Non-Opioid Pramipexole and Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Non-Opioid Pramipexole and Pain (NCT03842709), a randomized early/phase 1 study. The primary outcome is Brief Pain Inventory Score.

2. Clinical Question

The clinical question concerns an add-on treatment comparison, rather than a comparison of pramipexole with no pain care. Both groups are described as receiving standard treatment or routine care; the difference between the assigned arms is pramipexole versus placebo. The listed primary outcome is a Brief Pain Inventory score, described in the record as capturing the self-reported effect of pain on quality of life and pain severity at its worst on a 0-10 scale, with 10 representing worst pain.

The registry record gives an arm mean and standard deviation for each group, with 3 participants reported in each primary-outcome arm. It does not report a comparative estimate, confidence interval, or statistical test for the primary outcome. It also does not make clear whether the posted means represent endpoint scores or a change from baseline, although the outcome description refers to change in self-reported effect of pain on quality of life. The record therefore supports a description of the posted group summaries, but not a definitive estimate of the treatment contrast or its precision.

3. Trial Design

The registry describes a randomized, triple-masked, parallel trial, with an early phase 1 designation. The recorded enrollment is 13, and the status is completed. The trial was sponsored by the University of New Mexico. Its recorded start date is 2019-05-01 and its primary completion date is 2020-01-31.

The clinical arms compare standard treatment plus placebo with standard treatment plus pramipexole. Both descriptions refer to patients reporting sub-optimal results of pain therapy, and both retain routine care. The trial therefore assesses pramipexole as an addition to existing care, not as a replacement for it. The registry identifies pramipexole as an oral tablet intervention.

Enrollment and outcome denominators should be distinguished. Although the overall enrollment is recorded as 13, the primary outcome summaries list 3 participants in each arm. The registry record does not explain the relationship between the enrollment figure and these outcome counts. It does not report reasons for non-inclusion in the primary outcome summaries, withdrawals, or the number assessed at each time point. No further eligibility criteria or details of routine care are reported in the registry record.

The trial description also sets out a mechanistic research program involving inflammatory pathways and immune-cell measures. The brief summary describes aims involving NLRP3 and cytokines, including IL-1β, IL-6, TNF-α, and IL-10, as well as a proposed later phase focused on clinical pain. These stated aims provide context for the research rationale; they are not themselves evidence that the proposed biological effects occurred. The registry lists mRNA Results IL-1b as a secondary outcome, but numerical secondary-outcome results are not reported in the registry record. Allocation concealment procedures, the specific masking roles, treatment duration beyond the primary outcome timeframe, and the detailed statistical plan are not reported in the registry record.

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

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: 2 participants at enrollment did not complete the Pain Inventory questionnaire, and were withdrawn from the study very early in the study.

6. Primary Endpoint

The registry lists the primary outcome as Brief Pain Inventory Score, measured over 4 weeks.

The primary outcome is titled Brief Pain Inventory Score, with a timeframe of 4 weeks. The registry describes the measure as assessing change in the self-reported effect of pain on quality of life and says that the Brief Pain Inventory, Short Form, will be used. The description also refers to pain severity at its worst, recorded on a 0-10 scale, where 10 is worst pain.

A patient-reported pain measure is relevant because pain and its effect on daily life are experienced by the patient and cannot be fully characterized by a biological assay alone. A standardized questionnaire can make reports more structured and can support comparisons across participants and treatment groups. These are general reasons for using patient-reported outcomes; they do not establish that a particular questionnaire result is free of measurement error or that a change is clinically important.

The record describes the primary endpoint as a change, but the posted arm summaries are labeled as mean scores and do not identify a baseline value or explicitly state that the reported figures are changes from baseline. The registry record gives a mean of 8.0 with a standard deviation of 1.0 for standard treatment plus placebo, and a mean of 6.7 with a standard deviation of 3.2 for standard treatment plus pramipexole. It does not provide a treatment contrast, confidence interval, or test for the primary outcome. The record also does not report a threshold for interpreting a meaningful change. As a result, the posted summaries describe the reported scores but do not establish the size or precision of a change attributable to assignment.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean describe?

