Comparison of Depression Identification After Acute Coronary Syndrome: Quality of Life and Cost Outcomes: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison of Depression Identification After Acute Coronary Syndrome: Quality of Life and Cost Outcomes (NCT01993017), a randomized na study. The primary outcome is Quality-Adjusted Life Years (QALYs).

2. Clinical Question

The clinical question is about the outcomes associated with alternative approaches to identifying and responding to depressive symptoms after acute coronary syndrome. It is not a direct comparison of a single medication or psychotherapy: the AHA strategy offered treatment to people meeting the screening threshold, with treatment guided by participant preference. The registry describes the screening and notification procedures, but the available intervention text is truncated, so further details about implementation are not reported in the registry record.

The primary outcome, change in QALYs, combines information about quality and quantity of life in a single measure. Secondary outcomes address depression-free days and health care utilization costs. These outcomes provide different perspectives: one captures time without depression, while the other addresses expenditure. Their interpretation should remain distinct from the primary endpoint because each measures a different aspect of the trial question.

3. Trial Design

This was a randomized, single-masked, parallel-group trial listed as completed. The registry reports enrollment of 1501 and identifies Columbia University as the sponsor. The study began in 2013-11, and the primary completion date was 2018-07-31. The phase is listed as NA.

The three randomized strategies were AHA Depression Screen, Notify & Treat; Depression Screen & Notify; and No Depression Screen. In the first strategy, participants completed the PHQ-8 after randomization. Those with a score of at least 10 were offered treatment, delivered according to participant preference. In the notification strategy, a positive screen was to prompt a letter to the participant’s primary care provider. In the no-screen strategy, participants did not complete a PHQ-8 assessment at randomization and were not screened for depressive symptoms at that point.

The primary outcome was change in QALYs from baseline through 18 months, assessed using utility scores at baseline, 6, 12, and 18 months. The registry describes depression-free days and cost of health care utilization as secondary outcomes, both covering baseline through 18 months. The posted arm summaries include 499 participants in the AHA strategy, 501 in the notification strategy, and 500 in the no-screen strategy for the primary and secondary outcomes.

The record identifies the allocation as randomized and the model as parallel, but does not report the sequence-generation method, concealment procedures, or which parties were masked. Further details on recruitment, study sites, adherence, and the handling of participants who did not follow their assigned strategy are not reported in the registry record. Those omissions limit how fully the implementation and risk of bias can be assessed from the registry information alone.

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: 1 participant withdrew consent soon after randomization, and this participant's data was excluded from the study.

Overall Study

Reasons for not completing this period:

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 Quality-Adjusted Life Years (QALYs), measured over Baseline, 6, 12 and 18 months.

The primary endpoint is change in quality-adjusted life years from baseline through 18 months. A QALY combines the quality and quantity of life lived into a generic measure of disease burden. The registry describes one QALY as one year in perfect health. Utility scores used to construct the outcome range from 0, representing death, to 1, representing perfect health.

Utility was estimated using the Short Form-6 dimension, with scores derived from responses to the 12-Item Short-Form Health Survey, version 2. Assessments were made at baseline, 6, 12, and 18 months. The registry says QALYs across the follow-up period were calculated as the area under the curve, using linear interpolation between the observed assessments. Change was then defined by subtracting a baseline QALY from the observed QALY for the 18-month period; the baseline calculation assumed that the baseline utility score remained constant during that period.

This endpoint is used because it represents both health-related quality and duration in a single outcome, allowing broad comparison across health states. It does not directly measure depressive symptoms alone. Interpretation therefore depends on the construction of utility scores and the assumptions used to calculate the area under the curve. The registry record does not report additional detail about missing utility assessments or the analysis population used for the primary outcome.

