Implementation of Women's Health Patient Aligned Care Teams: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Implementation of Women's Health Patient Aligned Care Teams (NCT02039856), a randomized na study. The primary outcome is WH-PACT Achievement.

2. Clinical Question

The study asked whether an evidence-based quality improvement approach could support implementation of women’s health Patient Aligned Care Teams and improve reported achievement of the model. The comparison was between EBQI-supported WH-PACT implementation and routine WH-PACT implementation. The primary outcome concerned patient-reported access, communication, comprehensiveness, and gender-appropriateness of care over the period from baseline to 24-month.

The clinical and implementation context was the VA’s broader effort to use Patient Aligned Care Teams, based on the patient-centered medical home concept. The registry describes the intended approach as adapting team-based care to women Veterans, with comprehensive women’s health care in gender-sensitive care environments. The study therefore evaluates an implementation strategy, not a drug or other stand-alone clinical treatment.

The registry’s primary result is an odds ratio of 0.913, with a 95% confidence interval from 0.627 to 1.33 and p = 0.637. The estimate does not establish a clear difference between the approaches. Because the group ordering and the exact way the aggregate score was represented for the odds analysis are not reported in the registry record, the estimate should not be interpreted as a simple directional measure of better or worse achievement for one arm.

3. Trial Design

This was a randomized, parallel-group implementation study with no masking. The registry reports enrollment of 3900 and identifies the sponsor as the VA Office of Research and Development. The record lists the study status as completed, with a start date of 2014-05-09 and primary completion date of 2017-09-30. The phase is recorded as NA.

The study compared EBQI-supported WH-PACT implementation with routine WH-PACT implementation. The EBQI arm description characterizes the approach as a structured research-clinical partnership for facilitating implementation of new care models. The listed implementation activities include multilevel stakeholder engagement, quality improvement education and training, technical support, formative feedback, and external practice facilitation. National policy guidance is listed as the routine implementation approach. The registry does not report enough detail to reconstruct how each component was delivered, how often support occurred, or how local implementation varied.

The design is cluster-randomized. That feature matters because the assignment unit is a cluster rather than an individual patient: outcomes for people within the same cluster may be related. The registry record does not report the number of clusters, their sizes, or the allocation procedures in enough detail to describe them further. A simple analysis that treats every patient as independently randomized would not respect the design. The posted result is therefore presented using the sponsor’s own analysis rather than an individual-level re-analysis.

The primary outcome timeframe is described as baseline to 24-month. The primary analysis included patients who completed the 24-month survey, with one EBQI-arm patient excluded because outcome data were missing. The registry also lists provider and staff gender sensitivity, team functioning, provider and staff burnout, primary care and women’s health visits, hospitalization, and emergency room visits among secondary outcomes. The record does not provide enough detail to describe their measures or findings.

Although enrollment is listed as 3900, that figure should not be taken as the primary analysis denominator. The registry specifies a survey-completer analysis population, but does not report the total number of primary-outcome observations in the information. A protocol, detailed statistical plan, sample-size justification, interim analysis plan, and fuller description of cluster allocation 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The analysis included the patients who had completed the 24-month survey. One patient in the EBQI arm had missing data for outcome measure and was excluded from the analysis.

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 WH-PACT Achievement, measured over Baseline to 24-month.

WH-PACT achievement is described as an aggregate score based on four patient-reported domains: access to care, patient-provider communication, comprehensiveness of care, and gender-appropriateness of care. The registry gives the score range as -4 to +4 and states that a higher score means better PACT achievement. The intended timeframe is baseline to 24-month.

Using a combined endpoint can summarize several related aspects of care in one outcome. Here, the domains reflect whether patients experienced care as accessible, communicative, comprehensive, and appropriate to women’s health needs. In general, an aggregate measure can make a broad implementation goal easier to summarize, but it may also conceal differences among its component domains. A single overall result does not show whether any one domain changed differently from the others.

The registry describes the endpoint as an aggregate score, while the posted primary analysis reports an odds ratio. The record does not explain how the score was represented for that odds-based analysis, including whether or how it was categorized. That missing detail limits interpretation: readers cannot tell from the registry alone what precise event or threshold the odds refer to. The population is also restricted to patients completing the 24-month survey, rather than all enrolled participants. These endpoint and population details are important when interpreting the estimate, and they do not support treating the odds ratio as a direct summary of a change in the average score.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The sponsor reports a difference-in-differences analysis. In general, this method compares how an outcome changes over time in one group with how it changes over time in another group. Its purpose is to separate a change associated with the intervention group from changes that may also occur in the comparison group over the same period. The primary timeframe is baseline to 24-month, but the registry does not report the detailed model specification or all of its assumptions.

