Patient Convenience Study- NIS RELATE: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Patient Convenience Study- NIS RELATE (NCT02849509), a registered phase not stated study. The primary outcome is Mean PACT-Q2 Scores, for Patients in Cohort B, at Second Assessment Compared Between Treatment Groups.

2. Clinical Question

3. Trial Design

NCT02849509, titled Patient Convenience Study- NIS RELATE, was a completed, non-interventional study sponsored by Boehringer Ingelheim. It concerned patient perceptions of anticoagulant treatment and treatment convenience for stroke prophylaxis in atrial fibrillation. The registry record gives an enrollment of 1313, a start date of 2016-06-20, and a primary completion date of 2017-12-30. The condition listed is atrial fibrillation.

The study had two patient cohorts. Cohort A consisted of patients with NVAF who were taking VKA therapy and switched to Pradaxa. Cohort B consisted of newly diagnosed NVAF patients treated with either VKA or Pradaxa. The study description states a VKA-to-Pradaxa allocation ratio of 1:1 in Cohort B, but treatment allocation is not stated as randomized. Because treatment choice and treatment assignment are not described as randomized, comparisons may reflect differences between patients as well as differences in treatment.

The primary outcome concerned PACT-Q2 convenience and satisfaction scores for matched patients in Cohort B at the second assessment. The stated assessment window was Visit 2, 7-124 days after initiation on Pradaxa or VKA. The registry describes propensity-score matching using a variable-ratio, parallel, balanced 2:1, nearest-neighbour algorithm, with a caliper width of 0.05 and no replacement. PACT-Q2 assessments completed more than 1 day after treatment discontinuation or using an incorrect procedure were excluded from this analysis.

The record lists 11 outcome measures and 10 analyses. It also lists secondary outcomes concerning patient characteristics and PACT-Q measures. The registry record does not report the rationale for the enrollment target, a detailed statistical analysis plan, or how nonrandom treatment selection was addressed beyond the matching description.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The main analysis population consisted of all eligible patients (that is, all patients who took the prescribed treatment and without an important protocol violation) from all participating countries.

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: The population consisted of all eligible patients (that is, all patients who took the prescribed treatment and without an important protocol violation) from all participating countries.

6. Primary Endpoint

The registry lists the primary outcome as Mean PACT-Q2 Scores, for Patients in Cohort B, at Second Assessment Compared Between Treatment Groups, measured over Second assessment Visit 2 (7-124 days after initiation on Pradaxa or VKA).

The primary endpoint is the mean PACT-Q2 score at the second assessment for Cohort B, compared between propensity-score-matched patients treated with Pradaxa and VKA. PACT-Q2 has a convenience dimension and a satisfaction dimension. Each dimension ranges from 0 to 100, and higher scores indicate a better outcome. The record describes these as mean scores with standard deviation as the measure of dispersion.

These scores address patients’ reported experience of anticoagulant treatment. Convenience and satisfaction are distinct aspects of treatment perception, so the endpoint is not a measure of stroke prevention, bleeding, or another clinical event. It is used to describe how patients rate treatment, not to establish that a treatment prevents clinical outcomes or is safer.

The second assessment was scheduled within the stated window of Visit 2, 7-124 days after treatment initiation. The registry describes comparison of the mean convenience and satisfaction scores in matched groups. It does not report the observed means, standard deviations, between-group contrast, confidence interval, or test result. Consequently, the record does not allow a reader to assess the size or precision of the primary comparison.

The exclusion of PACT-Q2 forms completed more than 1 day after treatment discontinuation or using an incorrect procedure defines which records were eligible for this analysis. How other missing or incomplete questionnaire data were handled is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous measure: a mean PACT-Q2 score. A continuous outcome can take values across a scale rather than being restricted to event counts. The registry specifies the score range as 0 to 100 and states that higher scores indicate a better outcome. It treats convenience and satisfaction as separate score dimensions. Reporting a mean describes the central level of scores in a group, while a standard deviation describes how spread out scores are around that mean. Neither the group means nor the standard deviations for the primary comparison are reported in the registry record.

