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 Gown and Glove Use to Prevent the Spread of Infection in VA Community Living Centers (NCT01350479), a registered phase not stated study. The primary outcome is MRSA Transmission.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01350479 |
| Phase | Phase not stated |
| Condition | Methicillin-Resistant Staphylococcus Aureus |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 203 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
Population
Residents of VA community living centers, classified as MRSA colonized if they had a history of MRSA in the past year, or not MRSA colonized if they did not. Health care workers interacting with residents were also part of the outcome measurement: their gowns and gloves were swabbed during care interactions.
Intervention
The registry describes a goal of determining when health care workers should wear gowns and wash their hands while caring for residents colonized with MRSA. It does not describe intervention assignments or a specific intervention arm in the posted group definitions.
Comparator
The listed groups are residents with and without a history of MRSA in the past year. They are not described as assigned treatment and control groups. Allocation is not stated, so this is not a like-for-like controlled comparison.
Primary question
How often were gown or glove swabs positive for MRSA when health care workers provided care to residents in the two colonization groups? The registry defines the measurement as MRSA presence on a gown or glove worn for research purposes during a specific type of care.
The study addresses a practical tension described in the registry: gowns, gloves and hand washing may help prevent spread, while their use may detract from the patient-centered, home-like environment prioritized in nursing homes. Its stated goal was to identify when protective practices are most important. However, the posted outcome compares swab measurements associated with resident colonization categories; it does not report a direct test of gown-use or hand-washing strategies.
The registry reports enrollment of 203. It does not provide a primary outcome result showing the proportion of positive swabs in either group, or an estimate of the difference between them. Consequently, the clinical question is identifiable, but the posted results do not establish how frequently swabs were positive or whether the groups differed.
3. Trial Design
The registry describes a completed study sponsored by the VA Office of Research and Development. The start date is 2012-10-01 and the primary completion date is 2016-01-15. Enrollment was 203. The condition listed is Methicillin-Resistant Staphylococcus Aureus.
The two listed groups represent resident MRSA history: “MRSA colonized” means a history of MRSA in the past year; “Not MRSA colonized” means no history of MRSA in the past year. The registry does not describe these as randomized treatment arms. Allocation is not stated, and the groups are not a like-for-like control comparison. Differences in swab results between them, if reported, would therefore be descriptive associations and could not by themselves establish an effect of a gown, glove or hand-washing strategy.
The primary outcome is titled MRSA Transmission and is expressed as the proportion of swabs positive for MRSA. Swabs were taken from gowns or gloves worn by an enrolled health care worker for research purposes while providing a specific type of care to an enrolled resident. The measurement period was described as 6-25 episodes of care interactions scheduled over the 30 days following resident enrollment. The registry does not state how many such episodes were completed or how many swabs were collected.
The record lists 1 outcome measure and 0 analyses. It does not report a statistical analysis plan, a primary outcome estimate, or a statistical comparison. The entry therefore supports a description of the intended measurement and study groups, but not a reconstruction of an inferential trial analysis. Details such as the number of participating centers, the method of selecting residents or health care workers, and the exact allocation or assignment process are not reported in the registry record.
Planning illustrations based on an observed effect should be kept separate from the study design and its findings. The stated assumptions for those illustrations are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These are described as planning assumptions, not as the trial’s design or its own sample-size justification. The sample-size justification is 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.
Before assignment: Three participants withdrew from the study prior to cultures being obtained and were not assigned to a study group.
Overall Study
| Stage | MRSA Colonized | Not MRSA Colonized |
|---|---|---|
| STARTED | 94 | 106 |
| COMPLETED | 94 | 106 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: We analyzed the number of gown and glove swabs from HCW interacting with MRSA and non-MRSA colonized residents.
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 | MRSA Colonized | Not MRSA Colonized | Total |
|---|---|---|---|---|
| Participants analysed | 94 | 106 | 200 | |
| Age, Continuous | years | 73 (SD 13) | 70 (SD 13) | 71 (SD 13) |
| Sex: Female, Male: Female | Participants | 2 | 6 | 8 |
| Sex: Female, Male: Male | Participants | 92 | 100 | 192 |
| Region of Enrollment: United States | participants | 94 | 106 | 200 |
6. Primary Endpoint
The registry lists the primary outcome as MRSA Transmission, measured over Will be measured during 6-25 episodes of care interactions scheduled over the 30 days following resident enrollment.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Proportion of swabs positive for MRSA |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the proportion of swabs positive for MRSA. Each swab was taken from a gown or glove worn by a health care worker while providing a specific type of care to an enrolled resident. The registry frames a positive result as the presence of MRSA on that protective clothing or equipment. Such a measure can indicate contamination during care interactions and is relevant to a study concerned with possible spread between residents.
