AdheRence to Inhaled Corticosteroids in Asthma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for AdheRence to Inhaled Corticosteroids in Asthma (NCT03769519), a randomized na study. The primary outcome is Number of Participants Who Reported Experiences With the ARICA Program.

2. Clinical Question

The trial addressed whether an asthma adherence program could be piloted among adult African American patients with asthma, a population described in the registry record as facing a significant health problem partly affected by relatively low inhaled corticosteroid (ICS) adherence. ARICA was intended to support ICS adherence. The primary outcome, however, was not a measure of adherence or a test of whether asthma outcomes changed. It counted participants who reported experiences with the ARICA program through an in-depth, semi-structured qualitative interview.

The registry describes a randomized, parallel-group comparison. Participants assigned to ARICA received weekly texts and emails containing asthma details and myths, completed monthly surveys, and participated in asthma education sessions. The control group received scheduled texts and emails for monthly surveys after completing baseline questionnaires. The posted primary result concerns ARICA participants who completed the study, not a comparison of interview responses between groups.

The registry reports 12 participants for the primary outcome among 14 in the ARICA group. This count indicates how many participants are recorded for the outcome; it does not indicate whether their experiences were favorable, whether they adhered to ICS, or whether their asthma control changed. The registry does not report a corresponding control-group result, and no two-group estimate is available for this endpoint.

The trial also lists changes in patient-reported medication adherence, asthma control, and asthma-related quality of life as secondary outcomes. Their results are not reported in the registry record. Consequently, the central statistical question that can be addressed from the posted primary result is descriptive: how many ARICA participants were recorded as reporting program experiences, and what can that count establish? It cannot establish a comparative effect of ARICA on adherence or clinical outcomes.

3. Trial Design

AdheRence to Inhaled Corticosteroids in Asthma (ARICA) is recorded as a randomized, parallel-group behavioral study with no masking. The registry lists a total enrollment of 29. The study status is completed, and the recorded start date is 2020-02-27, with primary completion on 2020-08-19. The phase is listed as NA. Duke University is identified as the sponsor.

The intervention group received weekly texts and emails containing asthma details and myths, monthly surveys, and asthma education sessions. The control group was scheduled to receive texts and emails for monthly surveys after participants completed baseline questionnaires. The registry does not report further detail about the randomization procedure, such as the sequence-generation method or allocation concealment. It also does not report whether participants or study staff were masked; the overall masking entry is NONE.

The primary outcome is a count of participants who reported experiences with the ARICA program. Its time frame is 3 months, and the description specifies an in-depth, semi-structured qualitative interview. The outcome population is ARICA intervention participants who completed the study. The posted outcome data list 14 participants in the intervention group and a value of 12; the control group has no posted participant count or outcome value for this measure. The registry does not explain the difference between the overall enrollment and the group counts shown for this outcome.

Three secondary outcomes are listed: change in patient-reported medication adherence on the DOSE-Nonadherence (Voils) Questionnaire, change in asthma control on the Asthma Control Test, and change in asthma-related quality of life on the Marks Asthma-Related Quality of Life Questionnaire. Results for these outcomes are not reported in the registry record. The record lists four outcome measures overall, but does not provide inferential analyses for the posted outcomes.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Conducted qualitative interview of ARICA Intervention participants who completed the study.

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 Who Reported Experiences With the ARICA Program, measured over 3 months.

The primary endpoint counts participants who reported experiences with the ARICA program. The registry describes its measurement as an in-depth, semi-structured qualitative interview conducted with ARICA intervention participants who completed the study. Its time frame is 3 months. The posted result is 12 participants among 14 listed for the intervention group.

A count is useful for describing how many participants contributed to an interview-based assessment. In a pilot study, qualitative accounts can help characterize how participants experienced a program and identify topics that warrant further investigation. The count itself, however, is not a coded measure of whether an experience was positive or negative. The registry does not report interview themes, response categories, a scoring method, or a summary of the content of the interviews. Those details are not reported in the registry record.

This endpoint also differs from an adherence outcome. It does not quantify medication-taking behavior, and it does not measure asthma control or quality of life. Those topics appear among the listed secondary outcomes, but their results are not reported in the registry record. The interview count therefore describes participation in the primary assessment rather than an effect of ARICA on adherence or health status.

