This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Study to Investigate Real Life Effectiveness of Symbicort Maintenance and Reliever Therapy in Asthma Patients Across Asia (NCT00939341), a na phase 4 study. The primary outcome is Change in Asthma Control Questionnaire (ACQ(5)) Score From Baseline at a Regional Level.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00939341 |
| Phase | Phase 4 |
| Condition | Asthma |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 862 |
| Arms in the primary outcome | n/a |
| Lead sponsor | AstraZeneca |
| Results posted | Yes |
2. Clinical Question
Population
Patients with uncontrolled asthma in a real-life setting across Asia. The registry record does not give further eligibility details or a fuller description of the analysis population.
Intervention
Symbicort Maintenance and Reliever Therapy, using Symbicort Turbuhaler 160/4.5 µg delivered dose.
Comparator
The study purpose describes comparison with patients’ current therapy, but the registry record describes a single-group study and does not list a concurrent control group. Current therapy therefore provides context for the study question, not a like-for-like randomized comparison in the record.
Primary question
How did regional mean ACQ(5) score change from baseline to the average score during treatment, measured at Week 4, Week 8 and Week 12? The registry record specifies the outcome and its measurement period but does not report the numerical change or its confidence interval.
The study, titled SMARTASIA, concerns asthma control during real-life use of Symbicort maintenance and reliever therapy. The registry lists Asthma as the condition and describes the primary endpoint as change in Asthma Control Questionnaire (ACQ(5)) score at a regional level. Its stated purpose was to compare whether this regimen was more effective than patients’ current therapy in uncontrolled asthma. However, the recorded design is single-group, with allocation listed as NA and no masking. The registry does not identify a separate current-therapy arm or describe a concurrent comparison method. The primary question can therefore be read as a question about change over time among participants receiving the listed intervention; a causal contrast with another treatment is not established by the recorded design.
3. Trial Design
This is a completed phase 4 study with a single-group model and no masking. Allocation is listed as NA. The registry lists enrollment of 862 and describes Symbicort Turbuhaler 160/4.5 µg delivered dose as the intervention. The study title and summary place the work in a real-life setting among asthma patients across Asia. The recorded start is 2009-07 and primary completion is 2010-08.
The registry summary states that the study purpose was to compare Symbicort Maintenance and Reliever Therapy with patients’ current therapy in uncontrolled asthma. The design fields, however, do not describe a randomized comparison: they specify a single group, and the registry record does not list a control arm or allocation procedure. As a result, the stated comparison in the purpose should not be interpreted as evidence of a controlled treatment contrast. The registry record does not report how current therapy was documented or how any before-and-after comparison with it was handled.
The primary outcome was change in regional mean ACQ(5) score from baseline to the average during the treatment period, using scores at Week 4, Week 8 and Week 12. The record also lists country-level ACQ(5) change outcomes for China, India, Indonesia, Taiwan and Thailand, along with overall and domain-specific Asthma Quality of Life Questionnaire, Standardized Version outcomes. It lists 17 outcome measures and 0 analyses. The numerical results for the primary outcome are not reported in the registry record.
Details that would clarify implementation, such as the site structure, recruitment approach, adherence assessment, and protocol procedures, are not reported in the registry record. The record also does not report a statistical analysis plan, the handling of changes in treatment, or the approach to incomplete follow-up. These omissions limit how fully the real-life setting and the analysis can be characterized.
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: The study consisted of an initial screening visit followed by a 2-week run-in period before a 12-week treatment with investigational drug.