7. Results Posted in the Registry

• Depression Screen & Notify: mean -0.06 versus -0.06 on control; difference 0.00 (95% CI -0.02 to 0.02), standardized effect d = 0.00; z-test p = 1.000.
• No Depression Screen: mean -0.06 versus -0.06 on control; difference 0.00 (95% CI -0.02 to 0.02), standardized effect d = 0.00; z-test p = 1.000.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Depression-free Days

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Depression Screen & Notify: mean 351.30 versus 343.10 on control; difference 8.20 (95% CI -13.74 to 30.14), standardized effect d = 0.05; z-test p = 0.464.
  • No Depression Screen: mean 339.00 versus 343.10 on control; difference -4.10 (95% CI -26.15 to 17.95), standardized effect d = -0.02; z-test p = 0.716.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Depression Screen & Notify and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between No Depression Screen and the control. The interval gives the range of effects that remain compatible with the data.

Cost of Health Care Utilization

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Depression Screen & Notify: mean 6,204 versus 6,745 on control; difference -541.00 (95% CI -1,498 to 415.95), standardized effect d = -0.07; z-test p = 0.268.
  • No Depression Screen: mean 7,440 versus 6,745 on control; difference 695.00 (95% CI -511.87 to 1,902), standardized effect d = 0.07; z-test p = 0.259.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Depression Screen & Notify and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between No Depression Screen and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes extend the comparison beyond the primary QALY measure. Depression-free days address time without depression, while health care utilization costs address expenditure. Across these outcomes, the posted comparisons do not present a consistent, clearly separated pattern of differences between either comparison strategy and AHA Depression Screen, Notify & Treat. The confidence intervals span values on both sides of no difference. This broad pattern is compatible with uncertainty about the size and direction of the contrasts.

The secondary findings are not a substitute for the primary result. Each outcome measures a distinct construct and has its own scale, variability, and uncertainty. A pattern that is broadly consistent with the primary endpoint may add context, but it does not demonstrate that the strategies have identical effects on every dimension. Nor does it resolve uncertainty about the primary endpoint or create a single combined conclusion across all outcomes.

The record lists two secondary outcomes and does not report analyses for them from the sponsor. The posted pairwise comparisons are recalculations and are unadjusted. When multiple outcomes and comparisons are considered, the chance of obtaining at least one apparently notable result by chance can increase. In general, multiplicity adjustments or a prespecified hierarchy can help manage that issue, but the registry record does not report whether such a strategy was used. Unadjusted secondary results should therefore carry less weight than a prespecified primary analysis, especially when interpreting isolated findings.

The secondary outcomes can still be informative as descriptive evidence. Their role is to show what the posted summaries suggest across different aspects of health and cost, while recognizing that their estimates are uncertain and that the analysis plan for these outcomes is not reported in the registry record. They should not be treated as independent confirmation of the primary conclusion.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Depression-free Days
• Cost of Health Care Utilization

9. Statistical Interpretation

10. Statistical Methods Explained

What does the overall ANOVA test?

The sponsor reports an analysis of variance, or ANOVA, for the primary endpoint across all three randomized arms. In general, ANOVA evaluates whether the group means are consistent with a common mean, against the alternative that at least one mean differs. It is an overall test: by itself, it does not identify which groups might differ, or the size and precision of any particular pairwise contrast. The reported p-value is 0.98. The registry record does not report further details about covariate adjustment, model diagnostics, or whether any additional planned analyses were conducted.

What do the pairwise recalculations represent?

The recalculated comparisons contrast the mean change in QALYs in each non-control arm with the AHA Depression Screen, Notify & Treat arm. They use the posted group means, standard deviations, and analysis counts to form unadjusted differences and confidence intervals. These are straightforward summary-statistic comparisons, not the sponsor’s full analysis model. Each recalculated contrast is 0.0 at the reported precision, with an unadjusted p-value of 1.0. Since both comparisons use the same reference arm, their results are related rather than independent pieces of evidence.

Unadjusted means that these calculations do not account for other participant characteristics or variables. The registry record does not report whether the primary analysis used adjustment, how any such adjustment was specified, or whether the posted means are adjusted or unadjusted. The recalculations should therefore be read as a transparent comparison of posted summaries, not as a reconstruction of every feature of the trial’s analysis.

What does a standard deviation describe?

