Effects of Physical Training on Bone Turnover and Quality of Life in Osteopenic Postmenopausal Women.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Physical Training on Bone Turnover and Quality of Life in Osteopenic Postmenopausal Women. (NCT03195517), a non-randomized na study. The primary outcome is Variation in Serum Levels of Procollagen 1 N-terminal Peptide (P1NP).

2. Clinical Question

The research aim also concerned bone-cell turnover and quality of life. The registry lists variation in health-related quality of life as a secondary outcome, but does not report numerical secondary-outcome results in the registry record. The primary question is therefore narrower than the overall research aim: it concerns change in a circulating bone-formation marker over the stated baseline-to-Week 4 timeframe, rather than a direct measure of fractures, longer-term health, or quality of life.

Because participants were not randomly allocated, any observed difference between groups could reflect differences that existed before exercise began, as well as differences associated with the program. The registry record does not report enough information to assess how such baseline differences were handled. The question is best read as a comparison within a non-randomized study, not as a randomized estimate of the effect of exercise.

3. Trial Design

The study is registered as completed, with an enrollment of 33. It concerns postmenopausal women with low bone mass compatible with osteopenia. The registry lists physical exercise as the intervention and describes a comparison group receiving no additional physical exercise, with usual recommendations for fracture prevention. Allocation is non-randomized, masking is none, and the model is sequential.

The exercise program is described as taking place at the C.U.R.I.A.Mo. Institute of the University of Perugia. It consisted of 24 sessions over three months, held twice a week and supervised by trainers and medical doctors. The registry’s official title describes weight-bearing and resistance exercise, while the brief research aim refers to a high-impact exercise program. These descriptions provide the broad intervention context, but do not establish the specific exercise dose or adherence of each participant.

The primary outcome is variation in mean serum P1NP from baseline to Week 4, reported in mcg/L with standard deviation as the dispersion measure. The registry also lists health-related quality of life as a secondary outcome and records 10 outcome measures and 10 analyses. The record does not identify the numerical result for the primary outcome or provide enough detail to reconstruct the analyses.

The non-randomized allocation is central to interpretation. Without random assignment, measured and unmeasured participant characteristics may differ between the exercise and comparison groups. The record does not report whether adjustment was made for such differences, how participants entered the sequential study, or whether the groups were enrolled or assessed in a way that could affect comparability. The protocol’s sample-size justification, interim analyses, detailed statistical plan, and handling of missing observations 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.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Post-menopausal women with low bone mass at dual energy X-ray absorptiometry (DEXA) measurement, compatible with osteopenia (T-score between -1 DS and -2.5 DS)

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.

6. Primary Endpoint

The registry lists the primary outcome as Variation in Serum Levels of Procollagen 1 N-terminal Peptide (P1NP), measured over Baseline - Week 4.

The primary endpoint is variation in serum levels of procollagen 1 N-terminal peptide, abbreviated P1NP, from baseline to Week 4. The registry specifies that the outcome is a mean measured in mcg/L, with standard deviation used to describe dispersion. It describes P1NP as the most reliable commercially available serum marker of bone formation at the time of the record.

A mean conveys the average measured value or change for the analyzed group. A standard deviation describes how spread out individual observations are around that mean; it is not the uncertainty in the estimated mean. General statistical explanation: a confidence interval, when reported, describes a range of values compatible with the data and analysis assumptions, and conveys estimation precision. No primary-outcome confidence interval, group mean, standard deviation, or numerical change is reported in the registry record, so the magnitude and precision of the endpoint cannot be assessed from that record.

P1NP is a biomarker endpoint, not a direct measure of fracture occurrence or quality of life. A change in a marker should be interpreted as a change in the measured marker, rather than as proof of a clinical benefit. The registry also does not report a numerical endpoint result that would permit assessment of the direction or size of any change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods determine how observed measurements are converted into estimates and how uncertainty is described. The registry record identifies the endpoint as a mean continuous measure with standard deviation, but does not report a detailed analysis plan or the numerical primary result. The concepts below explain how such methods are generally interpreted; they do not describe unreported procedures as having been used in this study.

