Substituting Sitting With Standing and Walking in Free-living Conditions Improves Daily Glucose Profile in South Asians: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Substituting Sitting With Standing and Walking in Free-living Conditions Improves Daily Glucose Profile in South Asians (NCT04645875), a randomized na study. The primary outcome is Glycaemia.

2. Clinical Question

3. Trial Design

The registry describes a randomized, single-masked crossover trial. Participants completed the SIT and SITless regimens in different orders: one sequence began with SIT and then moved to SITless, while the other began with SITless and then moved to SIT. Randomization therefore concerned regimen order. The registry does not report who was masked, so the meaning of single masking cannot be specified further from the record.

Each regimen lasted 4 days. In the SIT regimen, participants were instructed to limit walking and standing during their waking day. In the SITless regimen, they were instructed to replace sitting with standing and self-perceived light physical activity, while also interrupting sitting regularly. Both regimens took place under free-living conditions, as stated in the study title and summary. The record does not report adherence measurements or how closely participants followed the instructions.

The registry lists enrollment of 18 and status as completed. It records a start date of 2020-11-19 and primary completion on 2021-07-31. The primary outcome summaries list 14 observations for each regimen. These outcome counts are not a basis for assuming that the two summaries represent independent groups: in a crossover study, regimen comparisons may involve repeated observations from the same participants. The analysis approach and the participant-level correspondence are not reported in the registry record.

The trial is listed as phase NA. The sponsor is the University of Bedfordshire. Three secondary outcomes are named: sitting time, standing time, and total stepping time. The registry record does not provide further details about their results in the registry record for this analysis.

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: Three days washout period. Exclusion criteria: known heart disease, diabetes, bloodborne diseases (e.g., HIV), liver disease, renal failure, pregnancy, recent or current smoker, taking any glucose or lipid-lowering medication, allergies to the test meals, other health issues (psychological or neurological disorders), and any other injuries that might limit the ability to perform light- intensity exercise.

First Intervention (4 days)

Washout (3 days)

Second Intervention (4 days)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Overweight/obese South Asians

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: 18 Overweight/obese South Asians

6. Primary Endpoint

The registry lists the primary outcome as Glycaemia, measured over Mean net incremental area under the curve for waking hours (16 h) interstitial glucose concentration per day for 4 valid days during each intervention.

The primary endpoint is titled Glycaemia. It measures the mean net incremental area under the curve for interstitial glucose concentration during waking hours, expressed for a normalized 16 h day. The analysis timeframe is described as 4 valid days during each intervention. For each day, the net incremental area was calculated by subtracting waking glucose concentration from the total area under the curve. Waking hours were identified separately for each participant using activPAL data, then normalized to 16 h.

The outcome is a continuous measure, and the registry reports a mean with a 95% confidence interval for each regimen. It describes the regimen-level value as the mean of valid days within that regimen. At least one valid day coinciding with both FGM and activPAL data was required in each experimental regimen for inclusion in the analysis.

As a general statistical explanation, an area-under-the-curve measure combines information across a period rather than representing a single reading. The net incremental form focuses on the area relative to the waking glucose concentration used as the reference. This can describe a daily glucose profile in a way that accounts for its time course, although it does not by itself establish the cause of a difference between regimens. The registry reports the unit as mmol/L.16 h.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it is a mean net incremental area under the curve for waking-hours interstitial glucose. Continuous outcomes can be summarized by a mean, which represents the average on the measurement scale. The registry reports this mean separately for each regimen, together with a 95% confidence interval. It does not report a standard deviation or another dispersion measure in the outcome summaries.

What does a confidence interval describe?

General statistical explanation: a confidence interval expresses uncertainty around an estimate under the assumptions of the method used to calculate it. A narrower interval indicates greater precision for that estimate than a wider interval, while the interval’s coverage interpretation depends on the statistical procedure and its assumptions. Here, the reported intervals are attached to the separate regimen means. They are not intervals for the difference between regimens, so they do not directly answer the primary comparative question.

The SIT mean is 98.5, with a 95% confidence interval of 82.7 to 114.4. The SITless mean is 89.4, with a 95% confidence interval of 73.5 to 105.2. The registry’s outcome measure uses the unit mmol/L.16 h. These are reported summaries; no further decimal places or derived effect estimate are needed to describe them.

Why does crossover design affect the comparison?

General statistical explanation: in a crossover design, participants receive more than one regimen, and each participant can contribute information under each condition. Outcomes from the same person are often correlated. A comparison that accounts for this within-person relationship can differ in precision from one that treats observations as independent. The registry identifies a randomized crossover model, but the statistical method used for the primary comparison is not reported in the registry record. It also does not state whether the analysis accounted for sequence, period, or possible carryover effects.

The regimen summaries list 14 observations for each condition. Because the record identifies a crossover, these should not be treated automatically as independent parallel-group samples. Nor can the number of paired observations be inferred solely by comparing the two displayed counts: details about which participants contributed to each regimen summary and the analysis population are not reported in the registry record.

