Effect of High Dose Fish Oil Supplementation After Recent Heart Attack Using Magnetic Resonance Imaging: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of High Dose Fish Oil Supplementation After Recent Heart Attack Using Magnetic Resonance Imaging (NCT00729430), a randomized phase 3 study. The primary outcome is Effect of Omega-3 Fatty Acids on Adverse Left Ventricular Remodeling.

2. Clinical Question

The registry frames the study as an evaluation of both a new magnetic resonance imaging technique and the effects of fish oil supplementation on heart health after a heart attack. The posted primary outcome is a continuous imaging measure: change in indexed left ventricular end-systolic volume from baseline to the post-treatment assessment. The comparison is between randomized arms, rather than a comparison of each arm with an external benchmark.

The posted results describe the high-dose omega-3 arm as having a mean percent change of -5.4, with a standard deviation of 16.6; the placebo arm had a mean of 1.2, with a standard deviation of 20.9. The listed mean difference is -6.6, and its confidence interval runs from -10.51 to -2.687. These statistics describe the registry-posted outcome; they do not by themselves establish how an individual participant experienced a change or what clinical importance that change had.

The study also lists secondary imaging outcomes concerning non-infarct myocardial fibrosis, left ventricular ejection fraction, and infarct size. Their registry-posted measurements are described as occurring in the 3-year follow-up period after a participant's last study visit. Eligibility details, the clinical threshold for an important change, and the original statistical rationale for selecting the endpoint are not reported in the registry record.

3. Trial Design

The registry identifies this as a Phase 3 randomized, triple-masked, parallel-group study sponsored by Brigham and Women's Hospital. The listed enrollment is 358, and the record status is completed. The study start is recorded as 2008-08 and primary completion as 2013-10. The two listed interventions are omega-3 fatty acids and placebo; each arm description specifies a 6-month treatment period.

The outcome summaries give 180 participants in the high-dose omega-3 fatty acid arm and 178 in the placebo arm. Those are the arm-specific counts attached to the posted primary and secondary outcome summaries. The registry record does not provide a fuller account of participant flow, exclusions after randomization, or the number included in each analysis beyond these outcome counts.

Random allocation and a parallel comparison support interpretation of the arm contrast as a randomized comparison, subject to how the trial was conducted and how outcomes were handled. The record labels the masking as triple, but does not report which groups of people were masked, how masking was maintained, or whether it was assessed. Allocation concealment procedures, stratification factors, and the method used to generate the allocation sequence are not reported in the registry record.

The primary outcome is assessed from baseline to post-treatment, with the description specifying the 6-month post-treatment point. Secondary outcomes have a different stated timeframe: the 3-year follow-up period after each participant's last study visit. The record therefore contains outcomes tied to both the treatment-period assessment and later follow-up. It does not report the original design assumptions, the planned analysis population, the handling of missed visits, or the details of the MRI acquisition and measurement procedures. The study description also mentions evaluating a new MRI technique, but the posted numerical outcome summaries do not report its validation characteristics.

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

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 Effect of Omega-3 Fatty Acids on Adverse Left Ventricular Remodeling, measured over Before and after study treatments.

The primary endpoint is the percent change in left ventricular end-systolic volume indexed to body surface area, measured from baseline to post-treatment at 6 months. Left ventricular end-systolic volume is the volume of blood in the left ventricle at the end of contraction; indexing it to body surface area expresses the volume in relation to body size. The registry describes the reported summary as a mean and gives standard deviation as the measure of spread.

This continuous imaging measure is used to assess ventricular remodeling: changes in the structure or function of the ventricle following the heart attack. The study's title and outcome description place the endpoint in that context. A percent-change measure expresses movement relative to a participant's baseline measure, while the arm means summarize the average observed change in each randomized group. The registry record does not report a threshold defining a clinically important difference or explain how such a threshold was chosen.

In the posted data, the mean percent change is -5.4 in the omega-3 arm and 1.2 in the placebo arm. A negative value indicates a decrease relative to baseline, while a positive value indicates an increase, as expressed by this outcome. The mean difference is reported as -6.6 for the omega-3 arm relative to placebo. These group summaries describe the measured imaging endpoint, not a direct measure of symptoms, quality of life, or survival. The registry record does not report the relationship between this endpoint and later clinical outcomes.

7. Results Posted in the Registry

• High Dose Omega-3 Fatty Acid Arm: mean -5.40 versus 1.20 on control; difference -6.60 (95% CI -10.51 to -2.69), standardized effect d = -0.35; z-test p = <0.001.

