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 Evaluation of the Mobile Acute Care of the Elderly (MACE) Unit (NCT00927160), a registered phase not stated study. The primary outcome is Length of Hospital Stay.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00927160 |
| Phase | Phase not stated |
| Condition | Model of Care for Hospitalized Older Adults |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 346 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Icahn School of Medicine at Mount Sinai |
| Results posted | Yes |
2. Clinical Question
Population
Older adults admitted to the hospital are the population described in the study. The registry record gives an enrollment of 346, but it does not report how many participants contributed data to the primary outcome or describe eligibility criteria in detail.
Intervention
The intervention is the Mobile Acute Care of the Elderly Unit, described as a unit to which elderly patients were admitted. The registry summary frames the study as an evaluation of whether this model of care is beneficial in improving patient outcomes.
Comparator
The comparison group consists of elderly patients admitted to the hospital’s general medicine service and described as receiving usual care. The registry does not state how patients were allocated to the two groups, so the comparison should not be treated as randomized.
Primary question
The primary outcome is length of hospital stay, measured in days. The clinical question is whether the recorded average length of stay differs between patients admitted to the MACE unit and patients admitted to the general medicine service. The registry record does not report the group results or an estimated difference.
3. Trial Design
This completed study evaluates a model of care for hospitalized older adults. The sponsor is Icahn School of Medicine at Mount Sinai. The registry lists a study start of 2009-06 and a primary completion of 2012-06. Enrollment is recorded as 346. These details describe the registered study, but enrollment does not establish how many participants had usable data for the primary outcome.
The MACE group is described as elderly patients admitted to the Mobile Acute Care of the Elderly Unit. The usual-care group is described as elderly patients admitted to the hospital’s general medicine service. The registry record does not state the allocation method. It therefore does not establish that participants were assigned at random, or that the two groups were comparable at the start of the study. The registry characterizes the arms as not being a like-for-like control comparison.
The primary outcome is length of hospital stay, expressed in days and summarized as a mean with standard deviation. Its timeframe is described as depending on hospital stay. Rehospitalization rate is listed as a secondary outcome. The registry lists two outcome measures but zero analyses. It does not report outcome results, an analytic sample, or methods used to account for differences between groups. The design information therefore establishes what was intended to be evaluated and how the groups were described, but does not establish the size or direction of any outcome difference.
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: No group assignment as this is observational.
Overall Study
| Stage | MACE Group | Usual Care Group |
|---|---|---|
| STARTED | 173 | 173 |
| COMPLETED | 173 | 173 |
| NOT COMPLETED | 0 | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | MACE Group | Usual Care Group | Total |
|---|---|---|---|---|
| Participants analysed | 173 | 173 | 346 | |
| Age Continuous | years | 85.2 (SD 5.3) | 84.7 (SD 5.4) | 85.0 (SD 5.4) |
| Sex: Female, Male: Female | Participants | 132 | 126 | 258 |
| Sex: Female, Male: Male | Participants | 41 | 47 | 88 |
| Region of Enrollment: United States | participants | 173 | 173 | 346 |
6. Primary Endpoint
The registry lists the primary outcome as Length of Hospital Stay, measured over Depending on hospital stay.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | days |
| Endpoint classification | Continuous Endpoint |
Length of hospital stay measures the time a patient remains in the hospital, recorded in days. The registry specifies a mean as the summary measure and standard deviation as the measure of dispersion. A mean describes the group’s average stay; a standard deviation describes how spread out individual stays are around that average. The registry gives the timeframe as depending on hospital stay.
As a primary outcome, length of stay is intended to address whether the care model is associated with a difference in the average duration of hospitalization. That makes it a measure of hospital use as well as a patient-level outcome, although the registry does not describe the exact operational rules for starting or ending the stay, or how transfers and other circumstances were handled.
The posted record does not include the mean, standard deviation, number analyzed, or a comparison estimate for either group. Consequently, it is not possible to describe the observed average stay, the variation in stays, or the precision of a between-group estimate from the registry record. Rehospitalization rate is listed as a secondary outcome, but its results and analysis details are also not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clear primary outcome: mean length of hospital stay in days. It also describes the two care settings being compared. However, the record does not post numerical outcome results or analyses. There is no group mean, standard deviation, estimated contrast, confidence interval, or test result for length of stay. The direction and magnitude of the observed comparison are therefore not reported in the registry record.
The enrollment of 346 describes the registered enrollment, not necessarily the number of participants included in an outcome analysis. The record does not specify how many participants had length-of-stay data, whether any participants were excluded from analysis, or whether the reported enrollment refers to all participants considered for the comparison. Without analyzed group counts and outcome summaries, the precision of a comparison cannot be assessed.
Allocation is not stated, and the registry describes the arms as not being a like-for-like control comparison. In general, when groups are formed without random assignment, differences in patient characteristics, admission circumstances, or care pathways may be related both to group membership and to length of stay. Such differences can complicate interpretation of an observed group contrast. The registry record does not report an adjustment strategy or enough baseline information to assess that possibility.
