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 Test of the Safety, Effectiveness, & Acceptability of An Improvised Dressing for Sickle Cell Leg Ulcers in the Tropics (NCT04479618), a randomized na study. The primary outcome is Number of Participants Who Experienced a Wound Complication (A Measure of Dressing Safety).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04479618 |
| Phase | NA |
| Condition | Sickle Cell Leg Ulcer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 48 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Benskin, Linda, PhD, RN, SRN (Ghana), CWCN, CWS, DAPWCA |
| Results posted | Yes |
2. Clinical Question
Population
People with sickle cell leg ulcers were the target population. The registry description says patients were to be recruited from three adjacent parishes and presented at UHWI, Mona. The posted enrollment is 48. The number of people meeting the full eligibility criteria and the detailed eligibility criteria are not reported in the registry record.
Intervention
The experimental option was an improvised dressing made using a cut-to-fit food-grade plastic material. The study description frames this as an economical dressing option and says the trial would assess safety, effectiveness, acceptability, pain, and quality of life. The complete intervention instructions are not reported in the registry record.
Comparator
The negative control was usual practice at UHWI, described as saline-soaked gauze covered with dry gauze and held in place with stretch gauze. The positive control was an advanced polymeric membrane dressing. The registry describes a three-arm, randomized comparison of these approaches.
Primary question
The primary endpoint was the number of participants who experienced a wound complication during the intervention. The central question was whether complication counts differed between usual practice and either dressing option. The registry also lists wound-area change, closure, pain, quality of life, acceptability, time, and material costs as secondary outcomes.
3. Trial Design
The registry identifies this as a randomized, single-masked, parallel-group trial with three interventions: usual practice, improvised dressings, and advanced dressings. The study description calls it evaluator-blinded. The identity of the masked party, the randomization method, and the allocation ratio are not reported in the registry record.
The registry lists enrollment as 48 and status as completed. The recorded start date is 2021-07-06, and the primary completion date is 2021-11-20. The posted primary endpoint describes potential complications assessed at least weekly for 12 weeks. The wound-area endpoint was measured at baseline and week 12. The closure outcome was assessed weekly through the end of the 12 week study period, with verification 2 weeks later.
The posted primary outcome groups contain 16.0 participants in usual practice, 13.0 in the improvised-dressing group, and 11.0 in the advanced-dressing group. These are the group sizes attached to the reported results; the registry does not explain how they relate to the overall enrollment entry. The study description refers to an intended recruitment of the first 120 eligible patients, but the posted enrollment is 48. The reason for the difference is not reported in the registry record.
The study summary says results would be reported using descriptive statistics and ANCOVA. The actual analysis plan, including covariate choices and whether analyses followed randomized assignment, is not reported in the registry record. The phase is listed as NA.
