Telephone Administered Psychotherapy for the Treatment of Depression for Veterans in Rural Areas: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Telephone Administered Psychotherapy for the Treatment of Depression for Veterans in Rural Areas (NCT00223652), a randomized phase 2 study. The primary outcome is Change in Severity of Depression Using Hamilton Depression Rating Scale.

2. Clinical Question

The trial asks whether telephone-administered cognitive-behavioral therapy (T-CBT), compared with treatment as usual, is associated with a change in depression severity among veterans served by community-based outpatient clinics in rural areas. The registry record identifies the primary measure as the Hamilton Depression Rating Scale (Ham-D), assessed at baseline, 12 weeks, and 20 weeks. It also describes an assessment at six-month follow-up, while the listed primary-outcome timeframe covers baseline, 12 weeks, and 20 weeks.

The registry’s stated purpose is to examine T-CBT for major depression among veterans served by clinics in VISN 21, serving rural areas in Northern California, and VISN 12, serving rural areas surrounding the Hines, IL VA Hospital. The posted primary outcome is a continuous measure of change in depression severity. However, the registry record does not provide a single reduced comparison across the multiple time points, and it does not report numerical outcome estimates in the record. Consequently, the direction and size of any difference between the groups cannot be characterized from these details.

3. Trial Design

This was a randomized, parallel-group Phase 2 trial with single masking. The registry record does not specify which individuals were masked. The listed enrollment was 85, and the status is completed. The sponsor was the US Department of Veterans Affairs. The record gives a start date of 2006-03 and a primary completion date of 2009-12.

Participants were assigned to telephone cognitive-behavioral therapy or treatment as usual. The intervention is classified as behavioral. The record’s summary places the study in community-based outpatient clinics serving rural areas in Northern California and areas surrounding the Hines, IL VA Hospital. It identifies VISN 21 and VISN 12 as the relevant service networks. More detailed eligibility criteria, recruitment procedures, allocation sequence generation, concealment procedures, and the exact content of treatment as usual are not reported in the registry record.

The primary outcome is continuous: change in depression severity on the Ham-D. The outcome description says evaluators assessed participants at baseline, 12 weeks, 20 weeks after treatment, and six-month follow-up. The primary-outcome timeframe is listed as baseline, 12 weeks, and 20 weeks; the six-month assessment is mentioned in the description but is not part of that listed timeframe. The analysis description says data from baseline, Week 12, and Week 20 were analyzed using a mixed-effects repeated measures model with random subject-specific intercepts.

The registry record lists six outcome measures and 12 analyses. It also names maintenance of treatment effect and the number of participants meeting criteria for major depression disorder at six-month follow-up among secondary outcomes. More detail about the individual secondary analyses is not reported in the registry record. The primary outcome has several categories or time points and is not reduced to one comparison in the posted record, so a single primary effect estimate cannot be described.

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.

T-CBT 12 Weeks, TAU 20 Weeks

T-CBT 20 Weeks, TAU 20 Weeks

T-CBT and TAU 6 Month Follow-up

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.

6. Primary Endpoint

The registry lists the primary outcome as Change in Severity of Depression Using Hamilton Depression Rating Scale, measured over Baseline, 12 weeks, 20 weeks.

The primary endpoint is change in depression severity measured with the Hamilton Depression Rating Scale. The registry describes evaluator-administered Ham-D assessments and states that the scale ranges from 0-52, with higher values indicating more severe depression. A score of 0-7 is considered normal, while scores of 20 or higher indicate moderate, severe, or very severe depression.

In general, a continuous symptom scale can represent gradations in severity rather than only whether a participant crosses a diagnostic threshold. Repeated measurement can describe how scores change over time and whether patterns differ between randomized groups. Those features make a scale-based outcome useful for studying change during and after an intervention, while the numerical interpretation still depends on the scale’s meaning and the analysis used.

The registry lists baseline, 12 weeks, and 20 weeks as the primary-outcome timeframe and describes a repeated-measures analysis across those time points. It also mentions a six-month follow-up assessment in the outcome description. The registry record does not report a single summarized group contrast, numerical change estimates, uncertainty intervals, or a p-value for the primary outcome. Therefore, the measurement and its intended interpretation can be described, but the magnitude and precision of the observed treatment-group pattern cannot be stated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a repeated-measures model do?

The registry describes a mixed-effects repeated measures model for the continuous Ham-D outcome, using random subject-specific intercepts. In general, repeated-measures methods account for the fact that multiple observations from one participant are related. A participant’s measurements may share stable characteristics, so analyzing them as if they were independent can misrepresent uncertainty. A subject-specific intercept allows the model to represent participant-to-participant differences in underlying score levels.

The record says that data across baseline, Week 12, and Week 20 were analyzed. A model of repeated observations can use the pattern of measurements over these visits to estimate changes and group patterns over time. The precise model formula, fixed effects, covariance assumptions, estimation method, and planned contrast are not reported in the registry record. The description therefore identifies the broad approach, but does not make it possible to reconstruct the analysis or its primary estimand.

How should the outcome scale be read?

