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 STeP IT UP CF: STimulating ImProved Health And Well-being In CysTic Fibrosis (NCT04018495), a registered phase not stated study. The primary outcome is Activity Tracker Utilization- Total Days of Use.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04018495 |
| Phase | Phase not stated |
| Condition | Cystic Fibrosis |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 21 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Medical College of Wisconsin |
| Results posted | Yes |
2. Clinical Question
Population
People with cystic fibrosis who were enrolled and willing to use a Fitbit tracker. The registry record reports enrollment of 21 participants; the described tracker-use group consists of CF patients at enrollment.
Intervention
Use of a Fitbit to measure activity and sleep during an observational period of 3 months, with the project focused on integrating tracker data with existing health information from the CF Foundation Patient Registry, Port CF.
Comparator
No like-for-like control comparison is described. The allocation method is not stated, and the record does not establish a randomized comparison. The tracker-use group is not presented as a treatment arm compared with a control arm.
Primary question
How many days did participants use the activity tracker during the 3-month observation period? The primary measure is total days of use, described as a mean with the full range. It is a measure of tracker utilization, not a clinical outcome or a comparison of treatment effects.
The study is identified as a pilot of integrating wearable fitness-tracker data with existing registry health data. Its clinical and statistical focus is therefore on observing tracker use and bringing information sources together. The listed secondary outcome concerns average GLI FEV1 from the first to the last day of Fitbit wear. The record does not report a result for that measure or explain how it was analyzed.
3. Trial Design
This completed study is described as a pilot integrating fitness-technology information with Port CF data. It concerns cystic fibrosis and was sponsored by the Medical College of Wisconsin. The record lists enrollment of 21 participants, a start date of 2019-09-10, and a primary completion date of 2022-08-24.
The described group consists of CF patients at enrollment who were willing to use a Fitbit tracker to measure activity and sleep during an observational period of 3 months. This is an observational tracker-use description, not a stated assignment to a treatment. The registry record does not state an allocation method, and it does not describe a like-for-like control comparison. Accordingly, differences between groups or causal effects of tracker use cannot be read from this design description.
The primary outcome is total days of activity-tracker use over 3 months. The record describes descriptive statistics, such as the mean, and identifies the dispersion as the full range. One secondary outcome is integration of cystic fibrosis registry lung-function data, expressed as average GLI FEV1 from the first to the last day of Fitbit wear. The record states that there are 4 outcome measures, but details for the other measures are not reported in the registry record.
The registry status is COMPLETED, but completion does not itself establish that results were analyzed or posted. The record lists 0 analyses. It does not report a protocol sample-size justification, analysis plan, interim analyses, or a statistical comparison. Any planning illustration based on an observed effect is distinct from the study’s design; the registry record does not report a trial-design justification using that illustration.
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 | CF Patients Using Fitbit for 3 Months |
|---|---|
| STARTED | 21 |
| COMPLETED | 20 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | CF Patients Using Fitbit for 3 Months |
|---|---|
| Physician Decision | 1 |
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 | CF Patients Using Fitbit for 3 Months |
|---|---|---|
| Participants analysed | 20 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 20 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 33 (SD 8) |
| Sex: Female, Male: Female | Participants | 13 |
| Sex: Female, Male: Male | Participants | 7 |
| 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 | 0 |
| Race (NIH/OMB): White | Participants | 20 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 20 |
6. Primary Endpoint
The registry lists the primary outcome as Activity Tracker Utilization- Total Days of Use, measured over 3 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | Total days used |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is activity-tracker utilization, measured as total days used during the 3-month observation period. The registry record describes a mean for the number of days of use and specifies the full range as the dispersion measure. It does not report the observed mean, range, or participant-level results.
Use days address whether participants wore or used the tracker over the observation period, rather than whether their health changed. For an integration pilot, this kind of measure can describe engagement with the technology and the availability of wearable data for linking with registry information. It can also reveal variation in use across participants when the full range is reported. Those are general statistical interpretations of a utilization measure; the registry record does not state a threshold for adequate use or a target level of adherence.
The endpoint should not be interpreted as a measure of physical activity itself. Total days used does not, on its own, describe activity intensity, sleep quality, or lung function. The record says the tracker was intended to measure activity and sleep, but the primary endpoint is days of use. The listed lung-function outcome is secondary and is defined separately as average GLI FEV1 from the first to the last day of Fitbit wear.
