Care Outcomes for Chiropractic Outpatient Veterans: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Care Outcomes for Chiropractic Outpatient Veterans (NCT03254719), a na na study. The primary outcome is Duration of Study Recruitment.

2. Clinical Question

The study also aimed to assess whether outcomes could be collected at baseline and at weeks 3, 5, 7, and 10; to help select measures for a future randomized trial; and to estimate preliminary intervention effects and variability for future planning. Those aims describe feasibility and preparation for later research, rather than a controlled test of comparative effectiveness. The registry record does not report results for those secondary objectives.

3. Trial Design

This was a completed, single-group pilot trial sponsored by Palmer College of Chiropractic. The registry lists an enrollment of 40 and records the study start as 2018-02-19 and primary completion as 2018-11-05. The phase is listed as NA. Allocation is listed as NA, masking as NONE, and the study model as SINGLE GROUP. These design features mean that participants were not allocated between a chiropractic-care group and a concurrent control group, and the trial was not masked.

All participants were described as receiving chiropractic care consistent with usual chiropractic procedures for chronic low back pain at the Iowa City VA Health Care System. They were also asked to complete study assessments. The registry lists the intervention category as study assessments, while the arm description specifies the chiropractic care and assessments received. It does not describe a comparison intervention.

The pilot was intended to inform a future, appropriately powered, multisite randomized controlled trial. Its stated objectives included monitoring recruitment and data collection, evaluating the success of collecting outcome measures, selecting measures for future use, and obtaining preliminary estimates of effects and variability. These are planning and feasibility goals. They do not turn this single-group design into a randomized comparison, and within-person changes over time would not by themselves establish what would have happened without the intervention.

The registry lists 16 outcome measures and 0 analyses. A scheduled set of assessments is described at baseline and weeks 3, 5, 7, and 10, but the record does not provide a completed analysis plan or numerical results for those outcomes. The specific sample-size justification, statistical analysis plan, analysis populations, and any interim analyses are not reported in the registry record. The listed study status is COMPLETED; that status does not itself establish that every planned assessment was collected or analyzed.

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

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 Duration of Study Recruitment, measured over From date of first participant enrolled to date last participant is enrolled, up to 8 months..

The primary endpoint is the duration of study recruitment, measured in months. The registry defines the interval as running from the date the first participant was enrolled to the date the last participant was enrolled, with a stated timeframe of up to 8 months. Investigators planned to monitor recruitment, enrollment, and data collection through a data capture program.

This endpoint addresses an operational question: whether recruitment can be completed within the period relevant to planning a larger study. In general, recruitment duration can help investigators assess whether the target population can be reached and whether a future trial’s recruitment approach is workable. It does not measure pain relief, functional change, or mental health symptoms. Those subjects appear among the broader planned assessments, but they are not the stated primary endpoint in this record.

The registry record does not report the observed recruitment duration, the dates of first and last enrollment, or a numerical primary endpoint result. Although enrollment is listed as 40, that total does not reveal how long recruitment took. The record also does not report a threshold for judging recruitment successful or a statistical method for analyzing this endpoint. Therefore, the stated endpoint and its purpose can be described, but its observed value and whether it met a feasibility target cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Several statistical ideas help distinguish the purpose of this pilot from what its registry record can establish. The explanations below are general; they do not imply that a particular unreported method was used in the trial.

What does a single-group design estimate?

In a single-group study, observations come from participants receiving the same described intervention, rather than from separate treatment and control groups. Such a design can document recruitment, assessment completion, and outcomes over time. If repeated measurements are analyzed, the observed within-participant change describes how measurements differed across visits among those assessed. In general, that change alone does not isolate the effect of the intervention: without a concurrent comparator, other influences on outcomes remain possible. The registry classifies this trial as SINGLE GROUP and reports no randomized comparison.

What does the recruitment endpoint capture?

The primary endpoint is a duration: the time from first enrollment to last enrollment, expressed in months. This is a feasibility measure, not a symptom scale or treatment-effect contrast. In general, recruitment duration can inform operational planning, but interpretation depends on the recruitment goal and the criteria for success. The registry states a timeframe of up to 8 months, but does not report the observed duration or a success threshold. Enrollment of 40 is a separate reported fact and cannot substitute for the missing duration result.

How should preliminary estimates be understood?

The stated secondary objectives include determining preliminary intervention effect sizes and variability to aid sample-size planning for a future randomized trial. In general, estimates from a small pilot can be imprecise, especially when they are based on limited outcome data; variability in those estimates can affect later planning. A confidence interval, in general, describes a range of values compatible with the data and the method used, rather than guaranteeing that the true value lies within that particular interval. No effect estimates, variability estimates, or confidence intervals are reported in the registry record, so their magnitude and precision cannot be assessed.