For a continuous outcome, the mean is the arithmetic average of the recorded values in a group. It gives a compact description of the group’s central value, but it does not show the full distribution. Different sets of participant scores can have the same mean while differing in how values are spread or in whether a few observations have substantial influence. The posted means are 8.0 for standard treatment plus placebo and 6.7 for standard treatment plus pramipexole. Because each summary lists 3 participants, the mean in either arm may be sensitive to the particular observations included.

The endpoint is described on a scale where 10 is worst pain. That direction helps interpret the scale itself: higher scores correspond to worse reported pain severity according to the outcome description. It does not settle whether the posted group values represent follow-up scores or changes from baseline. The registry record does not clarify that point, and it does not provide baseline values alongside the posted summaries.

What does the standard deviation add?

The standard deviation describes the spread of individual observations around a group mean. It is not a measure of how precisely the mean estimates a broader population value, and it is not a confidence interval. The reported standard deviations are 1.0 in the placebo arm and 3.2 in the pramipexole arm. The latter group’s scores are more dispersed in the posted data. When groups are small, estimates of both the mean and the spread can be unstable. A standard deviation alone does not show whether variation reflects treatment response, baseline differences, measurement fluctuation, or other factors.

A general statistical distinction is useful: the standard deviation describes participant-to-participant variation, while the standard error describes uncertainty in an estimated mean or contrast. A confidence interval is generally built from an estimate and its uncertainty, along with assumptions about the sampling process and analysis method. The registry record does not report standard errors or confidence intervals for this primary endpoint. No interval should be inferred from the means and standard deviations alone without additional assumptions and a defined analysis.

Why is a direct comparison needed?

The clinical question is comparative: it concerns assignment to pramipexole rather than placebo when both are added to routine care. Separate group means are not the same as a treatment-effect estimate. A direct analysis would specify the quantity being compared, such as a difference in follow-up scores or a difference in change from baseline, and would account for the trial’s analysis population and outcome data. The registry record does not report such an estimate. It also flags the continuous two-arm comparison as not estimable for the posted data, so no recalculated contrast is available.

In general, a confidence interval around a treatment contrast communicates both the estimated direction and the precision of that contrast. A p-value, when used, addresses compatibility with a null hypothesis under the assumptions of the chosen test; it does not quantify clinical importance or prove that a hypothesis is true or false. Neither a p-value nor a confidence interval for the primary comparison is reported in the registry record. These omissions prevent a formal assessment of statistical uncertainty from the posted summaries.

Why can unequal variation matter?

In general, statistical methods for comparing continuous outcomes may rely on assumptions about how observations vary within groups. When group variability differs, a method that assumes equal variances may give an inaccurate estimate of uncertainty. Methods that accommodate unequal variance are available, but choosing among them requires information about the outcome, analysis plan, and data structure. The observed standard deviations differ, but the small group counts make the spread estimates themselves uncertain. The registry record does not identify the test or model used for the primary comparison, or report an adjusted analysis. It would therefore be inappropriate to claim that a particular variance assumption was used or that a particular alternative analysis would be definitive.

What does the randomization tell us?

Random assignment is intended, in general, to make treatment groups comparable on average with respect to factors measured and unmeasured at baseline. It does not guarantee that groups are balanced in a small trial, and it does not eliminate the need to report baseline information, follow-up, and the analysis population. The record identifies the design as randomized, triple-masked, and parallel. It does not specify the masking roles or provide details of the allocation procedure. The design description is informative, but it cannot substitute for reporting the realized data and the analysis used.

Masking can, in general, reduce the influence of knowledge about assigned treatment on care, reporting, or assessment. The registry calls the trial triple-masked but does not state which people or roles were masked, or how masking was maintained. No more specific inference about masking procedures is supported by the record.

What can planning calculations say?

Sample-size calculations are planning tools. In general, they estimate how many participants per arm might be required under stated assumptions about the target effect, variability, significance level, allocation, and power. Such calculations are not observed power and do not describe what the completed trial demonstrated. The registry record describes a planning illustration based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. It distinguishes participants per arm for continuous outcomes from total events for time-to-event outcomes. Numerical planning results are not reported in the registry record, so no participant requirement can be stated.

A planning calculation based on an observed effect also depends on that effect estimate, which may be imprecise in a small trial. It should be read as an illustration under assumptions, not as proof that the original design was adequately or inadequately powered. The registry does not report the trial’s own sample-size justification or design assumptions. Any planning illustration should remain separate from the interpretation of observed results.