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.

Effect of Omega-3 Fatty Acids on Non-Infarct Myocardial Fibrosis

• 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:
  • High Dose Omega-3 Fatty Acid Arm: mean -2.10 versus 3.40 on control; difference -5.50 (95% CI -8.51 to -2.49), standardized effect d = -0.38; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for High Dose Omega-3 Fatty Acid Arm than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Effect of Omega-3 Fatty Acids on Left Ventricular Ejection Fraction

• 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:
  • High Dose Omega-3 Fatty Acids Arm: mean 4.80 versus 2.10 on control; difference 2.70 (95% CI 0.31 to 5.09), standardized effect d = 0.23; z-test p = 0.027.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for High Dose Omega-3 Fatty Acids Arm than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Effect of Omega-3 Fatty Acids on Infarct Size

• 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:
  • High Dose Omega-3 Fatty Acids Arm: mean -8.80 versus -1.90 on control; difference -6.90 (95% CI -17.19 to 3.39), standardized effect d = -0.14; z-test p = 0.189.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between High Dose Omega-3 Fatty Acids Arm and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcome summaries concern non-infarct myocardial fibrosis, left ventricular ejection fraction, and infarct size, with measurement described in the 3-year follow-up period after a participant's last study visit. Across these outcomes, the posted directions are not uniform: the omega-3 arm has a lower mean change for two measures and a higher mean change for another. Their precision also varies, with two confidence intervals excluding zero and one including zero.

This pattern is broadly compatible with the primary result in the sense that some secondary imaging contrasts also differ from zero, but it does not amount to a consistent pattern across every listed outcome. Nor does agreement in direction across some imaging measures independently confirm the primary finding: the endpoints are related but distinct, and the registry does not report an analysis linking changes in one measure to changes in another or to clinical events.

The secondary comparisons are unadjusted. When several outcomes are examined, a result that appears statistically notable can arise more readily by chance across the set unless a prespecified strategy controls the overall error rate or organizes confirmatory testing. The registry record does not report a multiplicity procedure, a hierarchy among outcomes, or which outcomes were considered confirmatory. For that reason, secondary p-values and intervals should carry less evidential weight than a single prespecified primary comparison, especially when considered individually.

The registry describes the secondary timeframe relative to each participant's last study visit, rather than giving a single fixed date from randomization. It does not report how follow-up timing, missing scans, or incomplete outcome data were handled. The summaries are therefore useful for describing the posted pattern, but do not resolve durability, mechanisms, or clinical relevance.

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

• Effect of Omega-3 Fatty Acids on Non-Infarct Myocardial Fibrosis
• Effect of Omega-3 Fatty Acids on Left Ventricular Ejection Fraction
• Effect of Omega-3 Fatty Acids on Infarct Size

9. Statistical Interpretation

10. Statistical Methods Explained

The registry reports continuous outcomes as means with standard deviations. A mean is the arithmetic average of the observed values in an arm. The standard deviation describes how dispersed individual measurements are around that mean: a larger value generally indicates more variation among participants. It is not the uncertainty of the mean itself, and it should not be read as a confidence interval.

What does the mean difference express?

The mean difference compares the average outcome in the omega-3 arm with the average in the placebo arm. For the primary outcome, the estimate is -6.6. The direction depends on the order of comparison: the reported estimate is for the high-dose omega-3 arm relative to placebo. A value below zero therefore indicates a lower mean percent change in the omega-3 arm on this endpoint. The estimate is expressed in the endpoint's units, percent change; it is not a relative risk or a percentage-point change in a binary outcome.

The posted comparison is unadjusted. In general, an unadjusted comparison contrasts group summaries without accounting for additional covariates in a regression model. Adjustment can be useful when an analysis plan specifies baseline factors or other variables, but whether such adjustments were planned or performed is not reported in the registry record. The record lists no reported formal analyses for the secondary outcomes.

How should the p-value be read?

A p-value evaluates how unusual data at least as incompatible with a null contrast of zero would be if that null model and the test assumptions held. The primary unadjusted p-value is <0.001. This is evidence against a zero mean difference under that test, but it is not the probability that the observed result arose by chance, the probability that the null is true, or a measure of clinical importance. A p-value also does not show whether the estimate is precise; the confidence interval conveys information about the range of contrasts compatible with the data under its method.

