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 Online Caregiver Psychoeducation and Support for Alzheimer's (NCT00416078), a randomized phase 2, phase 3 study. The primary outcome is Change in Caregiver Burden From Baseline.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00416078 |
| Phase | Phase 2, Phase 3 |
| Condition | Alzheimer's Disease |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 53 |
| Arms in the primary outcome | n/a |
| Lead sponsor | US Department of Veterans Affairs |
| Results posted | Yes |
2. Clinical Question
Population
Veterans with a clinical diagnosis of Alzheimer's disease or related memory difficulties and their caregiver or relatives. The registry record lists Alzheimer's disease as the condition. The study summary describes the intended population as VA patients with Alzheimer's disease or related memory difficulties and their caregivers. The number enrolled was 53. The record notes that data available for analyses vary because of loss to follow-up, deaths at different points in the protocol, and incomplete forms.
Intervention
Caregiver access to an intensive, interactive online education and support website for six months, embedded in one year of customary care. The registry record describes this as caregiver website support.
Comparator
Brief supportive telephone calls with project staff for six months, also embedded in one year of customary care. Both groups therefore received customary care; the comparison concerned the additional caregiver support approach.
Primary question
How did caregiver burden change from baseline to the end of treatment at six months in the two randomized groups? The primary outcome was change in the caregiver's score on the Zarit Short Burden Scale. The registry record does not report a numerical result for the comparison, so it does not establish the direction or size of any difference between groups.
The study summary describes hypotheses about patient problematic behavior, caregiver responses and burden, caregiver depression, medication adherence, and patients remaining at home during the twelve months after randomization. These are stated as hypotheses, not as findings. The named primary outcome is caregiver burden; the record also lists caregiver-reported patient medication adherence as a secondary outcome. Although six outcome measures and six analyses are listed, their numerical results are not reported in the registry record.
3. Trial Design
The registry record describes a randomized, parallel-group study with single masking and lists its phase as Phase 2 and Phase 3. Enrollment was 53. The record does not state which participants or study personnel were masked, and it does not report the allocation ratio or the randomization procedure. The study is marked completed.
Both groups received customary care over one year. In addition, caregivers in one group had access to an interactive online education and support website for six months. Caregivers in the other group received brief supportive telephone calls from project staff for six months. This design compares two different forms of added caregiver support, rather than added support against no added support.
The primary outcome was change in caregiver burden from baseline to the end of treatment at six months. The measure was the total score on the Zarit Short Burden Scale. The registry record describes the outcome as a least-squares mean with standard error, but does not report the group estimates or a numerical between-group comparison. It also does not report a confidence interval or a p-value for this primary outcome.
The study dates recorded are a start in 2007-08 and primary completion in 2012-06. The record describes the study as a pilot. It does not report a sample-size justification, a detailed statistical analysis plan, or enough information to determine the planned allocation ratio. The adverse-event denominators are reported separately and should not be treated as a statement of the number randomized to each group.
The registry record lists six outcome measures and six analyses, but does not provide numerical results for those analyses. It therefore supports a description of the design and intended outcomes, but not a quantitative estimate of the primary treatment contrast.
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 | Caregiver Website | Caregiver Phone Calls |
|---|---|---|
| STARTED | 29 | 24 |
| COMPLETED | 18 | 16 |
| NOT COMPLETED | 11 | 8 |
Reasons for not completing this period:
| Reason | Caregiver Website | Caregiver Phone Calls |
|---|---|---|
| Death | 3 | 4 |
| Withdrawal by Subject | 3 | 2 |
| Physician Decision | 1 | 0 |
| Lost to Follow-up | 4 | 2 |
Analysis population for the primary outcome, as defined in the registry: Data available for analyses vary due to missing data (lost to follow-up and deaths at different points in the protocol; incomplete forms)
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 | Caregiver Website | Caregiver Phone Calls | Total |
|---|---|---|---|---|
| Participants analysed | 29 | 24 | 53 | |
| Age, Continuous | years | 78.69 (SD 9.09) | 81.4 (SD 6.6) | 79.92 (SD 8.21) |
| Sex: Female, Male: Female | Participants | 7 | 5 | 12 |
| Sex: Female, Male: Male | Participants | 22 | 19 | 41 |
| Race/Ethnicity, Customized: Caucasian | patient participants | 20 | 19 | 39 |
| Race/Ethnicity, Customized: African-American | patient participants | 6 | 4 | 10 |
| Race/Ethnicity, Customized: Hispanic | patient participants | 1 | 1 | 2 |
| Race/Ethnicity, Customized: Unknown | patient participants | 2 | 0 | 2 |
| Region of Enrollment: United States | participants | 29 | 24 | 53 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Caregiver Burden From Baseline, measured over baseline to end-of-treatment (6 months).
