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 Functional Recovery and Caregiver Burden Following Surgery in the Elderly (NCT01382251), a registered phase not stated study. The primary outcome is Functional Autonomy Measurement System (SMAF).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01382251 |
| Phase | Phase not stated |
| Condition | Activities of Daily Living, Caregivers, Ambulatory Surgical Procedures |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 123 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Ottawa Hospital Research Institute |
| Results posted | Yes |
2. Clinical Question
Population
Older patients undergoing ambulatory surgery, with the stated primary objective focused on patients 65 years of age and older. Caregivers were spouses, family members, or friends identified as the patient’s primary source of support in the community.
Intervention
The record describes ambulatory surgery and assessment of patients after surgery. It does not identify a randomized treatment intervention or a separate surgical approach being tested against another approach.
Comparator
No like-for-like control group is described. Patients and caregivers are listed as groups, but these are different roles in the care relationship, not comparable treatment arms. Allocation is not stated.
Primary question
How does functional capacity, measured with the SMAF, change from baseline to one week and one month following ambulatory surgery in older patients?
The study’s stated purpose is to assess functional recovery and the effect of the current model of care on caregivers. The primary objective concerns patient functional capacity. The secondary objectives ask whether changes in function are associated with caregiver burden, quality of life, and pain-related interference. Caregiver burden is assessed with the Zarit Burden Interview, quality of life with the Short Form 12, and pain-related interference with the Brief Pain Inventory Functional Interference Score.
These objectives describe a study of recovery over time and relationships among measures, rather than a randomized comparison of alternative operations or care strategies. The registry record does not report numerical findings for the SMAF or the secondary measures, so the magnitude or direction of any observed change or association cannot be described.
3. Trial Design
The registry lists the study as completed, with enrollment of 123. The recorded start is 2010-07 and the primary completion date is 2012-01. The sponsor is Ottawa Hospital Research Institute. The study title is Functional Recovery and Caregiver Burden Following Surgery in the Elderly.
The described design centers on assessing older ambulatory surgical patients at baseline, one week, and one month following surgery. The primary measure is the SMAF. The secondary objectives concern caregiver burden, quality of life, and pain-related interference. This structure is consistent with planned observation of recovery and related measures over time; however, the registry record does not describe the detailed study procedures, recruitment approach, or visit schedule beyond the stated measurement time points.
Patients and caregivers are listed as groups. The patient group is described as patients undergoing ambulatory surgery. The caregiver group comprises spouses, family members, or friends identified as the patient’s primary source of support in the community. These groups have different roles and do not constitute a like-for-like control comparison. The registry indicates that allocation was not stated and that the study is not a randomized comparison.
The record lists four outcome measures and zero analyses. It does not report results for the primary outcome or the secondary measures. It also does not report a detailed statistical analysis plan, sample-size justification for the trial itself, or the number of participants contributing data at each assessment. The enrollment figure should therefore be read as the recorded study enrollment, not as a count of participants with complete outcome data. The safety results use a separate stated at-risk denominator, and the registry does not explain its relationship to enrollment.
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 | Ambulatory Surgery Patients | Ambulatory Surgery Caregivers |
|---|---|---|
| STARTED | 123 | 123 |
| COMPLETED | 102 | 102 |
| NOT COMPLETED | 21 | 21 |
Reasons for not completing this period:
| Reason | Ambulatory Surgery Patients | Ambulatory Surgery Caregivers |
|---|---|---|
| Surgeries cancelled or delayed | 16 | 16 |
| Lost to Follow-up | 4 | 4 |
| Contacted after study closed | 1 | 1 |
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: Demographic characteristics shown for those patients and caregivers completing study
| Characteristic | Unit | Ambulatory Surgery Patients | Ambulatory Surgery Caregivers | Total |
|---|---|---|---|---|
| Participants analysed | 102 | 102 | 204 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 30 | 30 |
| Age, Categorical: >=65 years | Participants | 102 | 72 | 174 |
| Sex: Female, Male: Female | Participants | 54 | 55 | 109 |
| Sex: Female, Male: Male | Participants | 48 | 47 | 95 |
| Region of Enrollment: Canada | participants | 102 | 102 | 204 |
6. Primary Endpoint
The registry lists the primary outcome as Functional Autonomy Measurement System (SMAF), measured over Baseline, one week, and one month following surgery.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the Functional Autonomy Measurement System, or SMAF, reported as a mean on a scale of units. The stated assessment times are baseline, one week, and one month following surgery. The measure has 29 items; each item is graded on a four-point scale: 0 means independent, 1 means needs supervision, 2 means needs help, and 3 means dependent. The total score ranges from 0 to 87, with higher scores indicating increased disability.
