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 Effect of Cannabis and Endocannabinoids on HIV Neuropathic Pain (NCT03099005), a randomized phase 2 study. The primary outcome is Phase 1 - Numerical Pain Rating Scale (NPRS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03099005 |
| Phase | Phase 2 |
| Condition | Cannabis, HIV Neuropathy, Pain Syndrome |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | Quadruple |
| Enrollment | 5 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Diego |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns people with HIV neuropathic pain. The registry record lists an enrollment of 5. It does not report additional eligibility details or a description of the participants’ baseline characteristics.
Intervention
Participants were assigned to sessions involving vaporized cannabis with different THC and CBD compositions. The low CBD session used 8 puffs containing 1.9% THC + 0.01% CBD. The medium CBD session used 4 puffs with that composition and 4 puffs containing 1.4% THC + 5.1% CBD. The high CBD session used 8 puffs containing 1.4% THC + 5.1% CBD.
Comparator
The sessions provide comparisons among the low, medium, and high CBD cannabis compositions. The registry record identifies a randomized crossover design but does not report the treatment sequence, washout interval, or specific planned pairwise comparisons.
Primary question
The listed primary outcome is the Numerical Pain Rating Scale, measured before study medication and 2 minutes after treatment. The record does not present one reduced comparison or numerical results for that outcome, so it does not establish how the pain ratings differed among the sessions.
3. Trial Design
The registry record describes a Phase 2, randomized, quadruple-masked crossover study sponsored by the University of California, San Diego. Enrollment is listed as 5, and the study status is completed. The record lists a study start date of 2018-07-01 and a primary completion date of 2022-12-31.
A crossover design means participants can receive more than one intervention condition, allowing comparisons across conditions within the same people. In general, this can help account for stable differences between participants. The record does not give the order in which the three sessions occurred, whether their order was randomized individually, or whether there was a washout period between sessions. Those details are important for understanding how the crossover was conducted and whether effects from one session could carry into another.
The three named conditions are Low CBD Session, Medium CBD Session, and High CBD Session. Each description specifies 8 inhaled puffs in the morning. The low session uses 1.9% THC + 0.01% CBD throughout; the high session uses 1.4% THC + 5.1% CBD throughout. In the medium session, 4 puffs use the low-session composition and 4 use the high-session composition. The record does not provide further details about the administration procedures or how session compliance was assessed.
Quadruple masking indicates that the record classifies the study as masked at four levels, but it does not identify which groups or roles were masked or explain how masking was maintained across products with different compositions. The protocol details, allocation procedures, and analysis plan are not reported in the registry record. Enrollment of 5 is a small basis for estimating differences, and the record does not report a sample-size justification.
The summary describes broader objectives involving acute effects of CBD/THC products, daily real-world cannabis use monitored with a text-messaging protocol called Individual Monitoring of Pain and Cannabis Taken (IMPACT), and relationships among cannabinoids, endocannabinoid biomarkers, and chronic neuropathic pain. The listed primary outcome and session descriptions concern the acute sessions; the record does not explain how the broader objectives relate to the enrollment and analyses reported for this study.
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
| Stage | Cannabis Administration Sessions |
|---|---|
| STARTED | 5 |
| Low CBD Session | 5 |
| Medium CBD Session | 5 |
| High CBD Session | 5 |
| COMPLETED | 5 |
| NOT COMPLETED | 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 | Cannabis Administration Sessions |
|---|---|---|
| Participants analysed | 5 | |
| Age, Continuous | years | 60 (SD 3.5) |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 4 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 |
| Race (NIH/OMB): White | Participants | 3 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Phase 1 - Numerical Pain Rating Scale (NPRS), measured over Pain is measured once before they receive study medication and then 2 minutes after drug treatment..
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Error |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The listed primary endpoint is the Phase 1 Numerical Pain Rating Scale (NPRS). It measures self-reported pain on a scale from 0 to 10: 0 indicates no pain, and 10 indicates the highest level of pain. The record says pain is measured once before participants receive study medication and again 2 minutes after drug treatment. It identifies the outcome parameter as a mean and the dispersion measure as a standard error.
A numerical rating scale gives participants a straightforward way to report pain intensity in a consistent format. Repeating the measure before and after a session can describe pain ratings at two time points. In general, a comparison of those measurements may be used to assess how ratings change over the specified interval, while comparisons across sessions can address whether recorded ratings differ among the cannabis compositions. The registry record does not specify which such comparison is the primary analysis.
