Orthosis of Acute Traumatic Rib Fractures Via RibFx Belt for Pain Alleviation and Improved Pulmonary Function: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Orthosis of Acute Traumatic Rib Fractures Via RibFx Belt for Pain Alleviation and Improved Pulmonary Function (NCT03846024), a non-randomized na study. The primary outcome is Rib Fracture Subjective Self-Reported Pain (Inpatient).

2. Clinical Question

3. Trial Design

The study is registered as a pre-post interventional trial for institutional quality improvement. Its allocation is non-randomized, its model is sequential, and masking is listed as none. These features matter when interpreting a comparison: participants were not assigned at random, and participants and study staff were not masked to the belt intervention. The registry record does not explain the allocation process in further detail or report whether the sequence corresponded to particular calendar periods.

The registered enrollment is 27. The study began on 2018-07-25, had a primary completion date of 2020-04-09, and is listed as terminated. The phase is recorded as NA. The registry identifies the University of Vermont Medical Center as sponsor.

The intervention was the RibFx orthosis belt. The description calls for wearing it during most of the day, excluding showering or bathing, and encourages—but does not require—night use. The control arm received the participating institution’s standard care. The registry description mentions oral and intravenous analgesia and multimodal pain control, but a complete description of the control protocol is not reported in the registry record. Details such as adherence measurement, treatment changes, and how the intervention and control periods were scheduled are also not reported in the registry record.

The registry’s non-randomized and sequential design means that arm comparisons should be read as observational comparisons within this study, not as a randomized treatment contrast. Differences between groups could reflect the belt, but could also reflect other differences in participants or care. The posted results do not include the primary outcome analysis needed to quantify a comparison.

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: Population described includes participants where data was collected regarding pain control during their inpatient stay (1 patient withdrawn prior to data collection).

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 Rib Fracture Subjective Self-Reported Pain (Inpatient), measured over Inpatient Stay.

The primary endpoint is subjective self-reported pain during the inpatient stay. The registry describes pain questionnaires using a scale from 1 to 10: a score of 1 denotes the lowest amount of pain, and a score of 10 denotes the highest. The registered summary measure is the mean, with standard deviation as the measure of dispersion. The stated endpoint timeframe is the inpatient stay.

Pain is relevant to the study’s stated aim because rib fractures can cause substantial pain, and the investigators sought to compare pain control with and without the belt. A patient-reported score captures the participant’s own experience rather than an indirect clinical marker. That is useful for a symptom-focused question, but it also means scores depend on self-report and on how and when questionnaires are administered. The registry record does not report further questionnaire procedures, such as the number or timing of assessments during admission, or how repeated reports were combined into a participant-level value.

The registry describes the endpoint population as participants whose inpatient pain data were collected, with one patient withdrawn before data collection. It does not report arm-specific means or standard deviations, the number contributing endpoint data in each arm, or an estimated between-arm difference. Consequently, the scale and its intended interpretation are clear, but the posted results do not show the observed pain scores or their comparative precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered primary endpoint is a continuous measure summarized by a mean and standard deviation. The record defines the pain scale as running from 1, the lowest amount of pain, to 10, the highest. The statistical interpretation of that measure depends on the actual values observed and on how the participant-level scores were constructed. The registry record does not report those values or the detailed scoring procedure.

What does a mean describe?

General statistical explanation: a mean describes the arithmetic average of observed values. It can provide a compact summary of a group’s pain scores, but it does not show how individual scores are distributed. The standard deviation describes the spread of values around the mean. A larger standard deviation indicates more variability in the measured scores; it does not, by itself, indicate whether the mean is estimated precisely. The registry names these as the planned summary measures but does not report the endpoint means or standard deviations.

How would a group comparison be interpreted?

General statistical explanation: an unadjusted comparison of group means describes the observed difference between the groups, without accounting for other characteristics. Its interpretation as an intervention effect requires caution when allocation is not randomized. Participant characteristics or care practices that differ between arms can be associated with the outcome and can influence the apparent contrast. The record identifies a non-randomized, sequential model, but does not report an adjusted analysis or the covariates that might have been considered.

A confidence interval, when reported, describes statistical uncertainty around an estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, but an interval does not eliminate bias from non-random allocation, measurement, or missing data. The registry record does not report a confidence interval for the primary endpoint. A p-value, if reported, would address compatibility with a specified null hypothesis under an analysis model; it would not measure the size or clinical importance of an effect. No primary endpoint p-value is reported in the registry record.

Why does the design affect the analysis?

General statistical explanation: with randomized assignment, allocation is designed to make treatment groups comparable on average. In a non-randomized study, group membership can be related to factors that also affect the outcome. A sequential design may also make comparisons vulnerable to changes over time if the groups were enrolled or treated in different periods. The registry record identifies the design as sequential, but does not report the allocation details or calendar relationship between arms. It is therefore not possible to assess from the record whether time trends were relevant or how they were addressed.

