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 Comparison of Quetiapine and Trazodone Treatment for Insomnia in Dually Diagnosed Veterans (NCT01662297), a randomized phase 4 study. The primary outcome is Change in Average Pittsburgh Sleep Quality Inventory (PSQI)Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01662297 |
| Phase | Phase 4 |
| Condition | Insomnia, Mental Health Disorder, Substance Use Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 1 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VA Connecticut Healthcare System |
| Results posted | Yes |
2. Clinical Question
Population
Veterans with insomnia and a history of addiction and mental health issues who were taking quetiapine and could enter the randomized trial. The registry record describes screening through an acceptability phase before trial enrollment. Its narrative reports that 3 subjects were randomized and only 1 provided data beyond baseline; the enrollment field reports 1.
Intervention
Switching from quetiapine to trazodone for insomnia. The randomized study was intended to compare this switch with remaining on quetiapine.
Comparator
Continuing quetiapine for insomnia. The record describes the study as randomized, open, and parallel, with no masking.
Primary question
How did average Pittsburgh Sleep Quality Index (PSQI) scores change from baseline to week 4, and how did that change compare between the trazodone and quetiapine groups? The registry also describes examining change through week 8. Higher PSQI scores indicate worse sleep quality, and the stated scale range is 0-21.
The study was registered as a phase 4 pilot comparative-effectiveness trial. Its stated purpose was to test whether staying on quetiapine had an advantage over switching to trazodone, while the primary outcome description calls the analysis non-superiority and frames the hypothesis as no significant difference between treatments. The registry record does not report a numerical PSQI result, an estimated between-group contrast, or a confidence interval. Consequently, the clinical question is identifiable, but the posted record does not establish how the treatments compared on the primary outcome.
3. Trial Design
The registry describes a randomized, open-label, parallel-group phase 4 pilot trial sponsored by VA Connecticut Healthcare System. Masking was listed as none. One arm continued quetiapine for insomnia; the other switched from quetiapine to trazodone. The study title and stated population concern veterans with insomnia and co-occurring mental health and substance use histories.
The planned work included two concurrent phases. The first was an acceptability phase: it was intended to document whether patients and physicians would agree to a switch from quetiapine, describe characteristics associated with willingness to switch, and record reasons for accepting or declining. It also served as a screening component for the randomized phase. The second phase involved consent and random assignment to continue quetiapine or switch to trazodone. These are descriptions of the study's planned structure, not evidence that each planned activity was completed.
The registry lists enrollment as 1. The primary-outcome narrative separately reports that 3 subjects were randomized and only 1 provided data beyond baseline. Those entries give different counts, and the registry record does not explain the difference. The record lists the study status as terminated. Its start is recorded as 2012-07 and primary completion as 2015-10.
The primary outcome was change in average PSQI score, with assessment at baseline, week 4, and week 8. The first four weeks were described as the active acute experiment phase and the main comparison period; week 8 was a follow-up point. Other listed outcomes included insomnia severity, sleepiness, general health, psychological symptoms, alcohol urges, heavy drinking days, negative urine drug screens, and a sleep index. Numerical results for these outcomes are not reported in the registry record.
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 | Quetiapine | Trazodone |
|---|---|---|
| STARTED | 0 | 1 |
| COMPLETED | 0 | 1 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: We had difficulty recruiting and retaining subjects for this study. 3 subjects were randomized and only 1 provided data beyond baseline.
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 | Quetiapine | Trazodone | Total |
|---|---|---|---|---|
| Participants analysed | 0 | 1 | 1 | |
| Age, Categorical: <=18 years | Participants | — | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | — | 1 | 1 |
| Age, Categorical: >=65 years | Participants | — | 0 | 0 |
| Age, Continuous | years | — | 60 (60 to 60) | 60 (60 to 60) |
| Sex: Female, Male: Female | Participants | — | 0 | 0 |
| Sex: Female, Male: Male | Participants | — | 1 | 1 |
| Region of Enrollment: United States | participants | — | 1 | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Average Pittsburgh Sleep Quality Inventory (PSQI)Score, measured over From baseline (week 0) to end of 4 week and end of week 8.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in average Pittsburgh Sleep Quality Index (PSQI) score from baseline, assessed at week 4 and week 8. The registry describes scores on a 0-21 scale, with higher scores indicating worse sleep quality. It identifies change from baseline to week 4 as the main outcome and the main between-group comparison, while also describing follow-up of change through week 8.