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 | Usual Practice (Negative Control) | Improvised Dressings (Experimental) | Advanced Dressings (Positive Control) |
|---|---|---|---|
| STARTED | 18 | 14 | 16 |
| COMPLETED | 16 | 13 | 11 |
| NOT COMPLETED | 2 | 1 | 5 |
Reasons for not completing this period:
| Reason | Usual Practice (Negative Control) | Improvised Dressings (Experimental) | Advanced Dressings (Positive Control) |
|---|---|---|---|
| Agreed to randomization, but withdrew when it did not lead to assignment to Group 2 | 1 | 0 | 1 |
| Lack of Efficacy | 1 | 0 | 0 |
| No reliable phone and unable to come in weekly | 0 | 1 | 1 |
| Unable to comply with protocol due to physical disability plus social isolation (no assistance) | 0 | 0 | 1 |
| Intellectually disabled; caregivers neglected to follow protocol | 0 | 0 | 1 |
| Emotionally unstable; (e.g.,data unreliable - completed four weeks' forms on day they were received) | 0 | 0 | 1 |
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 | Usual Practice (Negative Control) | Improvised Dressings (Experimental) | Advanced Dressings (Positive Control) | Total |
|---|---|---|---|---|---|
| Participants analysed | 16 | 13 | 11 | 40 | |
| Age, Continuous | years | 37.4 (23 to 49) | 44.2 (25 to 61) | 47.9 (29 to 64) | 42.15 (23 to 64) |
| Sex: Female, Male: Female | Participants | 7 | 3 | 6 | 16 |
| Sex: Female, Male: Male | Participants | 9 | 10 | 5 | 24 |
| Race/Ethnicity, Customized: Jamaicans of West African descent | Participants | 16 | 13 | 11 | 40 |
| Region of Enrollment: Jamaica | participants | 16 | 13 | 11 | 40 |
| Initial age of open Sickle Cell Leg Ulcer (SCLU), in weeks | weeks | 402 (5 to 1560) | 438 (17 to 2040) | 363 (6 to 1560) | 403 (5 to 2040) |
| Initial depth of study SCLU | millimeters | 3.94 (1 to 9) | 5.54 (2 to 10) | 4.09 (1 to 8) | 4.50 (1 to 10) |
| Initial area of study SCLU | centimeters squared | 43 (0.9 to 198) | 50.7 (1.7 to 304) | 42 (1.2 to 158) | 45.2 (0.9 to 304) |
| Mid-arm circumference indicates moderate malnutrition | Participants | 7 | 2 | 6 | 15 |
| Initial Wound Quality of Life Scores | units on a scale | 29.875 (5 to 61) | 41.385 (22 to 63) | 42.45 (6 to 63) | 40.825 (5 to 63) |
| ASCQ-Me baseline scores: Baseline ASCQ-Me Sickle-Cell Related Health History Scores (higher is worse) | units on a scale | 19.9 (1 to 30) | 23.8 (1 to 30) | 19.3 (8 to 30) | 21.0 (1 to 30) |
| ASCQ-Me baseline scores: Baseline ASCQ-Me weekly domain score totals (raw scores, not converted to t-scores) (Lower is Worse) | units on a scale | 85.2 (56 to 119) | 82.4 (38 to 110) | 78.0 (45 to 121) | 82.3 (38 to 121) |
| Social isolation (lives alone without nearby support) | Participants | 1 | 1 | 1 | 3 |
| Use of nicotine (e.g., smoking) in past week (yes/no) | Participants | 3 | 2 | 2 | 7 |
| Education level, in years | years | 11 (6 to 13) | 11 (9 to 16) | 9 (2 to 12) | 10.3 (2 to 16) |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Who Experienced a Wound Complication (A Measure of Dressing Safety), measured over During the intervention, potential complications were assessed for presence at least weekly for 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants who experienced a wound complication. The registry describes possible complications including suspected infection, healing-impairing maceration, and wound deterioration. When a complication was suspected, dressings were to be removed and the ulcer evaluated by medical staff blinded to treatment group. Participants and families were also asked to report delayed complications noted within 3 months of study completion.
A participant count is a binary-outcome summary at the individual level: each participant either experienced a complication or did not, according to the endpoint definition. The count is useful for comparing safety signals across randomized groups, while the group size provides the context needed to interpret that count. It does not describe how severe a complication was, how long it lasted, or whether complications differed in type unless those details are separately reported.
The registry says all observed complications were mild pseudomonas infections and resolved with dilute vinegar for fewer than two weeks. This endpoint therefore captures observed wound complications during the specified follow-up process; it is not a complete measure of every possible safety concern or of longer-term outcomes beyond the stated reporting period.
7. Results Posted in the Registry
- Improvised Dressings (Experimental): 0.0% (0/13) versus 25.0% (4/16) on control; risk difference -25.0 percentage points (95% CI -46.2 to -3.8); unadjusted two-proportion z-test p = 0.052.
