This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for QuickOpt Chronic Study (NCT01172067), a randomized na study. The primary outcome is Percent Change in Left Ventricular End Systolic Volume (LVESV) at 12 Months Compared to Baseline.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01172067 |
| Phase | NA |
| Condition | Heart Failure |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 400 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Abbott Medical Devices |
| Results posted | Yes |
2. Clinical Question
Population
Patients with heart failure receiving cardiac resynchronization therapy, described in the registry as CRTP/D patients. The primary outcome population comprised participants with LVESV measurements at baseline and 12 months: 108 in the QuickOpt group and 118 in the echocardiography group.
Intervention
Cardiac resynchronization therapy devices optimized using QuickOpt, described as optimization by QuickOpt (IEGM).
Comparator
Cardiac resynchronization therapy devices optimized using echocardiography, described as standard echocardiography techniques.
Primary question
Was percent change in left ventricular end-systolic volume from baseline to 12 months different between the QuickOpt and echocardiography groups? The registry describes the hypothesis as QuickOpt being not inferior by 10% to echo optimization for improvement in LVESV. The detailed definition of that non-inferiority margin is not reported in the registry record.
The clinical question is about the choice of device-optimization method, not a comparison of cardiac resynchronization therapy with no device treatment. Both groups received cardiac resynchronization therapy, while optimization was assigned by method. The outcome focuses on change in a measure of left ventricular volume over follow-up. The registry states that a decrease in percent change in LVESV indicates clinical improvement.
The reported group means are both negative, reflecting decreases from baseline on average. The registry’s primary comparison estimates the difference between those mean changes. This comparison can describe the observed separation between methods, but interpreting it as evidence of non-inferiority requires a clearly specified margin and an appropriate analysis. The record does not report enough detail to verify those elements.
3. Trial Design
QuickOpt Chronic Study (NCT01172067) is recorded as a completed, randomized, parallel-group study with triple masking. The registry lists an enrollment of 400 and heart failure as the condition. The sponsor is Abbott Medical Devices. The recorded study start is 2010-05, and primary completion is 2015-12.
The two study groups differed in how cardiac resynchronization therapy devices were optimized. The QuickOpt group used QuickOpt (IEGM); the echocardiography group used echo optimization. The registry lists cardiac resynchronization therapy and optimization using echocardiography among its interventions. It does not describe which people were masked, or how masking was maintained. Those details are not reported in the registry record.
The primary outcome was percent change in LVESV at 12 months compared with baseline, assessed using echocardiograms at both time points. The outcome population is described as 108 participants in the QuickOpt group and 118 in the echocardiography group with measurements at baseline and 12 months. These outcome counts are distinct from the overall enrollment. The registry does not provide a participant flow account explaining how the outcome population relates to enrollment, or why some participants lack measurements.
The study record lists one outcome measure and no posted analysis entries. The original statistical analysis plan, the original sample-size justification, any interim analyses, and details of the randomization procedure are not reported in the registry record. Therefore, the recorded design features support a broad description of the trial, but not a complete reconstruction of its protocol or analysis conduct.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Quickopt Group | Echocardiography Group |
|---|---|---|
| STARTED | 200 | 200 |
| COMPLETED | 153 | 163 |
| NOT COMPLETED | 47 | 37 |
Analysis population for the primary outcome, as defined in the registry: A total of 108 patients in the QuickOpt group and 118 patients in the Echocardiography group had LVESV measurements at both baseline and 12 months to allow comparison of the percent change in LVESV.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | QuickOpt Group | Echocardiography Group | Total |
|---|---|---|---|---|
| Participants analysed | 198 | 194 | 392 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 121 | 133 | 254 |
| Age, Categorical: >=65 years | Participants | 77 | 61 | 138 |
| Age, Continuous | years | 61.38 (SD 11.77) | 59.21 (SD 11.36) | 60.17 (SD 11.62) |
| Sex: Female, Male: Female | Participants | 49 | 54 | 103 |
| Sex: Female, Male: Male | Participants | 149 | 140 | 289 |
| Region of Enrollment: China | participants | 198 | 194 | 392 |
6. Primary Endpoint
The registry lists the primary outcome as Percent Change in Left Ventricular End Systolic Volume (LVESV) at 12 Months Compared to Baseline, measured over Baseline and12 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Percent change in LVESV |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is percent change in left ventricular end-systolic volume (LVESV) at 12 months compared with baseline. LVESV is a measure of left ventricular volume at the end of contraction. For this outcome, the registry states that a decrease in percent change at 12 months indicates clinical improvement. The endpoint therefore expresses the change in a cardiac volume measure over follow-up rather than a value at a single visit.