The Ham-D is described as ranging from 0-52, with higher scores indicating greater depression severity. The record says 0-7 is considered normal and scores of 20 or higher indicate moderate, severe, or very severe depression. These are scale interpretation statements, not trial results. They do not reveal the participants’ baseline scores, the scores at follow-up, or the amount of change in either group. Those values are not reported in the registry record.

In general, continuous outcomes preserve information about differences across the scale. Change scores describe how measurements differ from a reference assessment, while a repeated-measures model can represent measurements at multiple visits together. The choice between a single change contrast and a model-based time pattern affects what question an estimate answers. The registry record does not reduce the multi-time-point primary outcome to one comparison, so the precise target contrast cannot be read from the posted details.

What do precision and statistical significance mean?

General: an estimate is a numerical description of an effect or pattern, and its standard error reflects sampling uncertainty under the chosen model. A confidence interval combines an estimate with an uncertainty range, conditional on the method’s assumptions. A p-value measures how compatible the observed data are with a specified null model; it is not the probability that the null hypothesis is true, nor does it measure the size or practical importance of an effect.

The registry record does not report the primary estimate, its confidence interval, its standard error, or its p-value. Statistical significance and precision therefore cannot be assessed from the outcome description alone. The scale’s range and severity thresholds cannot substitute for those inferential results.

Why can over-dispersion matter?

General: over-dispersion arises when observed variability exceeds what a statistical model assumes. It can make model-based standard errors too small if the extra variation is ignored, which can make confidence intervals too narrow and tests too optimistic. The relevance of over-dispersion depends on the outcome distribution and model. The primary endpoint is described as a continuous measure analyzed with a mixed-effects repeated measures model; no over-dispersion assessment or adjustment is reported in the registry record. No claim about whether it occurred is therefore warranted.

How should planning assumptions be distinguished from trial results?

The registry’s sample-size assumptions describe 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 target effect is described as a stated fraction of the observed effect. These assumptions describe how a planning calculation is framed; they are not an observed trial outcome, and they do not provide evidence that a planned level of power was achieved.

General: planning calculations estimate the sample size needed for a specified effect and set of assumptions. They depend on the effect chosen, the variability, the significance level, allocation, and the analysis. A planning illustration is not observed power, and a sample-size calculation cannot replace reporting the estimated treatment contrast and its uncertainty. The registry record does not report a protocol sample-size justification or enough detail to establish whether the illustration matches the trial’s original design process.

Because the primary result is not reduced to a single comparison in the posted record, the central limitation is not a choice among competing numerical estimates; it is the absence of a reported primary contrast and its uncertainty. The model description can clarify the general analytical framework, but it cannot supply missing estimates or identify unreported model decisions.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures and 12 analyses, and identifies several secondary outcomes, including maintenance of treatment effect and the number of participants meeting criteria for major depression disorder at six-month follow-up. Multiple outcomes, time points, or analyses can create multiple opportunities to observe an apparently notable result. In general, multiplicity procedures can control or otherwise address the increased chance of false-positive findings when multiple comparisons are considered. The registry record does not report a multiplicity adjustment, a hierarchy of outcomes, or which analyses were designated confirmatory.

The record describes the primary endpoint at baseline, 12 weeks, and 20 weeks, but the primary result is not reduced to one comparison. It does not report a prespecified primary contrast, nor does it give numerical primary-outcome estimates and uncertainty. Whether all outcome measures and analyses were specified in advance is not reported in the registry record.

Missing-data handling is also not reported in the registry record. The mixed-effects repeated measures description does not, by itself, establish how missing assessments were addressed, what assumptions were made about missingness, or whether sensitivity analyses were conducted. The numbers analyzed at each visit, reasons for missing observations, and follow-up completeness are not reported in the registry record.

The analysis populations are not reported in the registry record. It is not stated whether the primary analysis included all randomized participants, only participants with available measurements, or another defined population. These details matter because the population analyzed and assumptions about missing outcomes can affect interpretation. No inference about the extent or impact of missing data or multiplicity can be made from the available registry description.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event record lists zero serious adverse events among 41 participants at risk in the telephone-administered cognitive-behavioral therapy group, and zero among 44 participants at risk in the treatment-as-usual group. These are recorded counts for the groups and denominators stated in the registry. They should be read as reports of no serious adverse events recorded in those entries, not as proof that no serious event could occur.

In general, a zero count in a trial does not establish zero underlying risk. The amount of information depends on the number observed, the duration and completeness of safety monitoring, and how events were defined and collected. The registry record does not report the event definitions, monitoring procedures, exposure duration, or a comparative safety analysis. It also lists no top serious-event terms.

Death counts are not reported in the registry record. The figures therefore do not support a conclusion about mortality. The record also distinguishes serious adverse events from other adverse events; it lists zero other adverse events in the stated group entries, but additional detail about event types, severity, and ascertainment is not reported. These figures are descriptive and do not, on their own, establish a safety difference between the groups.