- Advanced Dressings (Positive Control): 0.0% (0/11) versus 25.0% (4/16) on control; risk difference -25.0 percentage points (95% CI -46.2 to -3.8); unadjusted two-proportion z-test p = 0.072.
Risk difference: Improvised Dressings (Experimental)
95% CI: -46.2 to -3.8 percentage points
Recalculated from the posted summary statistics
8. Secondary Efficacy Endpoints
The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.
| Secondary outcome | Type | Effect measure | Estimate (95% CI) | Planning size, 80% power |
|---|---|---|---|---|
| Percent Change in Wound Surface Area From Baseline (A Measure of Effectiveness) | Continuous Endpoint | Mean difference | -24.16 (-55.88 to 7.56) | 60 per arm |
| Number of Participants Whose Wound Closed in 12 Weeks | Binary Endpoint | Risk difference | -6.2 pts (-18.1 to 5.6) | n/a |
Percent Change in Wound Surface Area From Baseline (A Measure of Effectiveness)
- Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
- Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
- Result:
- Improvised Dressings (Experimental): mean -25.81 versus -1.65 on control; difference -24.16 (95% CI -55.88 to 7.56), standardized effect d = -0.52; z-test p = 0.135.
- Advanced Dressings (Positive Control): mean -36.07 versus -1.65 on control; difference -34.42 (95% CI -73.56 to 4.71), standardized effect d = -0.64; z-test p = 0.085.
- Interpretation:
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Improvised Dressings (Experimental) and the control. The interval gives the range of effects that remain compatible with the data.
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Advanced Dressings (Positive Control) and the control. The interval gives the range of effects that remain compatible with the data.
Number of Participants Whose Wound Closed in 12 Weeks
- Endpoint type: Binary: the number of participants with the event, compared as proportions.
- Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
- Result:
- Improvised Dressings (Experimental): 0.0% (0/13) versus 6.2% (1/16) on control; risk difference -6.2 percentage points (95% CI -18.1 to 5.6); unadjusted two-proportion z-test p = 0.359.
- Advanced Dressings (Positive Control): 18.2% (2/11) versus 6.2% (1/16) on control; risk difference 11.9 percentage points (95% CI -13.8 to 37.6), risk ratio 2.91 (0.30–28.28); unadjusted two-proportion z-test p = 0.332.
- Interpretation:
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Improvised Dressings (Experimental) and the control. The interval gives the range of effects that remain compatible with the data.
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Advanced Dressings (Positive Control) and the control. The interval gives the range of effects that remain compatible with the data.
The secondary outcomes broaden the trial’s scope beyond the primary safety endpoint. They include wound-area change, closure, dressing choice after study completion as a proxy for acceptability, material costs, time spent on dressing changes, persistent and procedural pain, and wound-specific quality of life. These outcomes describe different aspects of the experience and burden of wound care, so they need not move together or produce a single overall ranking of the dressing options.
The available numerical results suggest varied patterns rather than a uniform signal across outcomes. The wound-area group means are negative in all three arms, with considerable variation around those means. Closure counts also differ across the groups, but the comparison intervals are broad. These secondary observations do not remove uncertainty in the primary complication comparison, and they do not establish that one dressing is preferable across safety, healing, pain, acceptability, and resource use.
The registry record does not report values for every listed secondary outcome or analyses for the full set. The record lists 9 secondary outcomes, while numerical results are present for wound-area change and closure. Results for the other listed outcomes are not reported in the registry record. This limits any account of how the outcomes collectively relate to the primary result.
Secondary analyses also carry less weight when many outcomes or comparisons are examined without a reported multiplicity strategy. Unadjusted results do not account for the chance of finding apparently notable patterns among multiple comparisons. The registry does not report a prespecified hierarchy, multiplicity adjustment, or confirmatory analysis plan. The secondary findings are consequently best treated as descriptive and exploratory, with their own uncertainty and missing reporting clearly in view.
