Severe Asthma, MepolizumaB and Affect: SAMBA Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Severe Asthma, MepolizumaB and Affect: SAMBA Study (NCT04680611), a registered phase not stated study. The primary outcome is Change in Emotional Composition (Using the Geneva Emotions Wheel).

2. Clinical Question

The study also considers emotional and affective outcomes for partners, and includes a qualitative component. Its registry summary characterizes the work as a real-life pragmatic, non-randomised study rather than a trial assigning participants to treatment groups. That distinction matters: differences across study phases or participant groups would not, by themselves, provide a randomized estimate of what treatment caused.

The primary measure concerns the intensity of individual emotions, rather than a single overall emotional-health score. Secondary outcomes cover affective state, asthma symptom control, functioning and quality of life, asthma-related quality of life, and illness perception. The registry states that changes in individual emotion scores were outcomes of interest, but does not report those results. The posted record therefore describes the question and measurement approach, but does not establish the direction, size, or precision of any change.

3. Trial Design

SAMBA is described as a real-life pragmatic non-randomised study with two quantitative phases and an additional qualitative component. The registry lists the study status as completed, an enrollment of 120, a start date of 2021-09-09, and a primary completion date of 2025-03-26. These record details describe the study but do not provide a participant flow or analysis population.

Phase 1 is a cross-sectional group of patients with severe eosinophilic asthma who are on Nucala treatment. The primary measure’s description specifically says that the change-from-baseline measure was not applicable to this phase. Phase 2 includes patients with severe eosinophilic asthma who are to start Nucala treatment, as well as their partners. The primary outcome is framed as change to one year after treatment starts. Phase 3 is a qualitative substudy involving a subgroup of patients from Phase 2 and their partners; the registry says the primary outcome measure was not included in that phase.

The intervention field says “no study intervention” and describes standard clinical care. Thus, the registry describes observation of outcomes in the context of treatment, not a randomized assignment to receive or not receive mepolizumab. Allocation is not stated, and the registry explicitly cautions that the arms are not a like-for-like control comparison. The record does not report the recruitment approach, treatment eligibility criteria, or detailed timing of assessments beyond the primary outcome timeframe.

There are six outcome measures listed in the record: the primary emotional-composition measure and secondary measures covering affective state, asthma symptoms, functioning and quality of life, asthma-related quality of life, and illness perception. A detailed statistical analysis plan, participant flow, and analysis populations are not reported in the registry record. The listed completion status should not be taken to mean that all planned analyses or results are present in this 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: This study had three phases. Participants in Phase 1 were 30 individuals who have already received mepolizumab treatment and were a different cohort from the participants in Phase 2. Participants in Phase 2 consisted of 45 individuals who were mepolizumab treatment naive at the time of enrolment and their romantic partners (n=45). Participants in Phase 3 were sub-set of participants from Phase 2.

Phase 1

Phase 2

Reasons for not completing this period:

Phase 3

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Phase 1 was cross sectional .This measure therefore was not applicable ( change from baseline to 1 year on treatment). Phase 3 was a qualitative substudy with participants from Phase 2 cohort and did not include this outcome 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: Phase 3 of this study was a qualitative sub-study with a sub-set of participants recruited from Phase 2. Baseline characteristics data was not collected separately for Phase 3.

6. Primary Endpoint

The registry lists the primary outcome as Change in Emotional Composition (Using the Geneva Emotions Wheel), measured over Change to one year after start of treatment.

The primary endpoint is change in emotional composition, measured using the Geneva Emotions Wheel. The registry describes a self-report questionnaire with 20 discrete emotions, classified by positive or negative valence. Participants mark the intensity of each emotion on a six-point Likert-type scale, with scoring from 0 for the smallest circles to 5 for the largest circles. In the registry’s description, lower scores indicate lower intensity and higher scores indicate higher intensity.

The listed timeframe is change to one year after treatment starts. Individual emotion scores are the outcomes of interest, so the endpoint is not described as a single combined score across all emotions. The measure is intended to capture potentially different emotional experiences rather than collapsing them into one direction or a general label such as “better” or “worse.” The registry does not give a threshold for a meaningful change or explain how the emotion-level results would be combined or interpreted.

The record says this change measure did not apply to Phase 1 because it was cross-sectional, and that Phase 3 was a qualitative substudy without this outcome measure. It does not post baseline and follow-up scores, changes, confidence intervals, or an analysis for the primary endpoint. Consequently, the measurement description can be explained, but the size and precision of any observed change cannot be assessed from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as continuous and specifies a mean with a 95% confidence interval. A continuous outcome can take values along a scale rather than being limited to categories such as yes or no. Here, each emotion has an intensity score on the Geneva Emotions Wheel, recorded from 0 to 5. Describing a mean is a way to summarize the central level of scores in an analyzed group, while retaining the scale’s interpretation: lower values represent lower emotion intensity and higher values represent higher intensity.

In general, a confidence interval communicates uncertainty around an estimate. A narrower interval indicates greater precision under the chosen statistical model and assumptions; a wider interval indicates more uncertainty. A confidence interval is not a guarantee that the true value lies within the displayed interval, and it does not alone tell whether a result is clinically or personally important. No primary-endpoint mean or confidence interval is posted in this record, so these ideas explain the specified summary method rather than an observed SAMBA result.