Overall Study
| Stage | Symbicort Turbuhaler |
|---|---|
| STARTED | 862 |
| COMPLETED | 796 |
| NOT COMPLETED | 66 |
Reasons for not completing this period:
| Reason | Symbicort Turbuhaler |
|---|---|
| Adverse Event | 15 |
| Pregnancy | 1 |
| Lost to Follow-up | 23 |
| Withdrawal by Subject | 13 |
| Protocol Violation | 6 |
| Incorrect enrolment | 8 |
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.
| Characteristic | Unit | Symbicort Turbuhaler |
|---|---|---|
| Participants analysed | 862 | |
| Age Continuous: All Participants | Years | 13.7 (SD 44.7) |
| Sex: Female, Male: Female | Participants | 455 |
| Sex: Female, Male: Male | Participants | 407 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Asthma Control Questionnaire (ACQ(5)) Score From Baseline at a Regional Level, measured over Baseline and 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | Units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in Asthma Control Questionnaire (ACQ(5)) score from baseline at a regional level. The ACQ(5) score is described as a 7-point Likert scale ranging from 0 to 6, with 0 representing good asthma control and 6 representing poor control. The endpoint is a continuous measure, and the registry specifies a regional mean change with a 95% confidence interval.
The change is defined from baseline, identified as Week 0, to the average score during treatment. That treatment-period average uses scores at Week 4, Week 8 and Week 12. This approach summarizes repeated assessments rather than relying only on a single score at the end of treatment. In general, a mean change can describe the average direction and magnitude of change in the measured group, while a confidence interval conveys uncertainty around that estimated mean. Neither conveys the full distribution of individual changes.
ACQ(5) is used as a measure of asthma control, so its score gives a structured way to track changes in that outcome over the treatment period. The registry record does not report the observed regional mean change, its confidence limits, or the number of participants included in this endpoint analysis. It is therefore not possible to characterize the size or precision of the observed change from the record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically relevant outcome and a defined period for assessing it: regional mean change in ACQ(5) from Week 0 to the average of scores at Week 4, Week 8 and Week 12. It also states the scale’s direction: lower scores correspond to better control and higher scores to poorer control. These details establish how an eventual estimate should be read. They do not establish what the estimate was.
No primary outcome estimate or confidence interval is reported in the registry record. Without those results, the direction, size and precision of the observed mean change cannot be described. The record also does not report the analyzed number of participants for this outcome, so the amount of outcome data contributing to the estimate is not stated. Enrollment of 862 is reported, but enrollment alone does not establish how many participants contributed to the primary analysis.
Design is important to the meaning of the stated study purpose. Although the summary frames the purpose as a comparison with patients’ current therapy, the recorded model is single-group and allocation is NA. The registry does not describe a concurrent control group. Change over time in a group receiving the listed intervention may be described, but it cannot by itself separate an intervention effect from other influences on change. General examples include natural variation in symptoms, changes in other care, expectations, or differences in who provides follow-up; the registry record does not say how these possibilities were assessed.
The endpoint uses multiple scores during treatment to form an average. In general, averaging repeated assessments can represent experience over a period rather than at one visit, but the resulting mean does not show whether individual participants followed similar or different patterns. The record does not report distributions of change, the proportion of participants with improvement or worsening, or a threshold for interpreting changes as important. No clinical-importance threshold is reported in the registry record.
The listed country-level ACQ(5) outcomes and quality-of-life outcomes broaden the set of questions addressed by the study. Their presence does not supply results or establish that any particular outcome changed. The record lists 17 outcome measures and 0 analyses, while numerical outcome findings are not reported in the registry record. With those limitations, interpretation should remain descriptive: the registry specifies what was intended to be measured, but does not provide the primary estimate needed to assess the observed change or its uncertainty.
9. Statistical Methods Explained
The registry record identifies a continuous primary outcome summarized by a mean and a 95% confidence interval. It does not report the numerical estimate, confidence limits, or a detailed statistical analysis plan. The concepts below are general explanations of how these statistics are commonly interpreted; they do not establish which exact procedures were used for this study.
What does a mean change describe?
A mean change summarizes the average difference between measurements at baseline and during treatment across the participants included in the analysis. For this outcome, the registry defines the treatment-period value as the average of ACQ(5) scores at Week 4, Week 8 and Week 12, compared with baseline at Week 0. Because the score runs from 0 for good control to 6 for poor control, a negative change would indicate movement toward lower scores and a positive change toward higher scores, if results were reported in that convention. The registry record does not state the sign convention used in any result display, and it does not report a mean change.
