Shifting Rehabilitation Paradigms in Skilled Nursing Facilities: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Shifting Rehabilitation Paradigms in Skilled Nursing Facilities (NCT02927171), a non-randomized na study. The primary outcome is Short Physical Performance Battery (SPPB).

2. Clinical Question

3. Trial Design

NCT02927171 is listed as a completed study titled “Shifting Rehabilitation Paradigms in Skilled Nursing Facilities,” sponsored by the VA Office of Research and Development. The registry lists a start date of 2016-02-28, a primary completion date of 2018-10-30, and enrollment of 104. The phase is listed as not applicable. Physical deconditioning is the recorded condition.

The design entries identify nonrandomized allocation, single masking, and a single-group model. Separately, the registry describes usual care and I-STRONGER, and its study summary frames intensive rehabilitation in relation to usual care. Those descriptions do not make the study a randomized, parallel-group trial: the record itself cautions that this is not a randomized comparison and that the arms are not a like-for-like control comparison. The relationship between the single-group design entry and the two arm descriptions is not explained in the registry record.

I-STRONGER is described as a progressive, high-intensity program combining strengthening and functional interventions, with the aim of facilitating independence in functional activities. Usual care is described as standard rehabilitation delivered by skilled nursing facility rehabilitation therapists. The I-STRONGER arm description ends before completing its account of therapist training and implementation, so further delivery details are not reported in the registry record.

The primary outcome is change in SPPB score between admission and discharge. The recorded timeframe notes an expected average length of stay of 21 days; that is a stated expectation, not a reported average observed for participants. Gait speed is listed as a secondary outcome. Although the record identifies three outcome measures overall, it does not report the full list or the results for those measures. The record does not give numerical results for the primary outcome, the analysis method, or the roles of those masked.

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: There were no exclusions of participants. All eligible, willing participants were allocated to one of two arms.

Overall Study

Reasons for not completing this period:

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: 1 participant in the I-STRONGER arm was lost to follow-up. They were discharged home early, and discharge outcomes were not assessed.

6. Primary Endpoint

The registry lists the primary outcome as Short Physical Performance Battery (SPPB), measured over Change from SNF Admission to SNF Discharge (Expected average length of stay: 21 days).

The primary endpoint is change in the Short Physical Performance Battery (SPPB) score from skilled nursing facility admission to discharge. The SPPB is described in the registry as a global measure of lower-extremity function comprising walking speed, chair stands, and balance tests. Its scale ranges from a minimum score of 0 to a maximum score of 12, with higher scores indicating better function.

Using a combined measure can provide a broader view of lower-extremity performance than focusing on a single task. Walking, rising from a chair, and maintaining balance reflect different aspects of physical function; a composite score brings those components into one outcome. This is a general explanation of why such a measure can be useful, not a claim about how the investigators chose it. The registry record does not report the rationale for selecting SPPB as the primary endpoint.

Assessing change between admission and discharge focuses the question on within-stay change rather than on a score at one time point alone. In general, a change score requires measurements at both time points and a clear approach to participants without one of those measurements. The registry record does not report the observed admission or discharge means, the mean change, its variability, or how missing measurements were handled. It also does not provide a numerical estimate of the primary outcome or its precision. The expected average length of stay of 21 days is a timeframe description, not a participant-level outcome result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary measure represent?

The SPPB is a continuous score, and the registry specifies that the primary parameter is a mean with standard deviation as its measure of dispersion. In general, a mean describes the average score or average change in a group. A standard deviation describes how spread out individual observations are around that mean. These answer different questions: the mean describes the group’s central outcome, while the standard deviation describes participant-to-participant variability.

The primary outcome is defined as change from admission to discharge. In general, an analysis of change uses measurements from both time points, and its interpretation depends on how the change is calculated and which participants contribute data. A mean change describes average within-person change among those included in the analysis, if calculated from paired measurements. The registry record does not report the calculation method, observed means, standard deviations, or primary analysis population. It is therefore not possible to verify how the stated endpoint was analyzed.

What does a comparison estimate require?

In general, an effect estimate comparing intervention conditions describes how outcomes differ between them under a specified analysis. A confidence interval expresses uncertainty around that estimate. For a nonrandomized study, baseline differences, participant selection, care delivery, and other factors can complicate causal interpretation. Statistical adjustment can sometimes address measured differences, but it cannot by itself guarantee that groups are comparable or remove bias from unmeasured factors.

Those general considerations matter particularly because this registry record identifies a single-group model and nonrandomized allocation while also describing usual care and I-STRONGER. It explicitly warns against treating the arms as a like-for-like control comparison. The record does not explain how the single-group entry relates to the arm descriptions, or report a comparison estimate or adjustment strategy. No method should be inferred from the presence of arm labels.