Secondary outcomes registered for this trial, for reference (only those above were recalculated):
- Percent Change in Wound Surface Area From Baseline (A Measure of Effectiveness)
- Number of Participants Whose Wound Closed in 12 Weeks
- Choice of Dressings After Study Completion (Which is a Proxy Measure for Dressing Acceptability)
- Total Materials Costs in US Dollars
- Average Number of Minutes/Week Spent Performing All Dressing Changes
- Change in Persistent Wound Pain: Faces Pain Scale - Revised (FPS-R)
- Procedural (Dressing Change) Wound Pain: Faces Pain Scale - Revised (FPS-R)
- Change in Patient Wound-specific Quality of Life: Wound-QoL Questionnaire
9. Statistical Interpretation
The primary outcome records 4.0 participants with a wound complication in usual practice, compared with 0.0 in the improvised-dressing group and 0.0 in the advanced-dressing group. The posted risk-difference estimates for each dressing group versus usual practice are -0.25, with confidence limits from -0.462 to -0.038. The unadjusted p-values are 0.052 for improvised dressings and 0.072 for advanced dressings.
In the direction used for these estimates, a negative risk difference indicates fewer observed complications in the dressing group than in usual practice. These results are a descriptive signal in favor of fewer recorded complications in the two dressing groups, but the numbers of events and participants are limited. The reported p-values do not meet the commonly used 0.05 threshold, while the reported confidence limits for the risk differences exclude zero. The confidence-interval method is not reported in the registry record, and the inferential results therefore should be read with that methodological information gap in mind rather than treated as a definitive resolution.
The observed event pattern does not establish that either dressing caused the difference. Randomization helps make groups comparable on average, but sparse events leave estimates sensitive to the outcomes of individual participants. The posted results also do not include an adjusted primary analysis or a reported analysis plan. Consequently, the primary endpoint supports a cautious account of what was observed, not a firm conclusion about comparative safety.
Other outcomes offer additional context but do not settle the primary question. Wound-area change and closure are relevant to healing, while pain, quality of life, acceptability, time, and costs address other dimensions of care. Results for only some of the listed secondary outcomes are present, and the registry does not report analyses for the full set. The available findings should therefore be interpreted as limited evidence from a small completed trial rather than as a comprehensive evaluation of the dressing options.
10. Statistical Methods Explained
What does randomization contribute?
Random assignment is intended to reduce systematic differences between treatment groups at the start of a trial. It supports a comparison of outcomes across assigned groups, but it does not guarantee that every characteristic is balanced, especially when group sizes and event counts are limited. The randomization sequence and allocation procedures are not reported in the registry record. The registry identifies the trial as randomized and parallel-group, so participants were assigned among the three dressing approaches rather than crossing between them as part of the stated design.
How should the complication counts be read?
The primary outcome is a count of participants who experienced a complication, not a count of every complication episode. The posted group results are 4.0 participants in usual practice, 0.0 in improvised dressings, and 0.0 in advanced dressings. A risk difference expresses the difference in event proportions between two groups. A negative estimate in these comparisons corresponds to a lower observed event proportion in the dressing group than in usual practice. The estimated risk difference is -0.25 for each comparison.
Because no complications were recorded in either dressing group, the estimates depend on a sparse event pattern. In general, sparse binary outcomes can produce uncertainty even when the observed groups look different. The point estimate describes the observed comparison, while inferential uncertainty reflects how much the result could vary under repeated sampling and the assumptions of the analysis. The registry record does not report the method used for the confidence intervals.
What do the p-values contribute?
A p-value describes how compatible the observed data are with a specified null model under the assumptions of the test; it is not the probability that the null hypothesis is true and does not measure the size or clinical importance of an effect. The unadjusted p-values for the primary comparisons are 0.052 and 0.072. They are not adjusted for the multiple outcomes and comparisons listed in the registry. The exact test or model used to obtain them is not reported in the registry record.
