A Direct-to-patient Intervention to Increase Rates of Osteoporosis Care: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Direct-to-patient Intervention to Increase Rates of Osteoporosis Care (NCT01907269), a randomized na study. The primary outcome is Number of Participants That Initiate an Osteoporosis Prescription Medication.

2. Clinical Question

The primary question concerns a participant-reported behavior, not a clinical event such as a fracture. The registry record describes a self-completed survey for assessing initiation of prescription osteoporosis medication. Its stated hypothesis is that intervention participants would receive more osteoporosis care, with prescription therapies among the outcomes of interest. The registry record does not report the number of participants in either arm who initiated medication, an effect estimate, or an uncertainty interval, so the direction and precision of the observed comparison cannot be assessed from the record.

The study also set out to assess reported use of calcium and vitamin D and reported receipt of bone mineral density testing. These outcomes reflect different aspects of care and should not be treated as interchangeable with prescription initiation. Whether the intervention changed any of these outcomes is not reported in the registry record.

3. Trial Design

This was a randomized, double-masked, parallel-group trial with a planned enrollment of 2684 participants. The registry lists the phase as NA and the study status as completed. The start date is 2013-08, and the primary completion date is 2015-10. The sponsor was the University of Alabama at Birmingham.

The intervention was behavioral and video-based. Its described content included personalized feedback about risk of subsequent fractures, customized osteoporosis-care information, and messages intended to promote engagement in care and doctor-patient communication. The registry description says content was tailored to barriers to care, age, and race or ethnicity. Usual care was the comparator, but its content is not described in the registry record.

The brief summary calls the study controlled and cluster-randomized, while the design fields identify randomized allocation and a parallel model. The cluster-randomized description matters for interpreting comparisons: outcomes from people in the same cluster may be related, so an analysis that treats every participant as statistically independent could give misleading uncertainty. The registry record does not report the cluster unit, number of clusters, allocation procedures, or the details of how clustering was accounted for in the sponsor’s analysis.

Masking is listed as double, but the registry record does not identify which groups of people were masked or explain how masking was maintained. The planned post-intervention assessment was at 6 months. The registry record identifies a primary outcome and secondary outcomes, but does not provide numerical results for them. It also does not report a statistical analysis entry or a detailed analysis plan.

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.

6 Month Outcome Measures Post-interventi

18 Month Outcome Measures Post-intervent

Analysis population for the primary outcome, as defined in the registry: For the Intent-to-Treat Analysis the data was imputed for non-responders.

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 Number of Participants That Initiate an Osteoporosis Prescription Medication, measured over 6 months post-intervention.

The primary endpoint is the number of participants who report initiating an osteoporosis prescription medication at 6 months post-intervention. It was assessed using a self-completed survey. The medication types named in the registry description are alendronate, calcitonin, denosumab, ibandronate, raloxifene, risedronate, teriparatide, and zoledronic acid. Initiation of estrogen hormone therapies was not included in the primary outcome definition.

This endpoint focuses on whether participants reported starting prescription osteoporosis treatment during the relevant assessment period. A participant count can communicate the frequency of the reported behavior in each arm, while a comparative effect estimate would describe how those frequencies differ between assigned groups. The registry record does not report the arm-specific counts or a comparative estimate, so the size and precision of any difference cannot be described.

Self-report allows the outcome to capture participants’ reported treatment initiation through a survey, but it is not the same measurement as confirmation from prescribing or medical records. The registry record does not describe validation procedures or provide further detail about how initiation was defined in the survey. For the stated intent-to-treat analysis, data were imputed for non-responders; the imputation method and its assumptions are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial’s design and endpoint define what a statistical comparison would need to address. The study was randomized, parallel-group, and described as cluster-randomized. Its primary endpoint is a participant count based on reported initiation of prescription osteoporosis medication at 6 months post-intervention. The registry record does not report the numerical comparison or a detailed statistical plan, so the discussion below explains general statistical principles rather than asserting which procedures the investigators used.

What does randomization contribute?

In general, random assignment helps create groups that can be compared without choosing treatment according to participants’ expected outcomes. Randomization does not guarantee that every characteristic is balanced in a particular trial, and it does not replace a suitable analysis. The registry record identifies randomized allocation but does not report the sequence-generation method, concealment procedures, or details of implementation.

The parallel-group design means the assigned groups are compared over the same general follow-up period rather than in a crossover sequence. The registry record lists double masking, but does not say who was masked. Masking can reduce the potential for expectations to influence care, reporting, or outcome assessment, depending on who is masked and how the endpoint is measured. The self-completed survey outcome makes the details of survey administration and masking potentially relevant, but those details are not reported.

Why does cluster randomization matter?

In general, cluster randomization assigns groups of people, rather than treating each person as an independently randomized unit. People within a cluster can share providers, settings, or other influences, and their outcomes may be more alike than outcomes from people in different clusters. This within-cluster association is called correlation. If an analysis ignores it, the apparent amount of independent information can be overstated and uncertainty can be understated.