What does matching contribute?

The primary comparison is described as involving propensity-score-matched patients in Cohort B. In general, a propensity score represents a model-based estimate of the likelihood of receiving a treatment given recorded characteristics. Matching patients on this score is intended to make the treatment groups more comparable with respect to measured characteristics associated with treatment selection. It is a design and analysis technique for observational data, not a substitute for random assignment.

The registry specifies a variable-ratio, parallel, balanced 2:1, nearest-neighbour matching algorithm, a caliper width of 0.05, and matching without replacement. Nearest-neighbour matching pairs or groups patients whose propensity scores are close; a caliper limits how far apart matched scores may be. Matching without replacement means a patient is not reused for another match. The record does not state which covariates entered the propensity-score model, how the model was fitted, or what balance was achieved after matching. Those details matter when judging whether measured baseline characteristics were adequately aligned and whether the matched sample represents the population of interest.

Even with good balance on recorded characteristics, matching cannot ensure balance on factors that were not measured or included. If treatment choice depended on such factors, the groups could remain different in ways relevant to patient-reported scores. In general, this is why an observational matched comparison supports a more cautious interpretation than a randomized comparison. The registry record does not report an adjustment strategy beyond the matching procedure in its primary-outcome description.

How should the score comparison be read?

The endpoint compares group means for the convenience and satisfaction dimensions at the second assessment. A mean difference, if reported, would describe the observed separation between those group averages on the stated scale. A confidence interval, in general, conveys the uncertainty around an estimate: narrower intervals indicate greater precision, while wider intervals indicate less precision. A confidence interval does not by itself establish that a difference is clinically important. The registry record does not report the mean estimates, a difference, or a confidence interval, so the precision of the primary comparison cannot be judged from this record.

The outcome description gives standard deviation as the dispersion measure. Standard deviation describes variation among individual scores; it is not the same as the uncertainty in an estimated mean or mean difference. The registry record does not provide a standard error or interval for the primary comparison. It also does not report a statistical test or p-value for that comparison. No conclusion about statistical significance can be drawn from the endpoint description alone.

What does the assessment window imply?

The second assessment is identified as Visit 2, 7-124 days after initiation on Pradaxa or VKA. This is a broad stated window rather than a single common measurement time. In general, variation in the timing of patient-reported assessments may matter if perceptions change over time. The record does not report how assessment timing was distributed across treatment groups or whether timing was incorporated into analysis, so its influence on the comparison cannot be evaluated.

The registry states that PACT-Q2 forms completed more than 1 day after discontinuation of treatment or using an incorrect procedure were excluded from the analysis. This makes the analysis dependent on valid and appropriately timed questionnaire records. The record does not describe other rules for incomplete forms, missing items, or missing follow-up assessments.

How do planning illustrations differ from observed results?

Any sample-size calculations described for this study are planning illustrations based on the observed effect, not the trial’s own design and not observed power. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. In general, a sample-size illustration estimates the amount of information that might be required under its assumptions; it does not show that an analysis had a particular probability of detecting an effect. The registry record does not report a sample-size justification from the study protocol.

The record states that time-to-event planning tables use the total number of events, while other planning tables use participants per arm. These are planning conventions, not observed study findings. They should not be confused with the enrollment or adverse-event counts. The listed analysis and outcome counts describe the scope of registry reporting, but the registry record does not provide a full statistical plan specifying all models, tests, or decision rules.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 11 outcome measures and 10 analyses, including the primary PACT-Q2 comparison and secondary measures involving baseline characteristics, PACT-Q2 scores in Cohort A, and PACT-Q1 items in Cohort B. When a study examines multiple outcomes or comparisons, the chance of at least one apparently notable result can increase. In general, a prespecified multiplicity strategy may help govern interpretation across such tests. A multiplicity adjustment or a prespecified hierarchy for interpreting outcomes is not reported in the registry record. The number of listed measures alone does not show whether or how multiplicity was addressed.

