The Impact of Nebivolol Versus Metoprolol on Quality of Life: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Impact of Nebivolol Versus Metoprolol on Quality of Life (NCT01441570), a randomized na study. The primary outcome is Quality of Life.

2. Clinical Question

Other stated aims included evaluating cost-effectiveness, urine protein excretion, renal function, and achievement or maintenance of a target blood pressure of ≤ 120/80 mmHg. These aims provide context for the broader study question, but the registry record does not report results for them beyond listing blood pressure as a secondary outcome. The available record therefore identifies what the investigators intended to evaluate, but it does not establish whether the observed questionnaire scores favored either drug or whether they changed during follow-up.

3. Trial Design

The registry describes a randomized, double-masked, parallel-group study comparing nebivolol with metoprolol succinate. In a randomized trial, assignment to the study groups is intended to limit systematic differences between groups at the start of treatment. A parallel-group design means that participants are assigned to one study drug group rather than crossing between the drugs. Masking is intended to reduce the influence of expectations on participants’ reports or study assessments. The registry does not describe who was masked or how masking was maintained.

The planned treatment and assessment period was 12 weeks. Baseline questionnaire scores were measured at the initial screening or enrollment visit, identified as Visit 1 at the beginning of week 1. Follow-up scores were measured at the end-of-study visit, identified as Visit 2 at the end of week 12. The outcome description also refers to an early termination visit as a possible endpoint for change measurement. Details about the timing and handling of early termination assessments are not reported in the registry record.

Enrollment was 11. The study status is listed as terminated, with a start date of 2012-02 and primary completion date of 2013-07. A reason for termination is not reported in the registry record. The registry lists no analyses and gives no primary outcome comparison, estimates, confidence intervals, or significance tests. Thus, the design description indicates a randomized comparison, but the posted record does not show whether the intended quality-of-life analysis was completed or what it found.

The registry lists blood pressure as a secondary outcome and describes additional aims involving cost-effectiveness, urine protein excretion, and renal function. It does not provide results for those aims. Nor does it report details such as the randomization method, allocation concealment, treatment adherence, or protocol deviations. The trial’s small enrollment is important context when considering how much information the record can provide, but the registry does not give a planned enrollment target or a sample-size justification.

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

Analysis population for the primary outcome, as defined in the registry: Adult (\>18 years of age) renal transplant recipients, both men and women, requiring pharmacotherapy for high blood pressure were evaluated for inclusion in this analysis.

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 Quality of Life, measured over 12 weeks; Baseline scores were measured at the Initial Screening/Enrollment Visit (Visit 1 - beginning of week 1); Follow-Up scores were measured at the End of the Study (Visit 2 - End of week 12).

The primary outcome was change in scores from screening or enrollment to the end of the study or early termination on four quality-of-life questionnaires. The measures were the SF-36v2 Health Survey, the International Index of Erectile Function for men, the Changes in Sexual Functioning Questionnaire for women, and the Multidimensional Assessment of Fatigue scale. Together, these instruments address general health-related quality of life, sexual functioning, and fatigue. The record describes the outcome as a mean of a continuous measure, with standard deviation as the dispersion measure.

These questionnaires capture different aspects of participants’ reported health and functioning. Their score ranges and directions are not interchangeable: for example, higher SF-36v2 scores indicate less disability, while higher MAF scores indicate more fatigue. The sexual-function questionnaires also have their own score interpretations, including stated thresholds for dysfunction. Consequently, a change must be interpreted in the context of the particular instrument rather than as a common unit shared by all four.

Repeated measurement before and after treatment can describe whether scores changed during the study period. Comparing changes between randomized groups could address whether the pattern differed between the drugs. However, the registry record does not report the scale-specific results, the direction or size of any change, or a statistical comparison. It also does not report which questionnaire was designated as the single primary measure if one was selected.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean and standard deviation describe?

General statistical explanation: a mean summarizes the average value of a continuous measure across participants. A standard deviation describes how spread out individual values are around that average. Both can help characterize questionnaire scores, but they do not by themselves show whether two groups differ or whether a change is meaningful. The registry identifies the primary outcome as a mean and standard deviation, yet no values are reported for any of the four questionnaires.

The questionnaires use different ranges and score directions. The SF-36v2 range is 0-100, with lower scores indicating more disability. The IIEF range is 5-25 and its stated score bands describe levels of erectile dysfunction. The CSFQ-14-F range is 14-70, with a score at or below 42 indicative of sexual dysfunction. The MAF range is 1-50, with higher scores indicating more fatigue. These scale-specific interpretations matter: an identical numerical change across two instruments would not have an identical meaning.