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("Standard Treatment + Placebo", "Standard Treatment + Pramipexole")
n   <- c(3, 3)
m   <- c(8, 6.7)
sp  <- c(1, 3.2)
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  Standard Treatment + Placebo  3  8.000  1.000  5.516  10.484
CARM  Standard Treatment + Pramipexole  3  6.700  3.200  -1.249  14.649

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists mRNA Results IL-1b as a secondary outcome, alongside the primary Brief Pain Inventory outcome. It records 2 outcome measures and 0 analyses. Numerical secondary-outcome results and a statistical analysis plan are not reported in the registry record. The record therefore does not explain whether multiple outcomes or multiple comparisons were planned, which outcomes were considered confirmatory, or whether any adjustment for multiplicity was intended.

In general, testing several outcomes or comparisons can increase the chance of finding an apparently notable result by chance. Multiplicity procedures can address that issue, but their choice depends on the planned family of tests and the inferential goals. Without a reported plan or secondary analysis results, it is not possible to assess how multiplicity was handled. The mechanistic aims in the brief summary do not establish which analyses were planned or completed.

Missing-data handling is also not reported in the registry record. The overall enrollment is 13, while the primary outcome summaries list 3 participants in each arm. The record does not explain the differences among these reported counts, give reasons for missing observations, or describe any imputation or sensitivity analyses. It does not state whether the posted summaries are based on all randomized participants, participants who completed follow-up, or another analysis population. Those details matter because conclusions can depend on who contributed outcome data and how absent measurements were treated.

The primary endpoint description refers to change, but the record does not state whether the displayed values are change scores or follow-up scores, nor does it report baseline measurements. The timing is listed as 4 weeks, but the details of measurement availability and analysis are not reported in the registry record. These gaps limit both the interpretation of the endpoint and assessment of potential bias. No conclusion about the direction or size of missing-data bias can be drawn from the record.

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.

Most frequent non-serious adverse event terms

The adverse-event record reports no serious adverse events in either group. The serious-event risk set is 6 for standard treatment plus placebo and 5 for standard treatment plus pramipexole; the reported serious-event count is 0 in each group. The record reports no deaths in either group.

For other, non-serious adverse events, the risk set is 6 in the placebo group and 5 in the pramipexole group. The reported count is 0 with placebo and 1 with pramipexole. These are the counts as recorded; the registry record does not describe the event term, severity beyond the serious/non-serious grouping, timing, or whether the event was considered related to treatment. No top serious-event terms are listed.

Risk-set counts for safety differ from the primary-outcome counts, and the registry record does not explain the difference. These safety figures are descriptive. A count of zero serious events in a small recorded risk set does not establish that serious events cannot occur or that treatments have equivalent safety. Likewise, the single reported other adverse event does not establish a causal relationship to pramipexole. The record does not provide detail sufficient to assess event rates across the trial or compare safety with precision. These counts should be read as the reported observations, not as a comprehensive estimate of safety.

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

The registry record provides a description of a randomized, triple-masked, parallel trial of pramipexole added to standard treatment compared with placebo added to standard treatment. It reports a Brief Pain Inventory mean of 8.0 with a standard deviation of 1.0 for the placebo arm and a mean of 6.7 with a standard deviation of 3.2 for the pramipexole arm. The outcome description indicates that higher severity scores correspond to worse pain. The reported means are descriptive group summaries; the registry does not report a direct treatment contrast or its uncertainty.

That distinction is central. A difference between group summaries is not, on its own, an estimate with known precision, and the record does not provide a confidence interval or a statistical test for the primary comparison. It also does not clarify whether the posted values are endpoint scores or changes from baseline. The comparative question therefore cannot be answered with a precise effect estimate from the registry record. The recorded enrollment and outcome denominators are not reconciled, and details about missing outcomes and the analysis population are absent.

The results do not establish that pramipexole improves pain, nor do they establish that it has no effect. The registry’s brief summary describes hypotheses about inflammatory mechanisms and intended research aims, but those statements are rationale rather than outcome findings. The listed secondary mRNA outcome has no numerical result in the registry record. The safety counts describe reported events in the listed risk sets, but they are not sufficient to establish comparative safety.