Because no control-group value is posted, the endpoint cannot support a direct comparison between randomized groups. Nor does the count alone establish how representative the interview accounts are of all ARICA participants. The registry does not report a comparison, uncertainty interval, or statistical test for this outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in the registry is limited. It identifies the design as randomized and parallel, gives the primary endpoint as a participant count, and posts an intervention-group result. It does not report an analysis for the primary endpoint or the secondary outcomes. The distinctions below explain how such information is generally interpreted; they are general statistical explanations, not claims about additional procedures used in this trial.

What does a participant count tell the reader?

A count describes how many people meet the definition of an outcome or are represented in a particular result. For this endpoint, the registry reports 12 participants among 14 listed for the ARICA outcome. The count is tied to an interview-based measure of experiences with the program. It is not a numerical score of the interviews, and it does not communicate whether an experience was favorable, unfavorable, or mixed. The registry does not describe a qualitative coding framework or report interview themes.

Counts are often straightforward to read, but their interpretation depends on the outcome definition and the population to which the count refers. The registry defines the population as intervention participants who completed the study and describes the assessment as a qualitative interview. It does not report a corresponding control outcome. The count therefore characterizes the posted intervention result, not a difference between groups.

Why is a randomized comparison unavailable?

In a randomized trial, the principal comparative interpretation generally relies on outcomes being available for the randomized groups under a defined analysis plan. A treatment-effect estimate contrasts outcomes between groups while accounting for the chosen outcome scale and analysis approach. Here, the primary outcome has no posted control value. A between-group contrast cannot be calculated from an intervention count alone, and no such estimate is reported in the registry record.

Randomization is a design feature; it does not itself supply missing outcome values or guarantee that every endpoint is comparable across groups. The primary endpoint is an interview about experiences with ARICA, and the outcome population is limited to intervention participants who completed the study. The registry does not describe a control-group interview or a method for comparing qualitative material across arms. Thus, the design label should not be mistaken for evidence of a comparative analysis of this endpoint.

What would an uncertainty interval mean?

General statistical explanation: a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the analysis. Its width depends on factors such as the amount of information and the variability of the data. A narrow interval indicates greater precision for the particular estimate, while a broad interval indicates less precision. An interval does not automatically address biases from missing data, measurement choices, or study design.

No confidence interval is posted for the interview count, and no interval can turn this single-group count into a comparison with control. The registry also does not report an inferential model or a p-value for the primary outcome. It would therefore be inappropriate to attach an unreported interval or significance test to the count.

What do the sample-size assumptions mean?

General statistical explanation: planning calculations can illustrate how many participants might be required to detect a specified effect under stated assumptions. Such calculations depend on the effect selected for detection, the significance level, the allocation scheme, and the method used to approximate the test's behavior. A planning illustration is not a measure of the probability that the completed study found a true effect. In particular, it is not observed power.

The registry describes planning assumptions based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. It also distinguishes total events for time-to-event calculations from participants per arm for other calculations. No resulting sample-size estimates appear in the clinical details for this analysis. The registry does not report the trial's own sample-size justification, so the planning assumptions should not be read as the original design rationale.

How should missing analyses be understood?

The registry lists no analyses. That absence means there are no posted analysis results to interpret for the listed outcomes; it does not establish why analyses are absent or whether analyses were conducted outside the registry. The record does not report a statistical analysis plan, model specifications, covariate adjustment, handling of repeated measurements, missing-data methods, or analysis population definitions beyond the primary endpoint's stated interview population. These omissions limit assessment of how the outcomes were handled and how robust any unposted conclusions might be.

General statistical explanation: over-dispersion matters when observed variability is greater than a model assumes. In that setting, standard errors may be too small if the extra variability is ignored, which can make intervals appear more precise than warranted. The primary posted result is a count from an interview-based outcome, and the registry provides no model or dispersion estimate. There is no basis to claim that over-dispersion was assessed or that a particular count model was used.

Similarly, a binary outcome analysis could compare event counts or proportions only when the outcome definitions and denominators are available for the relevant groups. The registry does not post the required control result for this primary endpoint. No adjustment or recalculation can replace that missing comparison. The appropriate statistical reading is therefore descriptive and limited to the posted count.