What would a change-from-baseline comparison address?

General statistical explanation: measuring participants at baseline and follow-up allows analysts to describe change over time. Comparing changes between randomized groups can address whether the groups had different patterns over the same interval. A within-group change alone does not establish that one treatment produced a different change from the other, because time-related effects and other influences may affect both groups.

For this study, the registry describes baseline measurement at the initial screening or enrollment visit and follow-up at the end of the study, after 12 weeks. It also allows an end-of-study or early termination visit in the primary outcome description. The record does not provide the actual before-and-after values, the between-group comparison, or details of how participants with missing follow-up measurements were handled. Therefore, no estimate of change or difference in change can be interpreted.

What role would a confidence interval play?

General statistical explanation: a confidence interval presents a range of estimates compatible with the observed data under the chosen statistical method. It communicates precision as well as direction and magnitude. A narrow interval indicates greater precision than a wide interval, while an interval spanning values on both sides of no difference may leave the direction uncertain. A confidence interval does not replace consideration of the scale’s clinical meaning or the study’s design.

No confidence interval is reported for the primary outcome in the registry record. There is consequently no reported estimate whose precision can be assessed. Likewise, no p-value is reported. The absence of a p-value should not be interpreted as evidence of no difference; it means the record does not provide a reported test result.

Why can small samples limit precision?

General statistical explanation: estimates based on a small number of participants are often more sensitive to the outcomes of individual participants and may be imprecise. Randomization helps protect against systematic allocation differences, but it does not guarantee that a small study will have balanced groups on every relevant characteristic. The registry records enrollment of 11. It does not report a planned sample size, a sample-size justification, or the number with complete primary outcome data. No claim about statistical power or the likelihood of detecting an effect can be made from the available record.

The registry lists planning assumptions for an illustrative sample-size calculation: a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as fractions of an observed effect. No observed primary effect or resulting planning counts are reported. Those assumptions are not evidence that the trial was designed with a particular sample size, and no planning illustration can substitute for observed results.

How should multiple measures be considered?

General statistical explanation: when several outcomes or comparisons are tested, the chance of at least one apparently unusual result can increase if each is treated as an independent primary test without adjustment. Analysts may define one primary comparison, use an adjustment, or describe results as exploratory, depending on the study plan. The registry identifies four quality-of-life questionnaires, but does not report a multiplicity strategy, a hierarchy among the measures, or which single comparison would govern an overall conclusion.

The record reports zero analyses. It does not describe a statistical analysis plan, model specification, assumptions for the questionnaire analyses, or handling of repeated measurements. Any detailed account of such methods would therefore be speculation. The appropriate reading is limited to the outcome definitions and design features that are actually documented.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome description includes four questionnaires, with separate instruments for general health, sexual functioning in men, sexual functioning in women, and fatigue. The registry record does not identify a single questionnaire as the sole primary measure, describe a hierarchy among them, or report a plan to address multiple outcomes. It also does not state whether additional analyses were prespecified or exploratory. Because the record lists no analyses, there are no reported results whose multiplicity handling can be evaluated.

Missing data are also not described. The registry does not report how many participants completed each questionnaire at baseline or follow-up, whether any assessments were unavailable, or how missing observations were handled. The outcome description allows measurement at an early termination visit, but does not explain how those observations would be incorporated or how participants without such a visit would be treated analytically. These details are not reported in the registry record.

The analysis populations are not described. The record does not state whether analyses were intended to include all randomized participants, only those who received treatment, or participants with complete outcome measurements. It does not report exclusions after randomization, adherence, or protocol deviations. These gaps matter because the group of participants included in an analysis can affect what the estimate represents. Without a stated approach and reported participant counts, the results cannot be assessed for missing-data or population-selection concerns.

These omissions do not establish that a particular method was or was not used; they indicate only that it is not reported in the registry record.

11. 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.

The registry reports serious adverse event counts for two groups. In the nebivolol group, 0 serious adverse events affected among 6 participants at risk. In the metoprolol group, 0 affected among 5 at risk. The registry also reports zero other adverse events among the same numbers at risk. No serious adverse event terms are listed.

These are counts from the enrolled study groups, not estimates of event rates in a broader population. With 11 participants enrolled overall, the record’s zero counts are limited evidence about safety and cannot establish that serious or other adverse events would not occur. The record does not describe the duration of safety surveillance beyond the study context or provide detail about how adverse events were collected and classified.

Death counts are not reported. A blank death count should not be read as a reported zero. The safety figures also do not indicate whether each participant completed follow-up or whether all participants had the same observation time. These details are not reported in the registry record.