The p-values and confidence limits should be considered together. The reported confidence limits for the risk differences are -0.462 to -0.038 for both comparisons, whereas the unadjusted p-values are 0.052 and 0.072. Different methods can yield different inferential summaries, but the specific methods cannot be reconciled from the registry record because the confidence-interval and test procedures are not described. This makes it important to avoid treating any single inferential statistic as a complete account.
How do the continuous outcomes differ?
Wound-area change is reported as a mean percentage change with a standard deviation. A mean summarizes the group average, while the standard deviation describes variation among individual observations around that average. The posted mean changes are -1.647 for usual practice, -25.81 for improvised dressings, and -36.07 for advanced dressings. The standard deviations are 59.18, 23.63, and 44.47, respectively. The registry does not report an adjusted analysis of these results.
The comparisons give mean differences of -24.16 for improvised dressings versus usual practice and -34.42 for advanced dressings versus usual practice. Their confidence intervals extend from -55.88 to 7.556 and from -73.56 to 4.71, respectively. Both ranges include zero, so the displayed estimates are compatible with a range of differences that includes no group difference under the interval procedure used. The interval procedure is not reported. The reported unadjusted p-values are 0.135 and 0.085.
What do the planning illustrations mean?
The wound-area and closure results include planning illustrations based on fractions of the observed effects. These are hypothetical sample-size calculations, not estimates of power achieved by the completed trial. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect set to the stated fraction of the observed effect. The illustrations are not the trial’s original design justification, which is not reported in the registry record. They should not be read as evidence that the trial had a particular probability of detecting an effect.
For binary outcomes, a risk difference compares group event proportions; for continuous outcomes, a mean difference compares group averages. Each effect measure answers a different question and depends on the endpoint’s scale. The posted comparisons are unadjusted. The registry summary mentions ANCOVA as a planned reporting approach, but the actual covariate-adjusted results and full statistical analysis plan are not reported in the registry record.
11. Confidence Intervals and Precision
The primary risk-difference estimates are -0.25 for both dressing comparisons, and each reported confidence interval ranges from -0.462 to -0.038. These intervals communicate uncertainty around the estimated differences under the method used to construct them. They span a broad range of possible magnitudes, even though the entire reported range is negative. The registry does not identify the interval method, which limits assessment of its assumptions.
The primary endpoint is based on 4.0 observed complication cases in usual practice and none in either dressing group. With few events, a small change in the observed data could have a material effect on an estimate. The confidence interval is therefore important alongside the point estimate; the point estimate alone would give an overly definite impression.
Precision is also limited for wound-area change. The confidence interval for the improvised-dressing mean difference runs from -55.88 to 7.556, and the interval for the advanced-dressing comparison runs from -73.56 to 4.71. Both include zero and cover effects in either direction. The standard deviations indicate substantial variability in the observed wound-area changes, particularly in usual practice and the advanced-dressing group. The registry does not report adjusted estimates or the method used for these intervals.
The closure comparison for advanced dressings has a confidence interval for the risk difference from -0.138 to 0.376. That span includes no difference as well as differences in either direction. Taken together, these intervals show that the posted estimates do not determine a narrow range of comparative outcomes. The planning illustrations are separate hypothetical calculations, not a substitute for the uncertainty in the observed estimates.
12. Multiplicity, Missing Data and Analysis Populations
The registry identifies a primary safety outcome and a broad set of secondary outcomes, but it does not report a detailed statistical analysis plan. The study summary says results would use descriptive statistics and ANCOVA. The registry record does not specify which outcomes would use ANCOVA, which covariates would be included, how the three groups would be compared, or which comparisons were intended as confirmatory.
No multiplicity procedure is reported. Multiple outcomes and pairwise comparisons can increase the chance of apparently noteworthy findings when each is assessed separately. Unadjusted p-values do not control that overall chance. The posted primary p-values are unadjusted, and the registry does not say whether any correction or hierarchy was planned. Secondary comparisons should therefore be interpreted cautiously rather than as independent confirmatory tests.