This is an indirect measure of transmission. A positive gown or glove swab documents MRSA presence on the sampled item; it does not, by itself, show that MRSA was transmitted to another resident or that a resident developed an infection. Nor does the endpoint directly measure the effect of wearing gowns, gloves or washing hands, because the group definitions are based on residents’ history of MRSA rather than stated protective-practice assignments.
The registry says measurements were scheduled over 6-25 episodes of care interactions during the 30 days following resident enrollment. It does not report the number of completed episodes, the number of swabs, the number positive, or the proportions for the groups. It also does not describe how repeated swabs from the same worker or resident were handled statistically. Without those details and the outcome results, the endpoint’s intended meaning is clear, but its observed frequency and precision cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a measurable question: whether MRSA was present on health care workers’ gowns or gloves during care of residents with different MRSA histories. It does not report the primary outcome values. There is no posted number of positive swabs, group-specific proportion, contrast between groups, confidence interval, or p-value. The direction, size and precision of any observed association therefore cannot be described.
The groups are defined by residents’ prior MRSA history, not by random assignment to a preventive practice. The record also states that allocation is not given and that the groups are not a like-for-like control comparison. This limits causal interpretation. Even if group-specific swab proportions were available, a difference could reflect differences between the residents, their care interactions, health care workers or other circumstances, as well as any protective practices. The record does not provide an analysis that separates these possibilities.
The endpoint itself is a contamination measure. MRSA detected on a gown or glove indicates its presence on the sampled item during a specified care interaction. It is not equivalent to a documented transmission event or an MRSA infection in another resident. The study’s stated motivation concerns prevention and care practices, but the posted measurement alone cannot establish whether a practice prevented infection or transmission.
The registry reports 203 enrolled participants, but does not state how many contributed primary endpoint observations or whether all scheduled care episodes were completed. It describes the measurement schedule as 6-25 episodes over the 30 days after enrollment, without reporting the realized number of swabs. Thus the denominator underlying a proportion and the extent of missing outcome information are not available.
The entry lists 0 analyses. No statistical method, adjustment, uncertainty estimate or primary comparison is reported in the registry record. The absence of these results does not establish that there was no difference; it means the posted record does not permit an estimate of the difference or its uncertainty. Planning illustrations based on a stated fraction of an observed effect are not trial findings, and their assumptions are not evidence of observed power. The registry also does not report a sample-size justification for the study’s own design.
Accordingly, the defensible reading is limited: the record describes a study intended to characterize MRSA swab positivity on gowns and gloves across resident colonization categories, but it does not post the results needed to judge the observed pattern. The study’s stated motivation should not be mistaken for an outcome finding.
9. Statistical Methods Explained
What does the endpoint represent? A proportion describes the share of observations meeting a specified condition. Here, the condition is a gown or glove swab testing positive for MRSA. Its interpretation depends on the definition of the observation and on the denominator: a swab is the measurement unit, rather than a resident, infection or transmission event. The registry labels the unit as the proportion of swabs positive for MRSA and describes swabs taken during specific care interactions. It does not post the number of swabs collected or positive, so the proportion cannot be checked or interpreted for precision from the record.
As a general statistical point, the proportion summarizes observed frequency in the sampled interactions. It does not establish why an item was positive, whether MRSA moved between people, or whether a resident acquired infection. Those are distinct outcomes requiring their own definitions and evidence. A swab from a gown or glove is a useful proxy for contamination in the context of the stated research question, but it is not interchangeable with a clinical infection outcome.
Why does the group definition matter? The study’s listed groups classify residents by whether they had a history of MRSA in the past year. They are not presented as randomized groups receiving different prevention strategies. In a randomized comparison, assignment is intended to make groups comparable apart from the intervention, on average. Here, allocation is not stated, and the registry explicitly cautions that the groups are not a like-for-like control comparison. A contrast between colonization categories would therefore describe the observed groups; it would not automatically estimate the causal effect of gown use, glove use or hand washing.
General statistical interpretation also depends on the unit of assignment and unit of measurement. The endpoint is collected from gowns or gloves during care interactions, while the group status belongs to residents. The record does not report how repeated observations involving the same resident or health care worker were accounted for. If observations from one person or care setting are related, treating every swab as independent could make uncertainty appear smaller than it is. Whether this issue arose, and how it was handled, are not reported in the registry record.
What would a confidence interval add? In general, a confidence interval communicates uncertainty around an estimated quantity, such as a group proportion or contrast. Its width depends on factors including the amount of information and the variability in observations. A narrow interval indicates greater precision under the method used; a wide interval indicates greater uncertainty. The registry does not report an interval for the primary outcome, so neither the precision of an estimate nor the range of values compatible with the data can be assessed.
