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 Internet-based Behavioral Pain Management (NCT01918189), a na na study. The primary outcome is Multidimensional Pain Inventory Interference Subscale.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01918189 |
| Phase | NA |
| Condition | Chronic Low Back Pain |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 59 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
Population
Veterans with chronic low back pain were the intended population. The registry record reports enrollment of 59 and states that 58 participants completed baseline. It does not report further eligibility details or participant characteristics in the information available for this analysis.
Intervention
Participants were offered 10 weeks of access to Pain EASE, an internet-delivered behavioral pain self-management intervention. The program was intended to teach pain coping skills for managing low back pain. The project also proposed examining participants’ experiences with usability and satisfaction.
Comparator
There was no separate comparator group: the registry classifies the study as single-group, and allocation is listed as NA. The record therefore does not describe a randomized or like-for-like control comparison. The endpoint is defined as change from baseline, not as a difference between intervention and control groups.
Primary question
The primary outcome was pain-related functional interference, measured with the Multidimensional Pain Inventory Interference Subscale. The planned measurement points were baseline and 10 weeks post-baseline. The registry record does not report the observed change or its confidence interval, so it does not establish the direction or size of the measured change.
3. Trial Design
The registry identifies NCT01918189 as a completed study titled “Internet-based Behavioral Pain Management.” Its official title is “Development of an Internet-based Behavioral Pain Management Intervention.” The sponsor is the VA Office of Research and Development. The recorded start date is 2014-07-01 and the primary completion date is 2018-10-31. The phase is listed as NA.
This was a single-group behavioral intervention study, not a randomized comparison. The intervention was 10 week Pain EASE access: behavioral pain self-management delivered via the Internet. Allocation is listed as NA, and masking is listed as none. With no separate comparator group, the primary outcome is evaluated as a change within the study group from baseline to follow-up; it cannot by itself estimate how outcomes would have changed under a different treatment or without the program.
The registry describes enrollment of 59. It reports that 17 of the 58 participants who completed baseline did not complete the 10-week post-baseline assessment. The record does not report why these participants lacked the endpoint assessment or how their missing outcomes were handled in the analysis.
The project aimed to develop and test use of the program for low back pain in Veterans, and to examine usability and satisfaction. Pain-related functional interference was the primary outcome. Other registered measures included pain intensity, mood, fatigue, sleep, and depression. The registry record does not report further details of the intervention schedule, adherence, or delivery beyond the 10-week Internet access description.
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 | 10 Week Pain EASE Access |
|---|---|
| STARTED | 59 |
| Completed Baseline Assessment | 58 |
| Completed Follow-up Assessment | 41 |
| COMPLETED | 41 |
| NOT COMPLETED | 18 |
Analysis population for the primary outcome, as defined in the registry: 17 of the 58 participants who completed baseline did not complete 10-week post-baseline assessment (study endpoint)
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.
Population: 59 participants enrolled in the study (i.e., signed informed consent) but 58 completed baseline measures and were included in outcomes analyses.
| Characteristic | Unit | 10 Week Pain EASE Access |
|---|---|---|
| Participants analysed | 58 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 46 |
| Age, Categorical: >=65 years | Participants | 12 |
| Age, Continuous | years | 55 (SD 12) |
| Sex: Female, Male: Female | Participants | 4 |
| Sex: Female, Male: Male | Participants | 54 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 54 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 3 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 19 |
| Race (NIH/OMB): White | Participants | 35 |
| Race (NIH/OMB): More than one race | Participants | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 3 |
| Region of Enrollment: United States | Participants | 58 |
| Multidimensional Pain Inventory Interference Subscale | units on a scale | 3.82 (SD 0.19) |
| Pain Intensity Numeric Rating Scale | units on a scale | 5.91 (SD 0.25) |
| Profile of Mood States | units on a scale | 49.53 (SD 5.62) |
| Multidimensional Fatigue Inventory | units on a scale | 14.05 (SD 0.52) |
| Medical Outcomes Study Sleep Scale | units on a scale | 50.09 (SD 3.80) |
| Beck Depression Inventory | units on a scale | 15.47 (SD 1.37) |
6. Primary Endpoint
The registry lists the primary outcome as Multidimensional Pain Inventory Interference Subscale, measured over baseline and 10 weeks post-baseline.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the change in pain-related functional interference from baseline to 10 weeks post-baseline. It uses the Interference subscale of the West Haven-Yale Multidimensional Pain Inventory. This self-report measure asks about the extent to which pain interferes with functioning. The registered description specifies a 9-item subscale with scores ranging from 0-6; lower scores indicate less pain-related interference and a better outcome.
