quebec Back Pain Disability Scale. It is a 20-item questionnaire about limitations in daily activities due to back pain. Scores range from 0-100%, with higher scores indicating greater back-pain-related disability. The registry identifies the measure as a mean with standard deviation and sets the primary timeframe as baseline to the 8-week post-intervention assessment.
A disability questionnaire focuses on how symptoms relate to everyday activity, rather than only describing pain intensity or a physical performance test. In general, a continuous score can be summarized by its mean and standard deviation: the mean describes the group’s average score, while the standard deviation describes variation among individual scores. A comparison of change between randomized groups would address whether their average disability trajectories differed over the assessment period.
The registry does not report the primary endpoint values, a between-group estimate, or an uncertainty interval. It also states that the primary outcome has several categories or time points and is not reduced to one comparison. Therefore, the endpoint’s definition and direction are clear, but a single numerical result for the primary question is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the trial’s comparison and primary measure, but it does not provide a numerical estimate for the primary outcome. It lists 0 analyses, and the primary outcome is not reduced to one comparison because it has several categories or time points. The posted record therefore does not support a quantified statement about the size, direction, or precision of a difference in disability between the two rehabilitation arms.
This absence matters because a group mean alone, even if it were available, would not fully answer a comparative question. Interpretation would ordinarily consider the difference between arms, how uncertain that estimate is, and the scale’s meaning. No primary-outcome means, standard deviations, confidence interval, or p-value are reported in the registry record. It is consequently not possible to distinguish a small estimated difference from a larger but imprecise one, or to assess whether the observed data are compatible with a range of effects.
The enrollment of 184 describes the recorded trial enrollment, not the number contributing to the primary endpoint analysis. The registry notes that withdrawals over time mean that the number analyzed in one or more rows differs from the overall number analyzed. Without arm-specific analyzed counts and endpoint values, the degree to which missing outcome data affect the primary comparison cannot be evaluated.
The safety information is more concrete: the record lists serious adverse events affecting 9 of 91 participants in the hip-focused arm and 4 of 93 in the spine-focused arm. It lists other adverse events affecting 47 of 91 and 39 of 93, respectively, and reports zero deaths in both arms. These are descriptive counts in the registry; details needed to interpret event timing, attribution, and statistical uncertainty are not reported.
Overall, the posted information describes a completed randomized trial and identifies its outcome domains, but it does not provide the primary outcome analysis needed to estimate the comparative disability result. The safety counts can be read as recorded events, not as proof that one intervention is safer or that the observed differences are reliable. No treatment effect conclusion follows from the registry record alone.
9. Statistical Methods Explained
A randomized parallel-group design assigns participants to one of two intervention groups and follows the groups as distinct arms. In general, randomization is intended to reduce systematic differences in baseline characteristics, while a parallel design means that participants remain in their assigned group rather than crossing between interventions. The record identifies random allocation and parallel arms, but does not report the allocation procedure, concealment method, or specific masking roles.
What does a mean and standard deviation describe?
The primary measure is continuous and is summarized in the registry as a mean with standard deviation. In general, a mean gives the average score in a group. A standard deviation describes how spread out individual scores are around that average. Neither statistic alone is a treatment comparison: a reader also needs the groups’ relevant scores or changes and an estimate contrasting the arms. Those primary endpoint values are not reported in the registry record.
The Quebec Back Pain Disability Scale ranges from 0-100%, with higher scores indicating greater disability related to back pain. For a baseline-to-follow-up question, an analysis might compare follow-up scores while accounting for baseline, or compare change from baseline between arms. These are general analytical approaches, not a claim about the method used in this trial. The specific primary analysis model is not reported in the registry record.
How should uncertainty be described?
In general, a confidence interval expresses the range of estimates compatible with the data under the chosen statistical model and its assumptions. A narrow interval indicates greater precision than a wide interval, while an interval that includes values on both sides of no difference may leave the direction or magnitude uncertain. A p-value addresses compatibility between the data and a specified null model; it does not measure the size or clinical importance of an effect. The registry record does not report a primary-outcome confidence interval or p-value, so these interpretations cannot be applied to this comparison.
Standard methods often rely on assumptions about the outcome distribution and the way observations are related. For a continuous score, model choice can affect standard errors and inference, especially if residuals are strongly non-normal or variability differs between groups. These are general considerations. The registry record does not report diagnostic checks, a variance model, or other details of the primary analysis.
What do planning calculations mean?
A sample-size planning illustration is different from an observed trial result. The assumptions recorded for the illustration include a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect defined as a stated fraction of the observed effect. Such calculations describe hypothetical planning requirements under those assumptions. They are not observed power and do not establish that the trial was adequately powered. The record does not report the trial’s own sample-size justification, and the numerical planning results are not reported in the registry record.
In general, power is the probability that a planned analysis will detect an effect of a specified size under the assumptions used. It is not a probability that a result is true, nor does it quantify the certainty of a completed trial’s estimate. Planning values based on an observed effect can be especially dependent on that estimate. Without a reported primary effect estimate and its uncertainty, such an illustration cannot substitute for the missing trial analysis.
