TextFluenza: Using Technology To Promote Flu Vaccination In Underserved Maternal And Child Populations: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for TextFluenza: Using Technology To Promote Flu Vaccination In Underserved Maternal And Child Populations (NCT01146912), a randomized na study. The primary outcome is Influenza Immunization: Pediatric.

2. Clinical Question

The study’s stated rationale is that immunization reminders may help reach populations for whom vaccination outreach is difficult, while systems for rapidly identifying and contacting large target populations have had limitations. It proposes evaluating tailored, targeted influenza text-message reminders in pediatric and pregnant populations. The primary result available in the registry record addresses pediatric immunization; it does not answer every question raised by the wider study description.

The comparison is about immunization status by a specified calendar cutoff, rather than the number of messages received, participants’ intentions, or later vaccination. The registry identifies the primary population as individuals unvaccinated by the time the intervention started for their cohort. The exact methods used to establish vaccination status, including how it was recorded or verified, are not reported in the registry record.

3. Trial Design

The registry classifies the study as randomized, single masked, and parallel, with phase listed as NA. Columbia University is named as the sponsor. The study began in 2010-06, its primary completion is listed as 2012-04, and its status is completed. The recorded enrollment is 30537. These study-level details cover the overall trial and should not be confused with the arm counts reported for the primary pediatric outcome.

The trial description concerns influenza immunization outreach among pediatric and pregnant populations. Its stated purpose is to implement and evaluate tailored, targeted text-message reminders in urban pediatric and pregnant populations. The listed intervention types include text messages and automated calls. Arm descriptions also identify text-message vaccine reminders, an automated phone call from a clinic, pregnant-women groups, and delayed pediatric groups. The registry record does not give a complete account of how all cohorts were organized or how the different interventions were assigned within them.

The primary result available for interpretation compares pediatric participants assigned to text-message vaccine reminders with automated phone calls against pediatric participants assigned to an automated phone call from the clinic only. The registry lists 3790 participants for the first arm and 3784 for the second. Those arm counts are not the same as the overall enrollment of 30537; the relationship between the overall enrollment and the primary-outcome analysis population is not explained in the registry record.

Random allocation can support a fair comparison when implemented and analyzed appropriately, but the details needed to evaluate implementation are not reported in the registry record. The method used to generate the allocation sequence, allocation concealment, the identity of the masked party, and the handling of participants who did not receive or complete their assigned intervention are not reported in the registry record. The protocol, detailed statistical plan, and sample-size justification are also 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.

Before assignment: Children previously vaccinated for influenza before the season of interest were excluded from primary analysis

Only the first 6 of 8 groups are shown.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Individuals unvaccinated by time intervention start for their cohort

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.

Only the first 6 of 8 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Influenza Immunization: Pediatric, measured over March 31, 2011.

The primary endpoint is the percentage of pediatric participants with influenza immunization by March 31, 2011. The registry specifies that the population consists of individuals who were unvaccinated when the intervention began for their cohort. The result is therefore a proportion assessed at a fixed time point, not a time-to-vaccination measure.

As a general statistical concept, a vaccination percentage gives a direct summary of how common the recorded outcome was in a defined group by a stated cutoff. It can be useful for comparing uptake between outreach strategies because it expresses the outcome in the same form for each group. The registry reports 43.6% in this discussion-message reminders and automated-call group and 39.9% in the automated-call-only group. These are the posted percentages; the record does not describe the underlying ascertainment process or report confidence intervals for them.

The endpoint is specific to pediatric participants and the stated cutoff. It does not itself describe whether vaccination occurred at a particular clinic, whether an appointment was attended, or how participants responded to reminders. Pediatric vaccination at an influenza clinic and attendance at an appointment are listed as secondary outcomes, but their results are not reported in the registry record. The definition and measurement details for the primary endpoint beyond the percentage, population, and cutoff are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a percentage, so its basic statistical interpretation is a proportion of participants meeting the endpoint definition by a fixed cutoff. The registry reports the percentage and an arm count for each of the two pediatric groups. It does not report individual participant outcomes, the exact denominator used to calculate each percentage, or an uncertainty estimate. The percentages can therefore be described as posted, but further calculations or tests cannot be justified from the information in the registry record.

