Communication Strategy to PROMOTE HPV Vaccination in Pharmacies: PROMOTE Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Communication Strategy to PROMOTE HPV Vaccination in Pharmacies: PROMOTE Study (NCT04660331), a non-randomized na study. The primary outcome is Acceptability of Providing HPV Vaccination to Children and of the Proposed Communication Strategy to Support HPV Vaccination.

2. Clinical Question

3. Trial Design

PROMOTE is a completed pilot study of a pharmacy multimodal communication strategy to promote HPV vaccination. The registry record lists an enrollment of 42 and a nonrandomized, parallel design with no masking. The phase is listed as NA. The study sponsor is Fred Hutchinson Cancer Center. The recorded study start was 2021-02-01, and primary completion was 2023-07-31.

The record describes two aims. Aim I involved a semi-structured interview, in person or by phone, lasting 90 minutes and focused on barriers and facilitators to HPV vaccination in pharmacies. Aim 2 included cognitive testing of survey questions, an online survey for pharmacy staff about the acceptability, appropriateness, and feasibility of providing HPV vaccination to children aged 9-17, and training and communication intervention activities. The description of Aim 2 is incomplete in the registry record, so its full sequence and content are not reported there.

The primary measure was assessed only among Aim 2 participants who completed all required Aim 2 protocol activities. This eligibility rule matters when interpreting the measured group: the primary outcome does not represent every enrolled participant by definition. The registry record does not report how many participants completed the required activities or contributed outcome data.

Because allocation was nonrandomized and the aims involved different activities, the record does not establish a like-for-like control comparison. The findings, if reported, would need to be interpreted in light of that design and the selected population contributing to the primary measure. Specific recruitment procedures, the number of pharmacies, and the analysis plan 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.

PROMOTE Key Informant Interviews (Aim 1)

PROMOTE Intervention (Aim 2)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: This outcome measure was only assessed for Aim 2 participants. Only Aim 2 participants who completed all required Aim 2 protocol activities were assessed for this measure.

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: Participants in the two Aim 1 arms are English-speaking pharmacy staff and parents or guardians of children aged 9-17. Participants in the Aim 2 arm are English-speaking pharmacy staff at enrolled sites participating in a remote, 1-part communication strategy intervention. There is no participant overlap between the groups.

6. Primary Endpoint

The registry lists the primary outcome as Acceptability of Providing HPV Vaccination to Children and of the Proposed Communication Strategy to Support HPV Vaccination, measured over Up to 6 months after baseline survey and communication training.

The primary endpoint is acceptability of providing HPV vaccination to children and of the proposed communication strategy to support HPV vaccination. It uses a survey developed by study researchers based upon the Implementation Outcomes Questionnaire. Survey responses use five ordered answer options scored from 1 to 5, with 1 indicating strongly disagree and 5 indicating strongly agree. Higher numerical scores indicate greater agreement that the intervention was acceptable for supporting HPV vaccination delivery to children aged 9-17. Scores for questions phrased in the reverse direction were reversed before the average scale was calculated.

This endpoint addresses perceptions about implementation, not vaccination uptake itself. It is relevant to a study testing communication and pharmacy practices because a strategy’s perceived acceptability can inform whether staff consider it suitable for use. The registry describes the measure as capturing change in participants’ perceptions pre/post training, with assessment up to 6 months after the baseline survey and communication training. It does not report the actual scale scores, the change estimate, or its precision. Consequently, the endpoint’s definition and intended interpretation are available, but the observed result is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the mean represent?

The registry defines the primary outcome as an average scale score calculated from numerical responses. Each survey question has five ordered response options, scored from 1 to 5. A mean condenses responses into a group-level summary, which can be useful for tracking average perceptions across an assessment period. It also hides some detail: participants with different response patterns can contribute to the same average. The registry record does not report item-level distributions or the number of completed surveys.

How should the scale be read?

Higher scores represent greater agreement that the intervention was acceptable to support HPV vaccination delivery to children aged 9-17. Reverse-worded questions were recoded in the opposite direction so that scores followed the stated interpretation. General statistical explanation: consistent scoring direction helps make an overall scale easier to interpret, but it does not by itself establish the scale’s reliability, validity, or sensitivity to change. Those properties are not reported in the registry record. The measure was developed by study researchers based upon the Implementation Outcomes Questionnaire.

