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 A Research Study Comparing Wegovy to Other Weight Management Drugs in People Living With Obesity in America (NCT05579249), a randomized phase 4 study. The primary outcome is Number of Participants Who Achieved Greater Than or Equal to (≥) 10.0 Percent (%) Body Weight Reduction (Yes/no).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05579249 |
| Phase | Phase 4 |
| Condition | Obesity |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 500 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novo Nordisk A/S |
| Results posted | Yes |
2. Clinical Question
Population
Participants with obesity in a multi-employer setting in the US. The study was conducted across three US-based employers, whose employees represented a range of demographic and job-function backgrounds, including hospitality, clerical, administrative, housekeeping, maintenance, and specialised employees. The registry record does not report further participant characteristics for the analyzed outcome.
Intervention
Semaglutide 2.4 mg, given as a once-weekly subcutaneous injection for 52 weeks, alongside a reduced-calorie diet and increased physical activity. The question concerns its performance in the study setting, not under conditions that differ from the registered study description.
Comparator
One of four commercially available anti-obesity medications, selected by the study doctor: orlistat, phentermine/topiramate, naltrexone/bupropion, or liraglutide. These medications were also used alongside a reduced-calorie diet and increased physical activity for 52 weeks. The registry record does not report how participants were distributed among the individual comparator medications.
Primary question
At the end of treatment, week 52, how many participants achieved at least 10.0% body-weight reduction? The registered primary outcome is a yes/no responder measure. Although the study was designed to compare treatment groups, comparative estimates and uncertainty for this outcome are not reported in the registry record. Therefore, the outcome definition alone does not establish the direction or size of any difference between groups.
3. Trial Design
This was a phase 4, randomized, open-label, parallel-group study with planned enrollment of 500 participants. It is described as a pragmatic clinical study in a multi-employer setting in the US. The registry record lists Novo Nordisk A/S as the sponsor, a study start date of 2023-01-19, primary completion on 2024-11-27, and a completed status.
Participants were assigned to semaglutide or to a group receiving one of four commercially available anti-obesity medications. The study description says the study doctor chose the comparator medication. The registry record does not report the allocation method beyond randomization, the allocation ratio, or the number of participants assigned to each medication. Masking is listed as none, so the study was open-label; the registry record does not describe any blinded outcome assessment.
Both treatment strategies were described as adjuncts to a reduced-calorie diet and increased physical activity. Semaglutide was specified as a once-weekly subcutaneous injection for 52 weeks. The comparator group was to receive one of the listed medications for 52 weeks. The registry record does not report details of adherence support, treatment switching, or other implementation features beyond the pragmatic study description.
The primary outcome is a binary measure of achieving at least 10.0% body-weight reduction at week 52. Listed secondary outcomes address percentage change in body weight, physical functioning and quality of life, larger body-weight reduction thresholds, study-product coverage, and work limitations. The registry record does not report a detailed protocol or statistical analysis plan.
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
| Stage | Semaglutide 2.4 mg | Other Anti-obesity Medications (AOMs) |
|---|---|---|
| STARTED | 250 | 250 |
| Full Analysis Set | 250 | 250 |
| Safety Analysis Set | 242 | 242 |
| COMPLETED | 214 | 191 |
| NOT COMPLETED | 36 | 59 |
Reasons for not completing this period:
| Reason | Semaglutide 2.4 mg | Other Anti-obesity Medications (AOMs) |
|---|---|---|
| Withdrawal by Subject | 1 | 3 |
| Lost to Follow-up | 33 | 52 |
| Physician Decision | 2 | 2 |
| Death | 0 | 2 |
Analysis population for the primary outcome, as defined in the registry: Full analysis set included all randomized participants. Overall number of participants analyzed = participants with available data for 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: Full analysis set included all randomized participants.