An average is useful for describing the center of a set of changes, but it can hide variation. Participants may have different changes, and an average alone does not show the spread, the number who improved or worsened, or whether changes were concentrated in a subgroup. Those additional summaries are not reported in the registry record.
How should a confidence interval be read?
In general, a confidence interval expresses the uncertainty associated with an estimated quantity under the assumptions of the statistical method used. A narrower interval indicates greater precision for that estimate than a wider interval, while an interval’s position relative to a reference value can inform interpretation. For a mean change, the reference of no average change is zero. A confidence interval does not mean that individual participant outcomes fall within its limits, nor does it account automatically for bias, design limitations, or unmeasured influences.
The primary outcome description specifies a 95% confidence interval, but the interval itself is not reported in the registry record. The method used to construct it, including any assumptions or adjustment for the study structure, is also not reported. Therefore, its numerical precision cannot be assessed.
Why does the design matter for statistical interpretation?
In general, a within-group change describes how an outcome differs over time among people measured in that group. A concurrent comparison can help distinguish changes associated with an intervention from changes that might also occur under another care condition, provided the comparison is designed and analyzed appropriately. This record describes a single-group model and does not list a concurrent control group. It therefore does not provide a like-for-like randomized contrast. Even a clearly estimated mean change would describe change in the observed group, not by itself establish that the intervention caused that change.
The registry summary’s stated comparison with current therapy does not resolve this design issue. The record does not report a method for constructing a controlled contrast with current therapy or details of a separate comparison group. A statistical analysis cannot be assumed to have overcome the limitations of the recorded design.
What can repeated assessments contribute?
Repeated measurements can characterize an outcome at more than one time during treatment. The specified average of Week 4, Week 8 and Week 12 scores gives weight to the treatment period rather than selecting only the final assessment. In general, using repeated measurements requires choices about how to handle incomplete visits, within-participant correlation and the target summary. The registry record defines the average but does not report the statistical procedure used to calculate it or how missing assessments were handled.
Repeated measurements from the same participant are related rather than independent observations. General statistical methods for repeated data account for this dependence when estimating uncertainty. The record does not state whether such a method was used, or whether the calculation used only participants with all specified scores. No particular method should be inferred from the endpoint description alone.
What is not reported about the analysis?
The registry record does not report an analysis population, exclusions, covariate adjustment, handling of missing data, or a detailed model. It also does not report hypothesis tests or a numerical primary result. The listed 0 analyses means that analysis results are not listed in the registry record; it does not establish what analyses may have been performed outside the record. These gaps prevent a full appraisal of the statistical implementation or independent checking of the reported endpoint.
The record includes planning assumptions for sample-size illustrations: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as stated fractions of the observed effect. These are planning illustrations, not observed power and not evidence that the study itself used that design. They do not match the recorded single-group model as a like-for-like control comparison. No sample-size justification for the actual trial design is reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 17 outcome measures. In addition to the regional primary ACQ(5) change, it includes country-level ACQ(5) changes for China, India, Indonesia, Taiwan and Thailand, and overall and domain-specific Asthma Quality of Life Questionnaire, Standardized Version outcomes. The record lists 0 analyses and does not provide numerical findings for these outcomes.
When a study examines several outcomes or subgroup results, general statistical practice recognizes that the chance of at least one apparently notable result can increase if many tests are conducted. Methods such as prespecifying a primary outcome, controlling a family-wise error rate, or treating secondary results as exploratory can address different multiplicity concerns. The registry record does not report a multiplicity strategy, a hierarchy of tests, or which outcomes were formally analyzed. It is not possible to infer whether adjustments were planned or used.
