Increasing Activity Post-Kidney Transplant With SystemCHANGE: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Increasing Activity Post-Kidney Transplant With SystemCHANGE (NCT03191630), a randomized na study. The primary outcome is Steps Taken Per Day by Using an Activity Tracker.

2. Clinical Question

The practical comparison is between offering an activity tracker alone and offering the tracker together with a behavioral intervention focused on influences on activity. Because the study was randomized, its design could support a comparison between assigned groups if suitable outcome data and an analysis were reported. Randomization does not by itself establish that the intervention changed activity: interpretation requires the observed group results, a defined comparison, and information about uncertainty and missing observations.

The registry lists steps taken per day as the primary outcome and describes the measure as steps averaged per day. It also names other outcomes, including walking capacity, blood pressure, quality of life, weight, pulse, body mass index, and waist circumference. Those outcomes provide context for the broader study, but they do not replace the primary question about activity. Detailed eligibility criteria, the exact intervention schedule, and participant characteristics are not reported in the registry record.

3. Trial Design

This was a randomized, parallel-group behavioral study with no masking reported. The registry lists Ohio State University as the sponsor, enrollment of 60, and study status as completed. The study dates are listed as starting 2017-10-01, with primary completion on 2020-04-30. The phase is listed as NA.

Participants were assigned to one of two groups. The control group used Fitbit activity trackers without receiving SystemCHANGE. The intervention group received SystemCHANGE together with an activity tracker. The registry describes the study as a pilot and frames the intervention around questions about influences on physical activity among kidney transplant recipients.

The primary outcome is steps taken per day, measured with an activity tracker. The stated time frame names T2 at 3months, T3 at 6months, and T4 at 12 months. The outcome description says steps were averaged per day, while the analysis population description says descriptive statistics were used to analyze the monthly average for daily steps at 12 months. The registry does not explain how monthly averages were constructed, how measurements at the other named time points were handled, or whether the intended primary comparison was between groups or within each group over time.

Random allocation and a parallel-group structure describe how the groups were formed and followed; they do not supply the outcome analysis. The registry record does not report a primary outcome estimate, the number of participants contributing primary outcome data, or an inferential comparison. Allocation concealment, recruitment details, eligibility criteria, intervention adherence, and the statistical plan are not reported in the registry record. Although enrollment is listed as 60, the adverse-event figures use different group-specific numbers at risk; those counts should not be treated as the number analyzed for the primary outcome.

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: There was no pre-assignment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Descriptive statistics were used to analyze the monthly average for daily steps at 12 months.

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: Control group: Consented participants (n = 4) did not start the study. Intervention group: Consented participants (n= 3) did not start study. Recruitment target of 60 participants was met. Therefore, the control group had 26 participants and intervention group had 27 participants.

6. Primary Endpoint

The registry lists the primary outcome as Steps Taken Per Day by Using an Activity Tracker, measured over (T2) 3months, (T3) 6months, & (T4)12 months.

The primary endpoint is steps taken per day, recorded with an activity tracker and expressed as an average of steps per day. The registry specifies T2 at 3months, T3 at 6months, and T4 at 12 months, and describes the primary analysis population as monthly average daily steps at 12 months.

Step counts are a direct measure of recorded physical activity. In general, repeated measurements can describe activity at different points during follow-up, while a prespecified comparison can assess whether the groups differ at a particular time or in their change over time. The choice matters: an average at one time point answers a different question from a comparison of trajectories across multiple time points. The registry record does not specify which contrast was intended as the primary estimand, how the monthly summary was defined, or how repeated measurements were modeled.

The endpoint is relevant to the study’s stated focus on physical activity, but a device-based measure represents recorded steps rather than every aspect of movement or health. In general, interpretation also depends on wear time, device use, and the handling of incomplete records. Those procedures are not reported in the registry record. No group means, standard deviations, effect estimate, confidence interval, or p-value for daily steps are reported, so the magnitude and precision of any between-group difference cannot be assessed from the registry results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized parallel-group study. In general, randomization is intended to make assigned groups comparable at the start with respect to both measured and unmeasured characteristics, on average. It does not guarantee balance in a particular small study, and it cannot address biases arising after assignment, such as differential missing measurements. The registry does not report the randomization procedure, allocation concealment, or baseline characteristics, so those features cannot be evaluated from this record.

What does a parallel-group comparison mean?

In a parallel design, participants remain assigned to their respective groups for the comparison. Here, the groups are Fitbit alone and SystemCHANGE with Fitbit. In general, an analysis by assigned group preserves the comparison created by randomization, even if participants do not fully follow the assigned intervention. Other analysis choices can answer different questions, but the registry does not report an analysis population definition or an approach to adherence. No primary outcome analysis is posted.

How should daily steps be summarized?