12. What the Result Does, and Does Not, Mean

The registry record establishes the study question, randomized parallel-group design, intervention and comparator, primary measurement, and broad analysis approach. It does not provide a single numerical primary-outcome comparison. As a result, the record does not show the direction, magnitude, or precision of the difference in depression severity between telephone cognitive-behavioral therapy and treatment as usual. No claim that one group had better or worse outcomes is supported by the posted primary-outcome details.

The outcome description explains how the Ham-D is interpreted and when assessments were intended. It does not report group means, change estimates, confidence intervals, or p-values. In general, an outcome measure and an analysis method describe what investigators planned to evaluate; they are not substitutes for the estimated results. The six-month follow-up is mentioned in the description, while the stated primary timeframe covers baseline, 12 weeks, and 20 weeks.

The record’s completion status and enrollment describe the trial’s administrative status and planned or recorded enrollment, not the size or reliability of an outcome effect. Likewise, the serious adverse-event entries are descriptive counts. Zero recorded serious events in the listed groups does not demonstrate absence of possible harm or establish equivalence between groups.

The trial therefore contributes a registry description of a clinically focused comparison in rural veterans, but the available outcome reporting is insufficient for a quantitative assessment of the primary question. The record does not report enough detail to assess the primary estimate, uncertainty, missing-data assumptions, multiplicity handling, or analysis population. Those omissions limit what can be inferred from the registry record and should not be filled by assumptions about the protocol or findings.

13. Why This Trial Matters Statistically

This trial is statistically notable for combining a randomized parallel-group design with repeated measurement of a continuous symptom scale. Such a design can address change over time while accounting for measurements collected from the same participant. The registry’s description of random subject-specific intercepts makes clear that the stated analysis recognized within-participant structure rather than treating every assessment as independent.

The case also illustrates why an outcome label and model description are not enough to interpret a trial result. The Ham-D scale, its range, and its severity thresholds provide context for the measure, while the repeated-measures model describes a broad analytical approach. But without a reported contrast and uncertainty interval, readers cannot judge the estimated difference or its precision. The primary outcome spans multiple time points and is not reduced to a single comparison in the registry record.

Multiple outcomes and analyses make transparent reporting especially important. The registry lists six outcome measures and 12 analyses, but does not report a multiplicity strategy or detailed analysis populations. Missing-data procedures and the exact primary contrast are also not reported. These omissions are relevant to judging how the estimates were selected and how robust they may be.

The record additionally shows the distinction between efficacy-oriented outcome measurement and safety reporting: serious-event counts are presented, but those counts alone do not quantify comparative risk. Overall, the statistical lesson is that design and method descriptions explain how a study can be analyzed, while inference requires accessible estimates, uncertainty, and enough detail to evaluate the analysis choices.

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 trial-specific limitation in the registry record is that the primary outcome has multiple time points and is not reduced to one comparison. Although the record identifies a mixed-effects repeated measures model, it does not report the estimated group pattern, a primary contrast, or uncertainty around an estimate. The numerical effect and its precision therefore cannot be assessed from this record.

The timing descriptions are not fully aligned: the primary-outcome timeframe lists baseline, 12 weeks, and 20 weeks, while the outcome description also mentions assessment at six-month follow-up. The record names maintenance of treatment effect as a secondary outcome, but does not provide the associated numerical results or details of that analysis. How the follow-up assessment relates to the primary model is not reported in the registry record.

Details needed to evaluate the analysis are also absent. The exact model specification, allocation procedures, masking role, primary contrast, missing-data approach, analysis populations, multiplicity plan, and baseline outcome summaries are not reported in the registry record. The eligibility criteria and the content of treatment as usual are not described in detail in the record. These gaps limit assessment of potential bias, model assumptions, and applicability beyond the stated rural clinic settings.

The safety entries report zero serious adverse events in both listed groups, but do not describe event definitions, observation time, or monitoring procedures; death counts are not reported in the registry record. Such sparse descriptive information cannot establish comparative safety. Finally, the planning assumptions are identified as an illustration based on the observed effect, not as the trial’s own design calculation. The protocol’s sample-size justification is not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Telephone Administered Psychotherapy for the Treatment of Depression for Veterans in Rural Areas — NCT00223652.
• Registry record last updated 2015-04-24; status last verified 2014-08.
• Results first posted 2014-12-17.
• 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.

18. Record Summary

This completed Phase 2 study was randomized, single-masked, and parallel-group, with enrollment of 85. The sponsor was the US Department of Veterans Affairs. Telephone cognitive-behavioral therapy was compared with treatment as usual among veterans served by community-based outpatient clinics in rural areas. The registry lists a start date of 2006-03 and primary completion date of 2009-12.

The primary outcome was change in Ham-D depression severity. The listed timeframe was baseline, 12 weeks, and 20 weeks, and the analysis description specifies a mixed-effects repeated measures model with random subject-specific intercepts. The outcome description also mentions six-month follow-up.

The registry record does not report a single primary comparison or its numerical result. Details on missing-data handling, multiplicity, and analysis populations are not reported. Serious adverse-event entries list zero events in each group; death counts are not reported in the registry record.