Missing-data handling is also not reported in the registry record. This matters because the primary endpoint requires baseline and treatment-period scores, and incomplete visits could affect which observations contribute to the average. The record does not state whether missing values were excluded, imputed, or addressed through a repeated-measures model. It does not report missingness by visit or the number included in the primary outcome analysis.
The registry record does not define an analysis population, such as all enrolled participants or a subset meeting specified criteria. Enrollment of 862 is reported, but the record does not establish that all enrolled participants contributed to every outcome. Without analysis-population and missing-data information, the extent to which estimates represent the enrolled group cannot be assessed.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Symbicort Turbuhaler | 12 | 862 | 1.4% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Symbicort Turbuhaler | 0 of 862 |
Most frequent serious adverse event terms
| Event term | Organ system | Symbicort Turbuhaler |
|---|---|---|
| Asthma | Respiratory, thoracic and mediastinal disorders | 2 of 862 |
| Headache | Nervous system disorders | 1 of 862 |
| Cerebral Infarction | Nervous system disorders | 1 of 862 |
| Myocardial Infarction | Cardiac disorders | 1 of 862 |
| Nasal Polyps | Respiratory, thoracic and mediastinal disorders | 1 of 862 |
| Post procedural haemorrhage | Surgical and medical procedures | 1 of 862 |
| Pneumonia | Infections and infestations | 1 of 862 |
| Inguinal hernia | Gastrointestinal disorders | 1 of 862 |
| Renal Cysts | Renal and urinary disorders | 1 of 862 |
| Appendicitis | Infections and infestations | 1 of 862 |
Serious events with the highest arm-level rate: asthma (0.2%), headache (0.1%), cerebral infarction (0.1%), myocardial infarction (0.1%), nasal polyps (0.1%).
The registry record lists 862 at risk for the Symbicort Turbuhaler group. It reports 12 serious adverse events and 0 other adverse events for that group. These are the recorded counts; the record does not give event descriptions for all serious events, exposure time, or a detailed account of how events were collected and classified.
The registry lists serious adverse event terms with percentages: Asthma at 0.2%; Headache, Cerebral Infarction, Myocardial Infarction, Nasal Polyps and Post procedural haemorrhage each at 0.1%. These entries describe the terms and percentages shown in the registry record. They should not be treated as a complete clinical narrative or as a comparison of risk against another treatment, because the record describes a single group and does not list a control group.
In general, safety counts require context about definitions, follow-up time, exposure and ascertainment. The registry record does not report enough detail to characterize those elements fully. The counts and listed terms describe what is recorded, but do not establish whether an event was caused by the intervention. The record also does not report deaths; the death value is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record establishes that SMARTASIA was a completed phase 4 study of Symbicort Maintenance and Reliever Therapy in asthma patients across Asia, with a single-group design. It specifies a primary measure of asthma control and a defined repeated-assessment period. It also records enrollment of 862 and safety counts for the Symbicort Turbuhaler group. These registry entries describe the study and its planned measurement; they do not provide the numerical primary outcome result.
Because the regional mean ACQ(5) change and its 95% confidence interval are not reported in the registry record, the observed direction, magnitude and precision of change cannot be evaluated from this record. The scale’s direction is known, but that alone cannot show whether scores changed or how consistently they changed among participants. No numerical threshold for clinical importance is reported, so the record also does not establish how a measured change would relate to such a threshold.
The study summary frames the question as comparison with current therapy, but the recorded model is single-group, allocation is NA, and no concurrent comparator is listed. As a result, the record does not provide a controlled estimate of how outcomes would differ under another treatment. A change from baseline, if reported, would be a within-group observation. In general, it could reflect several influences in addition to the intervention, and the registry record does not describe methods that would distinguish those influences.
The secondary outcomes and safety entries add context about the questions recorded and the events listed, but the registry does not report numerical results for the primary or secondary efficacy outcomes. The safety counts should not be interpreted as comparative risks or as proof of causation. Overall, the record supports a description of the study design, endpoint definition and recorded safety information. It does not support a conclusion about comparative effectiveness or a causal treatment effect.