The endpoint is a continuous measure, described as the mean or average number of steps per day. A mean summarizes the center of observed values; a standard deviation describes their spread around that mean. The registry identifies the standard deviation as the dispersion measure, but does not report group means or standard deviations. It states that daily steps were averaged and that monthly average daily steps at 12 months were analyzed descriptively. The exact rule for creating those averages, including how many days of tracker use were required, is not reported in the registry record.

General statistical point: an average can be informative, but its interpretation depends on the distribution and the quality of measurement. Step counts may vary substantially between participants and across days. In general, an analysis may need to account for repeated observations from the same participant, because observations within a person are related rather than independent. The registry names several follow-up times but does not report whether a repeated-measures model or any other model was used. It would therefore be inappropriate to attribute a particular modeling method to the study.

What would an effect estimate and confidence interval add?

In general, an effect estimate would express the between-group contrast on a defined scale, such as a difference in average daily steps, if that were the prespecified estimand. A confidence interval would indicate the uncertainty around that estimate under the assumptions of the analysis. A narrow interval would indicate greater precision than a wide interval, but neither an interval nor an estimate is reported in the registry record. No p-value or hypothesis-test result for the primary endpoint is reported either. Without these quantities, a statistical comparison cannot be reconstructed from the outcome description alone.

The registry’s primary description references more than one follow-up time point, while its analysis population description emphasizes the 12-month monthly average. General statistical point: defining one primary contrast in advance helps clarify which estimate is intended to answer the principal question. If several times or outcomes are tested, the chance of at least one apparently notable result can increase. Methods for addressing multiplicity depend on the prespecified aims and analysis plan. Those plans are not reported in the registry record, so it is not possible to say whether multiplicity adjustments were intended or used.

How should the planning illustration be understood?

The stated planning assumptions describe an illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The stated effect to detect is a fraction of the observed effect. For non-time-to-event outcomes, such as daily steps, the planning quantity is participants per arm for a selected power target. These are planning illustrations, not observed study results and not observed power. The registry does not report its own sample-size justification, and no calculated sample-size values are included in the record described. The illustration cannot be interpreted as the study’s original design calculation.

General statistical point: planning calculations depend on assumptions about the effect to detect, variability, allocation, and analysis method. An illustration that takes an observed effect as its starting point is conditional on that effect estimate and does not establish that the trial was adequately powered. Because the primary effect and variability are not reported, the planning illustration’s numerical implications cannot be assessed from the registry record.

The registry does not report the statistical analysis plan, model specification, covariate adjustment, handling of outliers, or software. No such methods should be assumed. The information that is available supports describing the design and planned outcome, but not reproducing or evaluating a primary endpoint analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry names several primary follow-up points: T2 at 3months, T3 at 6months, and T4 at 12 months. Its outcome description says the monthly average for daily steps at 12 months was analyzed descriptively. The record does not identify a single prespecified contrast across these time points, nor does it state whether the primary question concerned one time point, change over time, or a group-by-time pattern. It also lists multiple secondary outcomes. The statistical plan for handling multiple outcomes or time-point comparisons is not reported in the registry record.

General statistical point: evaluating many outcomes or time points can make it more likely that at least one result appears notable by chance. A prespecified hierarchy, adjustment method, or clearly exploratory interpretation can help readers understand such results. The registry record does not report whether any multiplicity procedure was planned or applied. Since no numerical outcome analyses are posted, there are no reported tests whose multiplicity adjustment can be assessed.

Missing-data handling is also not reported. The registry does not give the number of participants with usable tracker measurements at each time point, reasons for missing measurements, rules for excluding incomplete days, or methods for handling missing observations. It does not define whether the primary analysis included all randomized participants, only participants with recorded steps, or another population. In general, missingness can affect both the estimated group averages and their precision, especially if the reasons for missing data differ between groups.

The listed enrollment of 60 should not be treated as the endpoint analysis sample size. The adverse-event risk counts are 26 for control and 27 for intervention, but they do not identify the number contributing primary outcome data. The analysis populations and missing-data methods are not reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports no serious adverse events in either group: zero among 26 participants at risk in control and zero among 27 participants at risk in intervention. It also reports zero other adverse events and zero deaths in both groups. No top serious-event terms are listed.

These figures are event counts within the registry’s reporting, not estimates of comparative risk. Zero reported events does not establish that the underlying risk is zero, and the counts do not show whether adverse-event monitoring was equally complete or how long participants were followed for safety. The safety follow-up period, event definitions, ascertainment procedures, and handling of events after withdrawal are not reported in the registry record.

The adverse-event group counts should not be substituted for the number of participants with primary outcome measurements. Nor do these counts provide a formal comparison between groups. In general, interpreting safety requires attention to the number monitored, the observation period, and how consistently events were collected. The registry’s figures support only the narrow statement that no serious events, other events, or deaths were recorded in the reported group counts.

12. What the Result Does, and Does Not, Mean

The registry record establishes that a randomized pilot study compared activity trackers alone with activity trackers combined with SystemCHANGE among kidney transplant recipients. It specifies daily steps as the primary outcome and describes assessment at T2 at 3months, T3 at 6months, and T4 at 12 months. It also lists a range of secondary outcomes and reports adverse-event counts.

