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 Blind Child Melatonin Treatment Study (NCT00691444), a non-randomized na study. The primary outcome is Circadian Phase Marker, as Measured by the Melatonin Levels in Serial Salivary and/or Plasma Samples..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00691444 |
| Phase | NA |
| Condition | Blindness |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Oregon Health and Science University |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns blind children. The registry lists enrollment as 10, but it does not provide participant-level information or study results. The record therefore does not establish which children received treatment, how many completed follow-up, or what characteristics participants had.
Intervention
The registry describes melatonin treatment plans with doses of up to 0.5 mg daily, up to 10 mg daily, or up to 20 mg daily. Within each plan, the dose was to be reduced gradually if treatment worked, in an effort to identify the lowest effective dose. The description says that unsuccessful treatment would be stopped, with later enrollment in a different treatment plan.
Comparator
The registry identifies three arms, but allocation was non-randomized. The registry notes that these arms are not a like-for-like control comparison. It does not report how participants were assigned to plans or provide baseline information that would help assess whether the groups were comparable.
Primary question
The primary question was whether melatonin dose plans could synchronize blind children’s body clocks to the 24-hour day, assessed through circadian phase markers measured in serial salivary and/or plasma samples. The stated collection schedule was biweekly throughout the entire study. No measurements or outcome estimates are available in the registry record, so the question cannot be answered from the posted results.
3. Trial Design
The registry describes a parallel, non-randomized study sponsored by Oregon Health and Science University. The phase is listed as NA, masking as single, and allocation as non-randomized. The record does not identify who was masked or explain how masking was implemented. Non-randomized allocation means that the arms should not be interpreted as if participants had been assigned by chance to comparable groups. The registry itself cautions that the arms are not a like-for-like control comparison.
The three treatment plans used melatonin at up to 0.5 mg daily, up to 10 mg daily, or up to 20 mg daily. The descriptions say that doses would be reduced gradually when treatment worked, with the aim of identifying the lowest effective dose. If treatment was unsuccessful, participants would be taken off treatment and later enrolled in a different plan. These descriptions outline intended treatment pathways; they do not establish what participants actually received or how dose changes occurred.
The brief summary describes the primary focus as optimizing a melatonin dosing regimen to synchronize body clocks to the 24-hour day and calls the study a five-year study. The recorded start is 2002-09 and the primary completion is 2015-12. The status is terminated. The registry does not explain the reason for termination or report whether the planned follow-up was completed. It lists enrollment as 10, but no study data are available. That enrollment entry cannot substitute for information about treatment exposure, completion, or the numbers assessed for an outcome.
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 PI has retired from the institution. Sincere efforts were made to contact the PI/study team members, but were unsuccessful. No study data are available.
Overall Study
| Stage | 0.5mg Melatonin | 10mg Melatonin | 20mg Melatonin |
|---|---|---|---|
| STARTED | 0 | 0 | 0 |
| COMPLETED | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: The PI has retired from the institution. Sincere efforts were made to contact the PI/study team members, but were unsuccessful. No study data are available.
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: The PI has retired from the institution. Sincere efforts were made to contact the PI/study team members, but were unsuccessful. No study data are available.
| Characteristic | Unit | 0.5mg Melatonin | 10mg Melatonin | 20mg Melatonin | Total |
|---|---|---|---|---|---|
| Participants analysed | 0 | 0 | 0 | 0 | |
| Sex: Female, Male: Female | — | — | — | — | |
| Sex: Female, Male: Male | — | — | — | — | |
| Region of Enrollment: United States | participants | — | — | — | — |
6. Primary Endpoint
The registry lists the primary outcome as Circadian Phase Marker, as Measured by the Melatonin Levels in Serial Salivary and/or Plasma Samples., measured over biweekly throughout the entire study.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is described as a circadian phase marker measured through melatonin levels in serial salivary and/or plasma samples. Circadian phase is the timing of a body rhythm within the daily cycle. Repeated melatonin measurements can be used to characterize the timing of that marker, which is relevant to the stated study aim of synchronizing body clocks to the 24-hour day. The registry specifies collection biweekly throughout the entire study.