A mean summarizes the central level of the ratings for a group or condition. In general, a standard error describes the precision of an estimated mean, rather than the range of individual ratings. It is not a substitute for showing the underlying variability between participants. The posted record does not give NPRS means, standard errors, confidence intervals, or a numerical treatment contrast. Therefore, the measurement and its timing are described, but the magnitude and precision of any observed difference are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically interpretable outcome—self-reported pain intensity—and gives its scale and measurement timing. Those details clarify what the endpoint is intended to capture: a rating before medication and a rating 2 minutes after treatment. They do not, on their own, indicate whether ratings changed or how ratings compared between sessions.
No single primary-outcome comparison is presented. The record indicates that the primary outcome has several categories or time points and is not reduced to one comparison. It also lists 0 analyses. As a result, there is no reported estimate of a difference among the low, medium, and high CBD sessions to interpret, and no reported confidence interval or p-value for a primary comparison. The record does not report the numerical NPRS results.
This distinction matters because a study question and a study result are different things. The intervention descriptions make clear which compositions were intended for the sessions, and the endpoint description identifies what was measured. A result requires an analysis that connects those measurements to a specified comparison. Without that analysis and its numerical estimate, the direction, magnitude, and precision of any difference cannot be assessed from the registry record.
The enrollment of 5 also calls for caution when considering how precisely any estimate might characterize a wider population. In general, estimates based on few participants can be sensitive to individual observations and may have substantial uncertainty. The record does not report a confidence interval or another measure of uncertainty for the primary endpoint, so the amount of uncertainty cannot be quantified from the listed results.
The crossover structure could support within-participant comparisons in general, because each participant may contribute data under multiple conditions. However, interpretation depends on the actual treatment sequence, the handling of repeated measurements, and the analysis approach. These details are not reported in the registry record. It would therefore be inappropriate to assume that the endpoint was analyzed with a particular paired, repeated-measures, or adjusted method.
The registry record lists secondary outcomes for Patient Global Impression of Change, the Von Frey Test, the Marijuana Subscale of the Addiction Research Center Inventory, and levels of the endocannabinoid biomarker Anandamide (AEA). Their names indicate additional areas of measurement, but the record does not provide numerical results or analysis estimates for them. The listed outcomes cannot substitute for a primary endpoint comparison that is not reported.
The safety figures describe adverse events by session, but those counts do not answer the primary pain question. Nor can the session counts be treated as independent groups: this is a crossover study, and the record does not say whether the same participants contributed to each session’s safety figures. The statistical interpretation is consequently limited to the design, measurement definitions, and descriptive safety counts that are explicitly listed.
9. Statistical Methods Explained
The registry record identifies the study as randomized, quadruple-masked, and crossover, and lists a continuous primary outcome reported as a mean with standard error. It does not report a statistical analysis plan, a fitted model, an adjustment strategy, or numerical estimates for the primary endpoint. The explanations below describe general statistical concepts; they do not establish which methods were used in this study.
What does a crossover design compare?
In general, a crossover study exposes participants to multiple conditions and compares measurements across those conditions. Because the same participant can contribute measurements in more than one condition, comparisons can account for some stable differences between people. A crossover analysis also needs to consider the order of treatments, changes over time, and possible carryover from an earlier condition. The registry record does not report the session sequence, washout interval, or a model addressing these issues. The design label alone does not identify the analysis used.
What does the mean describe?
A mean is an average of measured values and provides a summary of the central level of a continuous outcome. For the NPRS, it would summarize pain ratings on the specified 0-to-10 scale for a condition or time point. A mean alone does not show how individual ratings vary. In general, it is most informative when accompanied by a measure of uncertainty and a clearly defined comparison.
How should a standard error be understood?
In general, a standard error describes the precision of an estimated statistic, such as a mean. A smaller standard error indicates less sampling uncertainty for that estimate under the method used; it does not mean that participants’ ratings were similar to one another. A standard error is also not itself a confidence interval. A confidence interval combines an estimate with an uncertainty range to show values compatible with the data under the analysis assumptions. The registry record names the standard error as the dispersion measure but reports no value for it and no confidence interval for the NPRS.
Why does the comparison need to be explicit?
A result is interpretable only when the comparison is clear. For example, an analysis could contrast two session conditions at a particular time point, or compare pre-treatment and post-treatment ratings within a condition. These answer different questions. The record says the endpoint has several categories or time points and is not reduced to one comparison. It does not report which contrast, if any, was designated as the main inferential target. Without that definition, a reader cannot map an effect estimate to a specific question.
What does masking contribute?
Masking is intended, in general, to limit the influence of knowledge about assigned conditions on study conduct, outcome assessment, or reporting. The record labels the design quadruple-masked. It does not identify the four masked roles or say how masking was maintained when the cannabis compositions differed. The label therefore describes the registered design classification, but it is not enough to evaluate the masking procedures or their success.