The study assessed the endpoint from echocardiograms at baseline and 12 months. Measuring participants at both time points makes it possible to compare change from baseline between the optimization groups. The question is whether the mean change differs according to whether the device was optimized with QuickOpt or echocardiography.
The outcome is continuous, and the registry reports group means and standard deviations. A mean summarizes the average change in each group, while the standard deviation describes how spread out individual changes were around that group mean. A group average does not describe every participant’s response, and the spread indicates that individual changes varied.
The registry reports this endpoint for 108 QuickOpt participants and 118 echocardiography participants with measurements at both time points. It does not report endpoint data for all enrolled participants or explain the reasons for missing measurements. The registry describes the study hypothesis as non-inferiority by 10%, but the detailed margin definition and analysis method are not reported in the registry record.
7. Results Posted in the Registry
- Echocardiography Group: mean -25.13 versus -24.69 on control; difference -0.44 (95% CI -9.56 to 8.68), standardized effect d = -0.01; z-test p = 0.925.
Mean difference: Echocardiography Group
95% CI: -9.56 to 8.68
Recalculated from the posted summary statistics
8. Statistical Interpretation
The mean percent change in LVESV was -24.69 in the QuickOpt group and -25.13 in the echocardiography group. The negative means indicate that average LVESV decreased from baseline in both groups, consistent with the registry’s description of a decrease as improvement. The means are close, but the comparison should be read with its uncertainty rather than by comparing point estimates alone.
The reported mean difference is -0.44, with a 95% confidence interval from -9.557 to 8.677. The estimate is close to zero, while the interval includes zero and extends in both directions. The data are therefore compatible with differences favoring either group as well as with little difference. The interval is broad relative to the point estimate, so the point estimate alone does not convey the uncertainty.
The unadjusted p-value is 0.925. This is not evidence that the groups are identical; it indicates that the observed result is not unusual under a no-difference model, given the assumptions of that test. A non-significant result does not establish equivalence or non-inferiority. In particular, the registry’s stated 10% non-inferiority hypothesis cannot be judged from the point estimate and p-value alone. The detailed margin, analysis specification, and formal non-inferiority conclusion are not reported in the registry record.
For a non-inferiority assessment, the estimate and confidence interval must be evaluated against a prespecified margin in the relevant direction. The interval’s limits matter because they describe which values remain compatible with the data, not just the most likely value. Since the record does not give the formal margin definition or the sponsor’s analysis, the posted comparison should be treated as a descriptive unadjusted comparison rather than as a complete demonstration of the stated hypothesis.
The standard deviations were 33.86 in the QuickOpt group and 36.06 in the echocardiography group. These values indicate substantial spread in individual changes relative to the group mean estimates. That variability helps explain why a small estimated difference does not imply that individual outcomes were nearly identical. The endpoint analysis includes participants with measurements at both time points, but the registry does not report how missing endpoint data were handled or whether this analysis follows an intention-to-treat approach.
Overall, the posted endpoint results show similar group means and an estimated between-group difference near zero, with a confidence interval that includes both negative and positive values. They do not, by themselves, establish equivalence, non-inferiority, or a causal clinical advantage for either optimization method.
9. Statistical Methods Explained
The primary outcome is a continuous measure, so the registry reports a mean and standard deviation for each group. A mean describes the average percent change in LVESV among participants included in that group’s endpoint analysis. A standard deviation describes the spread of participant-level changes around the mean. It is not the uncertainty around the mean; that uncertainty is reflected in the confidence interval for the group comparison.
What does the mean difference represent?
The comparison reports a mean difference of -0.44. Its sign depends on the order used to subtract the group means. Here, the reported estimate corresponds to the echocardiography mean relative to the QuickOpt mean. A negative estimate therefore means the echocardiography group’s mean change was more negative by the estimated amount. The difference is expressed on the endpoint’s percent-change scale. The estimate is a summary of group averages, not a statement that every participant in one group changed by that amount relative to a participant in the other group.