The record does not give a unit, parameter, detailed measurement procedure, threshold for success, or analysis definition for this endpoint. It also contains no measurements or analysis results. Consequently, it is not possible to describe the observed phase marker, the direction or size of any change, or how precisely an effect was estimated. The registry lists a Durability and Toxicity Side Effects Questionnaire as a secondary outcome, but does not report questionnaire results either. These outcomes describe what the study intended to assess; they do not establish findings.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the registry explicitly reports that no study data are available. It says that the principal investigator retired from the institution and that efforts to contact the principal investigator or study team members were unsuccessful. The record therefore contains no observed primary endpoint values, no comparison of outcomes among treatment plans, and no reported analyses. There is no basis for describing a melatonin-associated change in circadian phase or estimating its magnitude.
The non-randomized allocation also matters for interpretation. Even if outcome estimates had been posted, arm differences would not automatically represent effects caused by the dose plans. Assignment may be associated with participant characteristics, clinical decisions, prior responses, or other factors; the record does not report how allocation occurred or provide information with which to examine such possibilities. The registry specifically warns that the arms are not like-for-like controls. In the absence of data, there is no adjustment or design feature reported that could address this concern.
The registry lists enrollment as 10, but does not provide an analysis population, outcome denominators, follow-up completeness, or participant flow. Enrollment alone cannot reveal how many participants contributed endpoint measurements or questionnaire responses. It also cannot establish how often each dosing plan was used. The posted adverse-event groups have zero participants at risk and zero reported events, including serious events and deaths. With no study data available and nobody recorded as at risk in these outcome entries, those zeros should not be read as evidence that treatment caused no adverse events.
No effect estimate, uncertainty interval, test result, or analysis is reported. Precision cannot be assessed, and the registry does not support a conclusion about whether the endpoint changed or whether any change differed by dose plan. The study status is terminated, but the reason for termination is not reported in the registry record. The dates and status do not explain whether the termination was related to recruitment, feasibility, safety, funding, or another consideration.
Any sample-size planning illustration must also be kept separate from findings. The registry’s stated illustration assumptions refer to a fraction of an observed effect, but the record contains no study data from which an observed effect can be interpreted. Such planning quantities cannot serve as evidence of efficacy, safety, or observed power. The meaningful conclusion is limited: the record describes an intended dosing and measurement approach, but it supplies no results with which to evaluate it.
9. Statistical Methods Explained
The registry classifies the design as parallel and non-randomized. A parallel design means that treatment plans are organized as separate arms rather than as successive periods assigned under a crossover design. Non-randomized allocation means that chance assignment is not reported as the basis for treatment assignment. As a general statistical principle, random allocation can help balance both measured and unmeasured characteristics across groups. Without it, differences between groups may reflect how participants came to receive a plan as well as any effect of treatment. The record does not report the allocation procedure, so the extent or direction of possible imbalance cannot be assessed.
What can be inferred from the dose-plan descriptions?
The arm descriptions specify treatment up to 0.5 mg daily, up to 10 mg daily, and up to 20 mg daily. Each describes gradual dose reduction if treatment worked, with the aim of identifying the lowest effective dose. This is an adaptive treatment description, not a report of observed doses or response. The registry gives no participant-level treatment histories, dose changes, adherence information, or criteria used to decide that treatment worked. Accordingly, the dose descriptions cannot be treated as proof that participants received the maximum doses or followed the planned reductions.
In general, a comparison of dose plans requires a clearly defined outcome, a suitable comparison strategy, and information about who contributed data. For non-randomized arms, statistical adjustment may sometimes address measured differences, but it cannot guarantee removal of bias from unmeasured differences. Here the record reports no analyses or study data, so there is no adjusted or unadjusted estimate to interpret. It is also not possible to assess whether the study followed a prespecified statistical analysis plan; such a plan is not reported in the registry record.
How should uncertainty be understood?
In general, a confidence interval describes a range of effect values compatible with the data and the assumptions of an analysis. Its width conveys how precisely the effect has been estimated. The registry reports no endpoint estimate and no confidence interval, so there is no numerical estimate of precision. A p-value, when reported, addresses the compatibility of data with a statistical null model under specified assumptions; it does not measure the size or clinical importance of an effect. No p-value or test result is reported. Neither statistical significance nor lack of statistical significance can be inferred from this record.