What do significance tests and intervals tell readers?

As a general statistical principle, a significance test evaluates how compatible the data are with a specified null hypothesis under the test’s assumptions. A p-value does not measure the probability that a treatment is effective, nor does it quantify the size of an effect. An estimate and its confidence interval are generally more informative about magnitude and precision. The registry record does not report a primary-outcome p-value, confidence interval, or test procedure.

Standard errors and confidence intervals depend on the analysis and the variability and amount of data available. For a change outcome, uncertainty depends on the distribution of individual changes and on which paired observations are included. The variability of change cannot be recovered from separate time-point summaries alone unless additional information is available. No such summaries or covariance information are reported in the registry record, and no recalculated primary estimate is available to discuss.

How should planning illustrations be read?

The stated planning assumptions describe an illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is specified as a fraction of the observed effect. These are assumptions for an illustrative calculation; the registry record does not identify them as the study’s original design plan or sample-size justification. It does not report the protocol’s sample-size rationale.

In general, a sample-size calculation asks how many participants would be needed under specified assumptions to detect a target effect with a chosen power and significance level. Such a calculation is sensitive to the assumed effect, variability, allocation, and analysis method. A planning illustration is not observed power, and it cannot replace a reported estimate with uncertainty. The record does not report the observed primary effect needed to evaluate the planning illustration independently.

When outcomes are counts or event rates, over-dispersion—variability greater than a simple model expects—can affect standard errors and interval width. That is a general consideration, not a method identified for this continuous SPPB endpoint. The registry record does not report a model that would allow assessment of distributional assumptions, residual behavior, or other diagnostics.

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.

R code and output

arm <- c("Usual Care", "I-STRONGER")
n   <- c(53, 50)
m   <- c(3.6, 4.3)
sp  <- c(2.3, 2.7)
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  Usual Care  53  3.600  2.300  2.966  4.234
CARM  I-STRONGER  50  4.300  2.700  3.533  5.067

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies SPPB change as the primary outcome and gait speed as a secondary outcome. It also records three outcome measures overall, but does not list all of them or report their results. The record does not describe a multiplicity strategy, such as prioritizing outcomes in a prespecified order or adjusting inference when several hypotheses are tested. The existence and details of such a strategy are not reported in the registry record.

In general, testing several outcomes can increase the chance of obtaining at least one apparently notable result by chance. A prespecified primary endpoint helps clarify which question is central, while a multiplicity approach can address the interpretation of multiple tests. Without the analysis plan and outcome results, the effect of multiplicity on interpretation cannot be assessed. The record lists one analysis, but does not identify its model, outcome, or role in relation to the other measures.

Missing data are also important for a change endpoint because a participant needs relevant measurements over time to contribute to a change analysis. The registry record does not report the amount or pattern of missing SPPB data, reasons for missingness, imputation methods, or sensitivity analyses. It does not report whether the analysis included all enrolled participants, only those with complete measurements, or another defined analysis population. These omissions make it impossible to assess how missing outcomes may affect the estimate.

General statistical practice distinguishes the group enrolled from the population included in a particular analysis. The enrollment entry of 104 does not identify the number included in the SPPB analysis. Definitions of intention-to-treat, per-protocol, or other analysis populations are not reported in the registry record, so none should be presumed.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry reports serious adverse events and other adverse events separately for the named usual-care and I-STRONGER groups. For usual care, the record lists 0 serious events among 53 at risk and 0 other events among 53 at risk; deaths are listed as 0. For I-STRONGER, it lists 0 serious events among 50 at risk and 0 other events among 50 at risk; deaths are listed as 0. No serious-event terms are listed.

These are the recorded event counts, not proof that no adverse events occurred outside the registry’s defined collection or reporting process. The record does not describe event definitions, ascertainment procedures, follow-up completeness, severity classifications beyond the serious-event category, or the time at risk. It also does not explain how these groups relate to the single-group design entry. Because the record warns against treating the arms as like-for-like control groups, the counts should not be read as a comparative safety estimate.

In general, a zero count in a reported dataset does not establish that an event is impossible or that risk is absent. Interpreting safety requires attention to how events were sought, the period covered, and the completeness of observation. Those details are not reported in the registry record. No rates, risk differences, or comparative inferences are stated.

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

The registry record establishes that the study was intended to examine intensive therapeutic rehabilitation for older skilled nursing facility residents and identifies change in SPPB score as its primary outcome. It describes I-STRONGER as progressive, high-intensity strengthening and functional interventions and describes usual care as standard skilled nursing facility rehabilitation. These are descriptions of the study question and intervention, not numerical evidence of an outcome.