Methods for cluster-randomized studies account for the grouping when estimating effects and uncertainty. The appropriate method depends on the design and available data. The registry record does not report the cluster unit, cluster count, within-cluster correlation, or the sponsor’s specific model and adjustments. It explicitly cautions that a simple individual-level re-analysis would be misleading, so independent individual-level re-calculation is not appropriate for interpreting this study. The sponsor’s own analysis takes precedence for the cluster design, but its numerical results are not reported in the registry record.

What does the primary endpoint represent?

The primary endpoint is a count of participants who self-report initiating a specified osteoporosis prescription medication. In general, this kind of binary participant-level outcome can be summarized as the number meeting the outcome and the number assessed in each group, or compared using an effect measure suited to binary data. The choice of measure affects how the comparison is expressed. No effect measure or numerical estimate is reported in the registry record, so none can be interpreted for this trial.

Self-report measures what participants say occurred, rather than independently verified treatment records. In general, reporting may be affected by recall or understanding of the question. That is a measurement consideration, not evidence that the reports in this study were inaccurate. The registry record does not report validation or verification procedures.

How should uncertainty be understood?

In general, a confidence interval describes a range of effect estimates compatible with the data under the specified statistical model and its assumptions. A narrow interval indicates greater precision than a wide interval; it does not by itself establish clinical importance. A p-value, when reported, describes how unusual data at least as incompatible with a null hypothesis would be under that hypothesis and the analysis assumptions. Neither quantity is reported for the primary outcome in the registry record. The effect’s direction, magnitude, and precision therefore cannot be judged.

The registry record includes a sample-size planning illustration based on a stated fraction of the observed effect, a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It says that non-time-to-event illustrations are expressed as participants per arm. These assumptions describe planning calculations, not observed trial results or observed power. The actual calculated planning values are not reported in the registry record presented for interpretation, and no new sample-size calculation is appropriate without the necessary effect information. The registry record does not report the trial’s original design assumptions or sample-size justification.

What can be inferred from missing results?

Statistical interpretation requires estimates and uncertainty, not just a study question and an outcome definition. The record reports no analysis entries and no numerical primary or secondary results. It is therefore not possible to judge whether the data are compatible with a range of potentially important effects, whether an estimate is precise, or whether the intervention and comparator differ according to the sponsor’s analysis.

The planned comparison also involves more than one care outcome. In general, evaluating multiple outcomes can increase the chance of at least one apparently notable finding when many tests are conducted. Prespecified outcome hierarchies or adjustment procedures can address some multiplicity concerns, but the registry record does not report a multiplicity strategy. Without analysis results and the full statistical plan, multiplicity cannot be evaluated for this trial.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Video-based Intervention", "Usual Care")
n      <- c(1342, 1342)
events <- c(157, 153)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Video-based Intervention  1342  157  11.7  10.0  13.5  10.1  13.5  10.1  13.5
ARM  Usual Care  1342  153  11.4  9.7  13.2  9.8  13.2  9.8  13.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists five outcome measures overall. It identifies initiation of an osteoporosis prescription medication as the primary outcome and names reported calcium and vitamin D use, reported receipt of bone mineral density testing, and initiation of an osteoporosis prescription medication among the secondary outcomes. The details of every outcome measure are not reported in the registry record. The brief summary also states hypotheses about prescription therapies, calcium and vitamin D, and bone mineral density testing.

When several outcomes are examined, general statistical practice distinguishes a primary outcome from additional outcomes and considers whether the analysis plan controls or otherwise addresses multiplicity. Testing multiple outcomes can make isolated findings harder to interpret. The registry record does not report a multiplicity adjustment, testing hierarchy, or other strategy for handling multiple comparisons. No numerical outcome results are reported, so the practical effect of multiplicity on the findings cannot be assessed.

The intent-to-treat description states that data were imputed for non-responders. The registry record does not report the imputation method, assumptions, amount or pattern of missing data, or whether the same approach applied to each outcome. It also does not report whether sensitivity analyses were conducted. These omissions limit assessment of the robustness of the primary comparison to missing survey responses.

The record does not describe the analysis population in detail beyond its reference to an intent-to-treat analysis. It does not report participant flow, exclusions, adherence, or the number of participants contributing data to each outcome. The cluster-randomized design requires analysis that accounts for clustering, but the particular sponsor analysis and its handling of missing data are not described. These statistical-plan details are not reported in the registry record.

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

The registry record establishes that investigators planned a randomized trial of a tailored video-based intervention compared with usual care, with the goal of increasing osteoporosis care. It identifies participant-reported initiation of prescription osteoporosis medication at 6 months post-intervention as the primary outcome and describes a survey-based assessment. It also identifies reported calcium and vitamin D use and reported bone mineral density testing as care outcomes.

Those design details do not establish what happened to participants after assignment. The registry record does not report arm-specific counts, an estimated difference, a confidence interval, or a p-value for the primary outcome. It also does not report numerical results for the secondary outcomes. Consequently, the record cannot establish whether the intervention arm had more or fewer reported initiations than usual care, or how precisely any comparison was estimated.