What does a mean describe?

For a continuous outcome such as serum P1NP, a mean is an average across the observations included in an analysis. It can summarize a group’s measured values or the group’s average change, depending on the specific analysis. Here the outcome is described as variation from baseline to Week 4. The registry specifies the mean as the summary parameter, but does not clarify in the posted record exactly how individual variation was calculated or how baseline values were incorporated into the analysis.

A mean is useful for describing the center of a distribution, but it does not show every participant’s value or reveal the distribution’s shape. The standard deviation, also specified in the record, describes the spread of measurements around the mean. It should not be read as a confidence interval and does not, by itself, show how precisely the mean has been estimated. The primary result, including its mean and standard deviation, is not reported in the registry record.

What would a confidence interval add?

General statistical explanation: a confidence interval expresses uncertainty about an estimated quantity under the model and sampling assumptions used to construct it. A narrow interval indicates greater precision than a broad interval, but neither width nor location can be assessed without the interval itself. The registry record does not report a confidence interval for the primary endpoint. It also does not report a p-value for that endpoint, so statistical evidence against a specified null hypothesis cannot be evaluated from the record.

A p-value, when reported, is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of an effect. A p-value should be considered alongside an effect estimate and its uncertainty. In this case, the absent numerical result prevents that joint interpretation; no conclusion about statistical significance is supported by the registry record.

Why does allocation matter?

Random allocation can help balance both measured and unmeasured characteristics across study groups, on average. This study is explicitly non-randomized, and the registry notes that the arms are not a like-for-like control comparison. Observed group differences may therefore reflect the intervention, pre-existing differences, or other influences. Statistical adjustment can address some measured differences when suitable data and a suitable model are available, but it cannot automatically eliminate unmeasured confounding. Whether adjustment was performed and how it was specified are not reported in the registry record.

Masking is listed as none. In general, lack of masking can affect how outcomes are assessed or reported, especially when assessments involve judgment or participant reports. P1NP is a laboratory marker, but the record does not describe laboratory procedures, assessor masking, or other safeguards. It would be speculative to infer how these factors were managed.

How should the planning illustration be read?

The sample-size assumptions describe a planning illustration based on the observed effect, not the trial’s own design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is a stated fraction of the observed effect. For non-time-to-event outcomes, the illustration is expressed as participants per arm for a specified power. These are planning assumptions, not an analysis of the study’s observed power.

Such calculations ask what sample size might be needed under the chosen assumptions and target effect. They do not change the study’s observed enrollment, establish that the study was adequately powered, or show the probability that a result is true. The numerical planning outputs and observed effect are not reported in the registry record. The study’s own sample-size justification is also not reported there. General statistical explanation: sample-size planning depends on the target effect, variability, significance criterion, power target, and design assumptions; changing these assumptions changes the resulting planning estimate.

Why can over-dispersion matter?

General statistical explanation: over-dispersion occurs when outcome variability is greater than a model assumes. A model that underestimates variability can produce uncertainty estimates that are too small. The primary endpoint is continuous and summarized using a mean and standard deviation; the registry does not report a model or indicate that over-dispersion was assessed. The concept should not be taken as evidence that over-dispersion occurred in this study.

The record lists 10 outcome measures and 10 analyses. When multiple outcomes or analyses are examined, the chance of highlighting an apparently unusual result can increase if multiplicity is not addressed. The registry does not report a multiplicity adjustment or a prespecified hierarchy of outcomes. Without those details and the numerical results, it is not possible to judge how multiple testing affected interpretation.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures and 10 analyses. It identifies variation in P1NP as the primary outcome and variation in health-related quality of life as a secondary outcome. The health-related quality-of-life entry appears twice in the secondary-outcome list. The record does not clarify whether this duplication represents separate measures, repeated entries, or a clerical issue.