More generally, a completed trial record can contain useful descriptive information while leaving uncertainty about the primary comparison. Interpreting a treatment effect requires a clearly defined estimand, a stated analysis population, an appropriate method, and an estimate accompanied by uncertainty. Those elements are not reported for this primary outcome. The appropriate reading is consequently limited: the record gives arm-level summaries and adverse-event counts, but it does not provide the analysis needed to quantify how the assigned treatments compare.

14. Why This Trial Matters Statistically

This trial is statistically notable because the record combines a randomized design with sparse reported primary-outcome summaries. Random allocation is a strength of the design in general, but the primary summaries list 3 participants per arm, and the overall enrollment is recorded as 13. The record does not explain how the outcome counts relate to enrollment. That makes transparent reporting of participant flow and analysis populations particularly important for interpretation.

The primary endpoint is patient-reported and continuous, and the registry reports both a mean and a standard deviation for each arm. Those summaries convey central value and observed spread, but they do not replace a direct comparative estimate. In this case, the registry record does not report a confidence interval, p-value, or specified analysis for the primary contrast, and the comparison is marked as not estimable from the posted data. The reader can describe the numbers but cannot assess the precision of a treatment comparison.

The trial also links a clinical pain outcome to proposed biological mechanisms involving inflammatory pathways. Statistically, this makes it important to distinguish stated aims from measured and reported results. The record names an IL-1b mRNA secondary outcome but does not report numerical results or analyses for it. Without those results and a multiplicity plan, the mechanistic rationale cannot be treated as confirmation of a biological effect.

The safety data likewise illustrate why denominators and event descriptions matter. The record lists risk sets that differ from the primary outcome counts and reports few adverse events, but it does not explain the denominator differences or provide event-level detail. Overall, the statistical importance of the record lies in showing both what can be described and what remains uncertain: group-level scores and safety counts are recorded, while comparative precision, outcome completeness, and analysis details are not reported in the registry record.

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 main limitation for interpreting the primary result is that the registry reports arm-level means and standard deviations but no direct comparison, confidence interval, or hypothesis-test result. The record also marks a continuous two-arm comparison as not estimable from the posted data. Thus, the numerical summaries do not quantify the uncertainty around a treatment contrast.

The endpoint description refers to change in self-reported pain impact, while the result fields report mean scores without identifying them as changes or follow-up values. Baseline scores are not reported. This ambiguity limits interpretation of what the posted means represent. The record also does not report a threshold for a clinically meaningful difference, so the practical importance of the observed summaries cannot be determined from the registry record.

The outcome counts are small as reported, with 3 participants listed in each arm, and the overall enrollment is recorded as 13. The registry record does not reconcile these figures or state why participants are absent from the outcome summaries. It does not report participant flow, withdrawals, missing-data methods, analysis populations, or sensitivity analyses. The adverse-event risk sets also differ from the primary outcome counts, without an explanation in the registry record.

Other limitations include the absence of baseline characteristics, details of the allocation procedure, the identities of the roles included in triple masking, and a detailed statistical analysis plan. The record lists a secondary mRNA outcome but gives no numerical secondary result and no analyses. It does not report the trial’s own sample-size justification. The mechanistic statements are research aims and hypotheses; the record does not show results that establish those mechanisms. These limitations constrain conclusions about comparative efficacy, precision, safety, and biological effects.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Non-Opioid Pramipexole and Pain — NCT03842709.
• Registry record last updated 2024-10-23; status last verified 2024-10.
• Results first posted 2024-10-23.
• 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 completed, randomized, triple-masked, parallel early phase 1 trial sponsored by the University of New Mexico. Recorded enrollment is 13. Patients reporting sub-optimal results of pain therapy were assigned to standard treatment plus placebo or standard treatment plus pramipexole.

The primary outcome is a Brief Pain Inventory score at 4 weeks. The registry reports a mean of 8.0 with a standard deviation of 1.0 for placebo and a mean of 6.7 with a standard deviation of 3.2 for pramipexole; each arm summary lists 3 participants. A comparative estimate and its precision are not reported, and the record does not clarify whether the posted scores are changes from baseline or follow-up scores.

The registry lists mRNA Results IL-1b as a secondary outcome but does not report numerical results or analyses for it. It reports no serious adverse events or deaths in either group, and one other adverse event in the pramipexole group. The registry record does not reconcile the different outcome and safety counts or report missing-data handling, analysis populations, or a detailed statistical plan.