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | Standard Error |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in caregiver burden from baseline to the end of treatment at six months. Burden was assessed using the total score on the Zarit Short Burden Scale, a twelve-item instrument. Each item uses a Likert scale from 1 to 5 to rate frequency. The total score ranges from 12, corresponding to “never,” to 60, corresponding to “nearly always.” Higher scores indicate greater caregiver burden.
Change over time is used to describe whether burden scores shifted during the treatment period. Comparing change between randomized groups can help distinguish the observed course in one group from the course in the other, while recognizing that both groups received customary care and an additional support approach. The registry record describes the primary summary as a least-squares mean, a model-based mean estimate, and gives standard error as the measure of dispersion.
The outcome is relevant to the study's stated focus on caregiver experience. However, the registry record does not report the least-squares mean estimates, their standard errors, or a numerical contrast between groups. It also does not report a confidence interval or p-value for the primary outcome. Thus, the endpoint's definition and scale can be described, but the observed change and the precision of the comparison cannot be evaluated from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies caregiver burden change from baseline to six months as the primary outcome, but it does not report numerical results for that outcome. No group-specific least-squares means, standard errors, between-group estimate, confidence interval, or p-value are reported in the registry record. Without those quantities, it is not possible to describe whether the posted primary comparison favored either support approach, how large any difference was, or how precisely it was estimated.
This absence of a numerical primary result is different from a finding of no difference. A missing estimate does not show that the groups had the same burden change, and it does not establish that one approach had a larger effect. The record also cannot be used to assess whether an estimated difference would be clinically important. The scale's range and direction are defined, but the observed scores and change estimates are not available in the registry record.
The study summary describes expected benefits as hypotheses, including possible changes in caregiver burden and other outcomes. Hypotheses are not results. The record lists caregiver-reported medication adherence as a secondary outcome and indicates that there were six outcome measures and six analyses, but it does not report their numerical results. The stated hypotheses therefore cannot be treated as evidence that any of the listed outcomes changed.
The study enrolled 53 participants, and the record states that data available for analyses varied because of loss to follow-up, deaths at different points, and incomplete forms. This means the number of observations may differ across outcomes or time points. The registry record does not report the analysis population for the primary comparison, the amount of missing primary-outcome data, or the method used to address missingness. Those omissions make it difficult to judge how representative any analyzed participants would be, even if numerical estimates were available.
The record marks the trial completed and labels the study a pilot. Those design and status details do not substitute for outcome estimates. Overall, the available record allows readers to understand what was compared and how caregiver burden was defined, but it does not support an estimate of the primary effect or its uncertainty. Conclusions about benefit, absence of benefit, or equivalence would go beyond the reported results.
9. Statistical Methods Explained
The registry record describes the primary outcome as change in a continuous score and identifies the reported summary type as a least-squares mean with standard error. It does not provide the actual estimates or describe the model used to produce them. The concepts below are general explanations of these statistical summaries, not claims about unreported details of this study's analysis.
What does a least-squares mean represent?
A least-squares mean is a model-based estimate of an average. In general, a statistical model can account for factors included in that model when estimating group means. The estimate is therefore not necessarily identical to the simple arithmetic average among participants with observed scores. Which factors were included, how observations were handled, and what model assumptions were used are not reported in the registry record. It is not possible to determine from the record whether the least-squares means were adjusted for baseline burden or other characteristics.
What does the standard error describe?
In general, a standard error describes the sampling uncertainty of an estimate: how much the estimate would tend to vary across repeated studies under the same design and assumptions. It is not the same as the spread of individual participants' scores. A standard error can help quantify the precision of a mean estimate, but it does not by itself show the range of plausible values for a treatment contrast. The registry record names standard error as the dispersion measure but does not give its value for either group.
How does a confidence interval help?
In general, a confidence interval presents a range of values compatible with the data and a specified statistical procedure. For a between-group estimate, it communicates both the estimated direction and the uncertainty around its size. A narrow interval indicates greater precision than a wide interval, all else equal. The confidence level and interval for the primary comparison are not reported in the registry record. Without an estimate and interval, readers cannot assess whether the result is compatible with a range of effects or how much uncertainty remains.
What would a p-value answer?
In general, a p-value measures how surprising data at least as inconsistent with a specified null hypothesis would be if that hypothesis and the analysis assumptions were true. It is not the probability that the null hypothesis is true, nor is it a measure of the size or importance of an effect. The registry record does not report a primary-outcome p-value or enough information to reconstruct one. A p-value alone, even if available, would not replace the effect estimate and its confidence interval.
Why does the change score matter?
