Psychological Support for Patients With an Implantable Cardioverter Defibrillator: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Psychological Support for Patients With an Implantable Cardioverter Defibrillator (NCT00152763), a randomized phase 3 study. The primary outcome is Hospital Anxiety and Depression Scale - Depression Scale at Baseline.

2. Clinical Question

The study’s broader aims included evaluating psychosocial support for coping with an ICD, examining whether baseline anxiety and depression predicted ICD therapies, and exploring whether the intervention was associated with less need for appropriate ICD therapies. Those aims are not all answered by the posted primary result. In particular, the primary endpoint is explicitly measured at baseline, before a change attributable to the intervention could be assessed.

The posted comparisons separate participants by sex and care assignment: women receiving cognitive behaviour therapy are compared with women receiving usual care, and men in the cognitive therapy group are compared with men receiving usual care. This structure is important when reading the results. The baseline depression means describe the groups at that measurement time; differences between them are not estimates of treatment-induced improvement or worsening. The registry record does not report a primary follow-up depression result in the posted outcome summaries.

3. Trial Design

The registry describes a completed phase 3, randomized, single-masked, factorial study, with enrollment of 193. The study began in 2003-10, and primary completion was in 2007-09. The masking description identifies the study as single-masked, but which participants or study personnel were masked is not reported in the registry record.

The intervention was cognitive behaviour therapy tailored to psychological adaptation to an ICD. It consisted of eight telephone sessions, with a psycho-educational booklet for participants and a therapist manual. The comparator was usual cardiac care, defined by the care routinely offered at participating ICD treatment sites. Standard educational materials about heart disease and the ICD device were described for usual care. The usual-care description also refers to follow-up appointments and device interrogation, but the registry text is truncated before the description is complete.

The posted group summaries are divided by sex and care assignment. The four labels distinguish usual cardiac care and cognitive behaviour therapy or cognitive therapy groups for men and women. The registry identifies the design as factorial, but the factorial factors, their levels, and the planned statistical model are not reported in the registry record. Nor does the record explain how randomization was implemented or identify the party responsible for masking.

The primary outcome is a baseline depression-scale score. The registry describes the primary population as intention-to-treat analyses, with data on participants who died over follow-up omitted. The posted summaries do not include a follow-up depression outcome or a reported analysis entry. The registry lists 28 outcome measures, but the detailed posted summaries do not provide results for all of them. The design label and trial aims therefore provide context, while the posted data support interpretation only of the specific measures and comparisons reported.

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: Upon recruitment, participants completed baseline psychological assessment prior to being randomized to the experimental intervention arm (cognitive behaviour therapy) or usual care.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intention to treat analyses but data on participants who died over follow-up were omitted.

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 Hospital Anxiety and Depression Scale - Depression Scale at Baseline, measured over Baseline.

The primary endpoint is the Hospital Anxiety and Depression Scale depression subscale score at baseline. The registry describes it as a continuous psychometric measure of depressive symptoms, reported in units on a scale. Scores range from 0 to 24, with scores >= 8 described as clinically elevated; higher scores represent greater depressive symptoms.

A continuous scale retains gradations in reported symptom burden rather than reducing every participant to a simple elevated/not-elevated category. Its mean describes the average score in a group, while the standard deviation describes variation in individual scores around that mean. The posted results give group means and standard deviations, allowing readers to see both the average level and the spread of scores.

The timing is central to interpretation. This endpoint is measured at baseline, so its role in the posted results is to describe depressive symptoms at study entry and compare the reported groups at that point. It cannot, by itself, show whether cognitive behaviour therapy changed depression after treatment. Although the trial’s aims include psychological support and prediction of ICD therapies, those questions require follow-up or predictive analyses; such primary analyses are not reported in the registry record.

The registry says the intended population was analyzed on an intention-to-treat basis, but data on participants who died over follow-up were omitted. It does not report further detail about missing baseline scale values, the handling of other missing observations, or an adjusted analysis of the endpoint.

7. Results Posted in the Registry

• Cognitive Behaviour Therapy - Women: mean 7.47 versus 4.70 on control; difference 2.77 (95% CI 0.32 to 5.22), standardized effect d = 0.73; z-test p = 0.027.
• Usual Cardiac Care - Women: mean 5.35 versus 4.70 on control; difference 0.65 (95% CI -1.38 to 2.68), standardized effect d = 0.19; z-test p = 0.530.
• Cognitive Therapy Group - Men: mean 4.12 versus 4.70 on control; difference -0.58 (95% CI -1.77 to 0.61), standardized effect d = -0.16; z-test p = 0.341.