A standard deviation describes the spread of individual observations around a group mean. It is different from the standard error, which describes the uncertainty in an estimated mean. The primary endpoint is reported as a mean with a standard deviation. The secondary cost outcome is reported as a mean with a standard error, so its spread information is presented on a different basis. Comparisons of variability across outcomes should take that distinction into account.

In general, larger variation among participants makes a mean contrast less precisely estimated, unless offset by other design or data features. This matters because a group mean alone can obscure substantial variation in individual outcomes. The registry record does not report distributional plots or additional summaries that would describe the shape of the QALY changes.

How should the p-values be read?

A p-value describes how compatible the observed data are with a specified null hypothesis under the assumptions of the statistical test. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference. The sponsor’s p-value of 0.98 pertains to the overall ANOVA. The recalculated p-values of 1.0 pertain to separate unadjusted pairwise comparisons. Because the tests ask different questions, their p-values should not be treated as interchangeable.

Neither a large p-value nor a confidence interval containing zero proves equivalence. Demonstrating equivalence or non-inferiority would ordinarily require a prespecified margin and a corresponding analysis. Such a margin and analysis are not reported in the registry record. The trial’s reported superiority analysis is not, by itself, an equivalence assessment.

What does the planning illustration mean?

In general, sample-size planning estimates how many participants per arm might be needed to detect a specified effect under stated assumptions. The record describes an illustration based on the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Rows correspond to planning for 100%, 75%, and 50% of the observed effect, and distinguish participants per arm for 80% power from participants per arm for 90% power.

These figures are planning illustrations, not observed power and not the trial’s original design justification. The registry record does not report the trial’s own sample-size assumptions or justification. Planning from an observed effect also inherits uncertainty in that estimated effect; a small observed contrast can imply very large planning estimates without proving that such a contrast is the true effect. These calculations do not indicate how likely the trial was to detect its actual effect, and they should not be used to reinterpret the completed trial as having had a particular level of observed power.

Why does over-dispersion matter in general?

Over-dispersion occurs when observed variability exceeds what a statistical model assumes. In general, ignoring it can make standard errors too small and confidence intervals too narrow, yielding an overly optimistic impression of precision. The posted primary endpoint is analyzed as a continuous measure with a standard deviation, and the recalculations use those reported summaries. The registry record does not report an over-dispersion assessment or a model-based adjustment for it. This is a general statistical consideration, not a claim that over-dispersion occurred in this trial.

11. Confidence Intervals and Precision

The posted primary endpoint means are -0.06 in all three arms, to the precision reported. The recalculated pairwise mean differences are also 0.0. The confidence intervals for both contrasts include zero, so the summaries do not identify a clear direction of difference between either comparison arm and the AHA strategy. The registry reports no confidence intervals for the arm means themselves.

A confidence interval gives a range of values reasonably compatible with the data and the assumptions of the calculation. It conveys uncertainty about the estimated contrast, not a range containing a fixed proportion of individual participant outcomes. The pairwise intervals are not evidence that all values within their ranges are equally likely, and their inclusion of zero does not demonstrate equivalence. The registry record does not report a threshold for a clinically important QALY difference, so statistical precision cannot be translated into a conclusion about clinical importance.

The primary arm summaries include standard deviations of 0.2, 0.2, and 0.18. Those values describe variation among participants, not uncertainty in the mean. The pairwise confidence intervals reflect uncertainty in the estimated differences and are narrower than the spread among individual observations. This distinction helps explain why two arm means can be estimated with some precision even when individual outcomes vary.

Precision should also be interpreted in light of the outcome’s construction. Utility assessments were collected at baseline, 6, 12, and 18 months, and values between assessments were linearly interpolated for the area-under-the-curve calculation. The registry record does not report the extent of missing measurement data or how such data were handled. The confidence intervals therefore summarize uncertainty under the calculation and analysis details available in the record, rather than accounting for unreported sources of uncertainty.

12. Analyses Reported by the Sponsor

The sponsor’s reported primary analysis is an overall ANOVA across the three arms, with p = 0.98. The recalculated comparisons are pairwise, unadjusted contrasts between each non-control arm and AHA Depression Screen, Notify & Treat. They both yield a mean difference of 0.0 at the reported precision and an unadjusted p-value of 1.0. These analyses address related but distinct questions: the ANOVA assesses the overall pattern across arms, while the recalculations estimate specified pairwise differences.