What does randomization contribute?

As a general statistical principle, random allocation is intended to make comparison groups similar on average with respect to both measured and unmeasured characteristics before the intervention. That principle supports interpreting between-group contrasts as potentially informative about intervention assignment. It does not guarantee that the groups were balanced in a particular trial, establish that allocation was concealed, or show that all assigned participants were analyzed as intended. For this study, randomization is recorded, but the allocation method, concealment procedures, baseline characteristics, and analysis population are not reported in the registry record.

The posted percentages should not be treated as an adjusted analysis. No covariate-adjusted estimate or analysis method is reported. Whether adjustment was planned, whether clustering or cohort structure was considered, and how the trial’s different populations and intervention groups were incorporated into analyses are not reported in the registry record. As a general matter, an adjusted analysis may account for prespecified participant characteristics or design features, but it is interpretable only when its model, variables, and analysis population are described.

How should uncertainty be understood?

A confidence interval is a general statistical tool for conveying the precision of an estimate. It gives a range of values generated by a stated procedure and communicates how much uncertainty remains around an estimated proportion or contrast. A p-value is another general tool, commonly used to assess how compatible observed data are with a specified null hypothesis under model assumptions. Neither is a substitute for the effect estimate or for information about study conduct. The registry record reports no confidence interval or p-value for the primary pediatric comparison, so neither precision nor statistical significance can be evaluated from the posted outcome alone.

The record also does not report an inferential comparison, a model, or standard errors. It is therefore not appropriate to infer a statistical result from the two percentages or to construct one from the arm counts. In particular, no unadjusted recalculation is presented. The record’s analysis count is zero, and a sponsor analysis of this primary contrast is not reported in the registry record.

What does a fixed-time percentage capture?

In general, a fixed-time proportion counts whether an outcome has occurred by a specified date, rather than modeling when it occurred. Here the endpoint is influenza immunization by March 31, 2011. Such an endpoint is straightforward to express and aligns with a question about vaccination uptake by a target date. It does not describe the timing of vaccination before that date or changes after it. The registry does not report a time-to-event analysis, and none should be inferred from the percentage.

For a proportion to be interpreted fully, the outcome definition and denominator need to be clear. The registry describes the endpoint as the percentage of pediatric participants with influenza immunization and identifies the population as individuals unvaccinated by the time intervention began for their cohort. It does not explain the source of vaccination information, how unknown status was handled, or whether participants without a recorded outcome remained in the denominator. These measurement and denominator details are not reported in the registry record.

As a general concept, over-dispersion matters when observed variation is greater than a statistical model expects. In a study with grouped or clustered observations, outcomes within a group may be more alike than outcomes between groups; a simple model that assumes independent observations may then understate uncertainty. The registry’s parallel design and multiple population and intervention descriptions do not by themselves establish that clustering occurred or that over-dispersion was relevant. Grouping structure, any allowance for dependence, and related model choices are not reported in the registry record.

The sample-size assumptions described for planning illustrations are not the trial’s design justification. Such illustrations, in general, depend on assumptions about the target effect, significance level, allocation, and statistical approximation. They are planning exercises, not evidence of achieved power and not estimates of the trial’s actual design process. The registry record does not report the trial’s own sample-size justification, target effect, or planned power. There is no basis in the posted primary result for calling a sample-size illustration observed power.

The outcome is categorized as a count/other type in the registry, while the primary endpoint description expresses the result as a percentage. That record classification does not supply a statistical model or an inferential method. The registry also notes that values are missing or not estimable for a two-arm comparison of the count/other endpoint. Accordingly, the primary arm percentages can be stated descriptively, but a derived two-arm estimate should not be substituted for a sponsor analysis. If a discrepancy between a recalculation and a sponsor analysis were reported, the sponsor’s own analysis would take precedence; no recalculated result is presented for this comparison.