Rehospitalization rate is listed as a secondary outcome, but no result is posted. The adverse-event entries list zero participants at risk and zero affected in the recorded categories for both groups, while deaths are null. Those registry entries do not provide a reported analysis of safety, nor do they establish how adverse events were collected or whether the entries represent complete follow-up.
Overall, the posted record describes the study’s question and outcome definitions, not the answer to its primary question. No conclusion about the observed difference in length of stay, its statistical precision, or its clinical importance can be drawn from the posted results because those results are not reported in the registry record.
9. Statistical Methods Explained
Outcome scale and summary. The primary outcome is continuous: length of hospital stay in days. The registry specifies a mean and standard deviation. In general, a mean represents the average value in a group, while a standard deviation describes how much individual values tend to vary around that average. These summaries are useful for describing a continuous outcome, but they do not by themselves show the uncertainty in a comparison between groups. That requires information about the analyzed participants and a comparison estimate with an appropriate measure of precision.
Comparing groups. In general, an unadjusted comparison of means describes the difference observed between groups without accounting for other characteristics. An adjusted analysis can account for measured characteristics according to a specified statistical model. The registry record does not report a comparison estimate, an adjustment model, or any analysis at all. It is therefore not possible to identify whether the study’s results were analyzed as an unadjusted difference, through a model, or using another approach.
Precision and uncertainty. In general, a confidence interval gives a range of values compatible with the data and the assumptions of the analysis. Its width reflects uncertainty: a narrower interval indicates greater precision, while a wider interval indicates less precision. A confidence interval for a between-group effect would help readers assess both the range of plausible differences and whether clinically meaningful differences remain compatible with the data. No confidence interval or other precision estimate for length of stay is reported in the registry record.
A p-value, in general, describes how unusual the observed data, or data more extreme, would be under a specified null hypothesis and statistical model. It does not measure the size or clinical importance of an effect. The registry record reports no p-value and no test of the primary outcome. Without a result estimate and its uncertainty, a significance test alone would also be insufficient to characterize the comparison.
Distribution of length of stay. As a general statistical consideration, continuous outcomes can have distributions that are asymmetric or contain unusually long observations. Means and standard deviations may not fully describe such distributions. The choice of analysis can matter when the observed data depart from model assumptions. The registry record does not provide the distribution of stays, diagnostic checks, a transformation, or any alternative summary, so it is not possible to assess how the outcome distribution was handled.
Group formation and confounding. The record does not state how patients entered the MACE or usual-care group and explicitly does not present the arms as a like-for-like control comparison. In general, if treatment setting is associated with patient characteristics that also influence length of stay, a raw difference may combine the association of the care setting with differences in group composition. Statistical adjustment can address measured differences under appropriate assumptions, but it cannot automatically remove bias from unmeasured factors. No allocation procedure, baseline comparison, or adjustment approach is reported in the registry record.
Planning calculations and observed results. A sample-size calculation is a planning exercise based on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. It is not an observed result and does not show whether a study found an effect. Likewise, retrospective calculations based on observed summary statistics are not a substitute for the sponsor’s analysis. The registry record does not report the outcome summaries or analysis needed to interpret an observed effect or its planning implications. No planning assumptions from the original study design are reported in the registry record.
The record lists zero analyses. Accordingly, statistical interpretation is limited to the stated outcome scale and design descriptions; no inferential method, model fit, or estimated effect can be attributed to the study from the registry record.
10. Confidence Intervals for Each Arm
No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.
| Arm | Participants | Mean | Standard deviation | 95% CI for the mean |
|---|---|---|---|---|
| Mobile ACE | 173 | 4.600 | 3.300 | 4.105 to 5.095 |
| Usual Care | 173 | 6.800 | 7.600 | 5.659 to 7.941 |
R code and output
arm <- c("Mobile ACE", "Usual Care")
n <- c(173, 173)
m <- c(4.6, 6.8)
sp <- c(3.3, 7.6)
sd <- sp # posted standard deviations
for (i in seq_along(n)) {
se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}
CARM Mobile ACE 173 4.600 3.300 4.105 5.095
CARM Usual Care 173 6.800 7.600 5.659 7.94111. Multiplicity, Missing Data and Analysis Populations
The registry lists length of hospital stay as the primary outcome and rehospitalization rate as a secondary outcome, with two outcome measures in total. When a study examines multiple outcomes or multiple comparisons, the chance of obtaining a seemingly unusual result somewhere among them can increase. In general, investigators may address this issue by defining a primary outcome in advance, adjusting for multiple testing, or interpreting secondary findings as exploratory. The registry record does not report a multiplicity strategy, so it is not possible to determine how the two outcomes were handled statistically.
Missing-data methods are also not reported in the registry record. The record does not state whether all enrolled participants had outcome data, how incomplete length-of-stay information was handled, or whether any imputation or sensitivity analysis was used. These details matter because exclusions or missing observations can affect both the estimated group means and the comparability of the analyzed groups.