Not reporting an effect estimate is different from reporting an estimate near no difference. It is also different from showing that the groups are equivalent. Equivalence requires an appropriate design and analysis with a prespecified margin and sufficiently precise results; these are not reported in the registry record. Similarly, no claim about statistical significance or clinical importance can be made from the outcome definitions alone.

The primary outcome is self-reported initiation, not independently verified prescription use, fracture occurrence, or a direct measure of bone health. The registry record does not report whether self-reports were checked against medical or pharmacy records. The endpoint therefore describes the intended measurement, while its accuracy and the relationship to other clinical outcomes are not established by the available record.

The record’s mention of imputation for non-responders indicates that missing responses were addressed in the stated intent-to-treat analysis, but it does not disclose how. Its cluster-randomized design also means that the analysis must account for grouping. Since sponsor estimates and relevant methodological details are not reported, neither the effect nor the uncertainty can be interpreted. The available information supports a description of the research question and planned measurements, not a conclusion about treatment benefit or lack of benefit.

13. Why This Trial Matters Statistically

This trial raises several statistical issues that are especially relevant to behavioral interventions and care outcomes. First, the intervention was designed to influence engagement, communication, and care-seeking. The primary endpoint translates that aim into a measurable outcome: self-reported initiation of prescription osteoporosis medication at 6 months post-intervention. Clear outcome timing and definition are important because an intervention can affect behaviors at different stages of care, and those stages should not be conflated.

Second, the study is described as cluster-randomized. That design can be useful when an intervention or its delivery is organized around groups, but it changes how evidence should be analyzed. Outcomes within clusters may be correlated, and valid uncertainty estimates must account for the randomization structure. The registry record itself warns that a simple individual-level re-analysis would be misleading. That is an important reminder that a participant count alone does not identify the amount of independent information in a cluster trial.

Third, the endpoints are reported care behaviors rather than clinical outcomes such as subsequent fractures. This can make the analysis relevant to whether participants engage with care, while leaving distinct questions about verified treatment use and health outcomes unanswered. The registry record describes a survey-based primary measure, so the interpretation depends on what that measure captures.

Finally, the record illustrates why study design information is not a substitute for results. It gives the research question, intervention description, follow-up timing, and missing-data note, but does not report effect estimates or uncertainty. Without those results, readers cannot evaluate the magnitude or precision of a comparison. Complete reporting of cluster-aware estimates, outcome counts, missingness, and analysis methods is central to statistical interpretation.

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 most immediate limitation for interpreting this trial is that numerical primary and secondary outcome results are not reported in the registry record. Arm-specific counts, comparative effect estimates, confidence intervals, and p-values are absent. This prevents assessment of the direction, magnitude, precision, and statistical uncertainty of the comparisons.

The intervention description is informative about its intended components, but the registry record does not report implementation or adherence details. Usual care is not described in detail. The record also does not report participant eligibility criteria, baseline characteristics, recruitment details, or participant flow. These omissions limit assessment of the populations and care settings to which any findings might apply.

The study is described as cluster-randomized, but the cluster unit, number of clusters, and analysis method are not reported. Those details are important for assessing whether the statistical analysis reflected the allocation design. The record says that non-responders’ data were imputed for the intent-to-treat analysis, but it does not report the method, missingness pattern, or sensitivity analyses.

The primary endpoint relies on a self-completed survey. The registry record does not report validation against medical or pharmacy records, survey completion rates, or further operational details about determining medication initiation. It also lists double masking without identifying who was masked or how masking was maintained.

Finally, the registry record does not report the original sample-size justification, a detailed statistical analysis plan, or how multiple outcomes were handled. These specific gaps restrict appraisal of the methods and robustness of the analysis. They should not be mistaken for evidence that the study was conducted improperly; the relevant details are simply not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Direct-to-patient Intervention to Increase Rates of Osteoporosis Care — NCT01907269.
• Registry record last updated 2018-06-26; status last verified 2018-05.
• Results first posted 2018-06-26.
• 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

NCT01907269 is a completed randomized, double-masked, parallel-group study sponsored by the University of Alabama at Birmingham. The registry lists a planned enrollment of 2684, a start date of 2013-08, and a primary completion date of 2015-10. The phase is listed as NA.

The trial compared a tailored video-based behavioral intervention with usual care. The intervention included personalized fracture-risk feedback, customized osteoporosis-care information, and messages intended to encourage engagement in treatment and doctor-patient communication. The study is described as cluster-randomized.

The primary outcome was the number of participants reporting initiation of an osteoporosis prescription medication at 6 months post-intervention, assessed by self-completed survey. The registry states that non-responder data were imputed for the intent-to-treat analysis. Secondary outcomes include reported calcium and vitamin D use and reported bone mineral density testing.

Numerical outcome results, sponsor effect estimates, and detailed analysis methods are not reported in the registry record. Therefore, the record supports description of the trial question and design, but not a conclusion about the observed intervention effect.