The registry record does not identify the test used to calculate the p-value, whether it was one-sided or two-sided, or whether the comparison came from a prespecified model. Therefore, the p-value can be described as the posted unadjusted value, but further assumptions about the trial team's testing procedure are not warranted.

Why do spread and measurement matter?

Continuous imaging outcomes can vary among participants even when they belong to the same randomized arm. Standard deviations describe that observed variability. In general, greater variability makes a group mean less precisely estimated when other features are held constant. Measurement procedures also matter: differences in image acquisition, reading, or missing scans can affect the observed outcome. The registry description says the study evaluated a new MRI technique, but measurement reliability, reader procedures, and validation details are not reported in the registry record.

In general, over-dispersion means that observed variability is greater than a model assumes. If a statistical model fails to account for that extra variability, its standard errors may be too small and its intervals too narrow. The posted summaries use standard deviations, but the record does not state that over-dispersion was assessed or that a particular distributional model was fitted. This general issue should not be mistaken for evidence that over-dispersion occurred in this trial.

What does randomization contribute?

Randomization is intended to make treatment assignment independent of participants' measured and unmeasured characteristics on average. It supports a causal interpretation of an arm comparison when the allocation process is preserved and outcome data are handled appropriately. It does not guarantee that every characteristic is balanced in a particular trial or remove bias from missing outcomes, non-adherence, or selective reporting. The registry identifies random allocation but does not report the sequence-generation or concealment methods, baseline characteristics, adherence, or analysis population. Those details cannot be assessed from the posted record.

The parallel design means participants are assigned to one of the listed arms rather than crossing over between treatments, as described by the registry's design label. Triple masking can reduce the influence of expectations or knowledge of assignment, but the record does not identify who was masked or how masking was maintained. These design labels describe planned features; they do not answer whether masking was successful or whether treatment exposure differed between arms.

What are the limits of a registry summary?

Registry outcome summaries provide arm-level means, standard deviations, and comparison statistics, but they do not substitute for a full analysis report. The registry does not report a detailed statistical analysis plan, covariate adjustment, missing-data methods, sensitivity analyses, or multiplicity correction. It also does not report whether analyses followed intention-to-treat principles. Those absences limit the ability to evaluate the robustness of the estimates or reproduce the trial team's analysis.

The secondary outcomes have unadjusted comparisons. In general, when several outcomes are tested, the chance of at least one apparently notable result can increase unless the testing strategy accounts for multiplicity. That concern does not erase the reported estimates, but it lowers the weight that should be placed on isolated secondary p-values when the analysis plan is unknown. The registry record does not report whether these outcomes were confirmatory, exploratory, or part of a hierarchy.

11. Confidence Intervals and Precision

The primary mean difference is -6.6, with a 95% confidence interval from -10.51 to -2.687. A confidence interval is a range calculated by a statistical procedure that, under its assumptions, reflects uncertainty in the estimated contrast. It is not a range containing a specified proportion of individual participants' outcomes, and it does not mean there is a 95% probability that the true contrast lies inside this particular interval.

For the primary endpoint, the entire interval is below zero. This indicates that the posted contrast is statistically distinguishable from zero at the conventional interpretation associated with the reported interval, subject to the calculation and analysis assumptions. The limits also show that the estimate is not pinpoint precise: the data are compatible with contrasts across the interval, not only with the point estimate of -6.6. The interval does not establish whether any value in that range is clinically important, because an importance threshold is not reported in the registry record.

Confidence intervals for the secondary comparisons also differ in what they include. The intervals for non-infarct myocardial fibrosis and left ventricular ejection fraction do not include zero; the interval for infarct size includes zero. An interval that includes zero is compatible with both directions of contrast at the chosen confidence level, while an interval that excludes zero is not. These are unadjusted interval interpretations; the record does not report adjustment for the number of outcomes examined.

Precision depends on the amount of information and the variability of the measurements, among other factors. The arm standard deviations show that participant-level values vary around the reported means. The registry does not report missingness by outcome, the effective analysis populations beyond the posted arm counts, or the interval calculation method, so precision cannot be evaluated in full detail. The displayed intervals are uncertainty about group contrasts under their calculation assumptions, not guarantees about replication or individual response.

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 are expressed as participants per arm for these continuous outcomes. They are not totals across arms and are not event counts. The registry's planning illustration assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It uses the observed effect as its reference and considers planning for 100% of that observed effect, 75% of the observed effect, and 50% of the observed effect.