The standardized effect estimate is -0.013. A standardized effect expresses a difference relative to the variability of the measure, which can help describe the size of an effect on a scale independent of the endpoint’s units. It does not replace the original-scale estimate, and its interpretation depends on the standardization method. The registry record does not describe a separate adjusted model for this comparison.
What does a confidence interval add?
The 95% confidence interval for the mean difference runs from -9.557 to 8.677. In general, a confidence interval gives a range of values compatible with the observed data under the analysis assumptions and indicates the precision of an estimate. It is not a range containing a fixed proportion of individual participants’ outcomes. This interval crosses zero, so the results do not rule out either direction of difference at that confidence level. Its width also signals that the estimate is not precise enough to pin down a narrow range of plausible differences.
A confidence interval is particularly important when the study question is non-inferiority. The relevant question is not simply whether a conventional test finds a difference. Instead, the interval must be judged against the specified non-inferiority margin and direction. The registry states a hypothesis of not being inferior by 10%, but the margin’s detailed definition and the formal inferential procedure are not reported in the registry record. The reported interval should not be used to claim non-inferiority without that context.
What does the p-value say?
The unadjusted p-value is 0.925. In general, a p-value describes how compatible the observed test result is with a specified null model, assuming the test’s conditions hold. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference. A large p-value does not prove that the groups are equivalent. The p-value is identified as unadjusted; whether the original sponsor analysis used a different model or adjustment is not reported in the registry record.
The posted comparison is a simple unadjusted comparison of summary statistics. The registry does not report covariate adjustment, stratification, or a model accounting for repeated measurements. The outcome is a change from baseline, but the record does not describe the detailed statistical procedure used to obtain the sponsor’s primary analysis. Recalculated comparisons based on posted summaries are descriptive checks and do not replace a sponsor analysis. The registry record contains no posted analysis entries, so a sponsor-reported inferential analysis is not available in the record.
Why can variability affect precision?
Variation among participants affects how precisely a group mean difference can be estimated. Larger standard deviations generally make a given group difference harder to distinguish from sampling variation, while more observations can improve precision. These general relationships help explain why a point estimate close to zero can coexist with a confidence interval spanning a wider range. They do not establish why this study obtained its particular interval; the actual sample size rationale and statistical design assumptions are not reported in the registry record.
The primary outcome counts are 108 in the QuickOpt group and 118 in the echocardiography group. The registry states these participants had LVESV measurements at baseline and 12 months. It does not report how missing observations were treated, how the analysis population was defined, or whether all randomized participants were included in the planned primary analysis. Consequently, the summary comparison can be interpreted for the reported endpoint population, but its relationship to a full randomized-group analysis cannot be established from the record.
Over-dispersion is a general concern for count outcomes when their variability exceeds what a simple count model expects. It is not the central issue for this continuous LVESV comparison, for which the registry reports standard deviations. The safety figures are counts of people affected and are not presented with a formal comparative model. The record does not give statistical tests or confidence intervals for those safety comparisons.
Finally, randomization is intended to make treatment groups comparable on average, while masking can reduce some sources of bias. The registry records randomized allocation and triple masking, but does not describe the masking roles, sequence generation, allocation concealment, or analysis implementation. Those missing details limit assessment of how those design protections operated in practice.
10. Confidence Intervals and Precision
The mean difference estimate is -0.44, and its 95% confidence interval is -9.557 to 8.677. The interval includes zero. Thus the posted estimate is compatible with no average difference as well as with differences in either direction. The bounds also show that the data do not identify a narrowly defined value for the difference.
In general, a confidence interval describes uncertainty around an estimated quantity under the statistical method used. It is not an assurance that the true effect has a particular probability of lying inside this one calculated interval, nor does it describe the range of individual participants’ changes. Its width reflects both the observed variability and the amount of endpoint information contributing to the comparison.
The group standard deviations, 33.86 for QuickOpt and 36.06 for echocardiography, indicate considerable participant-level spread around the respective means. The reported endpoint counts are 108 and 118. These counts reflect participants with both baseline and 12-month measurements, not necessarily every randomized participant. The registry does not report the missing-data method or an analysis population definition, so the precision estimate cannot be interpreted as addressing uncertainty from missing outcomes.
The stated 10% non-inferiority hypothesis needs a margin definition and a formal decision rule to be assessed. Those details are not reported in the registry record. The confidence interval should therefore be read as uncertainty around the posted mean difference, not as a standalone non-inferiority finding. The unadjusted p-value of 0.925 does not replace that assessment, and a non-significant test does not demonstrate equality.