The analysis population is not described. The registry does not state whether analysis included all enrolled participants, only those with available outcome data, or a different subset. It also does not report participant flow between enrollment and analysis. The enrollment of 346 should therefore not be read as the number analyzed for the primary outcome.
The registry reports zero analyses. No analysis population, missing-data procedure, multiplicity handling, or sensitivity analysis is described in the registry record. These omissions prevent assessment of how robust any outcome finding might be to analytic choices or incomplete data.
12. What the Result Does, and Does Not, Mean
The registry record establishes that this study evaluated the Mobile Acute Care of the Elderly Unit against usual care for hospitalized older adults, with mean length of hospital stay as the primary outcome. It also identifies rehospitalization rate as a secondary outcome. These details clarify the question the study was intended to address, but they do not give the answer to that question.
No group-level results or statistical analyses are posted for length of stay. As a result, the registry does not establish whether the groups had different average stays, how large any observed difference was, or how precisely it was estimated. The same limitation applies to the secondary rehospitalization outcome. The absence of posted results should not be interpreted as evidence that the groups were the same, nor as evidence that one care setting produced a better outcome.
Even if a numerical difference were available, its interpretation would depend on how patients entered the groups, the characteristics of the participants, the analysis population, and the statistical methods used. The registry does not state the allocation process and cautions that the arms are not a like-for-like control comparison. An observed association in such a comparison would not, on its own, establish that the care model caused the difference.
In general, statistical significance and clinical importance are distinct. A small effect can be estimated precisely, while a potentially important effect can remain uncertain. The registry record supplies neither an effect estimate nor a precision measure for this primary outcome, so neither kind of judgment is possible from the posted results. The study’s stated purpose can be described, but a conclusion about benefit or lack of benefit cannot be drawn from the information recorded.
13. Why This Trial Matters Statistically
This study raises a useful statistical question about evaluating a care model in a hospital setting: how should differences in outcomes be interpreted when patients are admitted to different services? Length of stay is a continuous outcome, and the registry identifies the mean and standard deviation as its intended summaries. This makes it important to distinguish descriptive averages from an estimate of the difference between groups and the uncertainty around that estimate.
The registry’s description of the arms also highlights the role of study design. The MACE and usual-care groups are based on different hospital services, and allocation is not stated. When group formation is not established as random, a comparison can reflect differences in patient mix or care pathways as well as differences associated with the service. Statistical adjustment may help with measured factors, but interpretation still depends on the design and on assumptions that cannot be checked from the registry summary alone.
The record illustrates why outcome definitions and numerical results are both needed. A named primary outcome gives readers a focus, but without group summaries, an effect estimate, and a precision measure, readers cannot evaluate the size or uncertainty of a result. The registry lists zero analyses, leaving the planned comparison without a posted statistical result.
Finally, enrollment and analyzed sample size are not interchangeable. Knowing that enrollment was 346 does not reveal how many participants contributed to an outcome analysis or how missing observations were handled. That distinction is central to assessing precision and potential bias. The record is informative about the study question and setting, but its limited statistical reporting restricts what can be learned about the outcome comparison.
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 that it does not report results for the primary outcome. The group means, standard deviations, analyzed counts, estimated contrast, and precision of the comparison are not reported in the registry record. The secondary outcome, rehospitalization rate, also has no posted results. This prevents an assessment of the direction, magnitude, or uncertainty of either outcome.
The allocation method is not stated, and the registry explicitly notes that the arms are not a like-for-like control comparison. The record does not provide baseline characteristics or explain how potential differences between patients admitted to the two services were addressed. This limits interpretation of any comparison as an effect of the care model rather than an association between service and outcome.
The registry does not describe eligibility criteria in detail, participant flow, the number analyzed, missing-data handling, or the analysis population. It also does not report the statistical model, outcome-distribution checks, multiplicity approach, or sensitivity analyses. The enrollment figure therefore cannot establish the amount of information available for the primary analysis.
Adverse-event entries list zero at risk and zero affected in the recorded categories for both groups, with deaths recorded as null. The registry does not explain ascertainment, follow-up, or completeness for these entries. They should not be taken as a full comparative safety analysis. More broadly, the completed status and study dates do not supply outcome evidence when results and analyses are absent from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluation of the Mobile Acute Care of the Elderly (MACE) Unit — NCT00927160.
- Registry record last updated 2013-08-23; status last verified 2013-08.
- Results first posted 2013-08-14.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00927160 is a completed evaluation of the Mobile Acute Care of the Elderly Unit, sponsored by Icahn School of Medicine at Mount Sinai. The registry lists enrollment of 346, a study start of 2009-06, and primary completion of 2012-06. The comparison is between elderly patients admitted to the MACE unit and elderly patients admitted to the general medicine service.
The primary outcome is mean length of hospital stay in days, with standard deviation as the dispersion measure. Rehospitalization rate is listed as a secondary outcome. The registry records two outcome measures and zero analyses. It does not report outcome results, allocation methods, analysis populations, or statistical procedures. The record therefore describes the study question and outcome measures but does not provide a statistical answer to the primary question.