As a general measurement principle, a patient-reported sleep-quality score can capture a person’s experience over time rather than relying only on a single observation. A change score expresses how the measured value differs from that person's baseline; comparing change between randomized groups can describe whether the groups followed different average trajectories. The interpretation depends on the score’s direction: in this registry description, a higher PSQI score corresponds to worse sleep quality.
The registry record does not report the observed average scores, change estimates, variability, or a between-group estimate at either follow-up. It therefore does not show the size or precision of any primary-outcome difference. The record states that the primary analysis was intended to use repeated measures and that the study was described as a non-superiority analysis. A non-superiority framing does not, by itself, show that treatments are equivalent; the registry record does not report a numerical result or a margin defining an acceptable difference.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a clear primary question: compare change in average PSQI score between veterans assigned to remain on quetiapine and those assigned to switch to trazodone. The main comparison period was baseline to week 4, with additional follow-up through week 8. The scale ranges from 0-21, and higher scores indicate worse sleep quality. However, the registry record contains no numerical primary-outcome comparison. It reports no group means, changes, variability estimates, confidence interval, or p-value for PSQI.
The small amount of follow-up described is central to interpreting the record. The primary-outcome narrative says 3 subjects were randomized and only 1 provided data beyond baseline. The enrollment field lists 1, and the record does not explain the differing counts. With only 1 participant reported as providing data beyond baseline, the record cannot give a well-supported estimate of how average changes compare across two randomized groups. The absence of an estimate is not evidence that the groups had the same outcome.
The study's description uses a non-superiority framing and says the hypothesis is that there is no significant difference between treatments. A non-significant test, if one had been reported, would not by itself establish equivalence or show that any difference is unimportant. A precise interpretation would need an estimated contrast and its uncertainty, as well as a prespecified criterion for what range of differences would count as acceptably similar. Such a margin is not reported in the registry record, and no test result is posted.
The record also describes an acceptability phase, which is relevant to feasibility rather than a treatment-effect estimate. It was intended to assess willingness among patients and physicians to switch and to record reasons for their choices. The registry does not report results for that phase. It therefore does not establish how acceptable the proposed switch was, just as it does not establish a comparative PSQI outcome.
The posted information supports a description of the planned comparison, the outcome scale, the intended follow-up, and the difficulty retaining participants. It does not support a conclusion about which group had a larger average improvement, whether any difference was clinically important, or whether the treatments were similar. No interpretation of an unreported effect should be substituted for the missing estimate.
9. Statistical Methods Explained
What does a repeated-measures comparison mean?
The registry says that total PSQI scores were to be analyzed over time using repeated measures, with change from baseline to week 4 as the main comparison and assessment extending to week 8. As a general statistical explanation, repeated-measures methods are designed for outcomes recorded on the same participants at more than one time point. They can describe changes over time and compare patterns between groups while accounting for the fact that observations from one person are related to each other. Measurements from the same individual are not independent in the way measurements from different individuals may be.
The registry record does not report the specific repeated-measures model, its covariance assumptions, the exact contrast used to compare groups, or whether any adjustment variables were included. Those details should not be inferred from the general term “repeated measures.” The record also does not provide a fitted model result for the PSQI endpoint.
How should change from baseline be understood?
Change from baseline describes movement in a participant’s score relative to the starting measurement. For the PSQI, the record states that higher scores indicate worse sleep quality. In general, interpreting a change therefore requires attention to direction, the baseline score, the follow-up score, and variation among participants. A group average alone does not show how individual participants varied, and a group comparison requires an estimate of the difference in changes together with its uncertainty. No such numerical estimates are reported in the registry record.
Baseline adjustment and change-score analysis are related but not identical approaches, and the record does not specify enough detail to determine the exact implementation beyond its description of change over time. The scale’s stated range is 0-21. That range gives context for the measure, but it does not identify what size of change would matter to participants; a threshold for meaningful change is not reported in the registry record.
What does uncertainty add?
As a general statistical concept, a confidence interval gives a range of values compatible with the data under the model and its assumptions. A narrow interval indicates greater precision than a wide interval, while an interval spanning both potentially meaningful benefit and harm leaves substantial uncertainty. A p-value, when reported, addresses how compatible observed data are with a specified null hypothesis under a statistical model; it does not measure the probability that the null hypothesis is true, nor does it describe the clinical importance of an effect.
Neither a confidence interval nor a p-value for the primary PSQI comparison is reported in the registry record. The very limited follow-up noted in the primary-outcome narrative means that the record does not provide a basis for judging precision. This limitation is distinct from whether the planned statistical method was appropriate: a method cannot recover information that was not observed.
What can the non-superiority description establish?