The record does not flag a discrepancy between the reported and recalculated results. The recalculations are based only on posted summary statistics and are not a substitute for the sponsor’s analysis. They may not reproduce modeling choices, adjustment, or handling of data that are not described in the registry record. The sponsor’s analysis should therefore be understood as the trial’s reported primary test; the recalculated values provide a simple, transparent view of the pairwise contrasts from the available summaries.

The similar pattern across the overall test and pairwise summaries does not establish that the strategies are equivalent. The tests fail to show evidence of a difference, but the registry record does not report an equivalence margin or an equivalence analysis. The distinctions among the analysis types remain important even when their conclusions appear consistent.

13. Multiplicity, Missing Data and Analysis Populations

The registry reports one primary outcome, an overall ANOVA, and two secondary outcomes. It does not report a multiplicity plan, such as a hierarchy for testing endpoints or an adjustment across comparisons. This matters because evaluating multiple outcomes and contrasts can raise the chance that at least one result appears notable even when there is no corresponding underlying effect. The unadjusted pairwise p-values should therefore be read as descriptive comparisons rather than as evidence that multiplicity has been controlled.

The record does not report whether interim analyses were conducted, whether any stopping rules applied, or whether the analysis plan was prespecified in detail. Those items are not reported in the registry record. Without those details, it is not possible to assess whether the reported testing strategy accounts for repeated looks at the data or departures from planned analyses.

Missing-data handling is also not reported in the registry record. The outcome description identifies utility assessments at baseline, 6, 12, and 18 months, but does not state how incomplete follow-up or missing assessments were addressed. The posted group counts indicate the numbers contributing to the outcome summaries, but they do not explain why these counts differ across arms or whether all randomized participants were included in an intention-to-treat analysis.

The analysis population is not reported in the registry record. The record does not specify whether analyses followed assignment regardless of treatment received, were restricted to participants with complete outcome data, or used another population definition. This limits interpretation of the randomized comparison, particularly when considering adherence and follow-up. No inference about the extent or impact of missing data can be made from the posted information alone.

14. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The serious adverse event figures report zero affected participants in each arm, with the at-risk counts listed as 499 for AHA Depression Screen, Notify & Treat, 501 for Depression Screen & Notify, and 500 for No Depression Screen. This is a report of the registry’s serious-event summary, not a guarantee that no serious health events occurred under any definition or at any time. The record does not provide serious adverse event terms, and the top serious-event terms list is empty.

For other adverse events, the record reports 386 affected among 450 at risk in the AHA strategy, 398 among 455 at risk in the notification strategy, and 399 among 458 at risk in the no-screen strategy. These counts describe the registry’s reporting categories. The record does not provide event-specific details or explain why the at-risk counts differ from the outcome analysis counts.

The death counts reported are 23, 26, and 18, respectively, across the three arms. The registry information does not state the causes, timing, relationship to study interventions, or whether deaths overlap with other adverse-event categories. These figures should therefore be read as descriptive safety reporting, not as evidence that an intervention caused or prevented events. Comparative safety interpretation would require definitions and analytic details that are not reported in the registry record.

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

The posted primary results show the same mean change in QALYs, -0.06, in each randomized arm to the precision reported. The sponsor’s overall ANOVA has p = 0.98, and the simple pairwise recalculations show mean differences of 0.0. These statistics do not show evidence of a difference in the primary outcome across the strategies in the reported analyses.

That statement is narrower than saying the strategies have no effect, are identical, or are interchangeable. A failure to detect a difference is not proof that a difference is absent. The record does not report an equivalence margin or a non-inferiority analysis, and the confidence intervals allow a range of contrasts around zero. The results also do not establish what would happen in populations or settings beyond those represented in the trial.

The endpoint is an aggregate measure built from utility scores over time, with linear interpolation between assessment visits and a stated baseline assumption. It does not directly report every aspect of depressive symptoms, treatment uptake, quality of care, or individual experience. The secondary measures address different questions, and their unadjusted comparisons should not be merged into a single claim about overall benefit or cost-effectiveness. No cost-effectiveness analysis is reported in the registry record.