The primary endpoint involves serial measurements, collected biweekly throughout the entire study. Repeated measurements can capture timing patterns, but they also require an analysis that accounts for the correlation among measurements from the same participant. Treating repeated observations as independent can make uncertainty appear too small. This is a general issue for repeated-measures data, not a claim about an analysis performed in this study. The registry does not report a model, a method for handling within-participant correlation, a summary measure of phase, or an approach to missing serial samples.
The endpoint description names melatonin levels from salivary and/or plasma samples but does not specify the units, exact parameter, assay, or threshold that would define successful synchronization. Those details are important because they determine what the measurement represents and how results can be compared or interpreted. No further endpoint definition is reported in the registry record. Consequently, even a hypothetical numerical difference would need these methodological details before its meaning could be evaluated.
What do planning assumptions contribute?
The record states that its planning illustration uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It describes the target effect as a stated fraction of the observed effect. For time-to-event tables, it specifies total events; for other tables, it specifies participants per arm. These are planning assumptions, not evidence from the trial and not a description of its actual allocation. The study itself is non-randomized, and no observed effect is available in the registry record. Therefore, an illustration based on an observed effect cannot establish what the trial detected, how much power it had, or what sample size its investigators originally planned. The registry does not report its own sample-size justification.
Over-dispersion is a general concern when observed variation exceeds what a statistical model assumes. If ignored, standard errors may be understated and confidence intervals too narrow. The registry does not identify a count outcome or report an analysis requiring an over-dispersion adjustment, so this is a general methodological consideration rather than a feature that can be attributed to the study. In the absence of reported data and methods, the appropriate reading is descriptive: the record outlines an intended endpoint and dose plans but does not permit statistical reconstruction of a treatment effect.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 2 outcome measures, including the primary circadian phase marker and the secondary Durability and Toxicity Side Effects Questionnaire. It does not report a multiplicity strategy for interpreting results across outcomes, treatment arms, repeated measurements, or possible dose adjustments. Multiplicity is a general statistical issue: considering multiple comparisons can increase the chance of finding an apparently notable result by chance, and a planned approach helps define how such findings should be interpreted. No outcome analyses are available, so there are no reported findings to adjust or prioritize.
Missing-data methods and analysis populations are not reported in the registry record. The record does not state how missing salivary or plasma samples, incomplete questionnaire responses, withdrawal, or incomplete follow-up would have been handled. It also does not identify an intention-to-treat, per-protocol, or other analysis population. These omissions prevent assessment of whether the data used for any intended analysis would represent all enrolled participants, participants who received treatment, or another defined group.
The registry states that no study data are available after unsuccessful efforts to contact the principal investigator or study team members. This is different from a report that participants had no missing measurements: the data needed to assess completion and missingness are unavailable. The adverse-event entries list zero participants at risk and zero events, but do not provide an evaluable safety population. Those entries cannot resolve the absence of safety data. No imputation, sensitivity analysis, interim analysis, or other missing-data procedure is reported in the registry record.
11. What the Result Does, and Does Not, Mean
The record supports a description of the study’s purpose and planned approach: it concerned melatonin dose plans for blind children and sought to track a circadian phase marker using serial melatonin samples. It also supports a description of the registry design classifications, the planned dose ceilings, the intended gradual dose reduction when treatment worked, and the listed secondary questionnaire. These are design and protocol descriptions, not evidence that the plans were carried out as described or that any outcome changed.
The posted record does not establish that melatonin synchronized body clocks, that a particular dose plan was better than another, or that dose reduction identified an effective dose. It does not establish that melatonin was ineffective either. With no study data or outcome analyses, neither a positive nor a null treatment conclusion follows. The non-randomized design would also require caution in interpreting between-arm differences, even if such results were available, because the arms are not reported as like-for-like comparisons.
The zero adverse-event counts do not demonstrate absence of harm. The registry records zero participants at risk in those entries and separately states that no study data are available. Safety therefore remains unassessed in the posted record. Likewise, enrollment listed as 10 does not indicate how many participants completed treatment, contributed primary endpoint measurements, or completed the questionnaire.