Why can outcome distributions matter?
Some statistical models assume that the outcome variation follows a particular distribution. When data are more variable than that model expects, over-dispersion can make conventional standard errors too small and confidence intervals too narrow. More suitable variance methods may be needed in that setting. This is a general concept; the primary outcome is recorded as a continuous score, and the registry does not report an over-dispersion assessment or a method addressing it.
For any outcome, the analysis should make clear which participants contributed data, how repeated measurements were handled, and which comparison was prespecified. Those details are important for reproducibility and for interpreting uncertainty. The registry record does not report a detailed statistical analysis plan, interim analyses, or the method used to handle repeated time points. It also does not identify one primary comparison across the several categories or time points. As a result, the statistical interpretation is limited to the trial design, outcome definitions, and descriptive safety counts that are recorded.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 16 outcome measures, including disability, walking, mobility, chair-stand performance, movement-evoked pain, and depressive symptoms. Considering several outcomes or time points creates a multiplicity question: the more comparisons examined, the greater the chance that at least one result may appear unusual by chance. In general, a prespecified primary comparison and an explicit multiplicity approach help clarify which results are confirmatory and how to interpret secondary findings. The registry record does not report a multiplicity adjustment or a detailed hierarchy of statistical tests.
The primary outcome has several categories or time points and is not reduced to one comparison. The record does not report a single primary contrast, numerical estimates, or analysis results; it lists 0 analyses. It is therefore not possible to determine how multiple time points or categories were handled statistically, or whether any reported tests were adjusted for multiple comparisons.
Missing data are also relevant. The registry notes that some participants withdrew over time and that the number analyzed in one or more rows differs from the overall number analyzed. It does not report the number withdrawn by arm, reasons for withdrawal, the missing-data method, or whether the primary analysis followed an intention-to-treat principle. In general, complete-case analyses may be biased if participants with missing observations differ systematically from those with observed data. Methods that use all available observations also depend on assumptions about the missingness process. Those assumptions cannot be assessed from the registry record.
The analysis population, handling of protocol deviations, and use of any sensitivity analyses are not reported in the registry record. These gaps limit assessment of both multiplicity and the possible influence of missing outcomes.
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 |
|---|---|---|---|
| Hip-focused | 9 | 91 | 9.9% |
| Spine-focused | 4 | 93 | 4.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Hip-focused | 0 of 91 |
| Spine-focused | 0 of 93 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Hip-focused | 47 of 91 |
| Spine-focused | 39 of 93 |
Most frequent serious adverse event terms
| Event term | Organ system | Hip-focused | Spine-focused |
|---|---|---|---|
| Surgical and Medical Procedures-other, specify | Surgical and medical procedures | 2 of 91 | 1 of 93 |
| Chest Pain | Cardiac disorders | 2 of 91 | 0 of 93 |
| Myocardial Infarction | Cardiac disorders | 1 of 91 | 1 of 93 |
| Atrial Fibrillation | Cardiac disorders | 1 of 91 | 0 of 93 |
| Cardiac Disorders-others, specify | Cardiac disorders | 1 of 91 | 0 of 93 |
| Cough | Respiratory, thoracic and mediastinal disorders | 1 of 91 | 0 of 93 |
| Heart Failure | Cardiac disorders | 1 of 91 | 0 of 93 |
| Respiratory, Thoracic and Mediastinal Disorders-other, specify | Respiratory, thoracic and mediastinal disorders | 1 of 91 | 0 of 93 |
| Skin Infection | Skin and subcutaneous tissue disorders | 0 of 91 | 1 of 93 |
| Tremor | Nervous system disorders | 0 of 91 | 1 of 93 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Hip-focused | Spine-focused |
|---|---|---|---|
| Pain in extremity | Musculoskeletal and connective tissue disorders | 19 of 91 | 17 of 93 |
| Back pain | Musculoskeletal and connective tissue disorders | 17 of 91 | 16 of 93 |
| Myalgia | Musculoskeletal and connective tissue disorders | 11 of 91 | 13 of 93 |
| Fall | Injury, poisoning and procedural complications | 9 of 91 | 6 of 93 |
| Surgical and medical procedures-other, specify | Surgical and medical procedures | 6 of 91 | 6 of 93 |
Serious events with the highest arm-level rate: surgical and medical procedures-other, specify (2.2%), chest pain (2.2%), myocardial infarction (1.1%), atrial fibrillation (1.1%), cardiac disorders-others, specify (1.1%).
The registry reports serious adverse events by randomized arm. In the hip-focused arm, 9 of 91 participants were recorded as affected; in the spine-focused arm, 4 of 93 were recorded as affected. For other adverse events, the corresponding counts are 47 of 91 and 39 of 93. The registry reports zero deaths in each arm.
These counts describe participants recorded as affected, not necessarily the total number of individual events. The record does not report event-level timing, duration, severity beyond the serious classification, or whether investigators judged events related to an intervention. The listed serious-event terms include Surgical and Medical Procedures-other, specify (2.2%), Chest Pain (2.2%), Myocardial Infarction (1.1%), Atrial Fibrillation (1.1%), Cardiac Disorders-others, specify (1.1%), and Cough (1.1%). The record does not identify an arm for each listed term.