The intervention strategy included screening and an offer of treatment for participants meeting the threshold, with treatment based on participant preference. The findings therefore concern the assigned strategies as described, not the independent effect of cognitive behavioral therapy or antidepressant medication. Further information about treatment received, adherence, missing outcomes, and analysis populations is not reported in the registry record. Those limits matter when moving from an observed group comparison to explanations about why the outcomes were similar.

16. Why This Trial Matters Statistically

This trial is statistically informative because its primary question concerns a strategy rather than a single treatment: screening after acute coronary syndrome, communicating a positive screen, and offering follow-up treatment were considered as an approach to care. Comparing that strategy with notification alone and with no screening gives the outcome a practical, policy-oriented context while retaining randomized allocation.

The use of QALYs also illustrates the trade-offs of a broad composite measure. It makes quality and quantity of life part of one summary, but depends on utility measurement and on how measurements between visits are represented. The registry explicitly describes an area-under-the-curve approach and linear interpolation, making the endpoint’s construction relevant to interpretation rather than a technical detail alone.

The record also illustrates why overall tests, pairwise comparisons, confidence intervals, and p-values are not interchangeable. The sponsor reports an overall ANOVA; recalculations estimate pairwise mean contrasts from summaries. Both help characterize the posted data, but neither converts a non-significant result into evidence of equivalence. Planning illustrations based on observed effects are likewise not observed power or a record of the original design rationale.

Finally, secondary outcomes and adverse-event summaries broaden the context but bring their own interpretive limits. Multiple unadjusted comparisons, absent detail about missing data and analysis populations, and sparse safety descriptions constrain the strength of conclusions. Reading these elements together shows how trial results can be informative while still leaving important uncertainties about precision, implementation, and the scope of inference.

17. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record does not report several details needed to evaluate the trial methods fully. The randomization sequence and allocation concealment procedures are not described, and the meaning of single masking is not specified by masked role. The record also does not report recruitment settings, detailed eligibility criteria, or the extent to which participants followed their assigned screening and treatment strategy.

The available description of the AHA arm is truncated after stating that treatment would be delivered according to participant preference. Although the intervention list includes cognitive behavioral therapy and antidepressant medication, the registry text does not provide the remaining implementation details. This limits interpretation of what the treatment offer entailed in practice.

For the primary endpoint, the record explains utility measurement and the area-under-the-curve calculation, but does not report missing-data methods, analysis population, or additional modeling details. The reported group means and recalculations cannot establish how the sponsor handled incomplete follow-up or whether covariates were included. The recalculations are unadjusted and should not be treated as a full reproduction of the sponsor’s analysis.

The record does not report an equivalence margin, multiplicity strategy, interim analyses, or the trial’s own sample-size justification. The planning figures based on observed effects are not a substitute for those design details. Secondary outcome analyses are also not reported by the sponsor, and the adverse-event summaries lack event terms and explanatory context. These omissions do not invalidate the posted summaries, but they restrict what can be concluded about clinical importance, safety, generalizability, and robustness of analysis.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Comparison of Depression Identification After Acute Coronary Syndrome: Quality of Life and Cost Outcomes — NCT01993017.
• Registry record last updated 2023-04-14; status last verified 2023-04.
• Results first posted 2019-12-18.
• 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.

21. Record Summary

NCT01993017 is a completed randomized, single-masked, parallel-group trial sponsored by Columbia University. It enrolled 1501 people with acute coronary syndrome and compared AHA Depression Screen, Notify & Treat with Depression Screen & Notify and No Depression Screen. The primary outcome was change in QALYs from baseline through 18 months.

The sponsor reported an overall ANOVA with p = 0.98. The posted primary arm means are -0.06 in each group, and recalculated pairwise differences are 0.0 at the reported precision. The registry also lists depression-free days and cost of health care utilization as secondary outcomes. Important details about missing data, analysis populations, multiplicity, and implementation are not reported in the registry record.