Advance Care Planning Impact on the Consistency of Older Adults With Lung Cancer and Their Potential Surrogates Regarding Life-Sustaining Treatment Preferences: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Advance Care Planning Impact on the Consistency of Older Adults With Lung Cancer and Their Potential Surrogates Regarding Life-Sustaining Treatment Preferences (NCT06616909), a randomized na study. The primary outcome is Absolute Gap Score on m-LSPQ Total Score Baseline.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group trial with an intended one-to-one allocation to the ACP tabletop game or ACP manual. The study is listed as unmasked, meaning the registry does not identify masking for the trial. Its phase is recorded as not applicable. The sponsor was National Taiwan University Hospital. The registry lists the study as completed and gives an enrollment of 124.

The trial focused on older adults with lung cancer and potential surrogates, with a patient and surrogate forming a dyad. The primary outcome was the absolute gap between the two members’ m-LSPQ total scores. The registry describes measurement at baseline (T0), two weeks (T2), and six weeks (T3) after the intervention. State anxiety, measured with STAI-S, was a secondary outcome for patients and surrogates. It was assessed at baseline, immediately after the intervention (T1), two weeks, and six weeks.

The registry lists the study start as 2024-09-25 and primary completion as 2025-04-30. These dates describe the registered study timeline; they do not provide information about when individual participants were assessed or how complete follow-up was. The record does not report the randomization sequence method, allocation concealment, the details of intervention delivery, or whether adherence to either intervention was measured. It also does not describe a statistical analysis plan or explain how the planned enrollment was selected. Those details are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Randomization sequences were generated using a computer-generated random number table prior to study initiation. Allocation was concealed using sequentially numbered, sealed, opaque envelopes prepared by an independent researcher not involved in recruitment or data collection. Envelopes were opened sequentially after each dyad provided informed consent. Blinding of participants and researchers was not feasible given the nature of the behavioral interventions.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Patient and surrogate scores are reported separately. The absolute gap was calculated for each patient-surrogate dyad using complete data from both members. Counts in the gap row represent all individual participants contributing data. At baseline, 58 participants (29 dyads) in the experimental group and 62 participants (31 dyads) in the control group were analyzed. No imputation was performed.

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.

Population: Baseline characteristics are reported for individual participants (patients and surrogates). Randomization occurred at the dyad level. The 4 participants with unavailable baseline data (2 dyads in the experimental arm) had completed consent and randomization but withdrew before completing baseline questionnaires; their data were therefore excluded from baseline analyses but are included in the participant flow. Baseline N = 58 (experimental) vs 62 (control), total 120.

6. Primary Endpoint

The registry lists the primary outcome as Absolute Gap Score on m-LSPQ Total Score Baseline, measured over Baseline (T0).

The primary measure, the absolute gap score on the modified Life Support Preferences Questionnaire, represents the distance between a patient’s and that patient’s surrogate’s reported preferences. The questionnaire contains 45 items. Each item is rated from 1 (absolutely unwanted) to 5 (absolutely wanted); the item responses are summed separately for the patient and surrogate. The resulting total scores range from 45 to 225, with higher scores indicating a greater preference for receiving life-sustaining treatments.

For each dyad, the absolute gap is the absolute value of the difference between the surrogate’s total score and the patient’s total score. It ranges from 0 to 180. A score of 0 represents complete agreement, and smaller values indicate greater concordance. The absolute value makes the measure about the size of the disagreement, not its direction: it does not show whether the surrogate favors more or fewer treatments than the patient.

This measure addresses a distinct aspect of advance care planning: whether a potential surrogate’s stated preferences align with the patient’s. It does not measure whether a particular preference is correct, whether treatment would be received, or whether the dyad’s preferences remain unchanged over time. The registry identifies the primary outcome title as the baseline m-LSPQ absolute gap score and describes repeated assessments after the intervention. It does not report a numerical primary outcome result or clarify the primary between-group time-point contrast in the results information available in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the absolute gap represent?

The m-LSPQ produces separate total scores for each patient and surrogate. The dyad-level absolute gap captures how far apart those totals are, regardless of which member reports the higher preference score. This makes it possible to describe concordance as a magnitude. A zero gap means the reported totals are identical; a larger gap means the totals are farther apart. The absolute gap does not preserve direction, so it cannot indicate whether a surrogate’s total is above or below the patient’s total.

As a general statistical point, an outcome’s definition determines what a treatment contrast can mean. A comparison of mean absolute gaps would concern average distance between scores, not the proportion of dyads in complete agreement or the direction of preference differences. Those are different summaries and should not be inferred from an absolute-gap mean. The registry does not report a numerical comparison of the gap scores.

Why do the time points matter?