The SMAF is used to quantify functional capacity in a structured way. Its item-based scoring covers levels of assistance and dependence, allowing function to be described on a common scale at different assessment times. Repeated measurements can, in principle, describe whether participants’ scores change during recovery. This is a general explanation of how a repeated continuous measure can be used; it does not establish that a particular change occurred in this study.
The registry specifies the mean and standard deviation as the summary measures for this outcome. A mean describes the average score in the analysed group, while the standard deviation describes variability among individual scores. Neither measure is reported numerically in the registry record for the SMAF. As a result, the direction, size, and precision of any change between baseline and the later assessments cannot be evaluated from the posted results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s question and measurement plan, but it does not supply numerical results for the primary endpoint. The SMAF is specified for baseline, one week, and one month following surgery, yet no mean scores, standard deviations, changes, confidence intervals, or test results are reported. It is therefore not possible to describe the amount of functional change, its variability, or the precision with which it was estimated.
The record lists zero analyses. This is an important boundary on interpretation: the stated objectives are not evidence that the analyses were performed or that a particular result was found. The secondary objectives are to examine caregiver burden using the Zarit Burden Interview, quality of life using the Short Form 12, and pain interference using the Brief Pain Inventory Functional Interference Score. Numerical results for these outcomes are not reported in the registry record either. No correlation estimates or other inferential results are available to interpret.
In general, a mean can describe the average outcome in an analysed group, but it does not show how much participants differ from one another. A standard deviation describes the spread of observations, while a confidence interval, when reported, conveys uncertainty around an estimate under the assumptions of the analysis. Without the underlying outcome summaries or estimates, neither the size of a change nor its uncertainty can be assessed. This general statistical explanation should not be mistaken for a finding from this study.
The record reports enrollment of 123, while the serious-adverse-event group has 102 participants at risk. These counts refer to different fields in the registry; the record does not explain the difference or state how many participants contributed SMAF data at each time point. Enrollment alone cannot establish the analysed sample size, completeness of follow-up, or representativeness of the available outcome data.
The study is not described as a randomized comparison, and allocation is not stated. The patient and caregiver groups are not like-for-like control groups. Consequently, the record does not support a causal contrast between alternative treatments or care strategies. The most defensible interpretation is that the registry describes a planned assessment of postoperative function and related caregiver and patient measures, alongside limited safety counts, but posts no outcome analyses from which to quantify recovery or associations.
9. Statistical Methods Explained
The registry identifies the primary outcome as a continuous measure summarized by a mean and standard deviation. In general, a continuous outcome can take values across a scale rather than being limited to categories. The mean provides a measure of the group’s average score; the standard deviation describes how dispersed individual scores are around that average. These summaries answer different questions. A mean alone does not show whether scores are tightly clustered or widely spread, and a standard deviation is not a measure of uncertainty in the estimated mean.
What does repeated measurement contribute?
The SMAF is scheduled at baseline, one week, and one month following surgery. In general, repeated measurement can describe how an outcome changes within people over time, rather than comparing only separate groups. Measurements from the same person are usually related: a person’s score at one assessment may be associated with that person’s score at another. Statistical methods for repeated data need to account for this dependence when estimating changes and their uncertainty. The registry record does not report which method, if any, was used to analyse repeated SMAF measurements, or whether the stated assessments were completed as planned.
A change over time can be described in several ways, including comparing group averages across assessment times or estimating individual changes and then summarizing them. These approaches can have different assumptions and may use available observations differently. The registry record does not state the analytic definition of change, any adjustment variables, or how incomplete repeated observations were handled. No numerical SMAF results are reported, so no change estimate can be interpreted.
What do the secondary measures ask?
The secondary objectives address whether changes in functional capacity are associated with caregiver burden, quality of life, and pain-related interference. In general, an association describes how two measured quantities vary together. It does not, by itself, establish that one quantity caused the other to change. The registry names the Zarit Burden Interview, Short Form 12, and Brief Pain Inventory Functional Interference Score, but does not report estimates or methods for assessing these relationships. It also does not specify whether the secondary measures were collected at all the same time points as the SMAF.
There are several outcomes and questions in the stated objectives. In general, testing multiple outcomes can increase the chance of finding an apparently notable result by chance if many tests are conducted. Statistical plans may address this through a prespecified hierarchy, adjusted significance criteria, or careful emphasis on estimation rather than isolated tests. The registry record does not report a multiplicity strategy, the intended significance threshold for outcome analyses, or whether any outcomes were designated as exploratory beyond the primary and secondary descriptions.