Masking is listed as none. For a self-reported symptom, knowing whether the belt is being worn could affect expectations or reporting. This is a general measurement concern, not evidence that reporting bias occurred in this study. The registry record does not describe procedures to reduce or assess that possibility.

What does the planning information mean?

The registry’s sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The illustration is not the trial’s own design justification, and its numerical planning results are not reported in the record. A planning calculation describes how a hypothetical future study might be sized under stated assumptions; it is not evidence that the study had a particular probability of detecting an effect. Sample-size illustrations are not observed power.

General statistical explanation: planning calculations depend on assumptions about the effect to detect, variation in the outcome, the significance level, and the allocation scheme. If the assumed effect or variability is not appropriate, the resulting planning estimate may not reflect the requirements of a future study. The registry record does not report a protocol-based sample-size justification or the assumptions used for an original enrollment target.

What can be concluded from the posted analysis record?

The registry lists eight outcome measures but zero analyses. This means the record does not present a primary endpoint estimate or analysis that can be interpreted statistically. The endpoint definition alone does not reveal the observed scores, the between-arm contrast, or uncertainty around it. The record also does not report methods for handling repeated measurements, distributional checks, covariate adjustment, or sensitivity analyses. Those methods should not be presumed to have been used.

General statistical explanation: statistical methods are most informative when the analysis population, outcome definition, model, handling of missing observations, and uncertainty estimates are described alongside the results. Those details allow readers to evaluate whether the analysis matches the design and whether conclusions are robust to plausible assumptions. In this record, many of these analysis details are not reported, so the principal limitation is not a choice between competing statistical tests; it is that the endpoint analysis itself is absent.

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("RibFx Belt Arm", "Control")
n   <- c(12, 14)
m   <- c(5.96, 5.4)
sp  <- c(2.59, 1.85)
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  RibFx Belt Arm  12  5.960  2.590  4.314  7.606
CARM  Control  14  5.400  1.850  4.332  6.468

11. Multiplicity, Missing Data and Analysis Populations

The registry lists eight outcome measures, including inpatient and home incentive spirometry scores, pneumonia after rib fracture, and atelectasis after rib fracture. The primary endpoint is inpatient subjective self-reported pain. The registry record does not report the full outcome list beyond the named secondary outcomes, their analysis hierarchy, or which outcomes were designated as secondary versus exploratory in a statistical analysis plan.

When a study examines multiple outcomes, the chance of at least one apparently notable finding can increase if results are selectively emphasized. General statistical explanation: multiplicity procedures can control or describe this issue, but their appropriateness depends on the planned questions and analysis strategy. A correction method, testing hierarchy, or multiplicity plan is not reported in the registry record. No outcome analyses are reported, so the record does not allow assessment of how multiple comparisons were handled in practice.

The endpoint population description notes one patient withdrawn before pain data collection. The registry record does not report how many participants contributed primary endpoint data in each arm, why the withdrawal occurred, or whether other outcome values were missing. It also does not describe imputation, complete-case analysis, or sensitivity analyses for missing data. The number of participants analyzed for each secondary outcome is not reported in the registry record.

The analysis population is not described beyond the endpoint population statement. It is not reported whether analyses were intended to include all enrolled participants, only participants with observed outcome data, or another defined group. These details matter because exclusions and missing observations can affect the comparability of the groups, especially in a non-randomized study. With no analyses posted, the handling of incomplete observations and the impact of missing data cannot be evaluated.

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 records zero serious adverse events in the RibFx Belt Arm among 12 at risk and zero in Control among 15 at risk. It also records zero other adverse events in the RibFx Belt Arm among 12 at risk and zero in Control among 15 at risk. Deaths are recorded as zero in both arms, and no top serious adverse event terms are listed.

These are reported counts, not a guarantee that no adverse events occurred outside the registry’s ascertainment or reporting process. A zero count does not show that the underlying risk is zero, and it does not establish that the groups had equivalent safety. Interpretation depends on how events were defined, actively sought, and followed over time. Those procedures and the duration of safety follow-up are not reported in the registry record.

The listed at-risk counts are the denominators associated with the safety entries; they should not be assumed to be the same as the number contributing to every efficacy endpoint. The registry record does not describe how safety populations were defined or whether all enrolled participants were observed for the same period. These limitations are particularly important when reading zero-event entries, because limited observation or incomplete capture can leave uncommon events unobserved.

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

The registry record describes a study intended to examine whether a RibFx orthosis belt could improve inpatient pain reports among people with traumatic rib fractures managed without surgery. It defines a patient-reported pain scale, identifies the comparator as standard care, and records a non-randomized sequential design. These details explain the question and the broad structure of the comparison.

The record does not report primary endpoint values or an analysis comparing the arms. It therefore does not show whether the belt arm had lower or higher pain scores, how large any observed difference was, or how precisely a difference was estimated. The absence of a reported comparison cannot be interpreted as evidence that the belt has no effect, or as evidence that it does have an effect. The direction and magnitude are not established by the posted results.