The registry describes m-LSPQ assessments at baseline (T0), two weeks (T2), and six weeks (T3). Baseline measurement can describe the groups before the intervention, while later measurements can describe outcomes after it. A follow-up score, a change from baseline, and a treatment-by-time comparison answer different statistical questions. The registry record does not report which of these approaches was used for the primary analysis, or the exact time-point contrast designated as primary.

Repeated measurements from the same dyad are related rather than independent. As a general statistical principle, analysis of repeated observations should account for this dependence if more than one time point is modeled together. The registry does not state whether a repeated-measures model or another method was used. No assumptions about the selected model, covariance structure, or handling of incomplete repeated observations can be made from the registered outcome descriptions.

What can a mean and standard deviation tell readers?

The primary outcome is described as a continuous score with a mean and standard deviation. A mean gives a group’s average score, while a standard deviation describes the spread of individual scores around that average. Neither statistic alone establishes a difference between randomized groups. A treatment contrast with an uncertainty interval would be needed to describe the estimated difference and how precisely it was measured. The registry record does not report those statistics for the primary outcome.

In general, a confidence interval gives a range of estimates compatible with the data and the statistical method under its assumptions. A narrow interval indicates greater precision than a wide interval, but precision is not the same as clinical importance. A p-value, when reported, addresses compatibility with a specified statistical null under model assumptions; it does not measure the size or importance of an effect. No confidence interval or p-value for the primary comparison is reported in the registry record.

Why might analysis of dyads require care?

The patient and surrogate are paired: their responses form one dyad-level gap. The gap is defined only when both members’ relevant scores are available. The registry description says that complete data from both dyad members are used for the gap. This means a missing patient or surrogate score can prevent calculation of that dyad’s gap at that assessment. The record does not give complete-case counts at each time point or explain whether missing observations were addressed in another way.

As a general matter, analyzing only complete pairs can yield a result that is less representative if the availability of complete data is related to outcome or group assignment. That possibility cannot be evaluated without information about missingness and the analysis population. No claim about the direction or extent of missing data is warranted from the registry record.

What does the planning illustration mean?

The trial record describes a sample-size planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such an illustration is a planning calculation under its stated assumptions; it is not the trial’s observed power and is not evidence that the assumed effect occurred. The record does not report the trial’s own sample-size justification. Any sample-size values in the planning material should therefore be read as hypothetical participant requirements for the stated planning scenario, not as actual enrollment or outcome findings.

More generally, a planning calculation depends on the effect size chosen, variability assumptions, allocation, significance threshold, and desired power. If those assumptions differ from what is observed, the calculation may not describe the precision achieved in the trial. The registry does not explain how its planning effect was selected or whether the trial’s enrollment target was based on that illustration.

What cannot be inferred from the registry listings?

The registry lists 26 outcome measures and 44 analyses. These counts do not identify the statistical model, analysis hierarchy, covariate adjustment, or multiplicity procedure. They also do not show which results were obtained. The primary outcome description and the study summary provide the measurement framework, but the statistical analysis plan and numerical outcome findings are not reported in the registry record. Accordingly, no reanalysis or comparison can be reconstructed from the information available.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple outcome measures and analyses. Several occasions are described for the primary m-LSPQ measure, and state anxiety is listed for both patients and surrogates across four assessment times. Multiple outcomes and comparisons can create a multiplicity issue: as a general statistical concept, when many hypotheses are tested, the chance of at least one apparently notable result can increase unless the analysis strategy accounts for that testing. The registry record does not report a multiplicity adjustment, a testing hierarchy, or which secondary analyses were considered confirmatory.

The primary outcome description specifies that a gap score requires complete data from both members of a dyad. This defines the information needed to calculate the score, but it does not give the number of complete dyads at each assessment, the reasons for missing observations, or the method used to address missing data. The record does not report whether the analyses used all randomized participants, only participants with complete outcomes, or another analysis population. These details are not reported in the registry record.

Random allocation describes the planned assignment to the two groups; it does not by itself establish how participants were handled after assignment. The registry does not report whether participants were analyzed according to randomized group, how withdrawals were treated, or whether any sensitivity analyses were conducted. Without these details and the outcome counts, readers cannot assess the possible effect of incomplete follow-up or analysis choices on the estimated comparison.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry reports zero serious adverse events among 29 participants at risk in the ACP Tabletop Game group and zero among 31 participants at risk in the ACP Manual group. It also reports zero in the other adverse-event category for 29 and 31 participants at risk, respectively. The death count is zero in the game group and one in the manual group. The record lists no serious adverse-event terms.

These are event counts in the registry’s safety fields; they do not describe the nature, timing, or relationship of events to an intervention. Zero reported serious events should be read as the posted count, not as proof that no adverse experience occurred. The registry record does not provide further detail about safety monitoring, event definitions, follow-up duration for these counts, or the circumstances of the reported death. The figures also do not establish a comparative safety effect. In particular, a count difference alone, without fuller context and uncertainty, is not a basis for attributing an event to either intervention.