What would a pre/post comparison describe?

The registry says the survey was used to capture change in participants’ perceptions before and after training. In general, a pre/post analysis compares measurements from the same participants across time when paired observations are available. The resulting estimate describes average within-person change, or another specified summary of change, depending on the method. The registry record does not report the statistical procedure used, whether the analysis treated observations as paired, or how incomplete pairs were handled. It also does not report a primary outcome estimate, so the scale’s observed change cannot be interpreted.

What does a standard deviation add?

The primary measure is specified as a mean with a standard deviation. General statistical explanation: the standard deviation describes the spread of participant scores around the mean. It is not the same as the uncertainty in the estimated mean. A confidence interval, when reported, would communicate uncertainty about the estimate under the analysis assumptions. Neither the outcome standard deviation nor a confidence interval is reported in the registry record. No conclusion about the precision of the primary estimate can therefore be drawn.

Why does the design matter?

The registry lists a nonrandomized, parallel design with no masking, and the record does not describe a like-for-like control comparison. General statistical explanation: random allocation can help balance measured and unmeasured characteristics between comparison groups, while masking can limit some forms of influence on measurement or assessment. Their absence does not make descriptive results unusable, but it limits causal interpretation. A change observed after training would not, on its own, distinguish the effect of the communication strategy from other changes over time or study participation.

What do the planning assumptions mean?

The sample-size planning illustration is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It uses an effect defined as a stated fraction of the observed effect. These are planning assumptions, not a description of the trial’s own design or a report of trial results. The registry record does not report the effect value used, the resulting participant counts, or the particular fractions represented. Such illustrations indicate planning requirements under assumptions; they are not observed power and do not show that the study had a particular probability of detecting an effect.

General statistical explanation: normal approximations simplify calculations by using an approximate sampling distribution. Their suitability depends on the data and analysis conditions. The registry record does not report diagnostic checks or a detailed justification for the approximation. Equal allocation in a planning exercise should also not be mistaken for evidence that the enrolled participants were randomized or actually allocated equally.

What remains unspecified?

The registry lists six outcome measures and three analyses, but does not report the analysis methods or numerical results for the primary measure. The analysis model, treatment of repeated responses, any adjustment for baseline scores, and methods for handling missing data are not reported in the registry record. There is also no reported interval estimate or p-value for the primary outcome. Without these details, it is not possible to reconstruct or evaluate the inferential analysis from the registry information alone.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("PROMOTE Intervention (Aim 2)")
n   <- c(13)
m   <- c(4.1)
sp  <- c(0.664)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  PROMOTE Intervention (Aim 2)  13  4.100  0.664  3.699  4.501

11. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures and three analyses. It does not report whether the primary outcome was tested alongside other outcomes in a shared inferential framework, whether any multiplicity adjustment was planned, or how the three analyses relate to the outcomes. A multiplicity procedure is not reported in the registry record.

General statistical explanation: when several hypotheses are tested, the chance of at least one apparently notable result can increase if each test is treated independently at the same threshold. An adjustment can address that issue, but the appropriate approach depends on which outcomes and analyses are considered confirmatory and how they are related. Since the analysis plan and results are not reported, neither the extent of multiplicity nor its handling can be assessed.

The primary outcome population is limited to Aim 2 participants who completed all required Aim 2 protocol activities. The registry does not report the number meeting this criterion, the number with a baseline score, the number with a later score, or the number included in the analysis. Reasons for missing measurements and methods for handling missing data are not reported in the registry record. It is therefore not possible to determine whether the analysis used complete cases, imputation, or another approach.

General statistical explanation: complete-case results can be biased when the chance of having an observed measurement is related to the outcome or participant characteristics. Missing-data methods rely on assumptions, and sensitivity analyses can help assess how conclusions depend on those assumptions. No missing-data assumptions or sensitivity analyses are reported. The specific analysis population beyond the stated Aim 2 completion requirement is also not reported in the registry record.

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

The registry record establishes that PROMOTE was designed to assess pharmacy staff perceptions of HPV vaccination and a communication strategy, including a pre/post acceptability measure for eligible Aim 2 participants. It also describes a five-option survey scale and the intended direction of its scores. These details clarify what the primary endpoint was meant to represent.