How should precision be assessed?
In general, a confidence interval gives a range of values compatible with an estimate under the model and assumptions used. Its width reflects precision: a narrower interval indicates greater precision, while a wider interval indicates less. A p-value, when reported, addresses compatibility of the data with a specified null hypothesis under the analysis assumptions; it does not measure the size or practical importance of an effect. The registry record provides no outcome confidence intervals or p-values, so neither precision nor statistical evidence for a particular difference or association can be appraised.
The record includes a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect, and distinguishes per-arm participant counts for non-time-to-event outcomes from total event counts for time-to-event outcomes. This is a general planning calculation, not observed power and not evidence that the trial used those design assumptions. Because the record supplies no observed outcome effect and does not describe a randomized, equal-allocation comparison, the illustration cannot be treated as a reconstruction of the trial’s original design or analysis.
Over-dispersion is a general issue when data vary more than a statistical model assumes. If a model understates variability, it may produce uncertainty estimates that are too small and tests that appear more decisive than warranted. The registry does not report a model for the primary or secondary analyses, so there is no basis to determine whether over-dispersion was relevant or how it would have been handled. More broadly, the statistical methods used for the outcomes are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry describes a primary objective focused on SMAF functional capacity and secondary objectives concerning caregiver burden, quality of life, and pain-related interference. It lists four outcome measures, but does not report an analysis plan specifying how tests across outcomes or assessment times were prioritized. No adjustment for multiple testing, testing hierarchy, or other multiplicity strategy is reported in the registry record. Without that information and without posted analyses, the risk of interpreting an isolated result among several outcomes cannot be assessed.
Missing-data methods are also not reported in the registry record. The record does not state how many participants completed each assessment, whether participants missed visits or individual measures, how incomplete records were handled, or whether any imputation method was used. Those details matter because an analysis using only participants with complete repeated measurements may describe a different group from the full enrolled population if missingness is related to recovery or other measured characteristics. This is a general concern, not a claim about what happened in this study.
The analysis populations are not defined in the registry record. In particular, it does not specify which participants were included in the primary endpoint analysis or the secondary analyses. Enrollment was 123, and the safety group has 102 at risk; the record does not explain how these counts relate or how many contributed to each outcome. No numerical outcome analyses are posted, so the effects of missing observations, analysis-population choices, or multiplicity cannot be evaluated.
11. 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 |
|---|---|---|---|
| Ambulatory Surgery Patients | 4 | 102 | 3.9% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Ambulatory Surgery Patients | 0 of 102 |
Most frequent serious adverse event terms
| Event term | Organ system | Ambulatory Surgery Patients |
|---|---|---|
| Myocardial Infarction | Cardiac disorders | 1 of 102 |
| Transient Ischemic Attack | Nervous system disorders | 1 of 102 |
| Uncontrolled Pain | Injury, poisoning and procedural complications | 1 of 102 |
| Small Bowel Perforation | Injury, poisoning and procedural complications | 1 of 102 |
Serious events with the highest arm-level rate: myocardial infarction (1.0%), transient ischemic attack (1.0%), uncontrolled pain (1.0%), small bowel perforation (1.0%).
The serious-adverse-event group is labeled Ambulatory Surgery Patients. The registry reports 102 participants at risk and 4 affected by serious adverse events. It reports 0 affected by other adverse events in a group of 102 at risk. The serious terms listed are Myocardial Infarction, Transient Ischemic Attack, Uncontrolled Pain, and Small Bowel Perforation, each shown as 1.0%.
These are registry safety counts, not estimates of comparative risk. The record does not describe a like-for-like control group, and it does not report an allocation method. The listed serious-event terms should therefore be read as reported event categories, not as evidence that surgery caused an event or that a comparison between treatments was made. The registry also does not clarify whether an individual could contribute to more than one listed term or provide additional event-level detail.
The deaths field is not reported in the registry record. The safety denominator of 102 is distinct from the enrollment figure of 123, and the record does not explain that difference. These counts do not establish the completeness of safety follow-up or the number of participants with outcome data for functional recovery.
12. What the Result Does, and Does Not, Mean
The record documents a clinical question with practical relevance: how functional capacity changes after ambulatory surgery in older patients, and whether those changes relate to caregiver burden, quality of life, or pain interference. It identifies the SMAF as the primary measure and names the secondary instruments. This provides a useful account of the intended domains of assessment and their relationship to recovery and support needs.