What does the endpoint calculation represent?

The endpoint is based on the area under the interstitial glucose curve during waking hours. The daily net incremental area is calculated by subtracting waking glucose concentration from total area under the curve. Waking hours are identified for each participant from activPAL data and normalized to a 16 h day. The record says that each regimen’s variable was calculated as the mean of valid days in that regimen. A day had to coincide with both FGM and activPAL data, and a minimum of one valid day in each regimen was required for inclusion.

General statistical explanation: area-under-the-curve measures summarize a profile over time. Net incremental area uses a reference level so the measure reflects the area above or relative to that reference, according to the specified calculation. Normalization to a common waking duration makes the reported measure refer to a 16 h day, as described by the registry. It does not remove uncertainty from measurement, missing days, or differences in behavior.

Can the two confidence intervals test the regimen contrast?

No direct contrast interval is reported. General statistical explanation: an interval for each separate mean and an interval for a difference answer different questions. For a crossover comparison, the uncertainty of the within-person difference depends in part on the relationship between each participant’s observations under the two regimens. Separate means and intervals do not provide that covariance information. Consequently, deriving a valid paired comparison from these summaries alone is not justified.

The registry also does not report a p-value, a test statistic, a model specification, or an adjustment strategy. It is therefore not possible to determine from the record whether a formal hypothesis test was conducted or how its assumptions were assessed. No recalculated comparison is presented. The registry record does not flag a discrepancy between sponsor analysis and recalculation, but no recalculated contrast is available in the registry record.

What do planning illustrations mean?

General statistical explanation: sample-size planning estimates how many participants per arm might be needed under specified assumptions to detect a selected effect with a chosen power and significance level. Such calculations are hypothetical planning illustrations, not observed results and not evidence of the probability that this completed study detected an effect. The registry describes its planning approach as using the observed effect, a two-sided significance level of 0.05, equal allocation, a normal approximation, and fractions of the observed effect. No numerical planning results are reported in the record for this analysis. These assumptions should not be mistaken for the trial’s own design rationale; that rationale is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry names three secondary outcomes: sitting time, standing time, and total stepping time. It reports four outcome measures overall and no analysis entries. The statistical plan for handling multiple outcomes is not reported in the registry record. In general, testing several outcomes can increase the chance of at least one apparently unusual result when each is assessed separately; adjustment or a prespecified hierarchy can address that concern, but neither approach is described. No secondary-outcome results or multiplicity-adjusted findings are available in the registry record for this analysis.

The primary outcome description sets a minimum data requirement: each participant needed at least one valid day in each regimen, with coincident FGM and activPAL data. The registry reports 14 observations for each regimen and enrollment of 18. It does not explain missing observations, exclusions, withdrawal, or whether all randomized participants were analyzed. The analysis population is not reported in the registry record, nor is the handling of missing days beyond the stated minimum-valid-day rule.

The record does not report whether missing outcome data were imputed, whether participants were analyzed according to randomized sequence, or whether sensitivity analyses assessed the effect of missingness. These omissions limit assessment of how complete-case selection may have affected the posted summaries. They do not establish that the analysis was inappropriate; they mean the relevant analytic details are unavailable in the registry record.

The record also does not describe the prespecified statistical plan, any interim analyses, or a sample-size justification. The planning assumptions described for illustrations are not evidence of the original trial’s design rationale. Without an analysis plan and clearer participant-flow information, readers cannot verify whether the primary analysis followed a prespecified approach or how outcome availability influenced inclusion.

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.

For the SIT regimen, the registry lists 18 participants at risk for serious adverse events and 0 affected; it also lists 18 at risk for other adverse events and 0 affected. For the SITless regimen, the corresponding figures are 18 at risk and 0 affected for serious adverse events, and 18 at risk and 0 affected for other adverse events. Deaths are listed as 0 in both regimen groups. No serious adverse-event terms are listed.

These are the registry’s event counts for the two regimens. The record does not provide further detail about event definitions, collection procedures, follow-up beyond the intervention periods, or how events were attributed. The counts should therefore be understood as what was reported, not as proof that an event was impossible or that rare risks were ruled out.

Because the design is crossover, the regimen-specific at-risk counts should not be interpreted as independent parallel groups. The registry record does not explain whether the same participants contributed to safety monitoring under both regimens, although its design description identifies a crossover trial. Zero affected is a count, not an estimate that can establish the absence of risk.

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

The posted results show regimen-specific means for the primary glucose outcome. The SIT mean is 98.5 and the SITless mean is 89.4 in the recorded unit mmol/L.16 h. Each is accompanied by a 95% confidence interval: 82.7 to 114.4 for SIT and 73.5 to 105.2 for SITless. These summaries indicate that the posted mean is lower for SITless, while the intervals describe uncertainty around each separate mean.