How should planning illustrations be read?
Sample-size planning estimates are not observed study results and are not observed power. The planning assumptions described in the record use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. For time-to-event tables, the stated convention is total events; for other outcomes, it is participants per arm. These are general planning assumptions, not evidence that the crossover trial used a two-arm design or that its analysis followed those assumptions. No numerical planning estimates or sample-size justification are reported in the registry record.
In general, over-dispersion occurs when variability in data is greater than a model assumes. If present, it can make standard errors from an overly restrictive model too small and uncertainty appear narrower than it is. Whether over-dispersion is relevant depends on the outcome and analysis model. The registry record does not report a model for the NPRS or any diagnostic assessment, so there is no basis for saying that over-dispersion was assessed or affected the results.
More generally, a complete statistical account would identify the analysis population, outcome contrast, handling of repeated observations, missing-data approach, and uncertainty estimates. Those details are not reported in the registry record. The study’s design description and endpoint definition do not establish which analysis choices were made, and no specific model should be attributed to the study on the basis of the information listed.
10. Multiplicity, Missing Data and Analysis Populations
The registry record does not report how multiplicity was handled. Multiplicity can arise when several outcomes, time points, or treatment comparisons are examined. In general, testing many questions can increase the chance that at least one result appears unusual by chance. Statistical approaches may define a primary comparison in advance or adjust inference across a set of comparisons, but the record does not identify such a strategy.
The primary NPRS entry refers to multiple categories or time points and is not reduced to one comparison. The record lists 5 outcome measures and identifies several secondary outcomes, but it does not describe a hierarchy among them or state which analyses were intended to support formal inference. It lists 0 analyses. Accordingly, there is no reported basis for assessing the multiplicity of any outcome results.
Missing-data handling is not reported in the registry record. It does not state whether any NPRS measurements were missing, how missing observations were handled, or whether sensitivity analyses were planned. The enrollment figure of 5 does not establish how many participants contributed data to each outcome or session.
The analysis population is also not reported in the registry record. The record does not specify whether analyses were planned for all randomized participants, only participants with observed measurements, or another defined group. These omissions limit assessment of how representative any reported estimate would be, but no such primary estimate is listed. Interim analyses and stopping rules are not reported in the registry record either.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Low CBD Session | 0 | 5 | 0.0% |
| Medium CBD Session | 0 | 5 | 0.0% |
| High CBD Session | 0 | 5 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Low CBD Session | 0 of 5 |
| Medium CBD Session | 0 of 5 |
| High CBD Session | 0 of 5 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Low CBD Session | 3 of 5 |
| Medium CBD Session | 2 of 5 |
| High CBD Session | 2 of 5 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Low CBD Session | Medium CBD Session | High CBD Session |
|---|---|---|---|---|
| Dry Mouth | General disorders | 2 of 5 | 2 of 5 | 2 of 5 |
| Drowsiness | General disorders | 1 of 5 | 1 of 5 | 1 of 5 |
| Cognitive Impairment | General disorders | 1 of 5 | 0 of 5 | 0 of 5 |
The registry record lists serious adverse events for 5 participants at risk in each of the low, medium, and high CBD sessions. It records 0 participants affected by serious adverse events in each session. Deaths are listed as 0 in all three sessions. These figures describe the posted counts; they do not establish that no other safety outcomes occurred.
For other adverse events, the record lists 3 participants affected among 5 at risk in the Low CBD Session, 2 among 5 in the Medium CBD Session, and 2 among 5 in the High CBD Session. The record does not provide event terms for these other adverse events, their severity, timing, or whether they were judged related to treatment. It lists no top serious adverse-event terms.
Because the study is a crossover trial, participants may contribute to more than one session’s figures. The record does not explain whether the same people are represented across these session counts, so the counts should not be added or treated as independent groups. The small enrollment also means that these descriptive figures provide limited information about uncommon events. They are not a comparative safety analysis and do not establish a causal relationship between a session and an event.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, quadruple-masked Phase 2 crossover study was completed, with enrollment of 5 and three vaporized cannabis session compositions. It describes a pain rating collected before medication and 2 minutes after treatment, along with additional listed outcomes and descriptive adverse-event counts. These details clarify the study’s setting and measurement plan.
The record does not report numerical primary-outcome results or a single primary comparison. It therefore does not show the size or direction of any difference in pain ratings between session conditions, nor how precise such a difference might be. No conclusion about the primary pain outcome can be drawn from the design description alone.
In general, a result from a small crossover study may be informative about the measurements made in its participants, but its precision and broader applicability depend on the observed data, analysis, participant characteristics, and conduct of the study. The registry record does not report participant characteristics, the analysis model, confidence intervals, or missing-data handling. These gaps prevent assessment of those aspects of the evidence.