| Characteristic | Unit | Semaglutide 2.4 mg | Other Anti-obesity Medications (AOMs) | Total |
|---|---|---|---|---|
| Participants analysed | 250 | 250 | 500 | |
| Age, Continuous | Years | 40.6 (SD 9.3) | 42.0 (SD 10.3) | 41.3 (SD 9.8) |
| Sex: Female, Male: Female | Participants | 225 | 223 | 448 |
| Sex: Female, Male: Male | Participants | 25 | 27 | 52 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 159 | 150 | 309 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 91 | 100 | 191 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 10 | 8 | 18 |
| Race (NIH/OMB): Asian | Participants | 17 | 7 | 24 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 5 | 1 | 6 |
| Race (NIH/OMB): Black or African American | Participants | 23 | 27 | 50 |
| Race (NIH/OMB): White | Participants | 193 | 202 | 395 |
| Race (NIH/OMB): More than one race | Participants | 2 | 5 | 7 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Who Achieved Greater Than or Equal to (≥) 10.0 Percent (%) Body Weight Reduction (Yes/no), measured over At end of treatment (week 52).
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants who achieved at least 10.0% body-weight reduction by the end of treatment at week 52. Each participant is classified as either meeting or not meeting the threshold; the outcome is therefore a binary responder measure. The registry record describes the outcome as a count of participants with available data for this measure within the full analysis set, which it defines as all randomized participants.
A threshold endpoint can make a result easier to interpret as the number of participants reaching a prespecified level of change. It also compresses information: participants just below the threshold and participants with little or no change are both classified as not achieving the endpoint, while participants above it are counted as responders regardless of how far they exceed it. This is a general property of binary threshold outcomes, not a finding about participants in this study.
The endpoint is intended to support a comparison between semaglutide and the comparator medication group. A count by itself does not describe the comparative effect unless the corresponding group denominators and an analysis are also available. The registry record does not report a comparative estimate, confidence interval, or statistical test for this primary endpoint. The recorded outcome definition therefore identifies what was to be counted, but does not establish how the treatment groups compared.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically interpretable responder question: whether participants reached at least 10.0% body-weight reduction at week 52. However, the comparative primary-outcome result is not reported in the registry record. No group-specific responder counts, denominators for the primary outcome, effect estimate, confidence interval, or p-value are available in the stated details. The direction, magnitude, and precision of the primary comparison therefore cannot be described.
This distinction matters because a registered endpoint is not itself a result. Knowing the threshold and time point explains what the study intended to measure; it does not show how many participants met the threshold or whether the groups differed. Even if a result were statistically significant, a confidence interval would be needed to assess the range of comparative effects compatible with the data. That general interpretation cannot be applied numerically without the estimates.
The study is described as randomized, which is relevant to how treatment groups are intended to be compared. It does not remove the need to examine outcome completeness, analysis choices, and uncertainty. The registry record defines the primary population as all randomized participants, while the number analyzed for the outcome is limited to participants with available data. The record does not report the amount or pattern of missing outcome data, or how missingness was handled.
The secondary outcomes broaden the scope beyond the binary primary endpoint. They include percentage change in body weight; physical functioning and quality-of-life measures; thresholds for greater body-weight reductions; percentage of days covered by study product; coverage of at least 80% of days; and work limitations. These outcomes capture different aspects of response and study experience, but their comparative results are not reported in the registry record. No conclusions about those outcomes can be drawn from their names alone.
The serious adverse event figures are reported separately and should not be treated as substitutes for the missing primary efficacy comparison. They describe event counts in the treatment groups, not a complete assessment of comparative safety. The registry record also does not provide the analytical detail needed to interpret uncertainty around these counts. Overall, the available information describes the study question, design, outcome definitions, and selected safety counts, but does not establish the primary comparative result.
9. Statistical Methods Explained
What does a binary endpoint capture?
A binary endpoint assigns each participant to one of two outcome categories. In this study, those categories are achieving or not achieving at least 10.0% body-weight reduction at week 52. Analysis of a binary endpoint can compare the proportion of participants in each group who meet the definition, or use another prespecified measure of group difference. The registry record does not report which comparative measure or model was used for the primary outcome. The outcome is described as a count, but counts alone are difficult to compare when the numbers of participants with available outcome data differ between groups.