The 80% power column describes the planned number of participants per arm that, under those assumptions and for the specified effect, would give an 80% chance of rejecting a zero-difference null hypothesis if that effect were the true one. The 90% power column describes the corresponding planning target for a 90% chance. These are design calculations, not assurances that a future study will achieve those probabilities in practice; actual results depend on the true effect, variability, follow-up, and analysis.

For the primary outcome, planning for 100% of the observed effect corresponds to 129 participants per arm for 80% power and 172 participants per arm for 90% power. Planning for 75% corresponds to 228 and 306 participants per arm, respectively; planning for 50% corresponds to 513 and 687 participants per arm. Smaller effects require more participants under the same planning assumptions, because a smaller difference is harder to distinguish from random variation.

The trial's own original sample-size assumptions, including its intended detectable effect and planned power calculation, are not reported in the registry record. The planning values are based on the observed effect and are not observed power.

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 = -6.600; pooled standard deviation σ = 18.861.
2. n = 2 × (1.96 + 0.842)² × 18.861² / -6.600² = 128.2, rounded up to 129 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 <- -6.6                      # observed difference in means
sigma <- 18.8608602815937                     # 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(729430)
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 = 129 (80% power), 172 (90% power)
 75% of observed effect: n per arm = 228 (80% power), 306 (90% power)
 50% of observed effect: n per arm = 513 (80% power), 687 (90% power)
power.t.test: 129.2 
Simulated power at n = 129 per arm: 0.795 (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 one primary outcome and three secondary outcomes. The posted secondary comparisons have unadjusted p-values, while no reported analyses are listed for those outcomes. A multiplicity correction, testing hierarchy, or distinction between confirmatory and exploratory outcomes is not reported in the registry record. When more than one outcome is tested, the chance of at least one small p-value across the set can rise; adjustment or a prespecified hierarchy can address that issue. Without the analysis plan, the degree to which multiplicity affected interpretation cannot be determined.

Handling of missing data is also not reported in the registry record. The posted outcome counts are 180 in the high-dose omega-3 arm and 178 in the placebo arm, but the record does not explain whether these represent all randomized participants, all participants with an available measurement, or another analysis set. It does not describe missed MRI assessments, withdrawals, reasons for missingness, imputation, or sensitivity analyses. If the availability of an outcome is related to treatment assignment or participant status, a complete-case comparison may not represent the randomized groups in the same way as a full follow-up analysis.

The planned analysis population is not reported. In particular, the record does not state whether the main analysis was intention-to-treat, per-protocol, or another approach. It also does not report how protocol deviations, non-adherence, or post-randomization exclusions were handled. These details matter when assessing whether the arm comparison retains the protection intended by randomization.

The original statistical analysis plan, sample-size justification, interim analyses, and any prespecified covariate adjustments are not reported in the registry record. Their absence does not show that such procedures were not used; it means their use and details cannot be established from the record. The registry status is completed, but completion status alone does not provide these analysis details.

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

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: allergic reaction (tongue swelling) (0.6%), bleeding (0.0%).

The registry lists serious adverse event counts affecting 1 participant in the high-dose omega-3 fatty acid arm and 0 participants in the placebo arm. For other adverse events, it lists 18 affected participants in the omega-3 arm and 11 in the placebo arm. The at-risk counts displayed for these summaries are 180 and 178, respectively. The death counts are not reported in the registry record.

The serious-event terms listed include allergic reaction (tongue swelling), shown as 0.6%, and bleeding, shown as 0.0%. These are registry-listed terms and percentages; the record does not provide further event descriptions, timing, severity detail beyond the serious-event classification, or a statistical comparison. The percentage values should not be treated as a complete account of all safety outcomes.

These counts are descriptive. The registry record does not report a safety analysis plan, exposure-adjusted rates, or a formal comparison of adverse events. A difference in counts alone does not establish whether an event is caused by an intervention, and small counts can be imprecise. The summaries should be read alongside the limited safety information available, not as a comprehensive assessment of risk.

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

The primary registry result describes a difference between randomized groups in mean percent change in indexed left ventricular end-systolic volume from baseline to the post-treatment assessment. The omega-3 arm's reported mean change is -5.4, compared with 1.2 in the placebo arm, and the reported mean difference is -6.6. Its confidence interval does not include zero. This is a statistical finding about the specified imaging endpoint in the posted summaries.