The record does not report how missing outcome data were handled, whether all randomized participants were included in each analysis, or how participants with incomplete follow-up were treated. An analysis population, such as an intention-to-treat population, is not reported in the registry record. The posted group sizes differ by outcome in the available results; reasons for any outcome-specific differences are not reported.
The enrollment entry is 48, while the posted primary outcome groups contain 16.0, 13.0, and 11.0 participants. The record does not explain the relationship between the enrollment entry and the outcome-specific group counts. It also does not report participant flow, withdrawals, exclusions from analysis, or missingness by group. Without these details, the extent to which attrition or incomplete data could affect the comparisons cannot be assessed from the registry record.
The registry reports no analyses in its analysis listing. The numerical comparisons can be read as posted outcome summaries, but the record does not provide enough detail to verify the complete analysis process or determine whether the reported comparisons follow the planned model. This uncertainty is separate from sampling uncertainty and should be considered when interpreting the estimates.
13. 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 |
|---|---|---|---|
| Usual Practice (Negative Control) | 0 | 16 | 0.0% |
| Improvised Dressings (Experimental) | 0 | 13 | 0.0% |
| Advanced Dressings (Positive Control) | 0 | 11 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Usual Practice (Negative Control) | 0 of 16 |
| Improvised Dressings (Experimental) | 0 of 13 |
| Advanced Dressings (Positive Control) | 0 of 11 |
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 |
|---|---|
| Usual Practice (Negative Control) | 4 of 16 |
| Improvised Dressings (Experimental) | 0 of 13 |
| Advanced Dressings (Positive Control) | 0 of 11 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Usual Practice (Negative Control) | Improvised Dressings (Experimental) | Advanced Dressings (Positive Control) |
|---|---|---|---|---|
| Minor Pseudomonas infection | Skin and subcutaneous tissue disorders | 4 of 16 | 0 of 13 | 0 of 11 |
The serious adverse event figures list 0 serious events and 0 deaths in each group. The other adverse event counts are 4 in usual practice, 0 in improvised dressings, and 0 in advanced dressings. These counts are not a complete account of every possible safety outcome; they are the adverse-event figures recorded for the groups.
The registry separately reports 4 participants with a primary wound complication in usual practice and none in either dressing group. It describes all observed complications as mild pseudomonas infections that resolved with dilute vinegar for fewer than two weeks. The record does not report other serious adverse event terms.
Zero recorded serious events in a group does not establish that serious harms cannot occur. The group sizes are limited, and the follow-up described for the primary complication outcome was during the intervention, with delayed complications to be reported within 3 months of study completion. The figures should be read as observations in this trial, not as proof of absence of risk or as a comparison of all possible harms.
14. What the Result Does, and Does Not, Mean
The posted results describe fewer observed wound complications in the improvised- and advanced-dressing groups than in usual practice. The estimated risk differences are -0.25 for both comparisons, based on 4.0 complications in usual practice and 0.0 in each dressing group. Those observations are consistent with a possible difference, but the event counts are sparse and the unadjusted p-values are 0.052 and 0.072. The registry does not report enough methodological detail to resolve the difference between those p-values and the reported confidence intervals.
These findings do not show that either dressing caused the observed pattern, and they do not establish comparative effectiveness across all outcomes. The wound-area comparisons are imprecise, and the closure results are also uncertain. Several outcomes named in the registry, including pain, quality of life, acceptability, time, and costs, have no numerical results reported in the registry record.
The trial addresses a relevant clinical question in a particular setting: care for sickle cell leg ulcers in a tropical climate, with usual practice and an advanced dressing as comparators for an improvised option. Its completed status and posted outcome data make it possible to describe what was recorded. They do not make the available evidence comprehensive. The record does not report a full statistical analysis plan, missing-data handling, an analysis population, or participant flow.