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.

SF-36 Mental Component Summary Scale at Baseline

• 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:
  • Cognitive Behaviour Therapy - Women: mean 37.44 versus 45.90 on control; difference -8.46 (95% CI -15.49 to -1.43), standardized effect d = -0.63; z-test p = 0.018.
  • Usual Cardiac Care - Women: mean 42.33 versus 45.90 on control; difference -3.57 (95% CI -10.39 to 3.25), standardized effect d = -0.27; z-test p = 0.305.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Cognitive Behaviour Therapy - Women than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Usual Cardiac Care - Women and the control. The interval gives the range of effects that remain compatible with the data.

SF-36 Mental Component Summary Scale at 6-months Follow-up

• 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:
  • Cognitive Behaviour Therapy - Women: mean 43.82 versus 48.73 on control; difference -4.91 (95% CI -10.79 to 0.97), standardized effect d = -0.46; z-test p = 0.102.
  • Usual Cardiac Care - Women: mean 45.67 versus 48.73 on control; difference -3.06 (95% CI -8.88 to 2.76), standardized effect d = -0.29; z-test p = 0.303.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Cognitive Behaviour Therapy - Women 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 Usual Cardiac Care - Women and the control. The interval gives the range of effects that remain compatible with the data.

SF-36 Mental Component Summary Scale at 12-months Follow-up

• 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:
  • Cognitive Behaviour Therapy - Women: mean 46.26 versus 49.92 on control; difference -3.66 (95% CI -10.56 to 3.24), standardized effect d = -0.33; z-test p = 0.299.
  • Usual Cardiac Care - Women: mean 41.58 versus 49.92 on control; difference -8.34 (95% CI -13.37 to -3.31), standardized effect d = -0.81; z-test p = 0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Cognitive Behaviour Therapy - Women and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Usual Cardiac Care - Women than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted secondary summaries cover the SF-36 mental component at baseline and follow-up. They show that group means and mean differences vary across measurement times and between the sex-specific comparisons. The summaries are descriptive snapshots; they do not present a reported analysis of change over time or a test of whether the pattern of change differs between care groups.

These secondary findings offer context about mental quality-of-life scores alongside the primary baseline depression measure, but they are different constructs measured on different scales. A mental-component score should not be treated as interchangeable with a depression symptom score. Nor can an observed secondary difference establish a treatment effect without an analysis that addresses the timing, baseline values, group structure, and uncertainty.

The registry lists physical-component scores and the percentage of participants receiving ICD therapies among its secondary outcomes, but results for those outcomes are not reported in the registry record. The broader trial aims also refer to whether baseline anxiety and depression predict ICD therapies and whether the intervention affects appropriate ICD therapies. The posted secondary summaries do not report analyses answering those questions.

Unadjusted secondary results carry less weight because multiple outcomes and comparisons create more opportunities for chance findings. The registry record does not report a multiplicity strategy or a hierarchy specifying which secondary results should be considered confirmatory. In addition, the posted comparisons are not described as adjusted or longitudinal analyses. Their appropriate role is therefore to describe patterns that may merit attention, not to confirm efficacy or a causal mechanism. Interpretation should give priority to the endpoint’s timing and the breadth of uncertainty rather than selecting an isolated result.

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

• SF-36 Mental Component Summary Scale at Baseline
• SF-36 Mental Component Summary Scale at 6-months Follow-up
• SF-36 Mental Component Summary Scale at 12-months Follow-up
• SF-36 Physical Component Summary Score at Baseline
• SF-36 Physical Component Summary Score at 6-months Follow-up
• SF-36 Physical Component Summary Score at 12-months Follow-up
• Percentage of Participants Who Received ICD Therapies

9. Statistical Interpretation

10. Statistical Methods Explained

The posted continuous outcomes are summarized with means and standard deviations. A mean locates the group average on the scale. A standard deviation describes how dispersed participant scores are around that average; it is not the uncertainty of the mean itself. Uncertainty in a mean or a difference between means is instead reflected in its standard error and confidence interval.

What does a mean difference represent?