The primary outcome is defined as change from baseline to six months. In general, a change score reflects the difference between a participant's later and earlier measurements, and a group summary can describe average change. A comparison of group changes is distinct from comparing the groups' scores at one time point. How the change was calculated, how baseline values entered the analysis, and how missing follow-up scores were handled are not reported in the registry record. Those details can affect interpretation and should not be assumed.
What can the planning assumptions tell readers?
In general, a sample-size calculation uses assumptions about the effect to be detected, the significance level, allocation, and statistical model to illustrate the number of participants that might be needed for a chosen level of power. Such a calculation is a planning illustration, not an observed trial result and not evidence that the study had a particular probability of detecting an effect after the fact. The record describes planning assumptions based on the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. It does not report a trial-specific sample-size justification or a numerical planning result. These general assumptions do not establish that the study achieved its intended precision.
For continuous outcomes, model assumptions can matter. In general, a model needs to represent the data structure adequately; for example, repeated measurements on the same participant are related rather than independent. However, the registry record does not describe the fitted model, covariance assumptions, diagnostics, or handling of repeated measurements. Those methods cannot be inferred from the outcome label alone.
Nor can the unreported primary comparison be reconstructed from the enrollment total or the adverse-event counts. Those figures do not supply the group-specific burden changes or their uncertainty. The registry record supports a methodological description of the endpoint and design, but it does not contain the numerical inputs needed to assess the primary treatment contrast.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists six outcome measures and six analyses. It does not report how the analyses were prioritized beyond identifying caregiver burden change as the primary outcome, nor does it describe a strategy for controlling the chance of false-positive findings across multiple comparisons. Any adjustment for multiplicity, hierarchy among secondary outcomes, or distinction between confirmatory and exploratory analyses is not reported in the registry record. This matters because interpreting several statistical tests without a plan can make isolated findings harder to distinguish from chance patterns.
The record's study summary lists several hypothesized outcomes, including caregiver burden, caregiver depression, patient problematic behavior, medication adherence, and patients remaining at home. These statements describe study aims, not demonstrated effects. Numerical results for the six analyses are not reported in the registry record, so the outcomes cannot be compared or assessed for consistency.
Missing data are specifically noted. The record says that data available for analyses vary because of loss to follow-up, deaths at different points in the protocol, and incomplete forms. It does not report how many primary-outcome observations were missing, whether missingness differed between groups, or the assumptions and methods used to address missing values. It also does not report whether an intention-to-treat population, a per-protocol population, or another analysis population was used for the primary outcome.
In general, missing-data methods rely on assumptions about why values are absent. If the probability of missingness is related to unobserved outcomes, analyses limited to observed values can be misleading. This is a general statistical concern, not evidence that the results of this study were biased. Without details on the missing-data pattern and analysis method, the extent to which missingness could affect the primary comparison cannot be evaluated from 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 |
|---|---|---|---|
| Caregiver Website Support | 4 | 29 | 13.8% |
| Caregiver Brief Supportive Phone Calls | 5 | 24 | 20.8% |
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 |
|---|---|
| Caregiver Website Support | 0 of 29 |
| Caregiver Brief Supportive Phone Calls | 0 of 24 |
Most frequent serious adverse event terms
| Event term | Organ system | Caregiver Website Support | Caregiver Brief Supportive Phone Calls |
|---|---|---|---|
| fatal | Nervous system disorders | 3 of 29 | 4 of 24 |
| Hospitalization | General disorders | 1 of 29 | 1 of 24 |
Serious events with the highest arm-level rate: fatal (16.7%), hospitalization (4.2%).
The registry record reports serious adverse events for the two groups using denominators of 29 for caregiver website support and 24 for caregiver brief supportive telephone calls. It records 4 serious events in the website-support group and 5 in the telephone-call group. These are reported counts and denominators; they do not by themselves establish whether the groups differed in safety. The record does not provide a comparative analysis or uncertainty interval for these figures.
The registry record also lists “fatal” at 16.7% and “Hospitalization” at 4.2% among the top serious-event terms. It does not provide enough detail in this listing to assign those percentages to a particular group or explain their calculation. The deaths fields for the two groups are not reported. The term “fatal” in the event listing should therefore not be treated as a reported death count.
Serious adverse-event counts are not necessarily counts of participants with at least one event; the registry record does not clarify that distinction. Nor does it report event-level details, timing, relatedness to the intervention, or a formal between-group safety comparison. These figures describe what is recorded, but are insufficient to conclude that either support approach caused or prevented serious events.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized study compared two caregiver support approaches: access to an online education and support website for six months, and brief supportive telephone calls for six months. Both were delivered in the context of customary care over one year. The named primary outcome was change in caregiver burden from baseline to the six-month end of treatment, measured with the Zarit Short Burden Scale.
