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 Active for Life: Chronic Obstructive Pulmonary Disease (NCT03201198), a randomized na study. The primary outcome is Time Spent in Physical Activity as Measured by Upright Time (Minutes Per Day) Monitored by ActivPal Monitor.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03201198 |
| Phase | NA |
| Condition | Chronic Obstructive Pulmonary Disease |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 182 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Michigan |
| Results posted | Yes |
2. Clinical Question
Population
People with chronic obstructive pulmonary disease were eligible for this study. The registry describes the target population as people with COPD and identifies the primary measure as time spent upright during daily activity. It does not report further eligibility details in the record.
Intervention
Active Life was a behavioral program combining structured walking, functional circuit training, stretching, and behavior and educational components. The study examined whether this program could promote physical activity among people with COPD.
Comparator
The comparison group received chair exercises, behavioral relaxation, and health education. This was also a behavioral intervention, rather than a no-treatment comparator. The registry does not describe the intended contrast as usual care.
Primary question
The primary outcome was upright time, measured in minutes per day with an ActivPal monitor. The registry planned measurement at baseline and at four subsequent periods, extending through follow-up. It does not report the numerical outcome estimates or a single comparison of the two programs.
3. Trial Design
This was a randomized, parallel-group trial with single masking. The registry does not identify who was masked, so the masking designation should not be interpreted as specifying whether participants, intervention staff, outcome assessors, or analysts were unaware of allocation. The record lists the phase as NA. The sponsor was the University of Michigan, and the study status is completed.
The registry lists enrollment of 182 participants. Participants were assigned to Active Life or chair exercises. Both arms involved behavioral elements: Active Life included structured walking, functional circuit training, stretching, and behavior and educational components; the chair-exercise program included chair exercises, behavioral relaxation, and health education. The record does not provide further details about allocation procedures, concealment, or how the programs were delivered.
The primary outcome was measured repeatedly. Upright time was monitored for 7 consecutive days at each of five test periods, identified as T1 through T5. These periods were baseline, immediately after the intervention, and 3-month, 6-month, and 12-month follow-up. The registry states that a participant needed at least 4 of 7 valid monitoring days in a period for that period to meet its monitoring criterion. The number analyzed varied across measurement periods because participants withdrew, were unavailable for appointments, or were ill, among other reasons listed in the record.
The registry lists the Six-minute Walk Test as a secondary outcome and identifies 3 outcome measures overall. It does not report numerical primary-outcome estimates or analyses for the posted results summarized in the record. Further protocol details, including the planned statistical model and allocation ratio, 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.
Before assignment: A total of 182 subjects were enrolled and randomized across both groups. Five subjects were not able to complete baseline assessment leaving 177 randomized subjects who completed baseline assessment.
Overall Study
| Stage | Active Life | Chair Exercises |
|---|---|---|
| STARTED | 92 | 90 |
| COMPLETED | 55 | 50 |
| NOT COMPLETED | 37 | 40 |
Reasons for not completing this period:
| Reason | Active Life | Chair Exercises |
|---|---|---|
| Did not complete f reasons; lost to follow-up, subject withdrew, family illnesses, moving, etc. | 35 | 37 |
| Withdrawal by Subject | 2 | 3 |
Analysis population for the primary outcome, as defined in the registry: Number of participants who were analyzed at each time period (T1-T5) varied due to participants withdrawing, not being available to keep their test appointments, illness, etc. T1=baseline, T2=testing at completion of intervention, T3= 3 months following intervention, T4=6 months following intervention, T5=12 months following intervention
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 | Active Life | Chair Exercises | Total |
|---|---|---|---|---|
| Participants analysed | 92 | 90 | 182 | |
| Age, Continuous | years | 68.5 (SD 7.8) | 70.3 (SD 8.5) | 69.4 (SD 8.1) |
| Sex: Female, Male: Female | Participants | 37 | 38 | 75 |
| Sex: Female, Male: Male | Participants | 45 | 46 | 91 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 2 | 0 | 2 |
| Race (NIH/OMB): Asian | Participants | 1 | 2 | 3 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 9 | 13 | 22 |
| Race (NIH/OMB): White | Participants | 70 | 68 | 138 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 10 | 7 | 17 |
| FEV1%Predicted | Percent of actual to predicted | 53.77 (SD 15.6) | 56.99 (SD 13.5) | 55.4 (SD 14.5) |
6. Primary Endpoint
The registry lists the primary outcome as Time Spent in Physical Activity as Measured by Upright Time (Minutes Per Day) Monitored by ActivPal Monitor, measured over 7 days of continuous activity monitoring w as monitored on each participants at each of five test periods (T1-T5).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | minutes per day |
| Endpoint classification | Continuous Endpoint |
The primary endpoint measures time spent upright during physical activity, expressed as minutes per day and monitored with an ActivPal device. It was assessed over 7 consecutive days at each of five test periods: baseline, immediately after the intervention, and 3-month, 6-month, and 12-month follow-up. The registry describes the primary measure as a mean with standard deviation.