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("ARICA Intervention (Group 2)")
n      <- c(14)
events <- c(12)
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  ARICA Intervention (Group 2)  14  12  85.7  57.2  98.2  60.1  96.0  59.5  95.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists three secondary outcomes: change in patient-reported medication adherence, change in asthma control, and change in asthma-related quality of life. Their results are not reported in the registry record. The record lists no analyses, so there are no posted estimates or tests from which to assess how these outcomes were analyzed or interpreted.

Multiplicity arises when several outcomes or statistical tests are considered. General statistical explanation: evaluating multiple outcomes can increase the chance of finding at least one apparently notable result by chance, depending on the testing strategy. Researchers may address this through a prespecified hierarchy, adjustment procedure, or emphasis on estimation rather than isolated significance tests. The registry does not report a multiplicity strategy, an outcome hierarchy, or a statistical analysis plan. It is not possible to determine from the record whether multiplicity was addressed elsewhere.

Missing-data handling is also not reported in the registry record. The primary outcome population is described as ARICA participants who completed the study and took part in the qualitative interview. The posted value is 12 among 14 listed for the intervention outcome. The record does not explain whether other participants were eligible but did not complete an interview, how incomplete interviews were treated, or whether the posted denominator reflects all participants assigned to ARICA.

The registry reports an overall enrollment of 29, while the outcome and safety entries list group-specific counts. It does not explain how the analysis populations relate to total enrollment or whether any participants were excluded from particular outcomes. No intention-to-treat, per-protocol, or other analysis population is specified in the registry record. These gaps prevent a full account of participant flow and missingness.

General statistical explanation: missing outcome data can affect both precision and validity, especially if the likelihood of having a recorded outcome is related to participant characteristics or outcomes. The direction and size of any such effect cannot be determined without information about missingness and the analysis approach. The registry does not report enough detail to assess those issues for ARICA.

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 reports serious adverse events for participants listed as at risk in each group. In the control group, 14 participants were at risk and 0 were affected by a serious adverse event. In the ARICA intervention group, 15 were at risk and 0 were affected. The registry reports 0 other adverse events in each group. It also reports 0 deaths in the control group and 1 death in the ARICA group.

These figures are counts, not adjusted comparisons. The registry does not report the cause or timing of the death, whether it was considered related to the intervention, or any adjudication details. The event information does not establish causation. The entries also do not provide enough detail to evaluate differences in exposure time or other factors that could affect event counts.

The number at risk in the safety entries is distinct from the primary outcome population and should be read in the context of the relevant safety category. The registry record does not provide a narrative explaining the relationship between those safety denominators, overall enrollment, and the participants represented in the primary outcome. With no serious adverse events posted in either group, the registry offers descriptive counts but no comparative estimate or precision measure for serious-event risk.

General statistical explanation: rare or infrequent events can be difficult to compare reliably in small studies, and a zero count does not prove that an event cannot occur. Counts should be interpreted alongside event definitions, follow-up, exposure, and uncertainty. Those details are not reported in the registry record for these entries.

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

The result supports a narrow descriptive statement: the registry records 12 participants for the ARICA program-experience interview outcome among 14 participants listed for that intervention outcome. The primary assessment was an in-depth, semi-structured qualitative interview conducted among intervention participants who completed the study. The count indicates the number recorded for this endpoint, not the substance of the interviews.

The result does not establish that the program improved medication adherence. Adherence is named as a secondary outcome, but its result is not reported in the registry record. Nor does the primary count show a change in asthma control or asthma-related quality of life; results for those secondary outcomes are also not reported. The count is not an estimate of treatment effect, and the registry gives no control-group value for this primary endpoint.

The record also does not describe participants' views, identify themes, or indicate whether reported experiences were positive or negative. A count of interview participants cannot substitute for qualitative findings. Without interview content or an account of how responses were analyzed, readers cannot infer what participants said or what aspects of ARICA they considered important.

More broadly, the record does not report analysis methods, uncertainty estimates, or a statistical plan. It cannot support conclusions about the precision of an effect estimate for the primary endpoint because no comparative effect estimate is posted. The randomized design is relevant to the study's structure, but it does not resolve the absence of a control result for this outcome.