The primary-outcome description specifies exclusions for PACT-Q2 forms completed more than 1 day after treatment discontinuation or using an incorrect procedure. That rule explains some exclusions but does not describe the handling of all missing data. The registry record does not report how incomplete questionnaires, missing score items, or absent second assessments were treated. It also does not state whether an imputation method or a sensitivity analysis for missing data was used.

The primary endpoint is described for eligible, propensity-score-matched patients in Cohort B. The main analysis population is described as all eligible patients from all participating countries, defined as patients who took the prescribed treatment and had no important protocol violation, and propensity-score-matched patients. The registry record does not give further detail on how these population descriptions map to each analysis, or how many patients contributed to the primary endpoint.

Because numerical outcome results and detailed missing-data methods are not reported in the registry record, readers cannot assess the extent of missingness, the potential effect of exclusions, or whether conclusions were robust to alternative assumptions about missing scores.

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 5% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: international normalised ratio increased (0.6%), acute myocardial infarction (0.3%), overdose (0.3%), cerebral infarction (0.3%), haematuria (0.3%).

The registry lists serious adverse events and deaths separately for the three groups. In Cohort A, Switch Patients - Pradaxa, 5 of 379 patients at risk were reported as having a serious adverse event, and 1 death was reported. In Cohort B, New Patients - Pradaxa, 1 of 591 patients at risk had a serious adverse event, with 0 deaths reported. In Cohort B, New Patients - VKA, 6 of 343 patients at risk had a serious adverse event, with 0 deaths reported.

The registry reports 0 other adverse events in each group. These counts are descriptive. The record does not provide an adjusted comparative safety analysis, confidence intervals, or detail on event follow-up time. The groups also arise from a non-interventional study, and the record does not establish randomized allocation. The counts therefore should not be interpreted as a causal comparison or as proof that an event cannot occur.

The listed serious adverse-event terms include International normalised ratio increased at 0.6%, and Acute myocardial infarction, Overdose, Cerebral infarction, Haematuria, and Diverticulum intestinal haemorrhagic at 0.3% each. The registry record does not provide enough detail in this summary to interpret those term frequencies as comparative risks between treatment groups. A count of reported events describes what was recorded under the study’s reporting, not the complete safety profile of a treatment.

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

This study addresses how patients perceived anticoagulant treatment, with the primary question focused on PACT-Q2 convenience and satisfaction scores among propensity-score-matched patients newly diagnosed with NVAF. That patient-reported focus is distinct from an assessment of stroke prevention, systemic embolism, or other clinical efficacy outcomes. The registry’s outcome definition explains what higher scores mean, but no numerical primary results are reported in the registry record.

Without group means, a treatment contrast, and an uncertainty estimate, the size and precision of any difference in reported convenience or satisfaction cannot be judged. The record does not support a statement that one treatment produced better or worse scores. Nor does the absence of numerical primary results establish that the groups had equal scores. It leaves the primary comparison unresolved in the registry information described.

The non-interventional design also limits causal interpretation. Patients were not described as randomly assigned, and the record does not state how treatment selection occurred. Propensity-score matching can address differences in recorded factors included in its model, but it cannot rule out residual differences arising from unmeasured factors. The matching covariates and balance results are not reported in the registry record.

The safety counts provide descriptive information for the registry’s groups, but they do not establish comparative safety. The listed counts are not adjusted for differences between groups, and the record does not provide uncertainty intervals or enough detail to compare event rates over a shared follow-up period. The serious adverse-event terms should likewise be read as reported events rather than evidence of a causal treatment effect.

Overall, the record describes the study population, the patient-reported outcome, the matching approach, and selected adverse-event counts. It does not report enough primary outcome results to determine the observed PACT-Q2 comparison, and it does not establish that treatment caused any difference in perceptions or safety outcomes.