The most defensible interpretation is therefore bounded: the observed complication counts favor the two dressing groups numerically, while uncertainty and limitations in reporting prevent a definitive comparative conclusion. The study does not establish that a dressing works or does not work, and its results alone do not support medical advice.
15. Why This Trial Matters Statistically
This trial illustrates why statistical interpretation needs more than a comparison of group averages or event counts. The primary outcome has a striking observed pattern: complications were recorded in usual practice and not in the two dressing groups. Yet sparse events make the size and stability of the estimated differences uncertain. A point estimate can be informative about the direction of the observed pattern without establishing a reliable effect.
The record also shows why estimates, confidence intervals, and p-values should be considered together. The risk-difference intervals are entirely negative, while the unadjusted p-values are 0.052 and 0.072. Without the test and interval methods, this difference cannot be fully evaluated. Clear reporting of methods is essential for readers to understand what each statistic represents and why inferential summaries may not align.
The trial also raises common design and reporting questions. It has three randomized arms, multiple outcomes, and planned use of descriptive statistics and ANCOVA, but the actual model details, multiplicity strategy, analysis population, and missing-data procedures are not reported in the registry record. Those details matter because they affect how comparisons should be interpreted, especially when outcome data are limited.
Finally, the range of outcomes reflects that wound care involves more than a single safety measure. Healing, pain, quality of life, acceptability, time, and cost can all matter, but incomplete outcome reporting prevents a full assessment of their joint pattern. Statistically, this makes transparent reporting of estimates and uncertainty as important as the initial trial design.
16. 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 posted primary outcome groups are small, and the complication comparisons are based on few observed events. This limits precision and makes the estimates sensitive to individual outcomes. The confidence limits for the primary risk differences are broad, and the registry does not identify the method used to calculate them.
The record gives a completed status and an enrollment entry of 48, but the reasons the posted primary outcome group counts do not account for that entry are not reported. Participant flow, withdrawals, exclusions, and missing outcome data are not described. As a result, the completeness of follow-up and the handling of participants without outcome data cannot be assessed.
The study was conducted in the context described as Jamaica and UHWI, Mona, with recruitment planned from three adjacent parishes. The registry does not report site-level results or enough information to assess how well the results apply to other settings. The complication follow-up is described during the intervention, with delayed events requested within 3 months of study completion; longer-term outcomes are not reported.
The registry lists a broad set of secondary outcomes, but numerical findings are available for only wound-area change and closure. Results for pain, quality of life, acceptability, costs, and dressing-change time are not reported in the registry record. The actual analysis plan, multiplicity handling, adjusted primary analysis, and missing-data procedures are also not reported. These are trial-specific limitations on interpretation, in addition to the uncertainty inherent in the observed estimates.
17. Related Tutorials
18. Related Statistical Calculators
19. Sources
- ClinicalTrials.gov: Test of the Safety, Effectiveness, & Acceptability of An Improvised Dressing for Sickle Cell Leg Ulcers in the Tropics — NCT04479618.
- Registry record last updated 2023-09-28; status last verified 2023-09.
- Results first posted 2023-09-13.
- 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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20. Record Summary
The registry record describes a completed, randomized, single-masked, parallel-group trial comparing usual practice, improvised dressings, and advanced dressings for sickle cell leg ulcers. Enrollment is listed as 48. The primary endpoint counts participants with wound complications during the intervention, assessed at least weekly for 12 weeks.
The posted primary results record 4.0 participants with complications in usual practice and 0.0 in each dressing group. The estimated risk differences versus usual practice are -0.25 for both comparisons, with unadjusted p-values of 0.052 and 0.072. The record also gives numerical results for wound-area change and wound closure, but not for all listed secondary outcomes.
The record does not report a complete statistical analysis plan, multiplicity approach, missing-data handling, or analysis population. The observed pattern is informative but remains uncertain and incomplete.