A mean difference compares the average score in one group with the average score in the reference group. Its sign depends on the order of subtraction used for the comparison. A positive estimate indicates a higher group mean under that ordering; a negative estimate indicates a lower group mean. For the depression endpoint, higher scores indicate greater depressive symptoms, but the comparison remains a difference between baseline groups rather than a change caused by treatment.

The reported comparison results are recalculated, simple unadjusted comparisons based on the posted summary statistics. They are not adjusted for other participant characteristics or for the factorial structure. The registry record does not report the sponsor’s model specification, covariate adjustment, or a full statistical analysis plan. The unadjusted comparisons should therefore be read as descriptive analytical contrasts, not as a substitute for a prespecified adjusted trial analysis.

How should a confidence interval be read?

A confidence interval gives a range of effect estimates compatible with the observed data under the calculation method. It conveys uncertainty as well as the direction and size of the estimated difference. An interval that spans zero includes no group difference among the values compatible with the data; an interval that excludes zero indicates that the corresponding unadjusted comparison is inconsistent with zero at the interval’s confidence level. An interval does not give the probability that the true effect lies inside that particular range, and it does not account for sources of bias or limitations in the analysis.

What does the p-value add?

An unadjusted p-value measures how unusual the observed data, or data more extreme, would be under a specified no-difference model. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The p-values posted with the recalculated comparisons do not reflect adjustment for the many outcomes and comparisons, and the registry does not report a multiplicity plan. They should consequently be treated as exploratory evidence rather than as definitive evidence for a trial-wide conclusion.

Why does allocation and group structure matter?

The registry labels the trial randomized and factorial, while the posted summaries divide results by sex and care group. These splits create distinct comparisons, but the record does not state how the factorial factors were analyzed or whether a treatment-by-sex interaction was tested. Separate within-sex comparisons do not, on their own, demonstrate that the intervention effect differs between women and men. Establishing such a difference would require a direct interaction analysis, which is not reported in the registry record.

Different group sizes and variability also affect precision. A smaller group generally contributes less information about its mean, and greater within-group variability makes a group contrast less precise. These general statistical principles help explain why estimates can have different uncertainty even when outcomes use the same scale. They do not imply that a particular difference is important or that the intervention caused it.

What is the role of the baseline measure?

Baseline measurement can describe the starting distribution and may be used in an analysis of later outcomes. Here, however, the posted primary endpoint is itself at baseline. There is no posted primary depression score at follow-up against which a baseline-to-follow-up change can be assessed. Without a reported longitudinal analysis, the baseline comparison cannot be interpreted as evidence of improvement, decline, or treatment response.

The registry describes the primary population as intention-to-treat but says data on participants who died over follow-up were omitted. It does not explain how other missing scale values were handled, whether imputation was used, or whether sensitivity analyses were conducted. Those omissions matter because conclusions from an analysis can depend on which participants contribute data and how unavailable outcomes are treated.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data locate a group difference, not whether that difference is important. The confidence intervals for the recalculated primary comparisons provide a range of compatible baseline differences. For the women’s comparison, the interval excludes zero; for the men’s comparison, it includes zero. The latter therefore permits both a difference in one direction and a difference in the other direction under the unadjusted calculation. Neither interval can turn a baseline contrast into an intervention effect.

The estimates differ in precision partly because the group sizes differ, particularly for the women’s comparison, and because the scores vary within groups. Smaller groups and more variable measurements generally yield less precise estimates. The standard deviations describe that within-group variability, while the confidence intervals reflect uncertainty about the differences in group means.

A confidence interval is not a guarantee that the true effect falls inside its limits, nor does it incorporate unreported design choices, missing-data mechanisms, or bias. The posted intervals are associated with unadjusted recalculations. They do not account for multiplicity across the numerous outcome measures and comparisons, and they do not show what an adjusted factorial analysis might estimate. The registry record does not report such an analysis.

For secondary mental-component scores, the posted comparisons also show differing degrees of uncertainty across time and group. Their intervals should be read as estimates for those particular comparisons, not as a coherent repeated-measures analysis. In particular, they do not test whether group trajectories differ over time. That question requires a reported longitudinal model or other analysis that accounts for repeated observations; such details are not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures for these continuous comparisons are expressed as participants per arm, not as total events. They are illustrations calculated from the observed effect, not the trial’s original design justification. The assumptions stated for the illustration are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set at the stated fraction of the observed effect.