However, the registry does not report numerical SMAF results or analyses for any of the stated objectives. It therefore cannot establish whether average function changed, by how much, how variable the scores were, or how precisely any change was estimated. It also cannot show whether functional change was associated with caregiver burden, quality of life, or pain-related interference. The objectives are questions, not findings.
The study record also does not describe a randomized comparison. Patients and caregivers are distinct groups rather than alternative treatment arms, and allocation is not stated. Accordingly, the posted information does not support a causal conclusion about the effect of one surgical strategy, care model, or treatment relative to another. The serious-adverse-event counts provide safety information for the listed group but do not create a comparative safety estimate.
In general, interpreting a recovery study requires attention to the size of measured changes, variability between participants, uncertainty around estimates, and completeness of follow-up. It is also important to distinguish changes observed over time from changes attributable to a particular intervention. The registry record does not provide the results or methods needed to make those judgments. The meaning is therefore limited to the study’s stated aims, measurement plan, and recorded safety counts, rather than evidence about the magnitude or cause of recovery.
13. Why This Trial Matters Statistically
This study is statistically interesting because recovery is represented as a process measured at more than one time point, rather than as a single post-surgical status. The SMAF assessments at baseline, one week, and one month following surgery are intended to describe functional capacity across that period. Repeated measurements can be informative because they retain the time pattern of recovery, but they also require methods that account for the relationship between observations from the same person.
The secondary objectives broaden the statistical question beyond function itself. They ask whether changes in function are related to caregiver burden, quality of life, and pain-related interference. Such questions involve relationships among measures and should not be confused with causal effects. Clear reporting of estimates, uncertainty, analysis populations, and missing-data handling would be important for interpreting those relationships.
The record also illustrates why a study’s stated objectives should be separated from its available results. It names the measures and time points, but reports zero analyses and no numerical primary outcome findings. Without estimates and their precision, readers cannot judge the magnitude or consistency of functional change. The record’s distinction between enrollment and the safety denominator likewise highlights the need to report how many participants contributed to each analysis.
Finally, the study is not a randomized comparison, and patients and caregivers are not interchangeable groups. That design context constrains the claims that could be made even if numerical changes were available. The registry record is useful for understanding the questions asked, but its statistical contribution cannot be judged from outcome estimates that are not reported.
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.
A central limitation of the registry record is the absence of numerical results for the primary SMAF outcome and the listed secondary outcomes. Although the measure and assessment times are described, no means, standard deviations, changes, confidence intervals, or inferential analyses are reported. The registry lists zero analyses, so the objectives cannot be treated as completed statistical findings.
The record does not report the number of participants assessed at baseline, one week, or one month, nor does it define the analysis population for any outcome. Enrollment is 123, while 102 participants are listed as at risk in the safety group; the relationship between those figures is not explained. Missing-data procedures and follow-up completeness are not reported in the registry record.
The study is not described as a randomized comparison, and allocation is not stated. The patient and caregiver groups represent different roles, not a like-for-like control comparison. The record therefore offers no basis for estimating a comparative treatment effect. It also does not report the detailed statistical methods, multiplicity approach, adjustment variables, or a trial-specific sample-size justification.
The registry provides limited safety counts, but does not give further event-level context or explain how the safety population relates to the enrolled participants. The deaths field is not reported in the registry record. These limitations are specific to the available record and should not be read as evidence that procedures or analyses were absent from the full study; they are simply not described in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Functional Recovery and Caregiver Burden Following Surgery in the Elderly — NCT01382251.
- Registry record last updated 2014-01-20; status last verified 2013-12.
- Results first posted 2014-01-20.
- 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.
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18. Record Summary
Functional Recovery and Caregiver Burden Following Surgery in the Elderly is a completed study sponsored by Ottawa Hospital Research Institute. The recorded start is 2010-07, the primary completion date is 2012-01, and enrollment is 123.
The primary objective is to assess functional capacity with the SMAF at baseline, one week, and one month following surgery in patients 65 years of age and older. Secondary objectives concern caregiver burden, quality of life, and pain-related interference. The record lists four outcome measures and zero analyses.
The study is not a randomized comparison; allocation is not stated, and the patient and caregiver groups are not like-for-like controls. The registry reports safety counts for 102 ambulatory surgery patients at risk, including 4 affected by serious adverse events and 0 affected by other adverse events. Numerical outcome results are not reported in the registry record.