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 of Ozurdex® Treatment Practice in Patients With Macular Oedema Due to Retinal Vein Occlusion (NCT01618266), a registered phase not stated study. The primary outcome is Change From Baseline in Best Corrected Visual Acuity (BCVA) in the Study Eye.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01618266 |
| Phase | Phase not stated |
| Condition | Macular Edema, Retinal Vein Occlusion |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 375 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Allergan |
| Results posted | Yes |
2. Clinical Question
Population
Patients with macular oedema due to retinal vein occlusion treated at participating sites. The registry record lists 375 enrolled patients and identifies macular edema and retinal vein occlusion as the conditions studied. The primary outcome population is described as all enrolled patients.
Intervention
Dexamethasone intravitreal implant, identified as Ozurdex®. The description states that a 700 μg implant was administered into the eye according to physician judgment. The record presents this as a study of treatment practice rather than a fixed treatment assignment.
Comparator
No like-for-like control comparison is established in the registry record. It states that the study is not a randomized comparison, that allocation is not stated, and that the arms are not a like-for-like control comparison. The record therefore does not support interpreting the listed treatment data as a randomized treatment contrast.
Primary question
The primary outcome is change from baseline in best corrected visual acuity in the study eye, measured in letters, with assessments at baseline and Month 6. A positive change means more letters were read correctly and indicates improved visual acuity; a negative change means fewer letters were read correctly and indicates worsened visual acuity. The outcome results are not reported in the registry record, so the size and precision of any change cannot be described.
The study is titled as an examination of Ozurdex® treatment practice in patients with macular oedema due to retinal vein occlusion. Its epidemiological framing and physician-directed treatment mean the question is descriptive: what visual-acuity changes and safety events were recorded among patients treated in this setting? The registry record does not report a treatment-versus-control estimate for the primary outcome.
3. Trial Design
This is an epidemiological study of Ozurdex® use at sites treating patients with retinal vein occlusion. The brief description identifies the purpose as studying treatment practice in those sites. The registry record lists Allergan as sponsor, an enrollment of 375, and a status of completed. The listed study dates are 2011-11 for the start and 2013-04 for primary completion.
The intervention is a dexamethasone intravitreal implant. The arm description specifies a 700 μg implant administered into the eye according to physician judgment. This allows treatment decisions to reflect clinical practice, but the registry record does not describe a standardized decision rule or a treatment schedule. Those details are not reported in the registry record.
The record explicitly says this is not a randomized comparison; allocation is not stated, and the arms are not a like-for-like control comparison. Consequently, the listed design should not be read as a randomized controlled trial with balanced groups. Differences between groups, if any are presented elsewhere, could reflect differences in the patients or treatment decisions rather than treatment alone. The registry record does not report enough information to assess those possible differences.
The primary outcome is change from baseline in best corrected visual acuity in the study eye, measured in letters, with a timeframe of baseline and Month 6. Secondary outcomes are listed for subgroups defined by retinal vein occlusion type, prior treatment history, duration of macular oedema onset, and treatment received. The registry record lists 12 outcome measures, but reports no analyses. It does not report the enrollment distribution across these subgroups, the detailed follow-up procedures, or the rules used to handle treatment changes and incomplete follow-up.
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 | Ozurdex® (Dexamethasone Intravitreal Implant) |
|---|---|
| STARTED | 375 |
| COMPLETED | 279 |
| NOT COMPLETED | 96 |
Reasons for not completing this period:
| Reason | Ozurdex® (Dexamethasone Intravitreal Implant) |
|---|---|
| Lost to Follow-up | 9 |
| Treatment satisfaction | 10 |
| Other reasons | 11 |
| Lack of Efficacy | 23 |
| Protocol Violation | 43 |
Analysis population for the primary outcome, as defined in the registry: All enrolled patients
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 | Ozurdex® (Dexamethasone Intravitreal Implant) |
|---|---|---|
| Participants analysed | 375 | |
| Age, Continuous | Years | 70.31 (SD 11.19) |
| Sex: Female, Male: Female | Participants | 169 |
| Sex: Female, Male: Male | Participants | 206 |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Best Corrected Visual Acuity (BCVA) in the Study Eye, measured over Baseline, Month 6.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Letters |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change from baseline in best corrected visual acuity (BCVA) in the study eye. BCVA is assessed using an eye chart and recorded as the number of letters read correctly, on a scale ranging from 0 to 100 letters. The stated timeframe is baseline and Month 6.