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

The registry record establishes that investigators planned a randomized, double-masked, parallel-group comparison of nebivolol and metoprolol succinate in adult renal transplant recipients requiring medication for high blood pressure. The main stated question concerned changes in quality-of-life questionnaire scores over a 12-week treatment period. The record also identifies secondary aims related to blood pressure and other measures.

What the record does not establish is whether one drug was associated with better quality-of-life scores, whether scores changed in either group, or how large or precise any difference might have been. No primary outcome analysis is reported. Without group estimates and uncertainty measures, it is not possible to assess the direction, magnitude, or reliability of a comparison. The absence of reported results is not evidence that the drugs had identical outcomes.

The outcome description names four different questionnaires, whose scores address distinct aspects of health and have different ranges and directions. A finding on one scale would not necessarily apply to the other scales. Since no scale-specific values are reported, no interpretation about disability, sexual functioning, or fatigue can be made from the registry record.

The reported safety counts show zero serious and zero other adverse events affected in each group among the listed participants at risk. Those counts are descriptive and come from a small enrolled sample. They do not demonstrate the absence of risk. Death counts are not reported, and the record provides no analysis of the stated cost-effectiveness, urine protein, renal function, or blood pressure target aims.

The study is listed as terminated, but the reason is not reported. The record does not state whether termination occurred before all planned assessments or analyses were completed. As a result, readers should distinguish the planned research question from the findings actually documented: the question is clear, but the posted results do not answer it.

13. Why This Trial Matters Statistically

This trial is statistically notable because its central outcome is patient-reported quality of life, measured with several distinct instruments, while the registry record provides no outcome analysis. That distinction is important: a well-defined research question and a detailed outcome description are not substitutes for estimates of what happened to participants. Without results, readers cannot judge either the direction of change or its precision.

The study also illustrates why scale-specific interpretation matters. The four questionnaires cover different aspects of functioning and use different scoring ranges and directions. A numerical change cannot be interpreted without knowing which measure produced it and how that scale is scored. A collection of measures can offer a broader view, but it also raises the need to state how results will be organized and interpreted. The record does not report such an analysis approach.

Enrollment of 11 and the terminated status are relevant when considering how much information the trial could provide. The registry does not report the reason for termination, a planned enrollment target, or the number with completed follow-up. These missing details prevent readers from determining whether the study ended as planned or how the available sample related to the intended analysis.

Finally, the registry’s safety counts are useful as descriptive accounting but have limited reach. Zero events among the listed participants do not establish that events are impossible or that risks are absent. The record is a reminder that safety counts, treatment comparisons, and patient-reported outcomes answer different questions and require appropriate context.

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.

Several trial-specific limitations constrain interpretation. The registry lists an enrollment of 11 and a terminated status, but does not report why the study ended or whether the planned follow-up was completed. It does not provide a count of participants with baseline and follow-up quality-of-life assessments. Therefore, the completeness of the primary outcome data cannot be evaluated.

The primary outcome spans four questionnaires, each with a distinct score range and interpretation. The registry does not indicate whether all four were treated as equally important, whether one was selected as the principal measure, or how multiple outcome comparisons were to be interpreted. It gives no analysis results for any measure. The record also does not report a statistical analysis plan, model, or method for handling repeated measures and missing observations.

Important design details are not reported in the registry record, including the randomization procedure, allocation concealment, who was masked, treatment adherence, and protocol deviations. The record gives no sample-size justification or planned enrollment target. These omissions prevent assessment of how the study was intended to manage design and analysis risks.

The registry states additional aims concerning cost-effectiveness, urine protein excretion, renal function, and blood pressure, but does not report their results. Safety counts include zero affected in each group among the listed participants at risk, but the small enrollment and unreported death counts limit interpretation. These are limitations of what the registry record documents; they do not establish what may have been assessed or analyzed outside the record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The Impact of Nebivolol Versus Metoprolol on Quality of Life — NCT01441570.
• Registry record last updated 2017-04-20; status last verified 2017-03.
• Results first posted 2017-04-20.
• 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

The registry describes a randomized, double-masked, parallel-group study of nebivolol versus metoprolol succinate in adult renal transplant recipients requiring medication for high blood pressure. The primary outcome was change in four quality-of-life questionnaires between baseline and the end of a 12-week period or an early termination visit.

Enrollment was 11. The study is listed as terminated, with a start date of 2012-02 and primary completion date of 2013-07. The reason for termination is not reported in the registry record. The record lists no analyses and reports no primary outcome results. Safety counts report zero serious and zero other adverse events affected among 6 at risk in the nebivolol group and 5 at risk in the metoprolol group; death counts are not reported.