The record includes a general planning assumption for sample-size illustrations: two-sided significance level 0.05, equal allocation between two arms, a normal approximation, and a target effect expressed as a fraction of an observed effect. These are planning assumptions, not a description of the actual single-group trial allocation. A planning illustration estimates participants per arm for a future comparison under specified assumptions; it is not the number observed in this trial and is not observed power. Because the record reports 0 analyses and no numerical effect estimate, there is no posted observed effect from which to judge a trial-specific planning calculation. The sample-size justification for this pilot is not reported in the registry record.

Why do outcome measures and analysis plans matter?

The record lists 16 outcome measures and multiple domains, including disability, pain, self-efficacy, and mental health screening. In general, defining outcomes and analysis methods in advance helps clarify which question each measure addresses and how results will be interpreted. When many measures or time points are considered, the chance of finding at least one apparently notable result can increase if all are treated as independent opportunities to test a hypothesis. A prespecified multiplicity strategy can address that issue, but no such strategy is reported in the registry record. The number of listed measures alone does not show how many were analyzed, and the record lists 0 analyses.

In general, repeated measurements from the same person are related rather than independent. An analysis that uses several visits should account for that structure if it is intended to estimate change across time. Missing assessments can also affect interpretation: results from participants who complete follow-up may differ from results that would have been seen had all enrolled participants completed every visit. The registry identifies planned assessments at baseline and weeks 3, 5, 7, and 10, but does not report a method for handling repeated measurements or missing data.

What do the safety counts tell us?

Counts of participants with events are descriptive summaries. In general, they do not establish whether an event was caused by an intervention, and counts from a single group cannot provide a comparative safety estimate against a control group. The registry reports 40 at risk for both serious and other adverse events, with 0 affected by serious events and 5 affected by other events; deaths are listed as 0. It does not report the event definitions, collection period, or relatedness assessments. The posted numbers can be stated, but the available information does not support more detailed statistical interpretation.

In general, uncertainty is important even when a reported count is zero: an observed zero is not proof that an event could never occur. The record does not provide an interval estimate or a detailed account of surveillance, so the precision and scope of the safety summary cannot be quantified. This is particularly relevant when reading pilot data, whose role is to inform later study planning rather than to settle comparative questions.

10. Multiplicity, Missing Data and Analysis Populations

The record lists 16 outcome measures and describes assessment collection at baseline and weeks 3, 5, 7, and 10. The measures span different domains, including low back pain disability, pain assessment, self-efficacy, and mental health screening. Considering multiple outcomes and visits can create multiplicity: in general, the more statistical questions examined, the greater the chance that at least one result appears notable by chance. Investigators may address multiplicity by identifying a primary question in advance, adjusting inference, or treating secondary findings as exploratory. The registry record does not report a multiplicity strategy. It lists 0 analyses, so there are no posted outcome tests to interpret for multiplicity.

The record describes assessment collection as an objective but does not report how many participants completed each instrument or visit. It does not report missing-data amounts, reasons for missing assessments, or a method for handling missing observations. In general, incomplete follow-up can affect estimates when completion is related to participant characteristics or outcomes. Without completion counts and an analysis approach, the extent and possible consequences of missing data cannot be judged.

The analysis populations are also not reported in the registry record. It does not specify whether analyses were planned for all enrolled participants, for participants with available measurements, or for another defined group. Nor does it describe how participants who withdrew or missed visits would be treated analytically. The record’s enrollment of 40 should not be read as confirmation that 40 participants contributed data to every outcome.

The stated pilot objectives include evaluating success of outcome collection and informing outcome selection for a future trial. Those objectives make collection completeness relevant, but the registry record does not provide the results needed to evaluate it. A statistical analysis plan, prespecified handling of multiple outcomes, missingness, and analysis populations is not reported in the registry record.

11. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists 40 participants at risk for serious adverse events and 0 affected by a serious adverse event. It lists 40 at risk for other adverse events and 5 affected by other adverse events. Deaths are listed as 0, and no serious adverse-event terms are listed.

These are descriptive counts within the single treatment group. They do not compare the frequency of events with a control group, because no concurrent comparator is reported. The counts also do not establish whether events were caused by chiropractic care. The registry record does not report event descriptions, timing, severity, duration, relatedness, or the criteria used to classify serious and other adverse events.

In general, a zero count means that no affected participants were recorded in the specified category in the posted data; it does not prove that the risk is absent. The record does not provide an uncertainty interval or further information about how safety events were monitored. The five participants with other adverse events should not be interpreted as five events, since the posted figure is a count of affected participants. The available safety information supports only a narrow reading of the recorded counts.

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

The trial’s principal contribution, as described in the registry, is its pilot focus: testing the feasibility, safety, and acceptability of an integrative care pathway that includes chiropractic care for Veterans with chronic low back pain, with attention to mental health comorbidity. It also aimed to examine outcome collection and inform the choice of measures and planning for a future multisite randomized trial. These objectives are relevant to the design of subsequent research, but the stated aims are not results.