When an analysis considers multiple outcomes or multiple comparisons, some apparently notable results can arise by chance. General statistical explanation: a prespecified outcome hierarchy or a multiplicity adjustment can help control the interpretation of multiple tests. The registry record does not report a multiplicity strategy, a hierarchy beyond identifying the primary outcome, or which analyses were prespecified. It is therefore not possible to assess how multiple testing was handled.

The registry record does not report the number of participants with observed primary-outcome data, the number included in each analysis, or the extent and pattern of missing data. It does not describe an imputation method, a complete-case approach, or sensitivity analyses for missing observations. Those details are not reported in the registry record, so the potential effect of missingness on the result cannot be evaluated.

Analysis populations are also not described. The record does not state whether all enrolled participants were analyzed, whether inclusion depended on attending exercise sessions, or how participants who discontinued or deviated from the program were treated. No intention-to-treat or per-protocol analysis population is identified in the registry record. These omissions limit reproducibility and make it difficult to determine to whom any estimated result would apply.

The non-randomized allocation further heightens the importance of understanding group composition and analysis choices. The registry does not report baseline comparability or adjusted analyses. Without these details, neither multiplicity nor missing-data procedures can be used to resolve the more fundamental uncertainty about comparability between groups.

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’s adverse-event entry lists a combined group labelled “Control/Exercise Training.” It records 33 at risk for serious adverse events and 0 affected, with 0 deaths. For other adverse events, it records 33 at risk and 0 affected. These are the figures entered in the registry record, not a separate accounting for each study arm.

Because the safety group combines control and exercise training, the record does not show how many participants in each arm were at risk or whether events were recorded separately by arm. The zero affected counts therefore should not be interpreted as zero events in each group individually. The registry lists no top serious-event terms, but the entry does not provide a detailed narrative of event monitoring or follow-up.

General statistical explanation: a zero count in a recorded sample does not establish that the underlying risk is zero. The amount of information in a zero count depends on the population observed, follow-up, event definitions, and completeness of reporting. The record does not report enough detail about those features to quantify uncertainty around safety outcomes.

These figures concern recorded adverse events; they do not establish overall safety or explain whether less serious symptoms were actively collected. The registry record does not provide arm-specific event results or further detail on adverse-event ascertainment.

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

The record defines a study of exercise in postmenopausal women with low bone mass and identifies serum P1NP variation from baseline to Week 4 as the primary endpoint. It also describes a supervised exercise program and a comparison group receiving usual fracture-prevention recommendations without additional physical exercise. These registry entries establish the study’s broad question and structure, but not its primary result.

The numerical P1NP result is not reported in the registry record. There is therefore no reported estimate from which to describe the direction or magnitude of change, and no reported precision measure with which to judge uncertainty. The registry’s description of P1NP as a bone-formation marker does not substitute for an outcome estimate. Nor does the research aim establish that the marker changed.

Even a reported difference would need to be interpreted in light of the non-randomized allocation. Without random assignment, groups may differ in ways that affect the measured outcome. The record does not report baseline comparisons or adjustment methods that would help evaluate this possibility. Thus, the design does not support treating a potential group difference as an unambiguous causal effect of exercise.

The primary endpoint is a biomarker measured over the stated baseline-to-Week 4 timeframe. It is not itself a measure of fractures, broader clinical outcomes, or quality of life. The registry lists quality of life as a secondary outcome but provides no numerical secondary result in the registry record. Conclusions about those outcomes would therefore exceed the reported information.

The safety entry records zero serious adverse events and zero deaths in a combined control/exercise group. It cannot establish arm-specific event rates, and the record offers limited detail about event collection. The appropriate interpretation is narrow: the registry contains these recorded counts, while its design and reporting do not permit a broad conclusion about safety.