The safety entries report no serious adverse events in either group and one death in the ARICA group. They do not establish that the intervention caused the death or that it was unrelated; the registry does not report cause or relatedness. These figures should be read as recorded counts rather than as proof of safety or harm.

Accordingly, the posted primary result documents an interview count from a completed pilot study. Claims about adherence benefit, asthma outcomes, participants' overall appraisal, or comparative safety require information that is not reported in the registry record.

14. Why This Trial Matters Statistically

This study illustrates an important distinction between a trial's broad motivation and the endpoint that is actually posted as primary. The registry describes ARICA as an intervention intended to improve ICS adherence among adult African American patients with asthma. Its primary outcome is instead a count of participants reporting experiences with the program in a qualitative interview. Those questions may both matter in a pilot study, but they require different measurements and support different conclusions.

Statistically, the endpoint definition determines what an estimate means. A count of interview participants can describe the reach of an assessment, while a measure of adherence would require an adherence outcome and a defined comparison or change analysis. The registry lists adherence, asthma control, and quality of life as secondary outcomes, yet does not report their results. Keeping the distinction clear prevents a process or experience measure from being mistaken for evidence of a clinical or behavioral effect.

The record also shows why randomized design and comparative evidence should not be treated as interchangeable. Randomization is a design feature, but a comparison still requires outcomes in the relevant groups, an analysis plan, and appropriate reporting. The primary endpoint has no control value in the posted record, and no analysis is listed. The result can therefore be described but not interpreted as an intervention effect.

For biostatistical readers, the case also highlights the importance of transparent participant flow, endpoint definitions, analysis populations, missing-data handling, and reporting of uncertainty. These details make it possible to understand what a denominator represents and how much confidence to place in a result. Their absence does not imply that methods were not used, but it limits what can be assessed from the registry record.

The value of the posted information is consequently bounded: it documents a count from an interview-based assessment and records safety counts. It also makes clear which outcomes and analytical details remain unavailable in the registry record.

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 record leaves several trial-specific questions unanswered. It does not report the randomization sequence method, allocation concealment, recruitment details, eligibility criteria, or participant characteristics beyond the study's focus on adult African American patients with asthma. The overall masking entry is NONE, but the record does not describe who was aware of assignments or whether outcome interviewers were independent of the intervention team.

The primary outcome is described as an in-depth, semi-structured qualitative interview, but no interview guide, coding method, qualitative analysis approach, themes, or participant quotations are reported. The result is a count of 12 participants among 14 listed for the intervention outcome. The registry does not explain the relationship between those counts and total enrollment of 29, nor does it report a control-group outcome for the interview endpoint.

Three secondary outcomes are listed, but results are not reported in the registry record. No statistical analyses are listed. The record does not report a statistical analysis plan, sample-size justification, analysis populations, handling of missing data, prespecified outcome hierarchy, multiplicity procedure, or methods for repeated measurements. It is therefore not possible to assess the intended analysis or whether reported results follow a prespecified plan.

The safety record reports no serious adverse events in either group and one death in the ARICA group. Cause, timing, relatedness, and follow-up context are not reported in the registry record. The record provides no comparative uncertainty estimate for safety outcomes.

These reporting gaps constrain interpretation of the posted information; they do not establish what procedures may have been conducted but not entered in the registry. The primary result is best treated as a descriptive interview count rather than a comparative estimate of intervention effect.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: AdheRence to Inhaled Corticosteroids in Asthma — NCT03769519.
• Registry record last updated 2021-12-17; status last verified 2021-11.
• Results first posted 2021-12-17.
• 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

The registry identifies NCT03769519 as a completed, randomized, unmasked, parallel behavioral study sponsored by Duke University. Enrollment is listed as 29. The recorded study dates are 2020-02-27 for start and 2020-08-19 for primary completion.

ARICA participants received weekly asthma-information texts and emails, monthly surveys, and asthma education sessions. The control group received scheduled survey-related texts and emails. The primary outcome was a count of participants reporting ARICA experiences through a qualitative interview at 3 months. The registry reports 12 participants among 14 listed for the intervention outcome and no control result.

Changes in medication adherence, asthma control, and asthma-related quality of life are listed as secondary outcomes, but their results are not reported in the registry record. No analyses are listed. Safety entries report no serious adverse events in either group and one death in the ARICA group; further details about the death are not reported in the registry record.