The registry description gives the direction of interpretation: a positive change in letters read means visual acuity improved, while a negative change means it worsened. This makes the endpoint clinically interpretable as a change in measured visual function rather than simply a treatment-use measure. In statistical terms, it is a continuous outcome: participants can have different numerical changes, and a group mean can describe the average change. A standard deviation can describe how dispersed individual changes are around that mean.
Using change from baseline focuses on how the measured outcome differs from each participant’s initial value. In general, this can help describe the course of the measured outcome during follow-up, but it does not by itself establish that treatment caused the change. In a nonrandomized treatment-practice study, other differences among patients and clinical decisions may also contribute.
The registry record identifies the mean and standard deviation as the summary type, but the actual endpoint results are not reported in the registry record. Therefore, the direction, magnitude, and variability of the primary outcome cannot be characterized from the recorded results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary question concerns change in BCVA from baseline to Month 6 among enrolled patients. The registry record defines how to interpret the direction of change: a positive number of letters means improved visual acuity, and a negative number means worsened visual acuity. However, it does not report the mean change, standard deviation, confidence interval, or any test result for this endpoint. The observed direction, size, and precision of the primary outcome are therefore not reported in the registry record.
The record lists 375 enrolled patients and describes the primary population as all enrolled patients. Enrollment is not the same as the number with an observed Month 6 measurement. The number with available endpoint data, and how many were included in any analysis, are not reported in the registry record. Without those details, the amount of missing outcome information and its possible influence cannot be assessed.
The design also matters when interpreting any outcome estimates. The registry record describes an epidemiological study of treatment practice, states that it is not a randomized comparison, and says allocation is not stated and the arms are not a like-for-like control comparison. A change over time in a treated group would describe what happened to that group during follow-up; it would not, by itself, isolate the effect of the implant from other influences. A comparison between non-equivalent groups would likewise not provide the same protection against confounding as a randomized comparison.
Several secondary outcomes are defined by subgroups, including BRVO and CRVO, treatment history, timing of macular oedema onset, and patients only treated with Ozurdex®. These subgroup questions may describe variation in recorded change, but the registry record gives no subgroup results, sample sizes, or analyses. It is not possible to judge whether any apparent subgroup differences were substantial, precise, or based on limited observations.
For safety, the record lists 98 serious adverse events among 375 at risk and 252 other adverse events among 375 at risk in the Ozurdex® group. It also lists several serious adverse event terms with percentages. Those figures describe reported events in the recorded group; they are not a comparison against a control group. Deaths are not reported in the registry record. The safety details and their limitations are discussed separately below.
Overall, the registry record defines an observational treatment-practice study and its intended outcomes, but does not provide outcome analyses. It supports a description of the study question and certain safety counts, not a conclusion about the magnitude or statistical precision of BCVA change or a causal treatment effect.
9. Statistical Methods Explained
The primary outcome is continuous, because BCVA change is recorded numerically in letters. The registry record specifies that the intended summary is a mean with a standard deviation. A mean describes the average value across participants with measured outcomes. A standard deviation describes how much individual values vary around that mean; it is not a confidence interval and does not directly show how precisely the mean has been estimated.
What would a confidence interval add?
In general, a confidence interval gives a range of values compatible with the observed data under the statistical model used. Its width conveys the precision of an estimate: a narrower interval indicates greater precision, while a wider interval indicates greater uncertainty. The registry record does not report a confidence interval for the primary BCVA change, so the precision of that estimate cannot be assessed from the posted results.
What does change from baseline represent?
Change from baseline compares a participant’s follow-up measurement with their starting measurement. For this outcome, the registry description states that positive change means more letters were read correctly and negative change means fewer letters were read correctly. A mean change can summarize the group’s average trajectory, while the standard deviation can show how varied individual changes were. Neither summary alone explains why the change occurred. In general, changes over time can reflect treatment, underlying disease, other care, measurement variation, and who remains available for follow-up.
Why does the study design affect interpretation?
The registry record characterizes the study as epidemiological and states that it is not a randomized comparison. Allocation is not stated, and the arms are not described as a like-for-like control comparison. In general, random allocation helps make groups comparable in expectation, whereas treatment-practice data can reflect clinical decisions and differences among patients. Statistical adjustment can sometimes address measured differences, but the registry record does not report an analysis plan, adjusted estimates, or which covariates were considered. It is therefore not possible to determine whether any adjustment was used or how adequately potential confounding was addressed.
How should subgroup analyses be understood?
The listed secondary outcomes separate BCVA change by BRVO or CRVO diagnosis, prior treatment status, timing of macular oedema onset, and treatment history. Such analyses can describe whether outcome patterns differ across patient groups. In general, subgroup estimates are often less precise than an overall estimate because each subgroup includes fewer participants. Their interpretation also depends on how groups were defined and whether comparisons were planned in advance. Those details and the subgroup results are not reported in the registry record.