The outcome description emphasizes changes in individual emotion scores. This matters for interpretation: the measure covers emotions with positive and negative valence, and intensity is not the same as a single overall benefit or harm. A change in one emotion would not automatically imply a change in all others. The registry does not describe a rule for combining the individual emotions into a total score, nor does it report the results for any individual emotion.

What does the study design allow the analysis to say?

Phase 1 is cross-sectional and includes patients already on Nucala treatment. The primary change measure is explicitly described as not applicable to that phase. Phase 2 concerns patients starting treatment and their partners, with change to one year after treatment start as the primary timeframe. Phase 3 is qualitative and does not include this outcome. These phase distinctions mean the primary endpoint is not described as a common repeated measure across every group.

In general, a randomized comparison helps balance measured and unmeasured participant characteristics between assigned groups. This registry describes a non-randomised study and says allocation is not stated. It also cautions that the arms are not a like-for-like control comparison. Therefore, any observed within-person or between-group change would need to be interpreted in light of this design; the record does not support treating group differences as an isolated causal treatment effect.

The intervention field states that there is no study intervention and that patients receive standard clinical care. The study examines outcomes in a real-life treatment context. The registry does not provide a detailed model, covariate adjustment strategy, or other statistical method for accounting for differences among participants. Those methods are not reported in the registry record.

Why might over-dispersion matter?

Over-dispersion is a general issue for count outcomes: it occurs when observed variability is greater than a model’s assumptions allow. It can lead a model to understate uncertainty if the extra variability is ignored. The primary SAMBA outcome is described as a continuous mean, not a count outcome, and the registry does not report a model or an over-dispersion assessment. This concept therefore does not establish anything about the posted primary endpoint; it illustrates why methods should match the type and variability of the outcome.

What can planning calculations show?

Sample-size planning illustrations are not observed power and do not replace the trial’s results. In general, such illustrations use assumptions about the effect to detect and the analysis design to describe a hypothetical study’s requirements. The registry does not report its own sample-size justification or design assumptions. Any planning illustration based on an observed effect should not be read as evidence that the study had a particular probability of detecting an effect, or as an estimate of the trial’s actual findings.

The record does not report a detailed statistical analysis plan, handling of repeated measurements, confidence-interval calculation method, or whether analyses were adjusted for baseline values. It lists 0 analyses. Accordingly, it is possible to explain the outcome scale and the general meaning of the specified mean and confidence interval, but not to verify how the analysis was implemented or reproduce its estimates.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures, including a primary measure that concerns individual emotion scores and secondary measures across several domains. When an analysis examines many outcomes, general statistical practice recognizes a possibility of chance findings among multiple tests. An analysis plan may specify which outcomes are primary, how secondary results will be interpreted, and whether any adjustment or other strategy will be used. The registry identifies the primary outcome but does not report a multiplicity strategy or detailed analysis plan. It also reports 0 analyses, so the effect of any such choices cannot be evaluated from posted results.

Missing-data handling is not reported in the registry record. The record does not describe how incomplete questionnaires, missed follow-up assessments, or participants without endpoint measurements were handled. It also does not report the number analyzed for the primary outcome, reasons for missing observations, or any sensitivity analyses. Without this information, the potential influence of missing data on an estimate cannot be assessed.

Analysis populations are not reported in the registry record. The record does not say whether analyses included all eligible participants, only those with observed follow-up measurements, or another defined group. Nor does it give a participant flow connecting the enrollment entry to each phase and outcome. The registry’s enrollment of 120 should not be treated as the denominator for every endpoint analysis.

These omissions do not demonstrate that a particular method was or was not used; they mean the methods are not described in the registry record. Because outcome analyses are not posted, there are no estimates to assess for multiplicity, missing-data sensitivity, or the selected analysis population.

11. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: urinary track infecion and acute kidney injury (2.2%), diagnosis of very low proliferation mantle cell lymphoma (2.2%), transient loss of consciousness (2.2%), heart failure with reduced ejection fraction (2.2%), aki on background ckd (2.2%).

The adverse-event record lists five groups, with numbers at risk and numbers affected for serious events, other events, and deaths. For Phase 1 patients, the listed serious-event count is 0 among 30 at risk, and the other-event count is 0 among 30 at risk. For Phase 2 patients, the corresponding figures are 3 among 45 for serious events and 6 among 45 for other events. For Phase 2 partners, the figures are 1 among 45 for serious events and 2 among 45 for other events. Both Phase 3 groups list 0 serious events and 0 other events among 12 at risk in each group. The record lists deaths as 0 in every group.

These are descriptive registry counts, not a randomized safety comparison. The groups differ in their role and study phase, and the record cautions that the arms are not like-for-like controls. The listed serious-event terms each have 2.2% beside them, including urinary tract infection and acute kidney injury, transient loss of consciousness, and infective exacerbation of asthma. The record does not explain the denominator or method behind these term-specific percentages, so they should not be converted into a comparative risk estimate.