The safety entries report no serious adverse events or deaths in the listed session groups and list other adverse events for participants in each group. These counts are descriptive. They do not show whether events were related to cannabis, and they are not a substitute for a full safety analysis. Because the same participants may appear in multiple sessions, the session counts are not necessarily independent.
The appropriate interpretation is narrow: the record documents a study design, session compositions, endpoint definition, and safety counts, but it does not report an inferential result for the primary pain question. The absence of a reported comparison is not evidence that the sessions were equivalent or different. It means the registry record does not supply the result needed to judge that question.
13. Why This Trial Matters Statistically
This trial is statistically notable for combining a crossover structure with three intervention conditions and a small listed enrollment of 5. In general, a crossover design can compare measurements from the same participants across conditions, but it requires clear reporting of session order, timing, possible carryover, and the method used for repeated observations. Those details are not reported in the registry record, so the design label cannot by itself explain how the comparisons were analyzed.
The endpoint is also measured at two stated time points: once before study medication and 2 minutes after treatment. A clear analysis needs to distinguish a change over time within a session from a difference between session conditions. Since the registry record does not reduce the primary outcome’s several categories or time points to one comparison, readers cannot identify a single primary effect estimate to interpret.
These features illustrate why reporting the outcome definition is not enough. A useful statistical account also identifies the target comparison, estimate, uncertainty, analysis population, and handling of missing observations. With no primary analysis listed, it is not possible to assess whether the methods matched the crossover design or how precisely the pain ratings were estimated.
The safety counts offer another example of why design context matters. Participants may contribute observations under multiple session conditions, so the three sets of counts should not automatically be treated as independent groups. Clear reporting of participant-level overlap and event details would help readers understand what the counts represent.
More broadly, the record’s description of acute pain assessments sits alongside wider stated interests in daily cannabis use and endocannabinoid biomarkers. Separate questions require clearly identified outcomes and analyses. The listed registry information allows readers to distinguish those aims, but does not provide results for drawing statistical conclusions about them.
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 in interpreting this specific study arise from details not reported in the registry record. The enrollment is 5, but participant characteristics, eligibility criteria, and the number contributing observations to each outcome are not listed. Without these details, readers cannot judge the composition of the analyzed group or whether all enrolled participants contributed data to each session.
The session sequence, washout interval, and any precautions against carryover are not described. These are relevant to a crossover design because measurements in a later session can depend on the order or timing of earlier conditions. The masking label is given, but the roles masked and the procedures used to maintain masking are not reported.
The primary endpoint’s definition and measurement times are described, but the registry record does not give numerical NPRS results or a single comparison. It also does not report an analysis model, confidence intervals, missing-data methods, an analysis population, or a multiplicity strategy. The absence of these items means that the precision, robustness, and inferential interpretation of the primary outcome cannot be assessed from the registry entry.
Although the record describes broader objectives involving daily real-world cannabis use and endocannabinoid biomarkers, it does not explain their relationship to the listed acute sessions, enrollment, or analyses. The timing and methods for those objectives are not reported in the registry record. The record also does not provide detailed terms for other adverse events or an assessment of their relationship to treatment.
These limitations concern what can be evaluated from the registry record; they do not establish that the procedures or analyses were absent from the study itself. They do mean that the posted information is insufficient to independently assess the primary treatment comparison or the full safety profile.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effect of Cannabis and Endocannabinoids on HIV Neuropathic Pain — NCT03099005.
- Registry record last updated 2024-06-18; status last verified 2024-05.
- Results first posted 2024-06-18.
- 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.
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18. Record Summary
The registry record describes a completed, randomized, quadruple-masked Phase 2 crossover study sponsored by the University of California, San Diego. Enrollment is listed as 5. The study start date is 2018-07-01, and the primary completion date is 2022-12-31.
Three vaporized cannabis sessions are described, with low, medium, and high CBD compositions. The listed primary outcome is the Numerical Pain Rating Scale, measured before medication and 2 minutes after treatment, on a 0-to-10 scale. Secondary outcomes include Patient Global Impression of Change, the Von Frey Test, the Marijuana Subscale of the Addiction Research Center Inventory, and Anandamide (AEA) levels.
The record lists 0 analyses and does not report a single primary-outcome comparison or numerical NPRS results. Serious adverse events and deaths are listed as 0 in each session; other adverse events are listed for 3 participants in the low CBD session, 2 in the medium CBD session, and 2 in the high CBD session. Further details on analysis methods, missing data, participant characteristics, and session sequence are not reported in the registry record.