In short, the registry record documents a completed non-randomized study and its intended endpoint, but the posted information does not support a quantitative efficacy interpretation. Conclusions should remain limited to the design, measures, and safety counts that the record actually reports.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of why a clear endpoint does not by itself make a result interpretable. The registry specifies a continuous primary measure, its unit, summary parameter, dispersion measure, and timeframe. Those details help define what would need to be estimated. However, because the numerical primary result and its uncertainty are not reported in the registry record, readers cannot assess the observed change.

The non-randomized allocation is also important. A comparison between exercise and usual recommendations may be relevant to the study question, but without random allocation, differences between groups may have causes other than the intervention. A statistical analysis can describe associations or adjust for reported measured characteristics, but the record does not say whether such adjustment was done. This makes transparent reporting of group characteristics and analysis choices especially valuable.

The trial also illustrates the distinction between a biomarker and a clinical outcome. P1NP is identified as a bone-formation marker, while quality of life is listed as a secondary outcome. Those measures address different aspects of the research aim and should not be treated as interchangeable. Without numerical results, the registry cannot show how either outcome changed.

Finally, the safety entry demonstrates why context matters when reading zero counts. The adverse-event group combines control and exercise training, which prevents arm-specific interpretation. Clear reporting of who was observed, for how long, and in which group is necessary to understand event counts.

These statistical issues are not unique to exercise studies. They apply broadly to clinical research: outcome estimates need uncertainty measures, group comparisons need design context, and safety counts need clearly defined populations. The registry’s incomplete numerical results limit the inferences that can be drawn, regardless of the study’s research aim.

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 for interpretation is that the registry record does not report the numerical result for the primary endpoint. It therefore provides no mean change, standard deviation, confidence interval, or p-value for P1NP variation from baseline to Week 4. The direction, magnitude, and precision of the primary result cannot be assessed.

The non-randomized allocation limits causal interpretation. The record notes that the arms are not a like-for-like control comparison, but does not report baseline characteristics, group balance, or adjusted analyses. Whether measured differences were considered statistically is not reported in the registry record. Unmeasured differences cannot be ruled out from the information recorded.

Intervention information is also limited for evaluating exposure. The program is described as 24 supervised sessions over three months, held twice a week, but participant-level attendance, adherence, and completion are not reported in the registry record. The primary endpoint timeframe is baseline to Week 4, and the record does not explain how that measurement relates to the full program duration.

The record lists 10 outcome measures and 10 analyses but does not describe a multiplicity strategy or provide numerical results for the listed outcomes. It also does not report missing-data rates, analysis populations, or methods for handling missing observations. These omissions limit reproducibility and make it difficult to evaluate the robustness of any result.

For safety, the adverse-event entry combines control and exercise training, so results cannot be interpreted by arm. Event-collection procedures and follow-up details are not reported. The registry lists an enrollment of 33, but does not report the number analyzed for the primary endpoint. The study’s sample-size justification and detailed statistical plan are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of Physical Training on Bone Turnover and Quality of Life in Osteopenic Postmenopausal Women. — NCT03195517.
• Registry record last updated 2019-02-11; status last verified 2018-09.
• Results first posted 2019-02-11.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry describes a completed, non-randomized study of physical exercise in postmenopausal women with low bone mass compatible with osteopenia. Enrollment was 33. The exercise program involved 24 supervised sessions over three months, held twice a week; the comparison group received usual recommendations for fracture prevention and no additional physical exercise. Masking is listed as none, and the study model as sequential.

The primary outcome is mean variation in serum P1NP from baseline to Week 4, measured in mcg/L and described with standard deviation. Health-related quality of life is listed as a secondary outcome. The registry records 10 outcome measures and 10 analyses, but does not report a numerical primary result, detailed statistical plan, missing-data approach, or analysis populations.

The safety entry combines control and exercise training and records 0 serious adverse events, 0 other adverse events, and 0 deaths among the listed at-risk counts. The combined entry does not permit arm-specific interpretation.