10. Multiplicity, Missing Data and Analysis Populations

The registry names two secondary outcomes: pediatric participants vaccinated at an influenza clinic and attendance at an appointment. It records five outcome measures overall, but values for those secondary outcomes are not reported in the registry record. The listed outcomes raise a general multiplicity issue: when several outcomes or comparisons are tested, the chance of at least one apparently notable result can increase unless the analysis plan addresses that possibility. Whether the trial specified a primary testing hierarchy, adjusted for multiple comparisons, or treated secondary findings as exploratory is not reported in the registry record.

The record identifies a primary pediatric endpoint and its cutoff, but it does not provide the analysis plan, prespecified hypotheses, or the complete set of comparisons planned. The planned handling of multiple cohorts, intervention variants, or outcomes is not reported in the registry record. No multiplicity adjustment or interpretation of secondary results can therefore be inferred from the outcome labels alone.

Missing-data handling is also not described. The registry does not report the number of participants with missing vaccination status, the reasons for missingness, or whether missing outcomes were excluded, imputed, or otherwise addressed. The arm counts are listed, but the record does not state whether they are the denominators used for the outcome percentages. Analysis populations, including whether participants were analyzed according to randomized assignment, are not reported in the registry record.

As a general principle, missing outcomes can affect an estimate when the probability of being observed is related to the outcome or to group assignment. The direction and extent of any such effect depend on the pattern of missingness and the analysis approach. Because those details are absent, the posted percentages cannot establish that missing data had no influence. The registry’s lack of analysis entries also means there is no posted inferential output to clarify how these issues were handled.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry lists serious adverse events for several study groups. For the pediatric text-message reminders and automated-call group, it lists 4607 participants at risk and 0 serious events. For the pediatric automated-call-only group, it lists 4606 at risk and 0 serious events. The pregnant-women text-message and usual-care groups list 593 and 594 at risk, respectively, with 0 serious events in each. The delayed pediatric interactive text-message, conventional text-message, and usual-care groups list 1821, 1821, and 1820 at risk, respectively, with 0 serious events in each.

These figures describe the serious-event entries recorded for those groups. They do not establish that the true risk of a serious event was zero, nor do they describe events that may not have been captured or reported. Death counts are not reported in the registry record. Other-event entries list zero participants at risk and zero affected; those entries do not provide a usable account of non-serious adverse events. The registry record does not report detailed event definitions, surveillance procedures, event timing, or a safety comparison analysis. The listed safety counts should therefore be read as registry reporting, not as a complete assessment of safety.

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

The primary result establishes that the registry reports pediatric influenza immunization percentages by March 31, 2011, for two groups: 43.6% for text-message reminders with automated calls and 39.9% for automated calls from the clinic only. The recorded arm counts are 3790 and 3784. The percentages are numerically higher in the group receiving text-message reminders in addition to calls. This is a descriptive statement about the posted values, not a conclusion about whether the difference is statistically reliable or attributable to the added reminders.

The result does not establish the precision of the comparison because the registry record does not report a confidence interval or p-value. It also does not provide an adjusted effect estimate, a detailed analysis, or the exact denominators underlying the percentages. Without those details, the reader cannot determine how much uncertainty surrounds the contrast or whether missing outcome information affected it.

The result is limited to the specified pediatric population and outcome cutoff. It does not report the primary-outcome results for pregnant participants or for the other intervention groups named in the record. The two listed secondary outcomes are not accompanied by results in the registry record. Nor does the endpoint measure message engagement, appointment attendance, the timing of vaccination, or outcomes beyond the cutoff.

As a general statistical principle, an observed difference between randomized groups can be informative when the design, outcome ascertainment, and analysis are adequately documented. Randomization is recorded for this trial, but details needed to assess how assignment was implemented and how participants were analyzed are not reported in the registry record. The proper conclusion is therefore bounded: the posted percentages describe the recorded pediatric outcomes, while the available information does not support a definitive inferential or causal claim about the effect of adding text-message reminders.