What does difference-in-differences mean?

The method is intended to focus on changes, not just the outcome levels observed at the end of follow-up. A comparison of changes can account for shared time-related influences if the groups would otherwise have followed sufficiently similar trends. In general, that interpretation depends on assumptions about how outcomes would have evolved without the implementation approach. The registry record does not describe an assessment of those assumptions, the exact time points used in the model, or whether additional covariates were included. Those details should not be guessed.

The design is cluster-randomized, so patients within the same cluster may have correlated outcomes. In general, statistical methods for cluster-randomized studies need to account for this dependence. Treating every patient as an independent randomized unit can make uncertainty appear smaller than it should be. The posted analysis is the sponsor’s own cluster-aware analysis; a simple individual-level re-analysis would be misleading. The registry does not report cluster counts, cluster sizes, or the specific method used to account for clustering.

How should the odds ratio be read?

An odds ratio compares odds between groups or conditions. In general, its no-difference reference value represents equal odds, while values on either side indicate different relative odds depending on which group is placed in the numerator. The reported estimate is 0.913, with a 95% confidence interval from 0.627 to 1.33. Because the registry does not state the group ordering, the estimate cannot be assigned a direction in favor of either implementation approach from the record alone.

There is a further measurement issue: WH-PACT achievement is described as an aggregate score from -4 to +4, with higher values meaning better achievement, but the reported analysis uses an odds ratio. An odds ratio ordinarily concerns a binary outcome or a specified contrast. The registry record does not say how the aggregate score was converted into the outcome used in the model, what threshold might have been used, or what event was counted. Consequently, the odds ratio cannot be translated into a difference in score points, and the clinical or operational meaning of the modeled event is unclear.

What does the confidence interval contribute?

A confidence interval communicates the uncertainty around an estimate under the fitted model. It is more informative than a point estimate alone because it indicates the range of values reasonably compatible with the analysis. Here, the interval crosses the no-difference reference, which aligns with the reported p-value of 0.637: the analysis does not distinguish the observed estimate from no difference using the usual null-hypothesis framework. The interval also permits effects in either direction, so the result should be described as inconclusive rather than as proof of no effect.

In general, a p-value measures how unusual data at least as incompatible with a specified null model would be if that model and its assumptions held. It is not the probability that the null is true, and it does not measure the size or practical importance of an effect. The registry does not report a prespecified threshold for meaningful change in WH-PACT achievement, so statistical evidence and practical importance cannot be linked through a stated criterion.

Why can’t the posted summary be recalculated simply?

Summary-level recalculations that treat individuals as independently randomized would not retain the cluster structure. The registry specifically indicates that such an individual-level re-analysis would be misleading, and the posted result is therefore the sponsor’s own analysis. Reproducing that result would require the cluster structure and the model details, which are not reported. No independent re-calculated estimate should be substituted for the sponsor’s analysis.

The accompanying plots, tables, and planning section should be read as distinct from observed trial findings. General planning illustrations show how sample size requirements can depend on assumptions about effect size, allocation, and statistical thresholds. The stated planning assumptions use a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect specified as a fraction of the observed effect; these are illustrative calculations, not the trial’s own design justification and not observed power. The registry does not report its own sample-size justification.

10. Analyses Reported by the Sponsor

The posted estimate is the sponsor’s own difference-in-differences analysis: odds ratio 0.913, 95% confidence interval 0.627 to 1.33, and p = 0.637. The study is cluster-randomized, and a simple re-analysis based on individual-level summary information would fail to represent the dependence among participants in the same cluster. For that reason, the sponsor’s analysis takes precedence over any such simplified recalculation.

No independent re-calculated result should be used to challenge or replace the reported estimate. Reproducing the sponsor’s analysis would require its cluster-aware model and supporting design information, which are not reported in the registry record. This is not a claim that the sponsor’s model has been independently verified; it is a recognition that the posted result is the analysis appropriate to report from the available information.