They do not, by themselves, establish the size or precision of the within-person contrast. The registry does not report an estimate or confidence interval for that contrast, a p-value, or the model used for the comparison. It is therefore not possible to infer from the posted summaries alone whether the comparison met a statistical criterion or how uncertain the contrast was.

The result also applies to the specified short regimens and the population described as overweight or obese South Asian adults. The interventions were conducted under free-living conditions, and the outcome reflects waking-hours interstitial glucose summarized for a normalized 16 h day. The registry does not report adherence, long-term outcomes, or results in populations outside the one described. The posted summaries should not be extended beyond the study setting and outcome.

Statistical evidence and clinical importance are different questions. General statistical explanation: statistical precision concerns uncertainty in an estimate, while clinical importance requires judging the outcome in context and may involve considerations not captured by a statistical summary. The registry record does not state a threshold for clinical importance. The means and intervals alone cannot establish such importance.

The safety record lists no serious or other adverse events in either regimen group, but event counts do not prove that risk is absent. Overall, the record documents a completed randomized crossover trial and reports descriptive glucose summaries. The missing contrast analysis, analysis-plan details, and participant-flow information constrain how strongly the comparative findings can be interpreted.

13. Why This Trial Matters Statistically

This trial is statistically notable because its randomized crossover structure changes the meaning of the comparison. Rather than comparing two unrelated groups by design, a crossover assigns regimen order and can generate observations under both regimens within participants. That structure may allow a comparison to use within-person information, but it also makes the handling of repeated observations and regimen sequence important. The registry identifies the design but does not report the primary comparison method.

The endpoint is also a longitudinal summary: net incremental area under the interstitial glucose curve during waking hours, normalized to a 16 h day. It condenses time-varying measurements into one continuous outcome for each regimen. The record describes how waking hours and valid days were defined, which helps clarify what the reported means represent. At the same time, the daily averaging rule and minimum valid-day requirement make the availability and handling of repeated data relevant to interpretation.

The posted means are accompanied by confidence intervals, but the intervals relate to each regimen mean rather than the crossover contrast. This distinction illustrates why confidence intervals must be interpreted in relation to the estimand they describe. Without a contrast estimate and its uncertainty, readers cannot assess the primary comparative question using the summaries alone.

The record also makes visible the gap between a planning illustration and an actual trial design justification. The stated planning approach refers to specified assumptions, but the original sample-size rationale is not reported. More complete reporting of the analysis population, missing-data handling, and comparison model would make it easier to assess the precision and robustness of the primary result. These are statistical reporting considerations, not conclusions about the direction or importance of the outcome.

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 registry record does not report the primary between-regimen contrast, its confidence interval, a p-value, or the statistical model used. This is a central limitation for evaluating the comparative question. Separate means and confidence intervals cannot substitute for the uncertainty around the within-participant contrast in a crossover study.

Although randomization, single masking, and a crossover model are recorded, the record does not identify who was masked or describe the randomization procedure, sequence balance, or analysis of regimen order. It also does not state whether period effects or carryover were assessed. These are important design and analysis details for interpreting crossover results, but their absence from the registry record does not show that they were ignored.

Enrollment is listed as 18, while each regimen outcome summary has 14 observations. The record specifies a valid-day requirement but does not provide a participant flow, reasons for unavailable data, or the analysis population. It does not describe imputation, sensitivity analyses, or whether the outcome summaries include all randomized participants. Adherence to the behavioral instructions is also not reported.

The registry identifies three secondary outcomes, but their results and multiplicity strategy are not reported in the registry record for this analysis. The original sample-size justification and any interim analyses are also not reported in the registry record. Finally, the primary endpoint is a short-term waking-hours glucose summary over the intervention periods; the record does not provide evidence about longer-term outcomes. These limitations define what can be assessed from the registry information, rather than proving that any particular result is biased.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Substituting Sitting With Standing and Walking in Free-living Conditions Improves Daily Glucose Profile in South Asians — NCT04645875.
• Registry record last updated 2026-03-24; status last verified 2026-03.
• Results first posted 2026-03-24.
• 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

NCT04645875 is a completed randomized, single-masked crossover trial sponsored by the University of Bedfordshire. The registry lists enrollment of 18, a start date of 2020-11-19, and primary completion on 2021-07-31. The population is described as overweight or obese South Asian adults.

Participants followed SIT and SITless regimens in randomized order, with each regimen lasting 4 days. The primary outcome is mean net incremental area under the curve for waking-hours interstitial glucose, normalized to a 16 h day. The reported mean is 98.5 for SIT and 89.4 for SITless, with respective 95% confidence intervals of 82.7 to 114.4 and 73.5 to 105.2, in the recorded unit mmol/L.16 h.

The registry lists sitting time, standing time, and total stepping time as secondary outcomes. It reports no serious adverse events, other adverse events, or deaths in either regimen group. The primary contrast method, analysis population, missing-data handling, multiplicity strategy, and sample-size justification are not reported in the registry record.