As a general statistical concept, a continuous measure such as minutes per day can capture the amount of a behavior along a range, rather than reducing activity to a yes-or-no category. Repeated measurements can describe how the measure changes over time and whether the pattern differs between randomized groups. The record’s use of a multi-day monitoring period at each assessment is part of the endpoint definition; it does not establish how observations were combined or analyzed.
The registry required at least 4 of 7 monitoring days to be valid within a measurement period. This criterion defines when a period’s monitoring could count as valid, but it does not reveal how many participants met it or how missing days were handled in the analysis. The endpoint is a measure of upright time, not a direct report of every aspect of physical activity, functional capacity, or health. The Six-minute Walk Test is listed separately as a secondary outcome. Numerical values for the primary endpoint and its uncertainty are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes the trial question and the planned repeated measurement of upright time, but it does not report numerical primary-outcome results. In particular, no group means, standard deviations, estimated differences, confidence intervals, or p-values for upright time appear in the record. The record lists no analyses for these outcome measures. Consequently, the posted information does not establish the direction, size, or precision of a primary-outcome contrast between Active Life and chair exercises.
The endpoint was measured at baseline and at four follow-up periods. A comparison at one time point would answer a different question from a comparison of changes over time, and an overall repeated-measures analysis could address a broader time pattern. The registry identifies the time points but does not report which contrast was intended as the primary statistical test. It also does not report an analysis model that would clarify how baseline values, repeated observations, or incomplete follow-up were treated.
As a general statistical concept, an estimate describes the size and direction of an observed contrast, while a confidence interval describes the range of values compatible with the data under the analysis assumptions. A p-value addresses how compatible the observed data are with a specified null model; it does not measure clinical importance. Without posted estimates and uncertainty measures, these interpretations cannot be applied to this trial’s primary outcome.
The record notes that the number of participants analyzed differed across measurement periods. That makes it important to know which participants contributed to each estimate and how incomplete measurement was handled. Those details, including analysis-population definitions and missing-data methods, are not reported in the registry record. The registry’s description of reasons for variable follow-up does not establish whether missingness was related to outcomes or treatment assignment.
The record therefore supports a description of the design and endpoint, not a conclusion about the comparative effect of the programs. It is also not possible to assess whether any observed difference, if one was estimated elsewhere, was statistically precise or practically important from these registry entries alone. The posted serious adverse event counts are described separately and should not be treated as evidence about the primary physical-activity endpoint.
9. Statistical Methods Explained
What kind of outcome was measured?
Upright time in minutes per day is a continuous outcome. In general, continuous outcomes are summarized using a location measure, such as a mean, together with a measure of variability, such as a standard deviation. The registry identifies the primary parameter as a mean and the dispersion measure as a standard deviation. These summaries would describe the distribution of observed upright time, but numerical summaries are not reported in the registry record.
A standard deviation describes how dispersed individual measurements are around a mean. It is not the same as the uncertainty in a group mean or the uncertainty in a contrast between groups. Confidence intervals for a contrast would be needed to communicate the precision of that comparison. The record does not report such intervals for the primary outcome.
Why does repeated measurement matter?
The primary outcome was measured at T1 through T5, covering baseline, immediate post-intervention assessment, and follow-up through 12 months after the intervention. Repeated measurements allow a study to describe both the level of an outcome at particular times and its pattern across time. A group contrast at follow-up is not interchangeable with a contrast in change from baseline, and neither is automatically equivalent to a test of the full time pattern.
As a general statistical matter, observations from the same participant over time are related rather than independent. An analysis of repeated measurements usually needs to account for that within-participant relationship. The registry record does not report the statistical model, covariance structure, or primary time contrast used for the outcome. It is therefore not possible to determine whether the posted analysis, if any, modeled all periods jointly or focused on a particular assessment.
What can randomization contribute?
Random assignment is intended to make treatment groups comparable on average at the point of assignment, including with respect to factors that were not measured. This is a general property of randomization, not a guarantee that groups will be identical in a particular trial. The registry identifies the allocation as randomized but does not report the sequence-generation procedure, allocation concealment, or an assessment of baseline balance in the record.
The parallel design means participants were assigned to one of the two programs rather than crossing between them, according to the registry’s design description. Both programs included behavioral and educational components, so the study contrast concerns the programs as described, not exercise versus no intervention. The record does not report an analysis that separates the contribution of any individual program component.
How should uncertainty be understood?