It does not establish the size or direction of any difference in daily steps between groups. The record contains no group-level primary outcome summaries, between-group estimate, confidence interval, or p-value. It therefore cannot support a conclusion about whether recorded activity differed, how large a difference might have been, or how precisely an effect was estimated. The study’s completed status is not itself evidence about the primary result.

In general, a statistically detectable difference and a practically meaningful difference are not the same concept. Assessing either would require an interpretable effect estimate and relevant context. The registry does not report a threshold for a meaningful change in steps or the outcome values needed to compare with such a threshold. No inference about clinical benefit should be drawn from the intervention descriptions alone.

The zero adverse-event counts are also limited in scope. They describe what the registry recorded for the stated risk groups; they do not demonstrate absence of risk. The report does not give the safety observation period or ascertainment details.

The most defensible reading is that the registry documents the study’s design and intended measurements but leaves the primary outcome findings unavailable. The listed planning assumptions describe a sample-size illustration, not observed power or proof of adequacy. Without the outcome analysis, the intervention effect and its uncertainty remain not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically relevant because it illustrates the distinction between a registered design and a report of results. The record gives a clear broad contrast—Fitbit alone versus Fitbit plus SystemCHANGE—and identifies device-recorded daily steps as the primary outcome. Those details define what a result could address. They do not substitute for outcome summaries or an analysis.

The endpoint is measured repeatedly across named follow-up times, while the registry’s analysis description highlights the monthly average at 12 months. This makes the target comparison important. In general, a single-time-point contrast, a change from baseline, and a comparison of trajectories answer different questions. A clear estimand and analysis plan would help readers connect the repeated measurements to the study question. The registry record does not report those details.

The study is described as a pilot, and its enrollment is listed as 60. General statistical point: pilot studies can help establish feasibility and inform later research, but a small or exploratory study’s estimates may be imprecise. The amount of precision cannot be judged from enrollment alone; it requires the observed outcome variability and analysis sample size. Neither is reported for daily steps.

The stated planning illustration is another reason to distinguish design calculations from evidence. It is based on an observed effect and specified assumptions, but it is not observed power and does not establish that the original study was designed around those assumptions. The registry does not report the study’s own sample-size justification.

Finally, the record lists zero analyses, while describing a completed study and multiple outcomes. That gap limits independent statistical interpretation. Posting group summaries, participant counts at each time point, the primary contrast, and uncertainty estimates would allow readers to assess the magnitude and precision of the findings without inferring results from the design alone.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main trial-specific limitation in the registry record is the absence of numerical results for the primary endpoint. Although daily steps and the stated follow-up times are identified, no arm-level means, standard deviations, effect estimate, confidence interval, or p-value are reported. The record also does not clarify how the 12-month monthly average was constructed or how the other named time points contributed to the primary analysis.

The record does not report the number of participants with usable tracker data at any follow-up, the amount of missing data, reasons for missingness, or procedures for incomplete device records. It also does not define the primary analysis population or report whether analyses followed randomized assignment. These omissions prevent evaluation of attrition and the impact of missing measurements.

Further details relevant to interpretation are not reported in the registry record, including baseline characteristics, eligibility criteria, allocation procedures, intervention adherence, the statistical analysis plan, and methods for repeated measurements. Masking is listed as none, but the record does not explain whether outcome processing or analysis was blinded. The trial is described as a pilot, but its own sample-size justification is not reported.

The registry names secondary outcomes but supplies no numerical results for them. The safety record reports zero events in the stated group counts, but does not give the observation period or event-collection procedures. These limitations mean the record can describe the design and recorded event counts but cannot establish the estimated intervention effect, its precision, or the completeness of outcome and safety ascertainment.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Increasing Activity Post-Kidney Transplant With SystemCHANGE — NCT03191630.
• Registry record last updated 2021-03-23; status last verified 2021-02.
• Results first posted 2021-03-23.
• 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.

18. Record Summary

NCT03191630, titled “Increasing Activity Post-Kidney Transplant With SystemCHANGE,” is listed as a completed randomized, unmasked, parallel-group behavioral study sponsored by Ohio State University. Enrollment is listed as 60. The record gives a start date of 2017-10-01 and primary completion date of 2020-04-30.

The control group used Fitbit activity trackers alone; the intervention group received SystemCHANGE with a Fitbit. The primary outcome was steps taken per day, with named time points at T2 at 3months, T3 at 6months, and T4 at 12 months. The record describes analysis of the monthly average daily steps at 12 months, but reports no primary outcome estimate or statistical comparison. Secondary outcomes are listed, but their numerical results are not reported in the registry record.

Serious adverse events, other adverse events, and deaths are reported as zero in both groups, with 26 at risk in control and 27 in intervention. Details of outcome missingness, the analysis plan, and the study’s own sample-size justification are not reported in the registry record.