Thresholding is useful when the question focuses on reaching a defined level, but it discards detail about the amount of change within each category. Percentage change in body weight is also listed as a secondary outcome and retains more of that continuous variation. The registry record does not report comparative results for either endpoint.
How should randomization and masking be understood?
Randomization is intended to create treatment groups whose baseline characteristics are comparable on average, reducing the risk that treatment choice is systematically linked to participant characteristics. It does not guarantee identical groups, and it does not by itself resolve missing outcome data or departures from assigned treatment. The registry record identifies the study as randomized but does not report the allocation procedure, allocation ratio, or group sizes for the primary analysis.
Masking is listed as none. In an open-label study, participants and study personnel know the assigned treatment. This can be relevant to outcomes that involve participant reports, treatment satisfaction, work limitations, or judgments about symptoms. Body weight is more directly measured, but the registry record does not describe measurement procedures or whether outcome assessors were masked. These are general considerations; they do not establish that any particular bias occurred in this study.
What do estimates and confidence intervals contribute?
A comparative estimate expresses the observed difference or other contrast between groups using a defined statistical measure. A confidence interval describes the uncertainty around that estimate: narrower intervals indicate greater precision, while wider intervals indicate less precision. A confidence interval is not a guarantee that the true effect lies within its limits, and its interpretation depends on the analysis and assumptions. No primary comparative estimate or confidence interval is reported in the registry record, so the precision of the primary comparison cannot be assessed.
A p-value addresses how compatible the observed data are with a specified null hypothesis under the statistical model. It does not measure the size or importance of an effect. The registry record does not report a primary-outcome p-value or the statistical test used. A test result, even if available, would need to be considered alongside the estimated effect, its uncertainty, and the outcome definition.
What does the planning illustration describe?
The record describes a planning illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. Such calculations are planning scenarios: they illustrate the number of participants per arm associated with assumed conditions and a chosen power target. They are not observed trial results, and they are not observed power. The numerical planning results are not reported in the registry record.
The assumptions matter. A planning result based on an observed effect depends on that effect estimate and on the selected fraction of it; uncertainty in the observed effect is not necessarily captured by a simple illustration. Equal allocation is an assumption of the planning calculation, not evidence that the trial enrolled equal numbers in each group. The registry record does not report the original sample-size justification, the target power, or the full assumptions used for the trial's own design.
Why do outcome distributions matter?
Statistical methods should reflect the type and distribution of the outcome. A yes/no endpoint is not analyzed in the same way as a continuous score or a count of repeated events. For count outcomes, over-dispersion occurs when the observed variability exceeds what a basic count model assumes. If present, it can make standard errors too small unless the analysis accounts for the extra variability. This is a general methodological point; the registry record does not report whether over-dispersion was assessed or relevant to any analysis.
The secondary outcomes include binary, percentage, score, and coverage measures. Different outcome types may require different analytic approaches, and repeated measurements may require attention to within-participant correlation. The record does not provide enough analysis detail to identify the models, covariates, handling of repeated measures, or treatment of multiple outcomes. No particular approach should be assumed from the outcome names alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists the primary responder outcome and secondary outcomes covering body-weight change, physical function, quality of life, study-product coverage, and work limitations. When several outcomes or comparisons are examined, the chance of at least one apparently notable result can increase. Statistical procedures can address multiplicity, but the registry record does not report whether any adjustment was planned or used, how outcome priority was handled, or which comparisons were treated as confirmatory.
The primary analysis population is described as the full analysis set, including all randomized participants. For the primary outcome, the number analyzed is defined as the participants with available data for that outcome. This means the analysis denominator may not include every randomized participant if some outcome data are unavailable. The registry record does not report the number with missing week-52 data, reasons for missingness, or methods used to address missing values.