Descriptive counts should not be treated as a test of a safety difference. The registry does not report a comparative analysis or uncertainty interval for adverse events. Zero recorded deaths means no deaths are listed in these arms in the registry record; it does not establish that all possible harms were absent.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, double-masked, parallel-group trial compared hip-focused and spine-focused rehabilitation in older adults with chronic low back pain. It identifies the Quebec Back Pain Disability Scale as the primary outcome and describes what higher and lower scores mean. It also records secondary outcome domains and arm-level adverse-event counts.
What the record does not establish is the size or precision of the primary disability difference. No numerical primary estimate, confidence interval, or p-value is reported, and the multiple categories or time points are not reduced to a single comparison. The enrollment figure is not a substitute for outcome data or for the number analyzed at a particular assessment.
In general, a randomized comparison can support causal interpretation when the assigned groups are analyzed appropriately and missing data, adherence, and other design features are handled transparently. The registry record does not provide enough detail to assess those conditions fully. It does not describe the exact analysis population, treatment adherence, masking roles, or missing-data methods.
The adverse-event counts describe what was entered in the record, but do not by themselves show whether the arms differ reliably in risk. They also do not establish that an event was caused by treatment. The listed event terms and the zero deaths are descriptive registry information, not a complete account of all possible safety outcomes.
Accordingly, the record supports a description of the trial’s question, design, outcome definitions, and recorded adverse events. It does not support a conclusion about whether either rehabilitation approach produced a larger reduction in disability, nor a conclusion that either approach is safer. Those comparative claims require outcome estimates and uncertainty information that are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial addresses a statistical challenge common in rehabilitation research: the clinical population is described as having both hip and low back concerns, while the interventions focus on different regions. A randomized comparison can help distinguish the outcomes associated with the assigned approaches, but only if the analysis reports a clear contrast and sufficient information about uncertainty.
The primary outcome is a patient-reported disability scale, while the listed secondary outcomes span walking, mobility, strength-related performance, movement-evoked pain, and mood symptoms. These measures represent different domains and may have different distributions and interpretations. A clear analysis plan is important for distinguishing a prespecified primary question from exploratory comparisons across outcomes and assessment times.
The record also highlights why enrollment and outcome analysis counts should not be conflated. It records enrollment of 184 and notes that withdrawals over time led to differences in numbers analyzed across some rows. Reporting those analyzed counts by arm, along with the approach to missing data, would help readers judge how robust a comparison may be.
The statistical importance of the record is therefore not a numerical treatment conclusion. It is the need to connect a randomized design to transparent endpoint results, defined analysis populations, and uncertainty estimates. Those elements are not reported for the primary comparison in the registry record, so the clinical question remains quantitatively unresolved in the posted information.
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.
Several trial-specific details needed to evaluate the primary result are not reported in the registry record. Although the trial is described as double-masked, the record does not specify who was masked or how masking was implemented. It also does not report the randomization procedure, allocation concealment, actual allocation ratio, or the number assigned to each arm.
The record identifies the intervention arms by focus but does not describe treatment components, session frequency, duration, provider training, adherence, or whether the interventions differed in contact time. The title refers to manual therapy and strengthening for the hip, but further protocol details are not reported in the registry record. This limits interpretation of what each intervention consisted of and how reproducible it may be.
For the primary outcome, the record defines the scale and assessment timeframe but does not report arm-level scores, a between-arm estimate, confidence interval, or p-value. It also indicates that several categories or time points are not reduced to one comparison. A detailed analysis plan, rationale for sample size, interim analyses, multiplicity handling, and missing-data approach are not reported in the registry record.
The record notes withdrawals over time but does not give arm-specific withdrawal counts or reasons. It does not report the analysis population or sensitivity analyses. Safety information includes affected counts and selected serious-event terms, but event timing, attribution, and comparative uncertainty are not reported. These omissions limit both efficacy interpretation and assessment of safety differences.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Manual Therapy and Strengthening for the Hip in Older Adults With Chronic Low Back Pain — NCT04009837.
- Registry record last updated 2024-04-11; status last verified 2024-03.
- Results first posted 2024-04-11.
- 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
NCT04009837 is a completed randomized, double-masked, parallel-group trial sponsored by the University of Delaware. It enrolled 184 participants and compared hip-focused with spine-focused rehabilitation for older adults with chronic low back pain. The recorded start date is 2019-11-01, and primary completion is recorded as 2022-10-03.
The primary endpoint is the Quebec Back Pain Disability Scale from baseline to the 8-week post-intervention assessment. Higher scores indicate greater back-pain-related disability. The registry lists 16 outcome measures and notes withdrawals over time, but does not report a single numerical primary comparison or its uncertainty. Serious adverse events affected 9 of 91 participants in the hip-focused arm and 4 of 93 in the spine-focused arm; no deaths are recorded in either arm. The record does not provide enough outcome analysis to determine the comparative disability result.