The figures describe events recorded in this study and do not establish that treatment caused or prevented them. The registry does not provide further detail about event ascertainment, exposure duration, or how events were attributed.

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

The registry record establishes that SAMBA was designed to explore emotional and affective outcomes in a real-life setting for people with severe eosinophilic asthma receiving mepolizumab in standard clinical care, as well as outcomes involving their partners. It describes a Geneva Emotions Wheel measure focused on the intensity of individual emotions and a timeframe of change to one year after treatment starts. It also records a completed study status and lists secondary outcome domains.

However, the record does not post the primary outcome estimates. There is no reported mean change, 95% confidence interval, or analysis result for the Geneva Emotions Wheel. The posted record therefore does not show whether individual emotions changed, in which direction they changed, how large any change was, or how precisely it was estimated. The same limitation applies to the listed secondary outcomes: their names are present, but their results are not.

The study design does not describe random assignment or a like-for-like control group. Phase 1 includes patients already on treatment, Phase 2 includes patients starting treatment and their partners, and Phase 3 is a qualitative substudy. These groups serve different purposes and cannot be assumed to be directly comparable. Even if a before-and-after change were reported, this design alone would not separate treatment effects from other explanations for change.

The safety figures are descriptive event counts for the listed groups. They are not a controlled comparison and should not be treated as proof that treatment did or did not cause an event. The record also omits details needed to assess event ascertainment and the percentages attached to serious-event terms.

In short, the registry describes the study question, measures, phases, and selected safety figures, but does not provide the analyses needed to answer the primary question. The absence of posted outcome estimates is not evidence of no change; it is a limitation of what can be concluded from the registry record.

13. Why This Trial Matters Statistically

This study is statistically interesting because it places an emotional outcome alongside clinical and quality-of-life measures in severe eosinophilic asthma. The primary measure does not treat emotion as one undifferentiated quantity: it records intensities for 20 discrete emotions with positive or negative valence. That structure makes the definition and interpretation of each outcome important, especially because a change in one emotion need not imply a similar change in another.

The phases also illustrate a common challenge in real-life research. The record includes patients already on treatment, patients starting treatment, partners, and a qualitative substudy. These groups contribute different kinds of information, but do not create a randomized comparison. Statistical interpretation must account for the fact that group membership, treatment timing, and participant role are not interchangeable.

The registry’s warning that the arms are not a like-for-like control comparison is consequential. A careful analysis of change would need to describe who contributed measurements, how timepoints were handled, and what comparisons were intended. The registry does not report those analytic details or any outcome results. Thus the study’s statistical value in the posted record lies primarily in its stated measurement framework and design, rather than in evidence about the magnitude of an effect.

The record also highlights reporting needs for studies with multiple emotion-level outcomes and several secondary measures. Clear specification of analysis populations, missing-data handling, multiplicity, and uncertainty would help readers judge how robustly the results address the research question. Those details and analyses are not reported in the registry record, leaving the stated objectives without posted estimates to interpret.

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.

A central limitation is that the registry record lists 0 analyses and does not post results for the primary endpoint or the secondary outcomes. It is therefore not possible to describe observed emotional change or assess its precision from this record. The completed status does not supply those missing estimates.

The design is non-randomised, allocation is not stated, and the record explicitly cautions that the arms are not a like-for-like control comparison. Phase 1 is cross-sectional and already on treatment; Phase 2 concerns treatment initiation and includes partners; Phase 3 is qualitative and does not include the primary measure. These distinctions restrict direct comparisons across phases and groups.

The primary measure covers individual emotions, but the registry does not report a combined-score rule, a threshold for meaningful change, or the results for individual emotions. It also does not report detailed timing of assessments beyond the stated one-year timeframe, the number analyzed for each outcome, or participant flow across phases.

Important statistical details are absent: the analysis plan, missing-data methods, analysis populations, any adjustment for baseline measurements, and a strategy for multiple outcomes are not reported in the registry record. The record also does not explain the denominator or calculation behind the listed serious-event term percentages. These limitations concern what can be evaluated from the registry record and do not establish which methods may have been used elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Severe Asthma, MepolizumaB and Affect: SAMBA Study — NCT04680611.
• Registry record last updated 2026-07-13; status last verified 2025-12.
• Results first posted 2026-07-13.
• 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 NCT04680611, the SAMBA Study, as a completed, real-life pragmatic non-randomised study of emotional and affective outcomes related to mepolizumab in severe eosinophilic asthma and partners. It lists an enrollment of 120 and a primary completion date of 2025-03-26. The design has two quantitative phases and a qualitative substudy.

The primary outcome is change in individual Geneva Emotions Wheel scores to one year after treatment starts, summarized as a mean with a 95% confidence interval. The record says this measure was not applicable to cross-sectional Phase 1 and was not included in the Phase 3 qualitative substudy. It lists five secondary outcome domains and reports 0 analyses.

Serious and other adverse-event counts are listed by group, as are deaths. The registry does not post primary or secondary outcome estimates, a detailed statistical analysis plan, missing-data methods, or analysis populations. The posted record therefore supports a description of the research question and design, but not an assessment of the primary outcome’s observed change or precision.