It does not establish the size or direction of the primary outcome difference. Numerical group estimates, a between-group contrast, standard errors, confidence intervals, and p-values are not reported in the registry record. The absence of these results is not evidence that the approaches were equivalent, that they had no effect, or that one was superior. It simply means that the primary comparison cannot be quantified from this record.
The scale description explains how burden was measured and that higher scores indicate greater burden. It does not show how participants' scores changed. The study summary's proposed outcomes are hypotheses, not findings, and the registry record does not provide numerical findings for the listed secondary outcome of medication adherence or for the other outcome measures.
Enrollment was 53, and the registry record notes that analysis data varied because of loss to follow-up, deaths at different points, and incomplete forms. The analytic sample and missing-data method for the primary comparison are not reported. This limits interpretation of who contributed data and how missing observations may have influenced estimates.
Finally, the study is described as a pilot, and the record lists Phase 2 and Phase 3. These labels and the completed status describe the study record, not the magnitude, reliability, or clinical importance of an outcome. A sound interpretation must distinguish the trial's purpose and design from evidence about its results. Here, the design and endpoint are documented, but the primary numerical result is not reported.
13. Why This Trial Matters Statistically
This study illustrates why a clear endpoint definition is not enough to interpret a clinical trial. The record specifies caregiver burden as the primary outcome, identifies the instrument, describes its score direction and range, and names the six-month assessment period. Those details let readers understand what the investigators intended to measure. But without the outcome estimates and their uncertainty, readers cannot determine what the study observed about the primary comparison.
The design also makes the contrast important to state precisely. Both groups received customary care, while the additional caregiver support differed: website access in one group and brief telephone calls in the other. The statistical question is therefore about the comparison of these added approaches within customary care, not about either approach versus no care.
The record makes missingness visible by noting loss to follow-up, deaths at different points, and incomplete forms. That information highlights a central issue in longitudinal clinical research: the available observations may vary across outcomes and time points. Reporting how much data were available and how missing values were addressed would help readers evaluate the credibility and precision of an estimate.
It is also useful to distinguish a study's hypotheses from its results. The summary names several anticipated outcomes, but the record does not report numerical findings for them. Treating an aim as a finding would overstate the evidence. Likewise, serious-event counts provide a descriptive safety record but do not establish a comparative safety effect without suitable details and analysis.
For statistical interpretation, the most important lesson is that a registry record can document a randomized design and a meaningful endpoint while still leaving the main effect unquantifiable. Transparent reporting of estimates, uncertainty, analysis populations, and missing-data methods is essential for evaluating what a trial contributes.
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 this study from the registry record is that numerical results for the primary caregiver-burden comparison are not reported. The group-specific least-squares means, standard errors, contrast, confidence interval, and p-value are absent. This prevents assessment of direction, magnitude, and precision.
The record identifies an enrollment of 53 and describes a pilot study, but does not report the trial-specific sample-size justification or the intended allocation ratio. The adverse-event denominators are 29 and 24, but they do not establish the randomized group sizes or the numbers contributing to the primary-outcome analysis. The analysis population is not reported.
Missing data are acknowledged because of loss to follow-up, deaths at different points, and incomplete forms. The number of missing primary endpoint values, their distribution between groups, and the method used to handle them are not reported. This limits assessment of potential bias and precision.
The record describes the trial as single-masked but does not state who was masked. It also does not describe the randomization procedure, the statistical model, any baseline adjustment, or the assumptions used for repeated observations. The analysis plan and any method for addressing multiplicity across six outcomes and six analyses are not reported.
Safety reporting is limited to group counts and denominators and a listing of serious-event terms. The record does not clarify the event-level details, group attribution of the listed percentages, or the number of deaths. It does not report a comparative safety analysis. These gaps mean that neither efficacy nor safety can be quantitatively characterized from the registry record alone.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Online Caregiver Psychoeducation and Support for Alzheimer's — NCT00416078.
- Registry record last updated 2015-04-29; status last verified 2015-04.
- Results first posted 2015-04-29.
- 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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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry record describes a completed randomized, parallel-group study, listed as Phase 2 and Phase 3, with enrollment of 53. It compared six months of caregiver access to an online education and support website with six months of brief supportive telephone calls. Both support approaches were embedded in one year of customary care.
The primary outcome was change in caregiver burden from baseline to the six-month end of treatment, measured with the Zarit Short Burden Scale. Higher scale scores indicate greater burden. The record notes that analysis data varied because of loss to follow-up, deaths at different points, and incomplete forms.
Numerical results for the primary outcome are not reported in the registry record. Although six outcome measures and six analyses are listed, their numerical findings and the methods used to address missing data and multiplicity are not reported. Serious adverse-event counts are recorded as 4 of 29 and 5 of 24 in the two groups; the listed event terms do not provide a complete comparative safety analysis.