Missingness can affect interpretation if the availability of outcome data is related to treatment assignment or outcome status. Complete-case analysis, imputation, and sensitivity analyses make different assumptions; the registry record does not specify which methods were used. It also does not report a detailed statistical analysis plan, prespecified handling of protocol deviations, or the analyses supporting the listed secondary outcomes. Accordingly, the primary population definition is available, but the practical handling of missing data and multiplicity is not reported in the registry record.
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 |
|---|---|---|---|
| Semaglutide 2.4 mg | 3 | 242 | 1.2% |
| Other Anti-obesity Medications (AOMs) | 8 | 242 | 3.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Semaglutide 2.4 mg | 0 of 250 |
| Other Anti-obesity Medications (AOMs) | 2 of 250 |
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 |
|---|---|
| Semaglutide 2.4 mg | 0 of 242 |
| Other Anti-obesity Medications (AOMs) | 0 of 242 |
Most frequent serious adverse event terms
| Event term | Organ system | Semaglutide 2.4 mg | Other Anti-obesity Medications (AOMs) |
|---|---|---|---|
| Abortion spontaneous | Pregnancy, puerperium and perinatal conditions | 1 of 242 | 2 of 242 |
| Cholecystitis | Hepatobiliary disorders | 0 of 242 | 2 of 242 |
| Amyotrophic lateral sclerosis | Nervous system disorders | 1 of 242 | 0 of 242 |
| Atrioventricular block complete | Cardiac disorders | 1 of 242 | 0 of 242 |
| Drug hypersensitivity | Immune system disorders | 0 of 242 | 1 of 242 |
| Cardiac arrest | Cardiac disorders | 0 of 242 | 1 of 242 |
| Diverticulitis | Infections and infestations | 0 of 242 | 1 of 242 |
| Road traffic accident | Injury, poisoning and procedural complications | 0 of 242 | 1 of 242 |
| Suicide attempt | Psychiatric disorders | 0 of 242 | 1 of 242 |
Serious events with the highest arm-level rate: cholecystitis (0.8%), abortion spontaneous (0.8%), amyotrophic lateral sclerosis (0.4%), atrioventricular block complete (0.4%), drug hypersensitivity (0.4%).
The registry record lists serious adverse events affecting 3 participants in the semaglutide 2.4 mg group and 8 participants in the other anti-obesity medication group. Each group is listed with 242 participants at risk. Other adverse events are listed as affecting 0 participants in each group. Deaths are listed as 0 in the semaglutide group and 2 in the other anti-obesity medication group. These are descriptive counts; they do not, on their own, establish that treatment caused or prevented an event.
The registry record lists serious-event terms including Cholecystitis and Abortion spontaneous, each at 0.8%, and Amyotrophic lateral sclerosis, Atrioventricular block complete, Drug hypersensitivity, and Cardiac arrest, each at 0.4%. These are the percentages as reported. The record does not provide enough detail to determine the event-specific denominators, timing, relationship to study medication, or whether participants could contribute more than one event term.
Serious-event counts should be read in context: they are not estimates of the overall safety profile, and counts without comparative uncertainty do not establish a treatment difference. The registry record does not report confidence intervals or a statistical comparison for these safety figures.
12. What the Result Does, and Does Not, Mean
The record establishes that the study was designed to compare semaglutide with a group receiving one of four commercially available anti-obesity medications in a pragmatic, multi-employer US setting. It also establishes the registered primary question: the number of participants meeting the at least 10.0% body-weight reduction threshold at week 52. These details clarify the population, treatment strategies, outcome, and time point under study.
The record does not report the comparative primary-outcome results. It therefore does not support a conclusion about which group had more participants meeting the threshold, how large any difference was, or how precisely it was estimated. It also does not support conclusions about the listed secondary outcomes, because their comparative results are not reported in the registry record.