The remaining interpretive limits still apply to the sponsor analysis. The registry does not identify which group is the numerator or reference in the odds ratio, or explain how the WH-PACT aggregate score was expressed as an odds-based outcome. The reported confidence interval includes the no-difference reference, and the p-value does not establish a difference. The result should therefore be read as the sponsor’s cluster-aware estimate, with direction and outcome coding left unclear in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 outcome measures and 8 analyses. The primary endpoint is WH-PACT achievement; listed secondary outcomes include provider and staff gender sensitivity, team functioning, provider and staff burnout, primary care and women’s health care visits, hospitalization, and emergency room visits. The record gives a detailed estimate for the primary analysis, but does not provide corresponding results for the listed secondary outcomes.

When a study examines multiple outcomes, the chance of at least one apparently unusual result can increase if each is tested separately without accounting for the collection of tests. In general, multiplicity procedures can control that risk, but they may also affect the interpretation and precision of individual comparisons. Whether the analyses were adjusted for multiplicity, which outcomes were prespecified as primary or secondary in the full protocol, and how the analyses were organized are not reported in the registry record. The p-value for the primary analysis should therefore be read as the reported result, without assuming a particular multiplicity adjustment.

The registry says the primary analysis included patients who completed the 24-month survey and that one patient in the EBQI arm had missing outcome data and was excluded. It does not report the total number of patients with completed surveys, the number missing in the routine arm, the reasons for other missing data, or whether any imputation or sensitivity analysis was used. Those details are relevant because restricting analysis to survey completers may affect how well the analyzed group represents all enrolled participants.

The record also does not describe whether the primary analysis followed an intention-to-treat principle, how participants who did not complete follow-up were handled beyond the stated exclusion, or how missing information in the component measures was addressed. The enrollment figure of 3900 is not a substitute for the primary outcome denominator. Without fuller population and missing-data reporting, readers cannot assess the extent to which missingness may have influenced the primary estimate.

12. 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 summary reports zero serious events and zero other events among 2720 participants at risk in the EBQI-supported WH-PACT implementation group. In the routine WH-PACT implementation group, it reports zero serious events and zero other events among 1180 participants at risk. The summary also lists 5 deaths in the EBQI group and 3 deaths in the routine group.

These are counts in the registry record, not rates adjusted for follow-up time or differences between groups. No rate comparison should be inferred from the counts alone. The registry does not provide causes of death, timing, relatedness to the implementation approach, or additional narrative on these deaths. It also does not list serious adverse-event terms in the summary.

Because this is an implementation study, these figures should be read as the adverse-event information recorded for the study rather than as evidence about the safety of a clinical treatment. Zero recorded events does not establish that no events occurred outside the reporting definitions or observation process. The record does not give further detail on how adverse events were collected or classified. The counts are useful for describing what was posted, but they do not support causal conclusions.

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

The primary result does not demonstrate a clear difference in WH-PACT achievement between EBQI-supported implementation and routine implementation. The sponsor’s analysis reports an odds ratio of 0.913, with a 95% confidence interval from 0.627 to 1.33 and p = 0.637. The interval includes the no-difference reference, so the result is statistically inconclusive under the reported analysis.

That conclusion is narrower than saying the approaches are the same. Failure to distinguish the estimate from no difference does not establish equivalence, and the registry does not report an equivalence margin or a non-inferiority analysis. The confidence interval allows uncertainty in either direction. Nor does the result establish that the EBQI approach failed as an implementation strategy: the registry result is a comparison for a particular patient-reported endpoint and analysis population, not a complete evaluation of every process or secondary outcome.

The endpoint captures patient reports on access, communication, comprehensiveness, and gender-appropriateness, summarized as an aggregate score with higher values indicating better achievement. However, the reported odds ratio is not explained in relation to that score. Without the modeled outcome definition and group ordering, readers cannot convert the result into a meaningful score difference or confidently state which arm had higher odds of the modeled event.

The conclusion also applies to patients who completed the 24-month survey, not necessarily all enrolled participants. The registry notes one excluded EBQI-arm patient with missing outcome data, but does not fully describe the analysis denominator or other missing-data handling. Cluster randomization further means that the result depends on an analysis that accounts for grouping; an individual-level re-analysis is not an appropriate substitute.