11. 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.
| Effect to detect | Participants per arm, 80% power | Participants per arm, 90% power |
|---|---|---|
| 100% of the observed effect | 99,477 | 133,172 |
| 75% of the observed effect | 176,848 | 236,749 |
| 50% of the observed effect | 397,908 | 532,686 |
The sample-size figures are planning illustrations, not counts observed in the trial. For this continuous endpoint, the entries are participants per arm. The registry’s planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The target effect is set to a stated fraction of the observed effect. The original trial’s own sample-size assumptions and justification are not reported in the registry record.
The columns for 80% and 90% power describe different planning targets. In general, power is the chance that a specified statistical test will detect the effect used in the planning calculation, if that effect is the true one and the assumptions hold. The 80% column gives the estimated participants per arm for an 80% chance of detection; the 90% column gives the estimated participants per arm for a 90% chance. These are planning quantities, not guarantees about a future study’s result.
Rows planning for 100%, 75%, and 50% of the observed effect use progressively smaller target effects. Smaller effects are harder to distinguish from random variation, so they require more participants under the same planning assumptions. The resulting figures are very large because the observed between-group estimate is close to zero. They should not be read as the original trial’s planned enrollment or as evidence about the power of the completed trial.
This is not observed power. It is a hypothetical planning calculation based on the posted estimate and stated assumptions. The sample-size curve should be read as a visual presentation of how the planning requirement changes with the target effect, not as additional trial outcome evidence. For time-to-event outcomes, the general convention is to report total events; that convention does not apply to these continuous-outcome entries, which are participants per arm.
12. 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 z1−α/2 = 1.960) and the desired power (z1−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
- Observed difference Δ = -0.440; pooled standard deviation σ = 35.026.
- n = 2 × (1.96 + 0.842)2 × 35.0262 / -0.4402 = 99,476.9, rounded up to 99,477 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 <- -0.439999999999998 # observed difference in means
sigma <- 35.0263496731899 # 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(1172067)
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 = 99,477 (80% power), 133,172 (90% power)
75% of observed effect: n per arm = 176,848 (80% power), 236,749 (90% power)
50% of observed effect: n per arm = 397,908 (80% power), 532,686 (90% power)
power.t.test: 99477.8
Simulated power at n = 99,477 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.
13. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and no secondary outcomes. It also contains no posted analysis entries. That does not establish whether the original protocol included additional outcomes, analysis choices, or hypotheses; those details are not reported in the registry record.
Multiplicity arises when several outcomes, time points, subgroups, or statistical tests are examined. Testing many questions can increase the chance of at least one apparently noteworthy result by chance, so study plans often specify which comparison is primary and whether any adjustment is used. Here, the registry presents a single primary outcome, but it does not report a multiplicity strategy or whether additional analyses were conducted outside the posted record. The listed p-value is unadjusted.
The registry identifies 108 QuickOpt participants and 118 echocardiography participants with LVESV measurements at both baseline and 12 months. It does not provide a full accounting of missing outcome data, reasons for missingness, or procedures for handling missing values. It is therefore not possible to determine from the record whether missingness could have affected the group comparison or how sensitive the result is to alternative assumptions about missing outcomes.
The analysis population is not described in enough detail to determine whether the primary result follows an intention-to-treat approach, a per-protocol approach, or another definition. The total enrollment is 400, while the endpoint population is reported separately; the record does not explain the participant flow between these counts. It also does not describe exclusions, crossover, adherence, or protocol deviations for the primary analysis.
These omissions matter because missing-data handling and analysis populations can affect the interpretation of randomized comparisons. Randomization supports a fair comparison when groups are analyzed appropriately, but a registry summary without an analysis plan or participant flow cannot show whether that condition was met. The posted results remain informative as a description of the reported endpoint population, while the effect of unreported analysis choices cannot be assessed.
14. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Quickopt Group | 28 | 198 | 14.1% |
| Echocardiography Group | 19 | 194 | 9.8% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Quickopt Group | 23 of 198 |
| Echocardiography Group | 15 of 194 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Quickopt Group | 6 of 198 |
| Echocardiography Group | 6 of 194 |
Most frequent serious adverse event terms
| Event term | Organ system | Quickopt Group | Echocardiography Group |
|---|---|---|---|
| Death | Cardiac disorders | 15 of 198 | 13 of 194 |
| Hopitalization | Cardiac disorders | 3 of 198 | 1 of 194 |
| Heart Failure Deterioration; Death | Cardiac disorders | 2 of 198 | 0 of 194 |
| Cardiopulmonary arrest, death | Cardiac disorders | 2 of 198 | 0 of 194 |
| Junctional rhythm, hypotension | Cardiac disorders | 1 of 198 | 0 of 194 |
| Heart failure deterioration, hospitalization | Cardiac disorders | 0 of 198 | 1 of 194 |
| Heart failure deterioration, elevated left ventricular pacing threshold | Cardiac disorders | 1 of 198 | 0 of 194 |
| Heart failure deterioration, myocardial infarction, venous thrombosis, death | Cardiac disorders | 1 of 198 | 0 of 194 |
| Heart failure deterioration, phrenic nerve stimulation | Cardiac disorders | 0 of 198 | 1 of 194 |
| Myocardial ischemia, staged heart bypass surgery | Cardiac disorders | 0 of 198 | 1 of 194 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Quickopt Group | Echocardiography Group |
|---|---|---|---|
| Phrenic nerve stimulation | Cardiac disorders | 1 of 198 | 2 of 194 |
| Elevated left ventricular pacing threshold | Cardiac disorders | 2 of 198 | 0 of 194 |
| Coronary sinus dissection | Cardiac disorders | 1 of 198 | 0 of 194 |
| Right ventricular lead dislocation/displacement | Cardiac disorders | 1 of 198 | 0 of 194 |
| Right atrial lead dislocation/displacement | Cardiac disorders | 0 of 198 | 1 of 194 |
| Left ventricular lead dislocation/displacement | Cardiac disorders | 1 of 198 | 0 of 194 |
| Elevated pacing threshold of left ventricular lead; lead dislocation/displacem | Cardiac disorders | 0 of 198 | 1 of 194 |
| Infection at pacing system | Infections and infestations | 0 of 198 | 1 of 194 |
| Anaphylactic shock | Immune system disorders | 0 of 198 | 1 of 194 |
Serious events with the highest arm-level rate: death (7.6%), hopitalization (1.5%), heart failure deterioration; death (1.0%), cardiopulmonary arrest, death (1.0%), heart failure deterioration, hospitalization (0.5%).
The registry lists serious adverse events affecting 28 participants at risk of 198 in the Quickopt Group and 19 participants at risk of 194 in the Echocardiography group. It also lists other adverse events affecting 6 participants at risk of 198 in the Quickopt Group and 6 at risk of 194 in the Echocardiography group. These are counts of participants affected and participants at risk as recorded, not estimates from a comparative statistical model.
The record lists deaths as 23 in the Quickopt Group and 15 in the Echocardiography group. It does not provide a cause-specific breakdown for these counts in the listed group figures. The serious-event terms include Death (7.6%), Hopitalization (1.5%), Heart Failure Deterioration; Death (1.0%), Cardiopulmonary arrest, death (1.0%), Heart failure deterioration, hospitalization (0.5%), and Heart failure deterioration, phrenic nerve stimulation (0.5%).
These safety data should be read as registry-reported event summaries. They do not by themselves establish that an event was caused by a study intervention, and the record does not provide a formal statistical comparison or uncertainty interval for the groups. Differences in counts should not be treated as proof of a difference in risk.
15. What the Result Does, and Does Not, Mean
The posted primary result describes average LVESV changes in the participants with measurements at baseline and 12 months. The mean change was -24.69 for QuickOpt and -25.13 for echocardiography, with a reported mean difference of -0.44. The 95% confidence interval, -9.557 to 8.677, includes zero and spans values in either direction. The result therefore does not precisely distinguish the groups on this endpoint.
The estimate and interval do not establish that the optimization methods are equivalent. Nor do they establish the registry’s stated non-inferiority hypothesis. A formal non-inferiority conclusion depends on the definition of the 10% margin, the analysis population, and the prespecified statistical method. Those details and a formal sponsor analysis are not reported in the registry record. The unadjusted p-value of 0.925 does not resolve those missing details.
The endpoint is a measure of change in left ventricular volume, not a complete measure of every aspect of health or treatment experience. The primary comparison alone does not establish the effect of either optimization method on outcomes beyond the posted LVESV result. The safety summaries are descriptive counts and likewise do not establish causation or a formal between-group safety difference.