The record does not report the primary-outcome results. It therefore does not show the amount or direction of SPPB change, how variable participants’ changes were, or the precision of an estimated effect. It also does not provide a reported comparison estimate or analysis method. The absence of these results in the registry record should not be interpreted as evidence that there was no change or no difference.

The design entries require additional caution. The record states that allocation was nonrandomized and the model was single-group, while its summary and arm descriptions refer to I-STRONGER and usual care. The registry cautions that this is not a randomized comparison and that the arms are not a like-for-like control comparison. Without clarification of the design and analysis, the descriptions cannot support a randomized causal interpretation.

The listed adverse-event counts are zero in each reported category and group, with the stated numbers at risk. Those figures describe what the record reports, but the event definitions and ascertainment details are not given. They do not establish absence of risk or allow a reliable comparative safety conclusion.

Overall, the record supports describing the study’s aim, setting, endpoint, design labels, and recorded adverse-event counts. It does not support a conclusion that I-STRONGER did or did not improve function, nor does it quantify the uncertainty around an effect. Such conclusions require outcome estimates, analysis details, and information about missing data and participant flow, none of which are reported in the registry record.

14. Why This Trial Matters Statistically

This study illustrates why design labels and result estimates must be read together. The registry presents an intervention aim and descriptions of usual care and I-STRONGER, but identifies a single-group model and nonrandomized allocation. It also warns that the arms are not a like-for-like control comparison. That combination makes it especially important not to treat the arm descriptions as evidence of a randomized contrast.

It also demonstrates the distinction between an outcome definition and an outcome result. SPPB is described clearly enough to identify what the primary endpoint measures and the direction of its scale, and the timeframe is defined as change from admission to discharge. But a defined endpoint alone does not answer the clinical question. Without observed means or changes, variability, and an estimate of precision, readers cannot judge the magnitude or uncertainty of the functional outcome.

Registry enrollment is not interchangeable with the analysis population. The record lists enrollment of 104, but does not state how many had usable SPPB measurements or contributed to the primary analysis. For a change outcome, this matters because missing measurements can affect both the estimate and its precision. Transparent reporting of participant flow and missing-data handling is therefore important for evaluating the result.

The safety entries make a similar point: event counts are interpretable only alongside definitions, observation periods, and ascertainment methods. Zero recorded events are a description of the recorded counts, not a guarantee of no risk. Taken together, these features make the registry record useful for identifying the study’s stated aims and reporting gaps, while limiting conclusions about comparative effectiveness and safety.

15. 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 principal trial-specific limitation for interpretation is the mismatch between the single-group, nonrandomized design entries and the descriptions of two arms. The registry explicitly states that this is not a randomized comparison and that the arms are not a like-for-like control comparison. It does not explain how the study’s design and intervention descriptions fit together. A causal treatment contrast should not be inferred from those descriptions.

The registry record does not report numerical results for the primary SPPB outcome. It also does not report the analysis model, an effect estimate, a confidence interval, or a primary-outcome test result. As a result, the magnitude, direction, and precision of any observed functional change cannot be evaluated. The record does not provide observed admission and discharge values or the variability of changes.

Participant flow and analysis-population definitions are not reported. Although enrollment is listed as 104, the number contributing to the primary analysis and the completeness of admission and discharge measurements are not stated. Missing-data amounts, reasons, and handling methods are likewise not reported in the registry record. These gaps prevent assessment of whether the analyzed participants represent those enrolled.

The I-STRONGER description is incomplete, and details of implementation, adherence, and the role of masking are not reported. The record identifies single masking but does not specify who was masked. It does not give the full list of three outcome measures or a multiplicity strategy. For safety, event counts are reported, but definitions, ascertainment, and follow-up details are not. Each of these limitations narrows the conclusions that can be drawn from the registry information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Shifting Rehabilitation Paradigms in Skilled Nursing Facilities — NCT02927171.
• Registry record last updated 2020-04-03; status last verified 2020-03.
• Results first posted 2020-04-03.
• 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.

19. Record Summary

NCT02927171 is listed as a completed study sponsored by the VA Office of Research and Development, with enrollment of 104. It concerns physical deconditioning among older skilled nursing facility residents and evaluates an intensive therapeutic rehabilitation approach named I-STRONGER. The registry lists a single-group model and nonrandomized allocation, while also describing usual care and I-STRONGER; it cautions that these are not a randomized, like-for-like comparison.

The primary outcome is change in SPPB score from admission to discharge, with gait speed listed as a secondary outcome. The record does not report numerical primary-outcome results, an analysis method, missing-data handling, or analysis-population details. It reports zero serious and other adverse events in each listed group, with the corresponding at-risk counts, and zero deaths. Safety ascertainment details are not reported. Accordingly, the record describes the study question and some design and safety information but does not provide enough outcome information to quantify functional change or a comparative effect.