The registry identifies the study as completed and records enrollment of 40. It reports no primary recruitment-duration result and lists 0 analyses. Therefore, the posted information does not show whether recruitment was completed within the stated timeframe, whether assessments were successfully collected, or what changes occurred in pain, disability, or mental health measures. Planned assessment schedules and a list of instruments cannot substitute for analyzed outcome data.

The single-group design also limits causal interpretation. In general, if participants’ measurements change over time, that pattern cannot alone distinguish the intervention’s contribution from other possible influences. The record reports no randomized control group or masking. Accordingly, this trial cannot establish a comparative treatment effect from the information posted.

The reported safety counts are limited to 0 affected by serious adverse events, 5 affected by other adverse events, and 0 deaths among 40 participants at risk. The record lacks event details and a comparison group, so those counts should not be treated as a full comparative safety assessment.

The findings do not establish that chiropractic care is effective or ineffective, nor do they resolve whether a larger trial is feasible. The registry record does not report the data needed to answer those questions. It documents the intended pilot questions, design, enrollment, and selected safety counts; stronger conclusions require reported outcome analyses and, for comparative effects, an appropriate comparison design.

13. Why This Trial Matters Statistically

Pilot trials can be statistically useful even when their principal aims are operational rather than confirmatory. In general, recruitment experience, assessment completion, acceptability, and preliminary measurement variability can help investigators decide how to organize a later trial. This study’s stated purpose was to prepare for an appropriately powered multisite randomized controlled trial, and its primary endpoint focused on recruitment duration. That places feasibility at the center of the design rather than a direct comparison of clinical outcomes.

The range of planned measures is also relevant to future design. The registry lists 16 outcome measures and includes assessment of disability, pain, and mental health-related domains. Determining whether measures can be collected at the planned visits may help shape a later protocol. However, the registry record does not report collection success, measurement results, or the analyses that would allow readers to assess those aims.

Statistically, the single-group structure matters. Without a concurrent control condition, outcome changes cannot be separated from other time-related influences. A future randomized comparison could address a different question by estimating between-group differences, subject to its own design and analysis. The current record does not report results that quantify an intervention effect or its uncertainty, so it cannot serve as a numerical basis for judging such a difference.

The record’s completion status and enrollment total describe trial conduct at a broad level, while the absence of a reported recruitment-duration value leaves the primary feasibility result unresolved. Likewise, safety counts are informative as a narrow descriptive record but lack details needed for comparative interpretation. The statistical value of this trial is therefore best understood through its stated role in planning: it identifies the feasibility and outcome questions investigators intended to address, but the posted results do not show their answers.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations specific to the information in this registry record constrain interpretation. First, the primary endpoint is recruitment duration, but its observed value is not reported. The record gives a timeframe of up to 8 months, yet does not report first- and last-enrollment dates or whether recruitment met a defined target. The listed enrollment of 40 does not resolve that gap.

Second, the design is single-group, with no randomized allocation, masking, or concurrent comparator reported. This limits what can be inferred about treatment effects and prevents a direct comparison with an alternative condition. The stated emphasis on mental health comorbidity does not establish how many participants had any particular comorbidity; those counts are not reported in the registry record.

Third, although 16 outcome measures are listed and assessments were planned at baseline and weeks 3, 5, 7, and 10, the registry lists 0 analyses. It does not report outcome values, completion by visit, missing-data handling, analysis populations, or multiplicity methods. As a result, neither clinical changes nor the success of outcome collection can be assessed from the posted information.

Finally, the safety summary gives counts but not event descriptions, timing, severity, relatedness, or collection procedures. No serious adverse-event terms are listed. These omissions limit interpretation of the counts and do not permit a comparative safety assessment. The statistical analysis plan and the sample-size justification for this pilot are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Care Outcomes for Chiropractic Outpatient Veterans — NCT03254719.
• Registry record last updated 2020-05-18; status last verified 2020-05.
• Results first posted 2020-05-18.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry identifies NCT03254719 as the Care Outcomes for Chiropractic Outpatient Veterans Aim 3-pilot Trial, sponsored by Palmer College of Chiropractic. It is listed as COMPLETED, with enrollment of 40, a start date of 2018-02-19, and primary completion on 2018-11-05. The study model is single group, with allocation listed as NA and masking as NONE.

Participants received chiropractic care consistent with usual procedures for chronic low back pain at the Iowa City VA Health Care System and were asked to complete study assessments. The primary endpoint was recruitment duration in months, from first to last enrollment, within a stated timeframe of up to 8 months. The registry lists 16 outcome measures and 0 analyses. The recruitment result and clinical outcome analyses are not reported in the registry record.

The safety record lists 0 participants affected by serious adverse events, 5 affected by other adverse events, and 0 deaths among 40 at risk. These counts have no concurrent control comparison.