The 80% power column describes the number of participants per arm that the illustration estimates would be needed to have an 80% chance of detecting the selected effect under those assumptions. The 90% power column applies the same idea with a higher target chance of detection, and therefore generally calls for more participants per arm. These values are planning aids, not counts of participants observed in the trial.

Rows planning for 100%, 75%, and 50% of the observed effect ask how the required group size changes when the effect targeted for detection is reduced. A smaller effect is harder to distinguish from random variation, so the illustration requires more participants. The estimates depend on the observed effect and the stated simplifying assumptions; they should not be treated as a guarantee that a future study will attain its target.

These calculations are not observed power. Observed power is not a useful substitute for reading the estimated effect and its confidence interval. The registry record does not report the assumptions used for the trial’s original design or its original sample-size justification.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 2.770; pooled standard deviation σ = 3.771.
2. n = 2 × (1.96 + 0.842)² × 3.771² / 2.770² = 29.1, rounded up to 30 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 2.77                      # observed difference in means
sigma <- 3.77101601663965                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(152763)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 30 (80% power), 39 (90% power)
 75% of observed effect: n per arm = 52 (80% power), 70 (90% power)
 50% of observed effect: n per arm = 117 (80% power), 156 (90% power)
power.t.test: 30.1 
Simulated power at n = 30 per arm: 0.800 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists 28 outcome measures, and the posted material includes multiple groups, outcomes, and measurement times. Each additional comparison creates another opportunity for a result that appears notable by chance. The record does not report a multiplicity adjustment, a prespecified outcome hierarchy, or a plan for deciding which analyses were confirmatory. The unadjusted p-values should therefore be interpreted cautiously, especially when considered across primary and secondary outcomes together.

The registry labels the trial factorial, but does not report the statistical model used to represent the factorial design. It is not reported whether the analysis included interaction terms, whether sex-specific comparisons were planned in advance, or whether any subgroup comparisons were exploratory. Separate comparisons within men and women are not equivalent to a formal test that treatment effects differ by sex.

The primary population is described as intention-to-treat, but data on participants who died over follow-up were omitted. The registry record does not report the number of missing primary endpoint scores, the reasons for missingness other than that omission, or how remaining missing values were handled. It also does not report imputation, sensitivity analyses, or an assessment of whether missingness might differ between groups.

The record does not report whether interim analyses were planned or conducted, the original sample-size justification, or a detailed statistical analysis plan. No reported analysis entries are listed in the registry record for the displayed outcomes. These absences limit assessment of whether the posted comparisons match prespecified analyses and how the study addressed multiple testing, missing data, and its factorial structure.

15. 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.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: deaths (10.0%).

The serious adverse event summaries report 4 affected participants among 77 at risk in usual cardiac care for men, 1 among 19 in cognitive behaviour therapy for women, 2 among 20 in usual cardiac care for women, and 1 among 77 in the cognitive therapy group for men. These are group-level reported counts; they should be read in the context of the registry’s safety reporting rather than as a comparison establishing that one care assignment is safer.

“Deaths” is listed among the top serious event terms with 10.0%. The group-specific death fields are not reported in the registry record, so this term does not provide a group-by-group account of deaths. The other adverse event fields show zero at risk and zero affected across the groups. With no participants listed as at risk in those fields, those entries do not establish that no other adverse events occurred.

The registry does not report further detail about event definitions, severity assessment, relatedness to the intervention, or comparative statistical testing. The serious-event counts are descriptive safety information, not evidence of causal attribution or a powered safety comparison.

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

The posted results describe baseline depression scores and several secondary mental-component summaries in groups defined by sex and care assignment. The primary comparison for women has an unadjusted interval excluding zero, while the men’s primary comparison has an interval including zero. These findings describe baseline differences in the posted groups; they do not show that the intervention changed depression.

The distinction between an association at baseline and an effect of treatment is fundamental. A treatment effect requires a comparison that relates assignment to outcomes measured after treatment, usually with an analysis that respects the randomized design and relevant baseline information. The primary endpoint is explicitly at baseline. It cannot establish improvement, harm, or lack of effect from the eight-session intervention.

The results also do not answer whether baseline anxiety or depression predicts later ICD therapies, or whether psychosocial support reduces appropriate ICD therapies. Those aims are described in the registry, but the associated analyses are not reported in the registry record. Likewise, the available secondary mental-component summaries do not establish a difference in trajectories, and physical-component or ICD-therapy results are not reported.