13. Why This Trial Matters Statistically

The study is statistically notable for asking a patient-reported question in a non-interventional setting. PACT-Q2 convenience and satisfaction scores capture aspects of treatment experience that differ from clinical event outcomes. Keeping those constructs distinct helps prevent a patient-perception measure from being misread as evidence about stroke prevention or safety.

Its comparison also illustrates the role and limits of propensity-score matching. Matching can seek improved balance on measured characteristics when treatment groups arise through routine care rather than random assignment. The registry’s description of the matching algorithm is useful, but interpretation also depends on which characteristics entered the model and whether balance was achieved. Those details are not reported in the registry record. Matching therefore does not remove all concerns about confounding or make the treatment groups equivalent by design.

The endpoint’s timing and eligibility rules are relevant to analysis. PACT-Q2 was assessed at Visit 2 within the stated 7-124 day window, and forms completed more than 1 day after treatment discontinuation or using an incorrect procedure were excluded. These rules shape which questionnaire records contribute to the analysis. Other missing-data methods and the distribution of assessment timing are not reported, leaving uncertainty about the completeness and comparability of measured scores.

Finally, statistical interpretation requires estimates as well as outcome definitions. The registry describes the score scales and intended comparison but does not report primary means, a between-group estimate, or its precision. This means the research question and analytic approach can be understood, while the result itself cannot be evaluated from the reported primary-outcome information. That distinction is important when reading registry records: study completion and a specified analysis do not by themselves communicate the magnitude or certainty of a finding.

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 primary limitation for interpreting the study’s main question is that the registry record does not report the primary PACT-Q2 results. There are no reported means, standard deviations, treatment contrast, confidence interval, or p-value for the matched Cohort B comparison. The record therefore does not permit assessment of the observed difference or its precision.

The study is non-interventional, and the registry does not state that patients were randomized to treatment. The record does not explain how treatment was selected. Propensity-score matching is described, but the covariates in the score model, balance diagnostics, and any further adjustment methods are not reported. Residual confounding cannot be ruled out from the matching description alone.

The assessment window spans 7-124 days after treatment initiation. The registry does not report the actual timing of assessments by group or how timing differences were addressed. It specifies exclusions for PACT-Q2 forms completed more than 1 day after treatment discontinuation or using an incorrect procedure, but does not report broader missing-data procedures, completeness of questionnaires, or sensitivity analyses.

The registry lists multiple outcomes and analyses, but a multiplicity strategy is not reported. The primary outcome description gives the score dimensions and scale direction, yet the record does not provide a threshold for interpreting the importance of a score difference. It also does not report a detailed statistical analysis plan or a protocol-based sample-size justification. These limitations constrain both the interpretation of the intended comparison and the assessment of how robust any finding would be.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Patient Convenience Study- NIS RELATE — NCT02849509.
• Registry record last updated 2019-07-08; status last verified 2019-04.
• Results first posted 2019-07-08.
• 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

NCT02849509, Patient Convenience Study- NIS RELATE, was a completed non-interventional study sponsored by Boehringer Ingelheim. It concerned patients with atrial fibrillation receiving Pradaxa or a vitamin K antagonist for stroke prophylaxis. The registry record reports enrollment of 1313 and lists study dates from 2016-06-20 to primary completion on 2017-12-30.

The study included patients switching from VKA to Pradaxa and newly diagnosed patients treated with VKA or Pradaxa. Its primary outcome was the mean PACT-Q2 convenience and satisfaction scores at the second assessment for matched Cohort B patients. The registry describes propensity-score matching and specifies exclusions for certain PACT-Q2 records. It also lists secondary outcomes and adverse-event counts.

Numerical results for the primary PACT-Q2 comparison, detailed missing-data methods, matching covariates, and multiplicity procedures are not reported in the registry record. Accordingly, the record describes the planned comparison and study conduct but does not establish the magnitude or precision of the primary outcome difference.