The serious adverse event counts provide a limited descriptive account. They do not show whether the observed counts reflect a treatment effect, and the record does not give uncertainty estimates or sufficient event-level context for a fuller comparison. Absence of reported other adverse events in these group counts should not be interpreted as proof that no adverse events occurred outside the reported category or reporting scope.
More generally, a randomized design can strengthen a treatment comparison when the analysis and follow-up are appropriately reported, but it does not make unreported estimates available. The endpoint definition, sample-size assumptions, and descriptive safety counts are not substitutes for comparative outcome estimates. The registry record supports description of the registered study and selected results, but not a treatment recommendation or a claim that either strategy is more effective or safer.
13. Why This Trial Matters Statistically
This study addresses a comparative-effectiveness question in a setting intended to reflect medication use across multiple employers. The pragmatic description and varied job functions represented among employees make the setting relevant to understanding how a study can extend beyond a narrowly defined clinical environment. At the same time, the registry record does not report enough participant-level detail to determine how well the analyzed population represents other settings.
Statistically, the primary outcome illustrates the value and limitations of a responder threshold. Counting participants who reach a defined level can communicate an outcome in an accessible form, while losing information about the range of changes within each response category. The listed percentage-change outcome offers a different perspective, but the registry record does not provide its comparative result either.
The study also highlights why design labels alone do not answer an effectiveness question. Randomization is relevant, but interpretation requires group-specific outcomes, denominators, an estimate of the comparison, and measures of uncertainty. Open-label conduct and a comparator group that includes several medication options also make transparent reporting of implementation and analysis important. The record does not report how participants were distributed among those options.
Finally, reporting the analysis population and missing-data methods matters because the primary outcome is analyzed among participants with available data. Without the amount and handling of missing data, readers cannot fully assess how that denominator relates to all randomized participants. The study's topic and design make the question important, while the absence of comparative outcome estimates limits what can be learned from this registry record alone.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for interpretation is that comparative results for the primary and secondary outcomes are not reported in the registry record. The primary endpoint is defined, but the group-specific counts, denominators, effect estimate, confidence interval, and p-value are not available in the stated results. This prevents assessment of the direction, magnitude, and precision of the planned comparison.
The comparator group combines four medications, with the study doctor choosing the medication. The record does not report how many participants received each option or provide medication-specific outcome results. Consequently, the group-level comparison cannot be interpreted as a comparison with any one named comparator medication.
The record describes an open-label study but does not report details of outcome assessment, adherence, treatment changes, or the allocation procedure. The primary population includes all randomized participants, while the outcome analysis includes participants with available data; the number and pattern of missing outcomes and the methods used to handle them are not reported. These omissions limit assessment of potential bias and the relationship between the analyzed sample and the randomized population.
The registry record does not report the trial's original sample-size justification, a complete statistical analysis plan, multiplicity procedures, or comparative uncertainty for the safety counts. It also does not provide enough event-level detail to interpret the serious-event terms beyond the listed counts and percentages. These are limitations of the information reported in the registry record, not findings that establish a flaw in how the study was conducted.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Research Study Comparing Wegovy to Other Weight Management Drugs in People Living With Obesity in America — NCT05579249.
- Registry record last updated 2026-01-14; status last verified 2025-12.
- Results first posted 2026-01-14.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT05579249 is a completed phase 4, randomized, open-label, parallel-group pragmatic clinical study sponsored by Novo Nordisk A/S. It planned enrollment of 500 participants with obesity in a multi-employer US setting. The study compared semaglutide 2.4 mg with a group receiving one of four commercially available anti-obesity medications, alongside a reduced-calorie diet and increased physical activity. Semaglutide was specified once weekly for 52 weeks.
The primary endpoint was the number of participants achieving at least 10.0% body-weight reduction at week 52. Secondary outcomes addressed body-weight change, physical functioning and quality of life, study-product coverage, and work limitations. Comparative primary and secondary outcome estimates are not reported in the registry record. Serious adverse event counts and selected event terms are listed, but do not establish comparative safety effects.