Statistical significance is not a measure of clinical importance. The p-values do not tell readers whether an observed difference matters to participants, and the confidence intervals do not account for unreported analytical choices or multiplicity. The record also omits important details about missing observations, the factorial model, and which analyses were prespecified.

The safest conclusion is limited to the posted descriptive and recalculated comparisons. They show variation in baseline scores and secondary summaries, with uncertainty that differs across comparisons. They do not establish that cognitive behaviour therapy works or does not work, nor do they determine its effects on quality of life or ICD therapies.

17. Why This Trial Matters Statistically

This trial illustrates why the endpoint’s timing can matter more than the direction or p-value of a group difference. The primary outcome is a measure of depressive symptoms, but it is reported at baseline. A baseline contrast may describe how groups entered the study; it is not a post-treatment contrast and cannot be read as evidence of therapeutic change.

It also demonstrates the value of keeping group structure visible. The registry identifies a randomized factorial design and presents sex-specific care groups, but does not report a factorial analysis or an interaction test. Without those details, separate comparisons do not support a conclusion that treatment effects differ by sex. Statistical readers should distinguish the layout of the groups from the model used to analyze them.

Precision and multiplicity are equally relevant. Group sizes and score variability influence the width of uncertainty intervals, while the many listed outcomes and comparisons make isolated unadjusted p-values less persuasive. A transparent analysis plan would help readers understand which results were primary, how repeated outcomes were handled, and how the study addressed multiple testing.

Finally, the record makes clear that a registry entry can contain trial design and outcome summaries without reporting the analyses needed to answer every stated aim. Separating observed group summaries, unadjusted recalculations, and unreported causal or predictive questions helps prevent overinterpretation. This is a useful discipline for clinical researchers working with registry results, particularly when outcomes are measured at different times and participant data may be missing.

18. 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 endpoint is measured at baseline, which limits its relevance to evaluating intervention effects. The registry does not report a primary depression outcome at follow-up or a change analysis. As a result, the posted primary comparisons cannot establish whether depressive symptoms changed after the psychosocial intervention.

The posted comparisons are unadjusted recalculations from summary statistics. The registry does not report the planned model, adjustment variables, a factorial analysis, or an interaction test. The listed group comparisons therefore do not resolve whether observed differences reflect treatment assignment, baseline imbalance, or other group characteristics.

There are differences in group size, especially among the women’s groups, and the amount of variability differs across measures. These features affect precision. The confidence intervals communicate some sampling uncertainty but do not address multiplicity, missing-data assumptions, or bias. No multiplicity strategy is reported despite the registry’s listing of many outcomes.

The primary population description says data on participants who died over follow-up were omitted, but the record does not report details of other missing values, imputation, or sensitivity analyses. The masking description does not identify who was masked, and the usual-care description is incomplete in the registry text. The original sample-size justification and interim-analysis plan are not reported in the registry record.

Finally, results for some listed secondary outcomes, including physical-component scores and ICD-therapy outcomes, are not reported in the registry record. The available secondary summaries are not described as a repeated-measures analysis. These gaps restrict conclusions about quality-of-life trajectories, ICD therapy prediction, intervention effects, and safety comparisons.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Psychological Support for Patients With an Implantable Cardioverter Defibrillator — NCT00152763.
• Registry record last updated 2011-01-28; status last verified 2011-01.
• Results first posted 2011-01-28.
• 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.

22. Record Summary

The registry describes a completed phase 3 randomized, single-masked factorial trial of cognitive behaviour therapy and usual cardiac care for patients with an ICD. Enrollment was 193; the study began in 2003-10 and primary completion was in 2007-09. The intervention comprised eight telephone sessions tailored to psychological adaptation to an ICD, with a participant booklet and therapist manual.

The primary posted outcome is the baseline Hospital Anxiety and Depression Scale depression score. Group means and recalculated unadjusted comparisons are available, along with selected SF-36 mental-component summaries. Because the primary measure is at baseline, these results do not estimate change caused by the intervention. Analyses of several stated aims and listed secondary outcomes are not reported in the registry record.

The record does not report a detailed statistical plan, a multiplicity approach, a factorial model, or a full account of missing-data handling. Interpret the posted estimates as descriptive and unadjusted, with attention to their uncertainty and the outcome timing.