The primary outcome description calls the analysis non-superiority and states a hypothesis of no significant difference between treatments. In general, a failure to detect a statistically significant difference is not proof that effects are equivalent. Demonstrating similarity within a clinically acceptable range ordinarily requires a defined margin and an estimate precise enough to exclude differences outside that margin. The registry record does not report such a margin, a formal test result, or an estimate with uncertainty. It is therefore not possible to assess a non-superiority conclusion from the posted results.
The record's wording describes an intended analysis; it does not establish that the planned analysis was completed. The analyses count is 0, and the primary outcome is not reduced to a single comparison because it includes multiple time points. No sponsor analysis result for the primary outcome is reported.
How do planning calculations differ from trial findings?
As a general distinction, a sample-size planning illustration asks how many participants might be needed under stated assumptions to detect a specified effect with a chosen error rate and power. Such an illustration is not an observed outcome and is not a substitute for the trial's actual results. The registry's planning description refers to a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect expressed as a fraction of an observed effect. It does not report the trial’s own sample-size justification. No planning participant counts are reported in the record considered for this interpretation.
Planning quantities also cannot turn an under-recruited or incomplete study into a definitive result. The primary-outcome narrative reports only 1 participant with data beyond baseline, while the enrollment field lists 1 and the same narrative reports 3 randomized. These entries point to substantial limits on interpreting the intended between-group analysis. The record does not report enough completed outcome data to estimate a reliable group contrast.
10. Multiplicity, Missing Data and Analysis Populations
The study listed a primary sleep-quality outcome and several secondary outcomes, including insomnia severity, sleepiness, general health, psychological symptoms, alcohol urges, heavy drinking days, negative urine drug screens, and a sleep index. Multiple outcomes and multiple assessment times create opportunities to examine many results. As a general statistical principle, the more comparisons examined, the greater the chance that at least one may appear notable by chance unless the analysis plan accounts for multiplicity. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting the secondary outcomes.
The primary outcome itself includes baseline, week 4, and week 8 measurements. The record identifies baseline-to-week-4 change as the main comparison and also describes analysis through week 8, but it does not report how inference across time points was to be controlled or prioritized beyond that description. The registry record does not report an interim-analysis plan.
Missing follow-up is a major issue in the posted description: it says 3 subjects were randomized and only 1 provided data beyond baseline. The record does not explain why other participants lacked follow-up data, whether the participant with follow-up data had measurements at both later time points, or how missing values were handled. It also does not report an analysis population definition, an intention-to-treat approach, a per-protocol approach, or sensitivity analyses. These methods should not be assumed.
The enrollment field lists 1, which differs from the narrative count of 3 randomized. The registry record does not reconcile these entries. Without a documented analysis population and missing-data method, the target population represented by any hypothetical estimate is unclear. No primary or secondary outcome analysis is reported, so the consequences of these missing-data and multiplicity issues cannot be quantified from the 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 |
|---|---|---|---|
| Trazodone | 1 | 1 | 100.0% |
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 |
|---|---|
| Quetiapine | 0 of 0 |
| Trazodone | 1 of 1 |
Most frequent serious adverse event terms
| Event term | Organ system | Quetiapine | Trazodone |
|---|---|---|---|
| Death | Cardiac disorders | 0 of 0 | 1 of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Quetiapine | Trazodone |
|---|---|---|---|
| Nausea/Vomiting | Gastrointestinal disorders | 0 of 0 | 1 of 1 |
Serious events with the highest arm-level rate: death (100.0%).
The adverse-event record lists zero participants at risk and zero affected for serious and other events in the quetiapine group. In the trazodone group, it lists 1 participant at risk and 1 affected for serious events, and 1 at risk and 1 affected for other events. The listed top serious-event term is “Death,” with 100.0%. The group-level death counts are recorded as null rather than as a numerical count.
These entries should be read as sparse registry tallies, not as comparative safety rates. The record does not provide event narratives, timing, severity details beyond the serious-event classification, attribution to treatment, or an explanation connecting the listed term to the group-level entries. It also does not report a numerical death count by group. The 100.0% term entry does not establish the probability of an event in a broader population or prove that treatment caused an event.
With only 1 participant listed at risk in the trazodone group and zero listed at risk in the quetiapine group, there is no meaningful basis in these figures for a balanced safety comparison. The registry record does not provide enough detail to infer the clinical circumstances or causal relationship of the serious event. The counts describe what was entered in the record and should not be generalized beyond that limited reporting.
12. What the Result Does, and Does Not, Mean
The registry record establishes the intended comparison and its limitations, but it does not provide a numerical primary outcome result. It describes random assignment to continued quetiapine or a switch to trazodone, with change in PSQI score as the main endpoint at week 4 and additional follow-up at week 8. Higher scores indicate worse sleep quality on the stated 0-21 scale. No group-level changes, treatment contrast, confidence interval, or p-value are reported.