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

This trial addresses a practical and measurable question in advance care planning: whether a structured tabletop activity, compared with a manual, is associated with greater consistency between an older patient with lung cancer and a potential surrogate when they state preferences about life-sustaining treatment. The m-LSPQ gap operationalizes consistency as the distance between the pair’s total scores. That definition makes the target of measurement explicit, while leaving the actual comparative result unknown in the registry record.

The record does not report primary outcome values, treatment-effect estimates, uncertainty intervals, or p-values. It therefore does not show whether the game group had smaller or larger gaps than the manual group, or how precisely any difference was estimated. The same limitation applies to the listed anxiety outcomes. No conclusion about the observed comparative findings can be drawn from outcome names and assessment schedules alone.

Even if a difference in gap scores were reported, its meaning would be limited to the measured preference scores and the analyzed participants. The absolute gap does not convey which member favored more treatment, why preferences differed, or whether preferences would guide a later decision. It is not itself a measure of treatment received, patient health, quality of communication, or the correctness of a surrogate’s judgment. A statistical difference would also need to be considered alongside its size and precision, rather than interpreted from a significance label alone.

The registry lists a completed randomized trial with an enrollment of 124, but does not supply the outcome data necessary to judge the results. The appropriate reading is therefore that the record defines a randomized comparison and relevant outcomes, while the effectiveness question remains unanswered by the results reported in the registry record.

13. Why This Trial Matters Statistically

The trial is statistically notable for defining its primary outcome at the level of the patient-surrogate pair rather than treating patient and surrogate scores as interchangeable. The absolute gap directly represents the study’s stated interest in concordance. Because it discards direction, however, it answers a focused question about the magnitude of disagreement and not whether a surrogate tends to prefer more or fewer life-sustaining treatments than the patient.

The assessment schedule also raises an important design issue. Baseline and later measurements can support different kinds of comparisons, including a description of starting scores or an assessment of change over time. Those approaches are not equivalent. Clear reporting of the target time point, model, and treatment contrast would be needed to understand how the randomized comparison was analyzed. The registry describes multiple assessment occasions but does not report those analytic details.

Dyadic outcomes also make completeness important: the gap cannot be formed from just one member’s score. Transparent reporting of the number of complete pairs at each time point, missingness, and analysis population would help readers judge how well the analyzed data represent the randomized dyads. The registry record does not provide that information in sufficient detail.

Finally, the record’s outcome and analysis counts signal a broad set of measurements, while not explaining how the primary question was protected from selective emphasis among multiple results. The lack of numerical findings and analytic detail means the statistical contribution cannot be judged by an effect estimate. It does, however, make clear why complete reporting of dyadic outcomes, time-point contrasts, precision, and missing-data handling matters for this kind of trial.

14. Limitations

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

The main limitation of interpreting this trial from its registry record is the absence of numerical primary and secondary outcome results. The record does not report the group-level m-LSPQ gap scores, a between-group estimate, uncertainty intervals, or p-values. Thus, the size, direction, and precision of the trial’s primary comparison cannot be assessed.

The registered primary outcome title identifies the baseline gap, while the study summary also describes assessments at two weeks and six weeks after intervention. The registry record does not clarify which follow-up contrast, change score, or repeated-measures comparison was designated as the primary treatment effect. It also does not report the model or the statistical plan.

The outcome description says the gap uses complete data from both dyad members, but the registry does not fully report the number of analyzed dyads at each assessment or the handling of missing data. No details are reported about allocation concealment, intervention adherence, or analysis populations. The comparator manual is identified, but its content and delivery are not described.

The registry lists multiple outcomes and analyses without reporting how multiplicity was handled. Safety entries give counts but not event narratives, timing, attribution, or monitoring details. These limitations restrict both statistical interpretation and assessment of how the interventions were implemented. They do not establish that the trial had a particular design flaw or that any specific bias occurred; those matters are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Advance Care Planning Impact on the Consistency of Older Adults With Lung Cancer and Their Potential Surrogates Regarding Life-Sustaining Treatment Preferences — NCT06616909.
• Registry record last updated 2026-10-30; status last verified 2026-07.
• Results first posted 2026-10-30.
• 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.

18. Record Summary

NCT06616909 is a completed, randomized, parallel-group, unmasked trial sponsored by National Taiwan University Hospital. It enrolled 124 and compared an ACP tabletop game, “Walking with Wishes,” with an ACP manual among older adults with lung cancer and their potential surrogates. The primary measure was the absolute gap between patient and surrogate m-LSPQ total scores; secondary measures included state anxiety for both members of the dyad. Assessments were described at baseline and follow-up, with anxiety also assessed immediately after intervention. The registry record does not report numerical primary or secondary outcome results, the detailed analysis plan, or complete analysis-population and missing-data information. Its posted safety counts include zero serious adverse events in each group and one death in the ACP Manual group.