What do the planning illustrations mean?
The record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The target effect is expressed as a stated fraction of the observed effect. These are planning assumptions, not a description of the trial’s own design or proof that the study had a particular probability of detecting an effect. Sample sizes calculated from such assumptions are planning illustrations, not observed power. The registry record does not report a sample-size justification for the study, and the observed primary effect needed to interpret these illustrations is not reported in the registry record.
In general, over-dispersion means that observed variation is greater than a statistical model assumes. When that occurs, standard errors based on the narrower variance assumption may be too small, making estimates appear more precise than they are. This concept is relevant when choosing models for outcomes with extra variation, but the primary BCVA measure is described as continuous and summarized by a mean and standard deviation. The registry record does not report model details or a finding of over-dispersion.
The registry record lists 12 outcome measures and zero analyses. It does not report test statistics, p-values, confidence intervals, adjusted or unadjusted estimates, or a detailed statistical analysis plan. General explanations of these methods cannot substitute for the missing analyses; no statistical significance or precision claim can be made for the primary outcome from the record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 12 outcome measures, including the primary BCVA change and secondary measures for clinical subgroups. Considering several outcomes or subgroup comparisons can raise a multiplicity question: when many statistical tests are performed, the chance of at least one apparently unusual result can increase. In general, a prespecified strategy may control or otherwise address that issue. The registry record does not report whether any multiplicity adjustment, hierarchy, or other strategy was planned or used. It also lists zero analyses, so there are no reported test results to evaluate for multiplicity.
Missing data are another important consideration for a baseline-to-Month 6 endpoint. The record lists 375 enrolled patients, but it does not report how many had a usable Month 6 BCVA measurement, how many lacked follow-up, or why measurements were missing. It does not describe an imputation method, a complete-case analysis, or sensitivity analyses. In general, the implications of missing outcomes depend partly on why they are missing and on how the analysis handles them; those circumstances cannot be assessed from the registry record.
The primary population is described as all enrolled patients, but the record does not report the analysis population or confirm how participants with incomplete data were handled. The enrollment count should therefore not be interpreted as the number included in an endpoint analysis. The registry record also does not report subgroup denominators or whether subgroup definitions and analyses were prespecified.
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 |
|---|---|---|---|
| Ozurdex® (Dexamethasone Intravitreal Implant) | 98 | 375 | 26.1% |
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 |
|---|---|
| Ozurdex® (Dexamethasone Intravitreal Implant) | 252 of 375 |
Most frequent serious adverse event terms
| Event term | Organ system | Ozurdex® (Dexamethasone Intravitreal Implant) |
|---|---|---|
| Ocular Hypertension | Eye disorders | 32 of 375 |
| Cataract | Eye disorders | 26 of 375 |
| Glaucoma | Eye disorders | 6 of 375 |
| Cataract Surgery | Surgical and medical procedures | 3 of 375 |
| Vitreous Haemorrhage | Eye disorders | 3 of 375 |
| Stroke | Nervous system disorders | 2 of 375 |
| Pulmonary Embolism | Respiratory, thoracic and mediastinal disorders | 2 of 375 |
| Macular Fibrosis | Eye disorders | 2 of 375 |
| Death | General disorders | 2 of 375 |
| Cardiac Arrest | Cardiac disorders | 1 of 375 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Ozurdex® (Dexamethasone Intravitreal Implant) |
|---|---|---|
| Ocular Hypertension | Eye disorders | 128 of 375 |
| Cataract | Eye disorders | 124 of 375 |
Serious events with the highest arm-level rate: ocular hypertension (8.5%), cataract (6.9%), glaucoma (1.6%), cataract surgery (0.8%), vitreous haemorrhage (0.8%).
For the Ozurdex® group, the registry record lists 375 participants at risk for serious adverse events and 98 affected. For other adverse events, it lists 375 at risk and 252 affected. These are separate safety counts; the record does not describe them as a comparison with a control group. Deaths are not reported in the registry record.
The listed serious adverse event terms include Ocular Hypertension at 8.5%, Cataract at 6.9%, Glaucoma at 1.6%, Cataract Surgery at 0.8%, Vitreous Haemorrhage at 0.8%, and Stroke at 0.5%. These entries indicate the percentages recorded for those terms in the registry results. They do not establish whether an event was caused by treatment, and the record does not provide a comparative estimate that could distinguish treatment-related risk from background risk.
In general, safety counts need to be read in light of how events were defined, collected, and followed over time. Those details, along with event timing and participant-level overlap among terms, are not reported in the registry record. The figures describe reported events in this study group; they are not by themselves a causal safety comparison.