The endpoint is calculated as the 10-week post-baseline value minus the baseline value. Because of this direction, a negative change represents a lower score at follow-up than at baseline. The registry description identifies a reduction of 0.6 or greater as an indicator of meaningful improvement in physical functioning. That threshold gives context for interpreting a measured change; it does not substitute for the actual observed result or its uncertainty.
Functional interference is used to capture the impact of pain on day-to-day functioning, rather than pain intensity alone. The registry record does not report the endpoint’s observed mean change, confidence interval, or participant-level distribution. It therefore does not show whether the study group’s average interference score changed or how precisely any change was estimated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registered primary outcome is a mean change in pain-related functional interference between baseline and 10 weeks post-baseline. The registry specifies a least-squares mean and a 95% confidence interval for this continuous outcome. However, the registry record does not report the numerical mean change or confidence interval. Without those results, the direction, size, and precision of the average change cannot be assessed from this record.
The endpoint’s scoring direction is important. The 10-week value is subtracted from the baseline value, and lower interference scores indicate less interference. Thus, a negative change would correspond to a lower average score at follow-up, while a positive change would correspond to a higher average score. These are interpretations of the defined scale, not statements about the study’s observed result, which is not reported in the registry record.
The stated threshold of a reduction of 0.6 or greater is described as an indicator of meaningful improvement in physical functioning. It can help frame the magnitude of a reported change if one is available. The registry record does not report whether the mean change reached that threshold, nor does it provide a confidence interval that would show whether estimates near the threshold are uncertain.
This was a single-group study without a separate control group. Any measured pre-to-post change would describe the study group over time, but would not isolate the effect of Pain EASE from other possible explanations for change. The record does not report a randomized contrast, and it should not be interpreted as a like-for-like comparison with another condition.
Missing follow-up is also relevant to interpretation. The registry reports that 17 of the 58 participants who completed baseline did not complete the endpoint assessment. It does not report whether those with and without endpoint data differed, or what method was used to address missing values. If the observed endpoint analysis is based on participants with available follow-up, its interpretation may depend on how representative those participants are of the baseline group; the registry does not provide enough information to assess that issue.
The study is marked completed, but completion status is not a result. The registry lists six outcome measures and six analyses, yet the numerical outcome estimates are not reported in the record. The absence of those estimates does not establish that there was no change. It means the posted registry information does not permit a quantitative conclusion about the primary endpoint.
9. Statistical Methods Explained
What does the primary estimate represent?
The primary outcome is continuous: it is a score on a scale, and the registry specifies a least-squares mean. In general, a mean describes the average score or average change for the group being analyzed. A least-squares mean is an estimated mean from a statistical model; it can account for terms included in that model. The registry record does not report the model specification, so it is not possible to say which variables, if any, were included in the estimate.
The outcome is defined as the follow-up score minus the baseline score. This makes the estimate a within-group change over time, not a treatment-versus-control difference. A mean change condenses participant-level changes into a single group summary. It does not show how much participants varied, whether all participants changed in the same direction, or how many met the stated threshold for meaningful improvement. Those details are not reported in the registry record.
How should the confidence interval be read?
The registry specifies a 95% confidence interval for the primary estimate. In general, a confidence interval expresses the statistical uncertainty around an estimate under the assumptions of the method used. A narrower interval indicates greater precision, while a wider interval indicates less precision. The interval is not a range containing every participant’s outcome, and it does not describe the full spread of individual responses.
The registry record does not provide the actual confidence interval. Consequently, neither its width nor the values it covers can be evaluated. Without the estimate and interval, it is also not possible to judge whether the data are compatible with changes of different magnitudes or directions. Confidence intervals do not resolve limitations in the design, such as the absence of a control group or missing follow-up.
Why does the one-group design matter?
Because the study has a single group, its primary endpoint compares participants’ scores at baseline and follow-up. In general, before-and-after changes can reflect multiple influences over time, not only the intervention. A separate comparison group can help distinguish changes associated with an intervention from changes that might also occur without it, provided the design and analysis support that comparison. No such group is registered for this study, so the primary outcome cannot provide a randomized treatment contrast.