Randomization and masking are recorded design features, but the record does not give enough detail to evaluate how those procedures were implemented. The outcome population includes participants with measurements at both time points, and the registry does not explain missing observations or the analysis population. These limits mean the result should be interpreted as a comparison of the reported endpoint data, not as a complete account of all randomized participants or all analyses conducted.
In short, the posted data show similar group mean changes, with substantial uncertainty around the estimated difference. They do not provide a basis for medical advice or a claim that one method should be selected over the other.
16. Why This Trial Matters Statistically
This study raises an important statistical distinction between failing to detect a difference and demonstrating that two methods are sufficiently similar. The primary estimate, -0.44, is near zero, and the unadjusted p-value is 0.925. Neither fact by itself establishes equivalence or non-inferiority. A non-inferiority question needs a prespecified margin and a confidence interval judged against that margin.
The registry describes a 10% non-inferiority hypothesis, but does not report the detailed margin definition or the formal analysis plan. This makes the case useful for understanding why a study’s stated hypothesis is not enough to assess its statistical conclusion. The estimate and interval can be described, while the specific non-inferiority claim cannot be independently evaluated from the registry summary.
The endpoint also illustrates the difference between a mean and the distribution of individual outcomes. The group means are close, while the standard deviations are 33.86 and 36.06. Participants’ changes varied, so a small mean difference does not mean that individual outcomes were uniform or interchangeable.
Finally, the difference between overall enrollment and the endpoint counts highlights the importance of participant flow and missing-data reporting. The registry records 400 enrolled and reports endpoint measurements for 108 and 118 participants, but does not explain the relationship between those counts. Without missing-data methods and a defined analysis population, readers cannot fully assess how the endpoint comparison relates to the randomized groups.
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 the original sample-size justification, statistical analysis plan, interim-analysis plan, or detailed non-inferiority margin. The statement of a 10% hypothesis is not enough to establish the exact comparison rule or show whether the primary result met it. No sponsor analysis entries are posted, so the unadjusted comparison is not a substitute for a complete prespecified analysis.
The primary endpoint results are based on participants with measurements at baseline and 12 months: 108 in the QuickOpt group and 118 in the echocardiography group. Although overall enrollment is listed as 400, the record does not provide participant flow or reasons for the difference between enrollment and endpoint counts. Missing-data handling, exclusions, adherence, and analysis-population definitions are not reported.
The registry records randomized allocation and triple masking, but does not describe sequence generation, allocation concealment, which parties were masked, or how masking was maintained. The record also does not detail device optimization fidelity or crossovers. These gaps limit assessment of possible bias in implementation and analysis.
Only one outcome measure is listed, with no secondary outcomes or posted analyses. This does not show whether other analyses were planned or performed; the registry record does not report that information. The listed comparison is unadjusted, and the record does not describe covariate adjustment or sensitivity analyses.
The adverse-event summary gives counts and selected event terms but does not present formal comparative estimates or uncertainty intervals. The counts cannot establish causality. Taken together, these limitations mean the posted summaries support a narrow reading of the reported endpoint and safety data, rather than a comprehensive assessment of all protocol outcomes and analyses.
18. Related Tutorials
19. Related Statistical Calculators
20. Sources
- ClinicalTrials.gov: QuickOpt Chronic Study — NCT01172067.
- Registry record last updated 2019-10-08; status last verified 2019-09.
- Results first posted 2019-09-30.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
21. Record Summary
QuickOpt Chronic Study (NCT01172067) is recorded as a completed, randomized, parallel-group, triple-masked study sponsored by Abbott Medical Devices. The listed enrollment is 400. It compared cardiac resynchronization therapy device optimization using QuickOpt with optimization using echocardiography in patients with heart failure.
The primary outcome was percent change in LVESV from baseline to 12 months. The registry reports means of -24.69 for 108 QuickOpt participants and -25.13 for 118 echocardiography participants with measurements at both time points. The mean difference was -0.44, with a 95% confidence interval from -9.557 to 8.677 and an unadjusted p-value of 0.925.
The registry describes a 10% non-inferiority hypothesis but does not report the detailed margin or formal analysis plan. It lists one outcome measure and no posted analysis entries. Missing-data handling, analysis populations, and the original sample-size justification are not reported in the registry record.