12. What the Result Does, and Does Not, Mean
The record identifies an epidemiological study of dexamethasone intravitreal implant use in patients with macular oedema due to retinal vein occlusion. It specifies a primary visual-acuity outcome, how that outcome is measured, and the intended baseline-to-Month 6 timeframe. It also lists secondary outcomes for diagnostic and treatment-history subgroups and records safety counts for the Ozurdex® group.
What the record does not establish is the size or direction of the average BCVA change. No primary outcome estimate, standard deviation, confidence interval, or analysis result is reported in the registry record. The listed enrollment of 375 does not reveal how many participants contributed endpoint data. Consequently, neither the magnitude of change nor its precision can be described from the recorded results.
The design limits causal interpretation. The study is not a randomized comparison, allocation is not stated, and the arms are not a like-for-like control comparison. A measured change during follow-up would describe the experience of the observed patients, not necessarily the effect of the implant alone. Physician judgment determined administration, and the record does not describe a control group that could provide a comparable estimate of what would have happened without treatment.
The safety counts and serious adverse event percentages provide descriptive information, but the record does not establish causal attribution or a comparative safety difference. Deaths are not reported in the registry record. No treatment recommendation follows from these registry entries; they define what was studied and what was recorded, while leaving key outcome analyses unavailable.
13. Why This Trial Matters Statistically
This study matters statistically because it illustrates the distinction between documenting treatment practice and estimating a causal treatment effect. The record describes an epidemiological study in which the implant was administered according to physician judgment, and it explicitly notes that the study is not a randomized comparison. Those design features shape what an outcome estimate could mean, even if complete results were available.
The BCVA endpoint is a continuous measure with an interpretable direction: positive change means more letters read correctly, and negative change means fewer. Reporting a mean together with a measure of variability can describe both the average trajectory and differences among participants. But those summaries are not reported in the registry record, so the statistical question cannot be answered from the posted results.
The listed secondary outcomes also show why interpretation requires attention to analysis choices. Results split by diagnosis, prior treatment, or onset timing may answer narrower descriptive questions, but subgroup sizes and estimates are not reported. With multiple outcomes, the analysis plan and handling of multiplicity would matter; those details are not reported in the registry record either.
Finally, the enrollment count and safety counts should not be mistaken for a complete account of endpoint data or comparative evidence. The number contributing to Month 6 BCVA, missing-data handling, and statistical analyses are not reported. This record therefore demonstrates how study design, outcome availability, precision, and safety context all affect the conclusions that can responsibly be drawn.
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 registry record does not report the primary BCVA results or any statistical analyses. There is no reported mean change, standard deviation, confidence interval, or test result. This prevents assessment of the endpoint’s direction, magnitude, and precision.
Although enrollment is listed as 375, the number of participants with baseline and Month 6 BCVA measurements is not reported. Follow-up completeness, reasons for missing measurements, and missing-data methods are also not reported in the registry record. It is therefore unclear how the enrolled population relates to the population that could contribute to the primary outcome.
The treatment-practice design is another limitation for causal interpretation. The registry record says that the study is not a randomized comparison, allocation is not stated, and the arms are not a like-for-like control comparison. The implant was administered according to physician judgment. The record does not report a detailed account of treatment exposure over time, use of other care, or methods for addressing patient differences.
Although multiple subgroup outcomes are listed, subgroup sizes, estimates, and analysis methods are not reported. The registry record also does not report a multiplicity strategy, a detailed statistical plan, or a sample-size justification for the study. Safety information includes counts and selected serious adverse event terms, but event definitions, follow-up details, causal attribution, and comparative safety results are not reported. Deaths are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of Ozurdex® Treatment Practice in Patients With Macular Oedema Due to Retinal Vein Occlusion — NCT01618266.
- Registry record last updated 2016-03-14; status last verified 2016-02.
- Results first posted 2016-02-11.
- 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
The completed study, sponsored by Allergan, examined Ozurdex® treatment practice in patients with retinal vein occlusion and macular oedema. Enrollment was 375. The listed study start was 2011-11 and primary completion was 2013-04.
The primary endpoint was change from baseline to Month 6 in BCVA in the study eye, measured in letters. The registry record describes the study as epidemiological and not a randomized comparison; allocation is not stated, and the arms are not a like-for-like control comparison. It lists 12 outcome measures and zero analyses.
For the Ozurdex® group, the safety record lists 98 affected by serious adverse events among 375 at risk and 252 affected by other adverse events among 375 at risk. Deaths are not reported in the registry record. Primary outcome results and analysis details are not reported in the registry record.