The record lists allocation as NA and masking as none. It does not report a statistical plan or further model details. In particular, the registry record does not report how the primary analysis handled repeated measurements, missing outcomes, or potential covariates. It is therefore best to describe the estimand as the registered change measure and avoid assuming details of the analysis beyond the stated least-squares mean and confidence interval.
What do the planning assumptions mean?
The registry describes sample-size assumptions as a planning illustration based on the observed effect, rather than as the trial’s own design. The stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. These are planning conventions, not evidence that the study itself randomized participants between two arms. The registered design remains single-group.
In general, a sample-size illustration estimates the number of participants that might be needed under chosen assumptions to detect a specified effect with a chosen level of statistical power. Such a calculation is conditional on its assumptions and is not a measure of what the completed study achieved. The record’s planning description says that non-time-to-event illustrations are expressed as participants per arm. No numerical planning estimates are reported in the registry record available for this interpretation, and no observed-power conclusion can be drawn from that description.
Why can over-dispersion matter?
In general, over-dispersion means that observed variability is greater than a statistical model expects. When a model assumes less variability than the data contain, uncertainty may be understated and tests may appear more informative than warranted. This concept is relevant to some count or event models, but the registered primary endpoint is continuous and summarized as a mean change with a confidence interval. The registry record does not identify an over-dispersion adjustment or provide enough model details to assess whether one was relevant to any analysis.
These general explanations do not fill gaps in the registry record. The record does not report the numerical primary estimate, its confidence interval, the analysis model specification, or a complete statistical analysis plan. As a result, the registered endpoint and summary method can be described, but the calculation and inferential details cannot be independently assessed.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists six outcome measures and six analyses. The primary measure is pain-related functional interference; the listed secondary measures include pain intensity, mood, fatigue, sleep, and depression. When several outcomes or analyses are considered, the chance of at least one apparently unusual result can increase if each is assessed without adjustment. In general, multiplicity procedures can control that risk, but they may also affect the precision or interpretation of individual findings.
The registry record does not report whether any multiplicity adjustment was planned or used, how outcomes were prioritized beyond naming the primary endpoint, or whether analyses were prespecified in a statistical analysis plan. It therefore does not support a claim that the reported analyses were or were not adjusted for multiple testing.
For the primary endpoint, the registry reports that 17 of the 58 participants who completed baseline did not complete the 10-week post-baseline assessment. The record does not report the reasons for missing follow-up, the number included in the primary analysis, or the method used to handle missing outcomes. It also does not report sensitivity analyses examining the influence of missing data.
These gaps limit assessment of the analysis population and the robustness of any endpoint estimate. The registry record does not state whether the analysis included all enrolled participants, only participants with observed follow-up, or another defined group. No inference about the missing participants’ outcomes is warranted from the information recorded.
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 |
|---|---|---|---|
| 10 Week Pain EASE Access | 1 | 58 | 1.7% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| 10 Week Pain EASE Access | 0 of 58 |
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 |
|---|---|
| 10 Week Pain EASE Access | 0 of 58 |
Most frequent serious adverse event terms
| Event term | Organ system | 10 Week Pain EASE Access |
|---|---|---|
| psychiatric emergency room visit | Psychiatric disorders | 1 of 58 |
Serious events with the highest arm-level rate: psychiatric emergency room visit (1.7%).
The registry reports one serious adverse event among 58 participants at risk in the Pain EASE access group. It reports zero deaths. The listed serious event term is psychiatric emergency room visit, reported as 1.7%. These figures describe the safety information recorded for the study; they do not establish whether an event was caused by the intervention.
In general, an event count and its denominator should be read together. The denominator gives context for the number of participants at risk, while the event count indicates how many events were recorded under the registry’s reporting. A serious event is not necessarily caused by the intervention, and a count alone cannot establish a causal relationship. The record does not provide further case details or an assessment of relatedness.
The reported safety figures should also be interpreted within the study design and available follow-up. There was no separate comparator group, so the registry record does not offer a concurrent comparison of event rates. It does not report additional details about safety monitoring, event timing, or how the event was adjudicated. The available information supports describing the recorded event and death counts, but not a broader comparative safety conclusion.
12. What the Result Does, and Does Not, Mean
The record establishes that this completed, single-group study evaluated 10 weeks of Internet access to Pain EASE for Veterans with chronic low back pain. It also establishes the registered primary endpoint: change in pain-related functional interference from baseline to 10 weeks post-baseline, measured with the Multidimensional Pain Inventory Interference Subscale. The registry describes the scale and specifies a least-squares mean with a 95% confidence interval.