Because the posted results do not include a numerical estimate for the primary endpoint, the amount and variability of tracker use cannot be assessed from the registry record. No confidence interval, hypothesis test, or association with health outcomes is reported.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s purpose and its primary measure, but it does not provide a numerical result for total days of Fitbit use. It therefore does not show how many days participants used the tracker on average, how widely use varied, or how many participants contributed data to that endpoint. The specified full-range summary cannot be interpreted without the observed endpoints of that range.
The record also lists 0 analyses. No estimate of the primary outcome, uncertainty interval, hypothesis test, or effect estimate is reported in the registry record. The absence of those results means that the endpoint cannot be used to judge the extent of tracker utilization from this record. It is not evidence that tracker use was high or low, nor does it establish whether the proposed data integration was successful.
The study is identified as a pilot. Its stated focus is integrating wearable fitness-tracker data with existing health data from the CF Foundation Patient Registry, Port CF. The primary endpoint addresses tracker utilization, while the listed secondary outcome concerns average GLI FEV1 from the first to the last day of Fitbit wear. These outcomes address different questions: use of the device and a lung-function measure over the period of wear. No numerical secondary-outcome result is reported, so no change or pattern in lung function can be described.
The study is not described as a randomized comparison, and the record does not state an allocation method. The described tracker users therefore should not be treated as one arm in a controlled treatment comparison. In general, a control group can help distinguish changes associated with an intervention from changes that might occur over time or for other reasons. That distinction is unavailable in the design description posted for this study. The record also does not report an analysis that links tracker-use levels to lung function.
The registry lists enrollment of 21 participants. The safety entry reports 20 participants at risk in the Fitbit Tracker group. These are different counts for different record entries, and the reason for the difference is not reported in the registry record. The safety counts should not be used as the denominator for the primary utilization outcome unless the outcome analysis specifies that denominator; no such analysis is posted.
The planning assumptions describe an illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. These are planning assumptions, not evidence that this study used two arms or that it was designed around a reported effect. The record does not provide the observed effect or a protocol sample-size justification. Any sample-size illustration is not an observed study result and cannot substitute for an analysis of the enrolled participants.
9. Statistical Methods Explained
The outcome description is explicitly descriptive: the primary endpoint is total days of tracker use over 3 months, with the mean as a stated summary and the full range as the dispersion measure. Descriptive statistics characterize the data collected. They do not, by themselves, test a hypothesis or establish that an intervention caused an outcome. The registry record does not report the numerical summaries for this endpoint.
What does the mean describe?
In general, the mean is the arithmetic average of the observed values. For days of tracker use, it would provide a single summary of use across the participants included in an analysis. A mean can be affected by unusually high or low values, so it is useful to read it alongside a measure of spread. The record specifies the full range, which identifies the lowest and highest observed values. A range gives a direct sense of the span of the data, but it does not show how observations are distributed between those endpoints. Neither the mean nor the range is reported numerically in the posted results.
Why does the endpoint matter?
A use-days measure describes tracker utilization, not the amount or quality of activity or sleep. In general, wearable data are useful for an integration project only to the extent that usable observations are collected and can be associated with relevant registry information. The record describes integration as the project’s purpose, but it does not report technical success measures, completeness of linked records, or an analysis connecting utilization to the secondary lung-function outcome. Those results should not be inferred from the endpoint name.
What can an inferential analysis add?
In general, an inferential analysis estimates a quantity of interest and describes uncertainty in that estimate. A confidence interval is a range of values compatible with the data under the assumptions of the analysis; a narrower interval generally indicates greater precision. A hypothesis test addresses whether data are inconsistent with a specified null hypothesis under its assumptions. These methods require defined analysis procedures and results. The registry record lists 0 analyses and does not report a confidence interval, test, or model for the primary endpoint.
Because no control comparison is described, a between-group treatment-effect analysis is not supported by the posted design information. The record says allocation is not stated and that the arms are not a like-for-like control comparison. In general, an unadjusted comparison between non-comparable groups may reflect differences in who entered each group as well as differences associated with an exposure or intervention. No group comparison should be assumed from a planning illustration that uses equal allocation between two arms.
How should planning assumptions be read?
The planning assumptions describe a normal approximation, equal allocation between two arms, a two-sided significance level of 0.05, and an effect to detect expressed as a stated fraction of an observed effect. These are assumptions for a planning illustration rather than reported features of the trial’s actual design. The registry record does not give a protocol sample-size justification, identify a two-arm randomized design, or report the observed effect needed to interpret such an illustration. Planning sample sizes are hypothetical requirements under stated assumptions; they are not the number observed in this study and are not evidence of the study’s precision or findings.