13. Why This Trial Matters Statistically

This trial illustrates the distinction between a descriptive outcome and an inferential comparison. Two arm-specific percentages can show the direction of the observed pattern, but they do not by themselves establish how precisely that pattern has been estimated. The registry reports 43.6% and 39.9% for the primary pediatric outcome, but no confidence interval, p-value, or analysis result. A statistical reader should keep those two kinds of information separate rather than treating the numerical contrast as a significance finding.

The record also illustrates why the endpoint population and cutoff matter. The primary outcome concerns pediatric participants who were unvaccinated when the intervention started for their cohort and measures immunization by March 31, 2011. Results for another population, a different time horizon, or a different outcome cannot be inferred from this endpoint. That specificity helps prevent broad claims that extend beyond what was actually reported.

Finally, a large overall enrollment does not remove the need to understand the analysis population, denominator, missing data, and study design. The trial enrollment is 30537, whereas the primary arm entries list 3790 and 3784. The registry does not explain the relationship between these figures. Making that distinction explicit is important: enrollment, numbers assigned to particular groups, and numbers contributing to a specific outcome are not necessarily interchangeable concepts.

As a general lesson, randomized design, endpoint definition, data completeness, and statistical uncertainty all contribute to interpretation. The registry identifies randomization and a clear primary cutoff, but leaves important analytic details unreported. Reading the outcome with those boundaries in mind avoids turning an observed percentage into a stronger claim than the record can support.

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 primary outcome reporting is limited to the pediatric comparison between text-message reminders with automated calls and automated calls alone. Although the study description covers pediatric and pregnant populations and the record names additional intervention groups, their primary-outcome results are not reported in the registry record. The secondary outcomes of pediatric vaccination at an influenza clinic and appointment attendance also have no reported values in the registry record.

Important details needed to evaluate the primary percentages are absent. The registry does not specify the outcome ascertainment source, the precise denominator for each percentage, how unknown vaccination status was handled, or how many participants lacked outcome data. The arm counts are listed, but their relationship to the outcome denominators is not reported in the registry record. Allocation procedures, baseline characteristics, adherence, and the analysis population are also not reported in the registry record.

There is no posted estimate of uncertainty or inferential test for the primary comparison. A confidence interval, p-value, adjusted result, statistical model, and sponsor analysis are not reported in the registry record. The analysis count is zero, so the available data do not allow an assessment of the planned or completed inferential approach. The protocol, statistical analysis plan, sample-size justification, and any interim analyses are not reported in the registry record.

The study-level enrollment is 30537, but the primary arm entries list 3790 and 3784. The record does not explain the relationship between overall enrollment and the participants contributing to this outcome. The registry reports randomized, single-masked, parallel design labels, but does not describe the randomization process or identify who was masked. These limitations do not negate the posted percentages; they restrict how broadly and precisely those percentages can be interpreted.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: TextFluenza: Using Technology To Promote Flu Vaccination In Underserved Maternal And Child Populations — NCT01146912.
• Registry record last updated 2015-10-07; status last verified 2015-09.
• Results first posted 2013-05-31.
• 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 record describes a completed randomized, single-masked, parallel study sponsored by Columbia University, with enrollment of 30537. The study began in 2010-06 and has primary completion listed as 2012-04. It concerns influenza immunization outreach in pediatric and pregnant populations and includes text messages and automated calls among its interventions.

The primary result reported is pediatric influenza immunization by March 31, 2011, among participants unvaccinated when intervention began for their cohort. The registry lists 43.6% for text-message vaccine reminders with automated phone calls and 39.9% for an automated phone call from the clinic only, with arm counts of 3790 and 3784. The percentages are descriptive; no confidence interval, p-value, or analysis result is reported in the registry record.

The registry names pediatric vaccination at an influenza clinic and appointment attendance as secondary outcomes, but their results are not reported in the registry record. Serious-event entries list zero affected in the groups shown, while death counts are not reported in the registry record. Several design, outcome-ascertainment, denominator, and analysis details remain unreported, limiting assessment of uncertainty and generalization beyond the posted pediatric comparison.