13. Why This Trial Matters Statistically
This study is statistically notable for the contrast between its stated real-life comparison question and its recorded single-group design. The summary says the study aimed to compare Symbicort Maintenance and Reliever Therapy with patients’ current therapy, while the registry design fields identify one group and no allocation procedure. That distinction is essential: a before-and-after description and a controlled treatment comparison answer different questions.
The primary endpoint also illustrates how a repeated-measure summary defines the target quantity. Rather than using only a score at the end of treatment, the registry defines treatment-period ACQ(5) as the average at Week 4, Week 8 and Week 12, compared with baseline at Week 0. This specifies the intended summary clearly, while leaving important analysis details, including missing-visit handling and the confidence-interval method, unreported.
The outcome set spans regional asthma-control change, country-level ACQ(5) outcomes and quality-of-life measures. In general, a collection of outcomes can describe several aspects of a study question, but it also makes prespecification and multiplicity methods important to interpretation. The registry record does not report those methods or numerical outcome analyses.
Finally, the record lists enrollment and adverse-event information but does not report the primary estimate or its uncertainty. This illustrates why design and outcome definitions alone are not enough to judge the size or precision of a result. The registry record makes the intended measurement understandable, yet the absence of outcome estimates and analytic details sharply limits statistical conclusions.
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 limitation for interpreting efficacy is that the numerical primary outcome estimate and its 95% confidence interval are not reported in the registry record. The record therefore does not show the observed regional mean change, the precision of that estimate, or the number of participants contributing to the analysis.
The design is recorded as single-group, with allocation NA and no masking. Although the summary describes a comparison with current therapy, the registry record does not list a concurrent control group or a controlled analysis. Any reported before-and-after change would not, on its own, isolate an intervention effect from other influences over time.
The population description is limited to uncontrolled asthma patients in a real-life setting across Asia. Further eligibility criteria, recruitment details, site information and the analysis population are not reported in the registry record. The country-level outcomes name China, India, Indonesia, Taiwan and Thailand, but the record does not report country-specific enrollment or outcome estimates.
Important analytic details are also absent. The record does not report the statistical model, confidence-interval construction, missing-data procedure, handling of incomplete repeated assessments, covariate adjustment, or multiplicity strategy. It lists 17 outcome measures and 0 analyses, without numerical efficacy findings. Thus, the analysis choices and the relationship among the listed outcomes cannot be assessed.
For safety, the record gives event counts and selected serious-event terms but does not report exposure time, detailed ascertainment procedures, or a comparative group. These limitations constrain both the interpretation of counts and any assessment of causality. The registry record does not report a sample-size justification for the recorded single-group design; the stated planning assumptions are for illustrations involving equal allocation between two arms and should not be read as the study’s own design justification.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study to Investigate Real Life Effectiveness of Symbicort Maintenance and Reliever Therapy in Asthma Patients Across Asia — NCT00939341.
- Registry record last updated 2012-01-16; status last verified 2012-01.
- Results first posted 2011-11-28.
- 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.
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18. Record Summary
SMARTASIA is a completed phase 4 study of Symbicort Maintenance and Reliever Therapy in asthma patients across Asia. The registry record describes a single-group, unmasked design, allocation listed as NA, and enrollment of 862. The recorded start is 2009-07 and primary completion is 2010-08.
The primary outcome is regional mean change in ACQ(5) from baseline at Week 0 to the average of scores at Week 4, Week 8 and Week 12. The scale ranges from 0 to 6, with lower scores representing better asthma control. The numerical primary result and its 95% confidence interval are not reported in the registry record.
The record lists country-level ACQ(5) and quality-of-life outcomes, 17 outcome measures and 0 analyses. It reports 12 serious adverse events and 0 other adverse events in the Symbicort Turbuhaler group. The design does not include a listed concurrent comparator, so the record does not provide a like-for-like treatment comparison.