The registry record does not report the primary mean change or its confidence interval. It therefore does not show whether average interference scores went up or down, how large any change was, or how precisely it was estimated. It also does not report whether the stated reduction of 0.6 or greater was reached. The absence of these results should not be interpreted as evidence of no change; it means the numerical result cannot be assessed from the registry information.
Even if a pre-to-post change were reported, the single-group design would describe change over time rather than establish that the intervention caused that change. There is no separate control group in the registered design, and the registry does not describe a randomized comparison. Other influences on outcomes over time cannot be separated from the intervention by this design alone.
The follow-up information also matters: 17 of the 58 participants who completed baseline did not complete the endpoint assessment. The record does not explain why, describe how missing outcomes were handled, or state the analysis population. These omissions make it difficult to assess how missing follow-up might affect the endpoint estimate.
The safety record lists one serious adverse event among 58 participants at risk, zero deaths, and psychiatric emergency room visit at 1.7%. These are descriptive registry figures, not a comparative estimate of risk or evidence about causation. Overall, the record documents the study’s purpose, design, outcome definition, and some safety reporting, but does not provide the numerical outcome results needed to judge the observed primary change.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the distinction between measuring change and estimating a comparative treatment effect. The primary endpoint is a within-group change from baseline to follow-up. That measure can describe how scores differed over time among participants with data, but the single-group design does not provide a concurrent control contrast. The interpretation must stay aligned with that design.
The endpoint also connects a scale-based estimate to a stated threshold. The registry identifies a reduction of 0.6 or greater as an indicator of meaningful improvement in physical functioning. Such a threshold can help readers consider whether an estimated change may be important in context, while the mean and its confidence interval describe the group-level estimate and its precision. Because the registry record does not report those numerical results, neither comparison can be made for this study from the available information.
Missing follow-up is another important statistical issue. The record says that 17 of the 58 participants who completed baseline did not complete the endpoint assessment, but does not report how missing values were treated. The analysis population and handling of missing data can affect what a mean change represents, so these details are needed to assess the endpoint estimate fully.
The registry also lists several outcomes and analyses, but does not report a multiplicity approach or a statistical analysis plan. That absence does not imply a particular analytic choice; it identifies information needed to understand how multiple findings were interpreted. Together, the record illustrates why a clearly defined outcome is only one part of statistical interpretation: design, follow-up, analysis methods, and reported estimates are also essential.
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 most direct limitation of the registry information is that it does not report numerical results for the primary endpoint. The registered outcome and summary method are described, but no mean change or 95% confidence interval is available in the record. The direction, magnitude, and precision of the primary change therefore cannot be evaluated.
The single-group design has no separate control arm. A baseline-to-follow-up change cannot distinguish intervention-associated change from other changes over time. Allocation is listed as NA and masking as none; the registry does not describe a randomized comparison or a masked assessment process.
Follow-up was incomplete: 17 of the 58 participants who completed baseline did not complete the endpoint assessment. The registry record does not report reasons for noncompletion, the analysis population, the missing-data method, or sensitivity analyses. These omissions prevent evaluation of whether missing endpoint data could affect the reported estimate.
The registry record also does not report a detailed statistical analysis plan, the least-squares model specification, or whether multiplicity was addressed across the six outcome measures and six analyses. It does not provide participant characteristics beyond the stated population of Veterans with chronic low back pain, nor further information about adherence or usability findings. These are limits on what can be concluded from the record, rather than evidence that any particular result or analysis is invalid.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Internet-based Behavioral Pain Management — NCT01918189.
- Registry record last updated 2019-11-18; status last verified 2019-11.
- Results first posted 2019-10-11.
- 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
NCT01918189 is a completed, single-group study of 10 weeks of Internet-delivered Pain EASE behavioral pain self-management access for Veterans with chronic low back pain. The sponsor is the VA Office of Research and Development. The registry lists enrollment of 59 and identifies pain-related functional interference as the primary outcome, assessed as change from baseline to 10 weeks post-baseline.
The primary measure is the Multidimensional Pain Inventory Interference Subscale, summarized as a least-squares mean with a 95% confidence interval. The registry record does not report the numerical primary result or its interval. It reports that 17 of the 58 participants who completed baseline did not complete endpoint assessment. Safety reporting includes one serious adverse event among 58 participants at risk and zero deaths. The record does not provide a control-group comparison or enough detail to assess the missing-data method, analysis population, or multiplicity approach.