In general, a normal approximation uses a normal distribution to approximate the behavior of a statistic. How suitable that approximation is depends on the data and analysis. Equal allocation is an assumption about how participants are divided between comparison groups; it does not show that the study enrolled or assigned participants that way. The two-sided significance level describes a testing convention that allows evidence in either direction. None of these assumptions establishes that a test was conducted for the posted outcomes.
What is not available for statistical review?
The record does not report the analysis population for the primary endpoint, how incomplete tracker records were handled, or whether observations were excluded. It does not describe a missing-data method, covariate adjustment, a model for repeated observations, or a multiplicity procedure. Since outcome-specific numerical analyses are absent, precision, model fit, and sensitivity to analytic choices cannot be assessed. The record also does not report interim analyses or the statistical plan. These absences limit what can be concluded from the registry entry; they do not establish that a particular method was or was not used outside the information recorded there.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 4 outcome measures and identifies the primary utilization endpoint and a secondary lung-function outcome. Details of the other outcome measures are not reported in the registry record. It lists 0 analyses and provides no numerical estimates or tests for the outcomes. As a result, there are no posted outcome-specific analyses from which to assess the handling of multiple comparisons.
In general, multiplicity arises when several outcomes, comparisons, or analyses are examined. Repeated testing can increase the chance of a false-positive finding if each test is interpreted without accounting for the others. A statistical plan may identify a primary outcome, specify which analyses are confirmatory, or describe an adjustment procedure. The record identifies a primary endpoint, but does not report a multiplicity strategy or a fuller analysis plan. No adjustment method should be assumed.
Information about missing data is also not reported in the registry record. The entry does not state whether all enrolled participants contributed to the primary endpoint, how incomplete tracker use was handled, or whether any values were imputed. In general, missingness can affect both the number of observations available and the interpretation of a summary. Without an analysis population and a missing-data description, the primary endpoint’s denominator and potential sensitivity to incomplete observation cannot be assessed.
The analysis populations are not reported in the registry record. The entry gives enrollment of 21 participants, while the adverse-event entry lists 20 at risk in the Fitbit Tracker group; it does not explain how these counts relate to the endpoint analysis. No interim analysis or prespecified statistical plan is reported. Consequently, it is not possible to determine whether posted results reflect all enrolled participants or a defined subset.
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 |
|---|---|---|---|
| Interventional - Fitbit Tracker | 0 | 20 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Interventional - Fitbit Tracker | 0 of 20 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Interventional - Fitbit Tracker | 0 of 20 |
The serious adverse-event entry lists the Interventional - Fitbit Tracker group with 20 participants at risk and 0 participants affected by a serious adverse event. It also lists 20 at risk and 0 affected for other adverse events, and 0 deaths. No serious adverse-event terms are listed.
These figures describe the counts entered in the registry safety record. They are not a comparison against a control group, because no like-for-like control comparison is described. The entry also does not explain the difference between the enrollment of 21 participants and the 20 participants listed at risk for safety. That difference should be noted without assuming its cause.
A zero count in a registry entry means that no event was recorded in that category for the listed group in the posted record. It does not establish that an event was impossible, that all participants had complete safety follow-up, or that there were no events outside the reported categories. The registry record does not provide follow-up completeness or additional detail on safety monitoring. These counts should therefore be read as the recorded safety figures, not as a standalone estimate of risk or as evidence from a controlled safety comparison.
12. What the Result Does, and Does Not, Mean
The posted record describes a completed pilot focused on integrating Fitbit activity and sleep information with Port CF registry data. It identifies a clear utilization endpoint: total days of tracker use over 3 months, summarized descriptively by a mean and full range. The record also identifies a secondary measure involving average GLI FEV1 from the first to the last day of Fitbit wear.
The record does not include numerical results for either outcome. It therefore does not establish the average duration of tracker use, the spread of use, or the observed pattern in the listed lung-function measure. It also does not report a statistical analysis, uncertainty interval, or comparison between groups. The status COMPLETED refers to the study’s registry status; it does not supply missing outcome findings.