Statistically, the record offers no effect estimate, uncertainty interval, p-value, or defined analysis population. It cannot establish precision, statistical significance, or the size of any change. Planning illustrations are not observed power and do not replace results. The defensible interpretation is that a trial was registered with an intended circadian measurement strategy, but the available record does not contain findings that answer its clinical question.
12. Why This Trial Matters Statistically
This record illustrates why a registered question and an interpretable result are different things. The study describes a biologically relevant marker, serial collection, and dose plans intended to explore synchronization of body clocks. Those details help clarify what investigators intended to assess. Yet without measurements, analysis methods, or participant flow, readers cannot determine whether the planned endpoint was collected, how consistently it was assessed, or what the results mean.
The design also highlights the importance of the comparison structure. The registry identifies the study as non-randomized and cautions that its arms are not like-for-like controls. Dose-group comparisons are not automatically causal comparisons: differences in participant characteristics or clinical decisions can contribute to observed differences. This limitation is important even before considering modeling choices, because statistical adjustment cannot be evaluated without data and a reported analysis strategy.
Repeated measures add a further methodological consideration. Serial samples can describe change in timing over follow-up, but valid uncertainty estimates depend on accounting for the relationship among measurements from the same participant and defining how incomplete measurement series are handled. The registry does not report these methods. This absence makes it impossible to distinguish a planned measurement schedule from a completed and analyzed longitudinal dataset.
Finally, the record makes the limits of registry outcome entries clear. Zero event counts alongside zero participants at risk cannot establish a safety profile, especially when the record says no study data are available. Transparent reporting of analyses and denominators is essential for interpreting both benefits and harms. In this case, the statistically responsible conclusion is limited to the study’s stated aims and design; no treatment effect or safety estimate can be recovered from the posted results.
13. 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 principal limitation is that the registry reports no study data. It gives no primary endpoint values, secondary outcome results, analyses, or participant-level summaries. The reason recorded for this absence is that the principal investigator retired from the institution and efforts to contact the investigator or study team were unsuccessful. The registry does not provide further information about data custody, completion, or why the study was terminated.
The allocation was non-randomized, and the registry warns that the arms are not like-for-like comparisons. It does not explain how participants entered the arms, whether any baseline differences were assessed, or whether an adjustment strategy was planned. The single masking classification is not accompanied by information about who was masked or how masking was maintained. The record also does not report adherence, actual dosing, treatment changes, discontinuations, or participant flow.
The primary endpoint is described as a circadian phase marker measured from serial salivary and/or plasma samples, but the unit, parameter, detailed measurement method, and success criterion are not given. The stated schedule is biweekly throughout the entire study, yet completeness of the series is unknown. The registry does not describe how repeated measurements or missing samples would be analyzed. The secondary questionnaire is named, but its scoring and results are not reported.
Enrollment is listed as 10, but the record gives no outcome denominators or analysis populations. The adverse-event entries list zero participants at risk and zero events, which cannot be interpreted as evidence of no adverse events. The study is marked terminated, but the reason for termination is not reported in the registry record. These limitations prevent assessment of efficacy, precision, safety, or generalizability from the posted information.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Blind Child Melatonin Treatment Study — NCT00691444.
- Registry record last updated 2019-11-27; status last verified 2019-11.
- Results first posted 2019-11-27.
- 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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17. Record Summary
The registry describes a parallel, non-randomized study of melatonin dosing in blind children, sponsored by Oregon Health and Science University. It lists phase as NA, masking as single, enrollment as 10, and status as terminated. The recorded start is 2002-09 and primary completion is 2015-12.
The primary outcome is a circadian phase marker measured through melatonin levels in serial salivary and/or plasma samples, with collection described as biweekly throughout the entire study. The record lists a Durability and Toxicity Side Effects Questionnaire as a secondary outcome. Treatment plans specified melatonin up to 0.5 mg daily, up to 10 mg daily, or up to 20 mg daily, with gradual reduction if treatment worked.
The registry states that no study data are available and reports no analyses. The reason given is the principal investigator’s retirement and unsuccessful efforts to contact the investigator or study team members. As a result, the posted record contains no interpretable treatment-effect or safety findings.