In practical terms, the posted analysis gives an estimate and its uncertainty, but does not resolve whether the implementation approaches differed in the intended patient experience. It also does not establish how consistently the EBQI activities were delivered, what happened on each secondary outcome, or whether changes in particular care domains drove the aggregate result. Those questions require information that is not reported in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically informative because it evaluates an implementation strategy rather than a conventional drug-versus-control treatment. The intervention is a package of support activities intended to facilitate adaptation of WH-PACT care for women Veterans. That makes it important to distinguish the effect of an implementation approach from the effect of a clinical treatment itself.

The cluster-randomized design is also central to interpreting the evidence. When assignment occurs by cluster, outcomes among people in the same cluster may be more alike than outcomes among people in different clusters. Statistical analysis needs to respect that structure. The registry’s warning against a simple individual-level re-analysis illustrates a general principle: the design determines what forms of summary analysis are valid.

The primary outcome combines several patient-reported dimensions of care. This can make a broad implementation goal visible in a single endpoint, but the aggregate may hide different patterns across its component domains. The result is especially difficult to interpret because the registry describes a bounded score but reports an odds ratio without explaining the event definition or score transformation. Clear reporting of these links would help readers understand what the estimate represents.

The result also demonstrates why an estimate should be read alongside its uncertainty. A point estimate alone can appear decisive, while the confidence interval and p-value show that the posted analysis does not distinguish the result from no difference. At the same time, an inconclusive result is not proof that the approaches are identical. That distinction is important when assessing implementation research, where conclusions can depend on outcome definitions, cluster structures, survey completion, and delivery of the intervention package.

Finally, the record highlights the value of complete statistical reporting: cluster details, analysis populations, missing-data handling, multiplicity procedures, and the relationship between an outcome scale and the fitted model are all relevant to evaluating the result. The registry provides a useful high-level account, but leaves these interpretive elements unresolved.

15. 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 does not report the number of randomized clusters, cluster sizes, allocation procedures in detail, or the specific method used to account for clustering. These omissions limit readers’ ability to assess the design and reproduce the primary analysis. The sponsor’s own cluster-aware result is the appropriate posted estimate to discuss; an individual-level recalculation would not preserve the design.

The primary outcome is described as an aggregate score from -4 to +4, but the result is an odds ratio. The registry does not explain the modeled event, any threshold or categorization, or how the score entered the analysis. It also does not identify which implementation group is the numerator or reference. As a result, the reported estimate cannot be translated into a score difference or assigned a clear direction for the comparison.

The population is described as patients completing the 24-month survey, with one EBQI-arm patient excluded for missing outcome data. The registry does not report the analysis denominator, survey completion by arm, reasons for missingness, or imputation and sensitivity analyses. The enrollment figure alone cannot establish how representative the analyzed participants were of all enrolled participants.

The record lists 8 outcome measures and 8 analyses but does not report multiplicity procedures, the full prespecified analysis plan, or detailed results for the secondary outcomes in the material. A sample-size justification, interim analysis plan, and detailed model specification are also not reported in the registry record. The delivery, uptake, and consistency of the implementation components are not described sufficiently to assess how the intended package was enacted across clusters.

These limitations constrain interpretation of the posted result. They do not demonstrate that the analysis is invalid; rather, they identify what cannot be checked or concluded from the registry record alone.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Implementation of Women's Health Patient Aligned Care Teams — NCT02039856.
• Registry record last updated 2023-06-18; status last verified 2023-06.
• Results first posted 2019-08-21.
• 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.

19. Record Summary

NCT02039856 is a completed randomized, parallel, unmasked, cluster-randomized study sponsored by the VA Office of Research and Development. The record lists enrollment of 3900, a start date of 2014-05-09, and a primary completion date of 2017-09-30. It compares EBQI-supported WH-PACT implementation with routine WH-PACT implementation.

The primary outcome, WH-PACT achievement, is based on patient reports of access, communication, comprehensiveness, and gender-appropriateness of care. The analysis population consisted of patients completing the 24-month survey; one EBQI-arm patient with missing outcome data was excluded. The sponsor reports a difference-in-differences odds ratio of 0.913, with a 95% confidence interval from 0.627 to 1.33 and p = 0.637.

The interval includes the no-difference reference, and the result does not establish a difference between approaches. Interpretation is limited by unreported odds-ratio group ordering and the unexplained relationship between the aggregate score and the odds-based outcome. Cluster-level details, fuller missing-data information, and the detailed statistical plan are not reported in the registry record.