That finding does not, by itself, establish how large the difference is in clinical terms. The registry does not report a threshold for clinical importance, connect the imaging change to symptoms or quality of life, or show that a change in this endpoint predicts later outcomes in these participants. A group mean also does not describe the range of individual responses; the standard deviations indicate that values vary within both arms.

The results do not establish an effect on death, sudden cardiac death, recurrent heart attack, hospitalization, or any other clinical event. Although the listed conditions include myocardial infarction and sudden cardiac death, the registry-posted efficacy outcomes are imaging measures. Death counts are not reported in the registry record. The secondary imaging outcomes add context but are unadjusted and do not resolve the primary endpoint's clinical meaning.

The record also does not provide the detailed analysis plan, missing-data methods, or analysis population needed to evaluate all sources of uncertainty. Randomization and masking are important design features, but the registry does not report enough operational detail to assess their implementation. Thus, the posted results support a description of the measured group contrast, not a treatment recommendation or a broad claim about overall health outcomes.

17. Why This Trial Matters Statistically

This trial is statistically informative because it compares randomized groups on a continuous imaging endpoint and reports both arm-level means and a mean-difference estimate with a confidence interval. That combination makes it possible to distinguish the direction and scale of the observed contrast from the uncertainty around it. The primary interval lies below zero, while the secondary intervals show a less uniform pattern.

The trial also illustrates why statistical evidence and clinical interpretation are separate questions. A contrast can be distinguishable from zero without a registry-defined threshold showing that its size is important to participants. The measured endpoint concerns ventricular remodeling, while the registry does not report a direct link between that measure and clinical events. Interpreting an imaging result therefore requires attention to what was measured and what was not.

Another statistical issue is the set of outcomes. The primary result is more readily interpreted as a focal comparison, whereas three secondary endpoints raise multiplicity concerns because the registry does not report a correction plan or hierarchy. The unadjusted secondary results should not be treated as equivalent to independent confirmatory evidence.

Finally, the registry record highlights the importance of analysis transparency. It identifies the design and posts numerical summaries, but does not report several details needed to evaluate missingness, analysis populations, or the original sample-size rationale. The trial's planning illustration is based on the observed effect; it is useful for understanding how assumptions about effect size influence planning, but it cannot stand in for the study's original design calculation.

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.

Several limitations specific to this registry record constrain interpretation. The primary endpoint is an imaging measure assessed from baseline to post-treatment, and the registry does not report a clinical importance threshold or how the measure relates to subsequent patient-centered outcomes. The description mentions evaluation of a new MRI technique, but does not provide technical validation, reliability, or reader-agreement information.

The primary outcome is assessed at the 6-month post-treatment point, while the secondary outcomes are described as measured during the 3-year follow-up period after a participant's last study visit. The record does not provide exact assessment timing by participant, follow-up completeness, or how differences in timing were handled. It also does not give the amount or pattern of missing outcome data.

Eligibility criteria are not reported in detail, so the range of people represented cannot be fully assessed from the registry summary. The record also does not provide baseline characteristics, adherence, treatment discontinuation, allocation concealment procedures, or who was masked. These details are relevant to judging how well the randomized comparison was implemented and how broadly its results might apply.

Analysis limitations include the absence of a reported statistical analysis plan, analysis population, missing-data approach, or multiplicity strategy. The posted secondary results are unadjusted, and the record does not state whether they were confirmatory. The original sample-size assumptions and any interim-analysis plan are not reported in the registry record. These are limitations of the available registry information; their absence does not establish that the procedures were absent from the conduct of the study.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Effect of High Dose Fish Oil Supplementation After Recent Heart Attack Using Magnetic Resonance Imaging — NCT00729430.
• Registry record last updated 2017-06-01; status last verified 2017-05.
• Results first posted 2017-06-01.
• 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 record describes a completed Phase 3 randomized, triple-masked, parallel-group study sponsored by Brigham and Women's Hospital, with enrollment listed as 358. Participants with a recent myocardial infarction were assigned to high-dose omega-3 fatty acids or placebo for 6 months. The primary outcome was percent change in left ventricular end-systolic volume indexed to body surface area from baseline to post-treatment.

The posted primary mean difference was -6.6, with a 95% confidence interval from -10.51 to -2.687 and an unadjusted p-value of <0.001. Three secondary imaging outcomes were also posted, with unadjusted comparisons. Their pattern and uncertainty are not uniform. The record does not report a multiplicity plan, missing-data methods, analysis population, or the trial's original sample-size assumptions, so those aspects cannot be evaluated from the registry summary.