In general, an estimate is most informative when considered alongside its uncertainty. A confidence interval can show whether the data are compatible with a broad range of effects or a narrower range, subject to the model and assumptions used. A p-value alone would not convey the magnitude of an effect or its practical meaning. No primary-outcome estimate, confidence interval, or p-value is reported in the registry record, so these features cannot be assessed for this comparison.
Statistical significance and importance are distinct concepts. A small difference can be estimated precisely, and a potentially meaningful difference can remain uncertain when data are limited; these are general possibilities rather than descriptions of this trial’s results. The record does not state a threshold for a meaningful change in upright time or report a comparison against such a threshold.
What do the planning assumptions mean?
The registry’s sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. Such planning calculations address how many participants per arm might be needed under the chosen assumptions; they are not the trial’s observed results and are not observed power.
The record does not report the trial’s own sample-size justification or establish that these illustrative assumptions were used to design the study. No numerical sample-size illustration values are included in the record, so no specific planning requirement can be interpreted. In general, planning calculations depend on the target effect, outcome variability, significance level, allocation, and analysis assumptions. A calculation based on an observed effect can be especially dependent on that effect estimate, and it should not be mistaken for evidence that a study did or did not detect an effect.
The registry does not report the primary analysis method, any adjustment for multiple testing, or interim analyses. These absences limit what can be said about the planned inferential procedure. Statistical interpretation should therefore remain anchored to what is actually posted: the study design, the endpoint definition, and the reported safety counts, without inferring unreported tests or effect estimates.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint was measured at five time periods, while the registry does not reduce it to one comparison. Multiple time points can create multiple possible contrasts, such as separate comparisons at each assessment or a joint assessment of change over time. As a general statistical matter, testing many contrasts can increase the chance of at least one nominally significant result unless the analysis plan addresses multiplicity. The registry record does not report a multiplicity strategy, a designated primary time-point contrast, or an analysis plan that would clarify this issue.
The record lists no analyses for the outcomes in the results. It therefore contains no reported primary-outcome estimate or test to interpret in relation to multiplicity. The Six-minute Walk Test is identified as a secondary outcome, and 3 outcome measures are listed overall, but the record does not report how conclusions across outcomes were to be controlled or prioritized.
Missingness is relevant because the number of participants analyzed varied by time period. The registry names withdrawal, unavailability for testing appointments, and illness among the reasons. It also states that a period required at least 4 of 7 valid monitoring days. That criterion does not specify how participants with fewer valid days were handled, whether partial monitoring was used, or whether missing outcome values were imputed.
Methods for handling missing data, definitions of the analysis populations, and whether all randomized participants were included in the primary analysis are not reported in the registry record. In general, missing-data methods rely on assumptions about why measurements are absent; the reasons for missingness and the chosen assumptions can affect estimates. The available description is not sufficient to judge those assumptions or to assess whether differences in follow-up could have influenced a comparison.
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 |
|---|---|---|---|
| Active Life | 7 | 82 | 8.5% |
| Chair Exercises | 5 | 84 | 6.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Active Life | 4 of 82 |
| Chair Exercises | 1 of 84 |
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 |
|---|---|
| Active Life | 17 of 82 |
| Chair Exercises | 12 of 84 |
Most frequent serious adverse event terms
| Event term | Organ system | Active Life | Chair Exercises |
|---|---|---|---|
| acute exacerbation requiring hospitalization | Respiratory, thoracic and mediastinal disorders | 7 of 82 | 5 of 84 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Active Life | Chair Exercises |
|---|---|---|---|
| Fall with non-serious injury | Injury, poisoning and procedural complications | 11 of 82 | 7 of 84 |
| Exercise intolerance due to pain or injury, non-serious | Musculoskeletal and connective tissue disorders | 6 of 82 | 5 of 84 |
Serious events with the highest arm-level rate: acute exacerbation requiring hospitalization (8.5%).
The registry reports serious adverse events and other adverse events separately for the two groups. For Active Life, 7 participants were affected by serious adverse events out of 82 at risk, and 17 were affected by other adverse events out of 82 at risk. For Chair Exercises, 5 participants were affected by serious adverse events out of 84 at risk, and 12 were affected by other adverse events out of 84 at risk. The record also reports 4 deaths in Active Life and 1 in Chair Exercises.
These are counts reported by group; they do not by themselves establish that an event was caused by an intervention. The registry does not provide event-level timing, individual clinical details, or an adjusted comparison of safety outcomes. It also does not explain in this record whether the death counts overlap with the serious adverse event counts, so they should be read as separately reported figures rather than added together.
The most frequent serious adverse event term listed is acute exacerbation requiring hospitalization, reported as 8.5%. The record does not specify its distribution by group in the information. A percentage or count is a descriptive safety measure; interpretation also depends on event definitions, observation time, and the completeness of reporting. Those details are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, parallel-group study compared Active Life with chair exercises among people with chronic obstructive pulmonary disease. Its primary outcome was upright time measured over seven-day monitoring periods at baseline and four subsequent assessments. The design description and endpoint definition make clear what the study set out to examine, but the record does not report numerical results for that primary question.