The record does not report the primary outcome values. It therefore does not show whether average acceptability scores increased, decreased, or remained similar after training, nor does it establish how precise an estimated change would be. It also does not report a result for HPV vaccination uptake. The study’s aim of increasing vaccination rates should not be confused with a reported finding that vaccination rates changed.

Even if a pre/post difference were reported, the nonrandomized design without a like-for-like control comparison would constrain causal claims. General statistical explanation: a measured change over time is not automatically attributable to the intervention, because other influences may change over the same period. The registry record does not describe a design that separates those influences from the communication strategy.

The primary measure applies only to Aim 2 participants who completed all required Aim 2 protocol activities. Its interpretation would therefore pertain to that defined group, not necessarily to all enrolled participants or all pharmacy staff. The enrollment of 42 does not tell readers how many contributed primary outcome data. That number and the outcome results are not reported in the registry record.

The study can be understood as a pilot focused on implementation perceptions and pharmacy communication. Its record does not support a conclusion about the effectiveness of the strategy, the magnitude of any change, or the generalizability of the findings. Such conclusions would require reported results and an analysis appropriate to the study design.

13. Why This Trial Matters Statistically

This study raises a statistical question that differs from a conventional efficacy comparison: how to measure perceptions about implementing a communication strategy in pharmacies. Acceptability is an implementation-related outcome, while vaccination uptake is a distinct outcome. Keeping those constructs separate is important because an average survey score cannot be treated as a vaccination rate or as evidence that vaccination behavior changed.

The registry also illustrates why population definitions matter. The primary measure was restricted to Aim 2 participants who completed all required activities. That restriction defines who could contribute to the primary endpoint and makes the number of eligible and analyzed participants essential for interpreting any reported estimate. Those counts are not reported in the registry record.

Statistically, a pre/post design can describe change in perceptions, but a nonrandomized design without a like-for-like control comparison does not isolate the strategy’s causal contribution. Transparent reporting of the estimate, variability, missing data, and analysis method would be needed to judge the size and precision of any observed change. The registry record does not report those primary outcome details.

The record also distinguishes planning calculations from observed evidence. Sample-size illustrations rely on assumptions, including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They are planning aids, not trial results or observed power. This distinction is particularly relevant in a pilot, where descriptive learning and feasibility questions may be central but cannot be inferred from a planning calculation alone.

14. Limitations

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

The registry record provides limited detail on the conduct and analysis of the pilot. Aim 2’s arm description is truncated, and the full content, sequence, and delivery of the training and communication activities are not reported. The number of participating pharmacies, recruitment methods, participant characteristics, and distribution of participants across study activities are also not reported in the registry record.

The primary measure is a researcher-developed survey based upon the Implementation Outcomes Questionnaire. The registry describes its scoring and intended interpretation, but does not report psychometric information, item-level results, or how the scale performed in this study. That limits assessment of how consistently or sensitively the measure captured perceptions.

Although the overall enrollment is 42, the record does not report the number of Aim 2 participants who completed all required activities or contributed primary outcome data. It also does not report the primary mean, standard deviation, change estimate, confidence interval, or p-value. Missing-data methods, analysis specifications, and any sensitivity analyses are not reported in the registry record.

The nonrandomized design and lack of a like-for-like control comparison limit causal interpretation. The registry identifies the study as completed, but does not give enough information to assess whether changes in perceptions can be separated from other influences over time. The adverse-event record lists zero participants at risk and zero events in the recorded categories; with no participants at risk reported, those entries do not establish an absence of adverse events among an evaluated population.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Communication Strategy to PROMOTE HPV Vaccination in Pharmacies: PROMOTE Study — NCT04660331.
• Registry record last updated 2024-10-09; status last verified 2024-10.
• Results first posted 2024-10-09.
• 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

PROMOTE is a completed pilot study sponsored by Fred Hutchinson Cancer Center, with enrollment of 42. It used a nonrandomized, parallel design with no masking, and the phase is listed as NA. The study dates in the registry are 2021-02-01 for start and 2023-07-31 for primary completion.

The study explored pharmacy communication about HPV vaccination. Its primary measure concerned acceptability of providing HPV vaccination to children and of the communication strategy, using an average score from a five-option survey. Only Aim 2 participants completing all required Aim 2 activities were assessed for this measure. The registry record describes the endpoint and its intended timeframe, but does not report its numerical results, analysis details, or the number included in the primary analysis.