The primary-outcome narrative states that 3 subjects were randomized and only 1 provided data beyond baseline. The enrollment field lists 1, and the record does not explain the difference. This sparse follow-up, alongside the absence of an outcome estimate, means the posted information cannot show whether average sleep-quality changes differed between groups. It also cannot show that the groups were equivalent or that any difference was small.
The stated non-superiority framing should not be interpreted as a finding of similar outcomes. In general, absence of a statistically significant difference is not the same as evidence of equivalence; the latter requires an appropriate margin and adequate precision. Neither a margin nor a numerical comparison is reported in the registry record.
The record also does not report results from the acceptability phase or numerical results for the listed secondary outcomes. Its safety entries are sparse and do not support a reliable comparative safety assessment. The trial therefore contributes information about the intended design and the difficulty recruiting and retaining participants, but the posted record does not answer the comparative-effectiveness question with an interpretable treatment-effect estimate.
13. Why This Trial Matters Statistically
This trial is statistically instructive because it distinguishes a clearly stated research question from the evidence needed to answer it. The registry identifies two randomized groups, a primary sleep-quality measure, and a main comparison period. Yet the primary-outcome narrative reports that only 1 participant provided data beyond baseline, and no numerical comparison is reported. A prespecified endpoint and a planned analysis cannot substitute for enough observed outcomes to estimate a treatment contrast with useful precision.
The record also illustrates why enrollment and follow-up counts must be read carefully. The enrollment field lists 1, whereas the narrative says 3 subjects were randomized. The record does not reconcile the figures. It also shows that randomization alone does not guarantee a useful between-group estimate: incomplete outcome collection can sharply limit what the randomized design can tell readers.
Another statistical lesson concerns non-superiority language. A stated aim of finding no significant difference does not demonstrate that treatments are similar. Similarity claims depend on a defined acceptable range and sufficient precision, neither of which is reported for the primary outcome. Reporting estimates and uncertainty is essential for distinguishing an inconclusive result from evidence that a difference is small.
Finally, the pilot and acceptability aims matter for feasibility, but their intended role is not the same as an efficacy comparison. The registry record describes those aims without posting their results. This makes the study useful for understanding how design, recruitment, follow-up, and analysis reporting shape the strength of conclusions that can be drawn from a clinical trial record.
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 most important limitation in the registry record is the very limited follow-up described for the primary outcome: 3 subjects were randomized and only 1 provided data beyond baseline. The enrollment field separately reports 1, and the record does not explain the mismatch. No numerical PSQI result is posted, so there is no effect estimate or measure of uncertainty to interpret.
The study was open and had no masking, according to the registry. The record does not report procedures that might address the potential influence of participants’ or clinicians’ knowledge of treatment assignment. It also does not report details of the repeated-measures model, missing-data handling, analysis populations, multiplicity control, or a non-superiority margin. These omissions prevent evaluation of how the planned statistical analysis was implemented.
The primary endpoint description names week 4 as the main comparison and includes follow-up at week 8, but no outcome values at either time are posted. The record does not report why participants did not provide follow-up data or whether the available participant contributed observations at each planned time point. This limits interpretation of retention and of the completeness of outcome measurement.
The registry lists several secondary outcomes, but no analyses are reported. Safety information is also sparse, with very small recorded counts and no detailed event narratives or attribution information. The acceptability phase is described as part of the study plan, but its results are not reported. These limitations mean the record documents intended methods and recruitment challenges more clearly than it documents comparative outcomes.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Comparison of Quetiapine and Trazodone Treatment for Insomnia in Dually Diagnosed Veterans — NCT01662297.
- Registry record last updated 2018-10-16; status last verified 2018-10.
- Results first posted 2018-10-16.
- 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
NCT01662297 is a phase 4 randomized, open, parallel-group pilot trial comparing continued quetiapine with switching to trazodone for insomnia in veterans with mental health and substance use histories. The primary endpoint was change in average PSQI score, with baseline-to-week-4 change identified as the main comparison and follow-up through week 8. Higher scores indicate worse sleep quality on a 0-21 scale.
The registry lists enrollment as 1, while the primary-outcome narrative reports 3 randomized and 1 with data beyond baseline. The record is marked terminated and reports no primary outcome analysis. It does not provide a numerical treatment comparison, confidence interval, or p-value. The posted record therefore describes the study question and substantial recruitment and retention difficulties, but does not establish the comparative PSQI outcome.