Without means, standard deviations, contrasts, confidence intervals, or p-values, the direction and magnitude of any difference in physical activity cannot be determined from the posted record. No conclusion about whether the programs changed upright time, whether their outcomes differed, or how precise any difference might be is supported by the available primary-outcome information. The record also does not report a threshold for interpreting a change as meaningful.
The safety counts are descriptive and should be interpreted in context. They do not establish a causal relationship between an intervention and an adverse event, and the record does not report a formal comparison of safety outcomes. The listed deaths and adverse events are not substitutes for the missing primary-outcome analysis.
As a general principle, a completed trial and a registry record with a defined endpoint do not, by themselves, show what the trial found. An interpretation of comparative effects requires reported estimates, an account of uncertainty, and enough information about the analysis and participant inclusion to judge how those estimates were obtained. Here, the registry provides some design and monitoring details but not those elements for the primary outcome.
The study should therefore be read as a record of a comparison that was planned and completed, with its primary outcome specified but its numerical results not reported in the registry record. This distinction is important: absence of a posted estimate is not evidence of no effect, and it is not evidence of a benefit. It leaves the primary statistical question unresolved in this record.
13. Why This Trial Matters Statistically
This trial illustrates the difference between a clearly defined outcome and a reported outcome result. The registry specifies upright time, its unit, the monitoring device, and repeated assessment periods. These details help explain what the study intended to measure. Yet without group summaries and a contrast with uncertainty, readers cannot evaluate the comparative finding. Statistical transparency depends not only on identifying an endpoint but also on reporting how it was analyzed and what the data estimate.
The repeated-measures structure is statistically important. Baseline and follow-up observations can support questions about levels at particular times and about patterns over time, but those questions are not interchangeable. A registry record that identifies multiple periods without reporting a primary contrast leaves uncertainty about which estimand was central to the analysis. The record does not report the model or the approach to multiple testing.
The endpoint also makes data completeness relevant. Participants needed at least 4 of 7 valid monitoring days at a period, and the number analyzed varied over time. That combination makes it important to report how monitoring validity, missed appointments, withdrawal, and illness affected analysis populations. The record gives reasons for varying numbers but not the statistical handling of incomplete observations.
Finally, the record distinguishes the intervention programs in a way that matters for interpretation: both were behavioral programs, with different exercise and educational components. Any comparative effect would pertain to the programs as delivered, not to a single isolated component. Since numerical outcome results are not reported, the statistical value of the record is primarily in clarifying the design and the limits of the evidence available there.
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 of the registry record is that it does not report numerical results for the primary endpoint. No group means, standard deviations, effect estimates, confidence intervals, or p-values are available for the repeated upright-time measurements. The record lists no outcome analyses. This prevents evaluation of effect direction, magnitude, and precision.
The primary outcome spans five assessment periods, but the record does not identify a single primary contrast or explain how the time points were incorporated into an analysis. The statistical model, multiplicity approach, and any adjustment for baseline measurements are not reported in the registry record. The designation of single masking is also not accompanied by identification of who was masked.
The number of participants analyzed varied by period. The record gives withdrawal, missed appointments, and illness as reasons, and specifies a minimum of 4 valid days within a 7-day monitoring period. It does not report how many observations failed that criterion, how missing periods were handled, which participants were included in each analysis, or whether sensitivity analyses assessed the effect of missing data.
The record lists the Six-minute Walk Test as a secondary outcome and 3 outcome measures overall, but it does not report their numerical findings in the information. The safety information is also limited: it presents group counts and a serious-event term, without event-level details or a formal comparative analysis. These limitations describe gaps in the registry record and should not be taken as evidence that analyses or details were absent from all study materials.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Active for Life: Chronic Obstructive Pulmonary Disease — NCT03201198.
- Registry record last updated 2024-04-17; status last verified 2024-03.
- Results first posted 2024-04-17.
- 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 record describes a completed randomized, parallel-group trial sponsored by the University of Michigan, with enrollment of 182 participants. It compared Active Life, a behavioral program including structured walking, circuit training, stretching, and educational components, with chair exercises, relaxation, and health education. The study had single masking; who was masked is not reported in the registry record.
The primary outcome was upright time in minutes per day, monitored over 7 consecutive days at baseline and four follow-up periods. The registry states that at least 4 valid monitoring days were required at each period and that the number analyzed varied over time. The Six-minute Walk Test is listed as a secondary outcome.
Numerical primary-outcome results and analyses are not reported in the registry record. Serious and other adverse event counts are reported by group, along with deaths and a serious-event term. The registry does not provide a primary effect estimate or its precision, so the comparative physical-activity result cannot be interpreted from this record.