Even if a numerical difference were available, the non-randomized design would require caution about attributing it to the belt. General statistical explanation: treatment groups can differ in characteristics related to the outcome, and sequential enrollment can coincide with changes in care or participant mix. Masking is listed as none, while the primary measure is self-reported. These features can affect the interpretation of a comparison, though the record does not show that any particular bias occurred.

The safety entries report zero serious and zero other adverse events in both arms, with deaths recorded as zero. Those counts are useful as registry entries but do not demonstrate absence of risk, because event definitions, follow-up duration, and ascertainment procedures are not reported. The study is listed as terminated, but the reason for termination is not reported in the registry record.

In short, the registry record supports an account of what the study set out to compare, but not an estimate of the primary endpoint effect. Claims that the belt reduces pain, fails to reduce pain, or has established safety would exceed what the posted results report.

14. Why This Trial Matters Statistically

This study illustrates why a clearly defined clinical question is not enough to support an effect estimate. The registry identifies a patient-centered outcome, a comparator, and a device intervention, but it does not report the primary endpoint analysis. Without group summaries and a comparative estimate, readers cannot assess the observed pattern or its precision. Statistical interpretation depends on reported results as well as on the outcome definition.

The design makes transparent reporting especially important. Allocation is non-randomized and sequential, so a comparison may reflect differences between groups beyond belt use. Information about how participants entered each arm, what characteristics were measured, and whether adjustment was planned would help readers assess comparability. Those details are not reported in the registry record.

The primary outcome is self-reported pain, which is directly relevant to the study question but potentially sensitive to measurement conditions and expectations. Because masking is listed as none, the record’s measurement procedures and timing would be useful for interpreting results. Such details are not reported in the registry record. This is a general issue in symptom research, not a claim that the study’s reports were biased.

The record also highlights the distinction between a sample-size planning illustration and an analysis of observed data. Planning assumptions can inform a future study, but they do not substitute for a reported estimate and its uncertainty. The registry’s sample-size assumptions are explicitly described as an illustration based on an observed effect, rather than the trial’s original design justification.

Finally, safety counts require context about follow-up and ascertainment. Zero recorded events is a count, not proof of no risk. Clear reporting of outcome results, analysis populations, missing-data handling, and safety methods would make the evidence easier to evaluate. In this record, the principal statistical contribution is the description of a clinical question whose outcome results remain unreported.

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 largest limitation for interpreting this trial is that the registry record does not report the primary endpoint results. It gives the scale and summary measure but not the arm-specific means, standard deviations, contrast, confidence interval, or p-value. The effect and its precision therefore cannot be assessed.

The non-randomized allocation limits causal interpretation. Differences between the arms could arise from participant characteristics or care practices rather than the belt. The sequential model may also make time-related differences relevant, but the relationship between sequence and calendar time is not reported. The registry does not report an adjusted analysis or details that would show how comparability was assessed.

The primary endpoint is self-reported and masking is listed as none. This creates a general possibility that expectations or measurement conditions could influence reported pain, but the record does not report procedures for questionnaire administration or methods to assess reporting effects. It also does not specify how multiple inpatient reports, if collected, were reduced to the mean outcome.

One patient is described as withdrawn before pain data collection. Beyond that statement, the amount and reasons for missing endpoint data are not reported in the registry record. The record does not describe the analysis population, missing-data methods, or sensitivity analyses. The study is listed as terminated, but its reason for termination and any consequences for data collection are not reported.

Additional limitations include the absence of a reported sample-size justification, multiplicity plan, and analysis details. The registry lists eight outcome measures and zero analyses. The full control-care description, adherence information, and safety follow-up procedures are also not reported. These gaps prevent a detailed assessment of outcome completeness, analysis choices, and the strength of any treatment-effect conclusion.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Orthosis of Acute Traumatic Rib Fractures Via RibFx Belt for Pain Alleviation and Improved Pulmonary Function — NCT03846024.
• Registry record last updated 2023-01-12; status last verified 2022-12.
• Results first posted 2023-01-12.
• 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

The registry record describes a pre-post interventional quality-improvement study of a RibFx orthosis belt for acute traumatic rib fractures. It is non-randomized, sequential, and unmasked; enrollment is 27, and status is terminated. The primary endpoint is mean inpatient self-reported pain on a scale from 1, the lowest amount of pain, to 10, the highest, with standard deviation as the dispersion measure.

The intervention arm was assigned the belt, while the control arm received institutional standard care. The endpoint population statement notes one patient withdrawn before pain data collection. The registry lists eight outcome measures and zero analyses. It does not report the primary endpoint results, analysis methods, or reason for termination.

Safety entries record zero serious and zero other adverse events in each arm, and zero deaths in both arms. Event ascertainment and follow-up details are not reported in the registry record. The posted information defines the study question and design but does not establish the direction, size, or precision of a pain outcome difference.