The design description concerns participants willing to use a Fitbit and does not state an allocation method or describe a like-for-like control group. Consequently, the posted information cannot support a causal claim about the effect of tracker use or a treatment comparison. Even if a change in a health measure had been reported, interpretation would depend on the analysis, completeness of follow-up, and design. Those details are not reported in the registry record.
The safety entry records 0 serious adverse events, 0 other adverse events, and 0 deaths among 20 participants listed at risk. These counts are limited to the registry safety entry and do not establish comparative safety. The record does not explain the safety denominator or its relation to enrollment of 21 participants.
In general, a pilot can inform whether data collection and integration processes merit further evaluation, but conclusions require reported results and methods. The registry entry conveys the project’s purpose and selected measures; without the outcome analyses, it does not show the degree of utilization or the performance of the intended integration. Planning illustrations, if considered, are not substitutes for observed results or for the trial’s own design justification.
13. Why This Trial Matters Statistically
This study is statistically interesting because it connects two forms of information: wearable measurements of activity and sleep, and existing health information in Port CF. For a data-integration project, the ability to collect and align observations is part of the research question, not merely a technical detail. The primary endpoint, total days of tracker use, is relevant to whether the wearable produced data over the observation period.
The endpoint also illustrates why a concise summary needs context. A mean can describe typical use across analyzed participants, while the full range can indicate how far the observed values extend. In general, these summaries complement one another, but neither reveals the shape of the distribution or the reason for variation. The registry record names both summaries without reporting their values, so the amount and variability of use remain unknown.
The study also highlights the distinction between a pilot’s purpose and a comparative efficacy question. The posted design describes willing tracker users and does not identify a control group or allocation method. This does not make the utilization question unimportant; it means that the study description should be interpreted on its own terms rather than as a randomized comparison.
Statistically, the gap between a defined outcome and an absent analysis is consequential. Without the estimated mean, range, analysis population, or missing-data handling, readers cannot assess precision or the representativeness of the observed use. Without outcome results for the listed lung-function measure, the relationship between tracker use and health data is also not established. The record’s stated integration aim is informative, but a result demonstrating integration performance is not reported.
Finally, the safety counts show why denominators and record definitions matter: enrollment is 21, while the safety entry lists 20 at risk. The registry record does not explain the difference. Making that distinction visible helps prevent readers from treating different registry counts as interchangeable.
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 principal limitation of the registry information is the absence of numerical results for the primary endpoint. Although the endpoint and its intended summaries are named, the mean and full range are not reported. The number of participants contributing to that endpoint and the handling of incomplete tracker observations are also not reported in the registry record.
The design information is limited for comparative interpretation. The allocation method is not stated, and the registry record says the arms are not a like-for-like control comparison. The described group consists of participants willing to use a Fitbit; the record does not report how willingness or participation affected the set of people observed. No causal effect should be inferred from this description.
The record lists 4 outcome measures but gives details for the primary endpoint and one secondary outcome. It does not report numerical results for the secondary lung-function measure or details for the other measures. An analysis plan, interim analyses, multiplicity handling, and missing-data procedures are not reported. This prevents assessment of whether analytic decisions were prespecified and how they might influence interpretation.
The safety entry lists 20 participants at risk, whereas enrollment is 21; the registry record does not explain the difference. The safety counts are not accompanied by follow-up completeness or further event details. The record also does not provide a protocol sample-size justification. Planning assumptions using an observed effect are not a substitute for that justification, and the observed effect itself is not reported.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: STeP IT UP CF: STimulating ImProved Health And Well-being In CysTic Fibrosis — NCT04018495.
- Registry record last updated 2025-02-03; status last verified 2025-01.
- Results first posted 2025-02-03.
- 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 identifies NCT04018495 as a completed pilot concerning cystic fibrosis. The study, sponsored by the Medical College of Wisconsin, focused on integrating Fitbit activity and sleep data with existing health information from the CF Foundation Patient Registry, Port CF. Enrollment was 21; the listed start date is 2019-09-10 and the primary completion date is 2022-08-24.
The primary outcome is total days of tracker use over 3 months, with a mean and full range specified. The listed secondary outcome concerns average GLI FEV1 from the first to the last day of Fitbit wear. The registry record lists 4 outcome measures and 0 analyses, and does not report numerical results for the primary or secondary outcome.
The described tracker users are not presented as a like-for-like control comparison, and allocation is not stated. The safety record lists 0 serious adverse events, 0 other adverse events, and 0 deaths among 20 participants at risk. It does not explain the difference between that safety count and enrollment.