A p-value, if reported, would address how compatible the observed data are with a specified statistical model and null hypothesis. It would not measure the probability that the hypothesis is true, establish clinical importance, or correct for limitations in group comparability. No p-value or statistical test is listed in the registry record. The analysis method and any adjustment for differences between groups are also not reported in the registry record.
What does over-dispersion mean in general? For count outcomes, over-dispersion occurs when variation is greater than a chosen model expects. It can make standard errors and tests unreliable if the model assumes less variation than the data contain. The posted primary endpoint is a proportion of positive swabs, not a reported count comparison, and the registry does not identify a model or dispersion parameter. There is therefore no basis to claim that over-dispersion was assessed or that a particular model was used.
How should planning illustrations be read? A planning calculation estimates the sample size associated with stated assumptions and a target effect. It is not an observed result and does not show that a trial had a particular probability of detecting an effect after the data were collected. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a stated fraction of the observed effect. The assumptions are explicitly described as planning illustrations rather than the trial’s own design. No trial-specific sample-size justification is reported in the registry record, and planning calculations should not be presented as observed power.
More broadly, a planned sample size depends on the outcome definition, expected effect, variability, design and analysis assumptions. When actual outcome counts, an effect estimate and the model are unavailable, a planning illustration cannot substitute for an analysis of the trial’s results. The registry record provides no primary outcome calculation to which such an illustration can be anchored in an independently interpretable way.
What can be inferred from the registry entry? It gives the study objective, the outcome definition, the groups, the scheduled observation period and some safety counts. It does not give the statistical analysis needed to quantify an association or its uncertainty. Statistical methods should not be inferred from the outcome type or from the general study goal. In particular, the record does not specify an analysis population, handling of repeated measures, missing-data procedures, covariate adjustment, or multiplicity control.
10. Multiplicity, Missing Data and Analysis Populations
The record lists 1 outcome measure and 0 analyses. It identifies MRSA Transmission as the primary outcome, but does not report a statistical analysis or a set of secondary outcome tests. The registry does not describe whether there were additional analyses outside the posted record, or whether multiple comparisons were planned. A multiplicity strategy is not reported in the registry record.
In general, multiplicity arises when researchers conduct several tests or examine several outcomes, groups, time points or subgroups. The more comparisons made, the greater the chance that at least one result may appear unusual by chance if each is interpreted without adjustment. Adjustment methods can address this concern, but their appropriateness depends on the analysis plan and the scientific questions. Since no analysis plan or test results are posted, it is not possible to determine whether multiplicity was relevant to the analyses conducted or how it was handled.
The registry describes a scheduled measurement period of 6-25 care interaction episodes over the 30 days following resident enrollment. It does not report how many episodes were completed, how many swabs were collected, or how many participants contributed endpoint data. Missing outcome data and the method used to handle them are not reported in the registry record. Nor does the entry describe whether an observation was excluded when a swab was unavailable, or how the investigators addressed incomplete follow-up.
The analysis population is also not described. The record does not state whether the outcome analysis included all enrolled residents, only residents with at least one usable swab, or another defined population. No reasons for exclusions or withdrawals are reported. Without these details, readers cannot assess whether the analyzed observations represent all enrolled participants or whether missingness could have affected the group proportions.
These omissions do not show that multiplicity or missing data necessarily biased the results. They mean the registry record does not provide enough information to evaluate those issues. A complete interpretation would require the analysis populations, outcome denominators, missing-data procedures and any planned approach to multiple comparisons.
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 |
|---|---|---|---|
| MRSA Colonized | 9 | 94 | 9.6% |
| Not MRSA Colonized | 8 | 106 | 7.5% |
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 |
|---|---|
| MRSA Colonized | 0 of 0 |
| Not MRSA Colonized | 0 of 0 |
Most frequent serious adverse event terms
| Event term | Organ system | MRSA Colonized | Not MRSA Colonized |
|---|---|---|---|
| Hospitalization | General disorders | 9 of 94 | 6 of 106 |
| Death | General disorders | 0 of 94 | 2 of 106 |
Serious events with the highest arm-level rate: hospitalization (9.6%), death (1.9%).
The registry lists serious adverse event figures for the MRSA Colonized group and the Not MRSA Colonized group. It records 94 at risk and 9 affected in the MRSA Colonized group, and 106 at risk and 8 affected in the Not MRSA Colonized group. These are counts of participants at risk and affected as entered in the record; they do not describe the primary gown and glove swab endpoint.
The registry’s top serious terms are Hospitalization at 9.6% and Death at 1.9%. These terms are reported separately from the group-specific counts, and the record does not specify their group distribution in the information available. The death counts for both groups are listed as null, so the group-specific death figures are not reported in the registry record. The listed term “Death” should not be read as a group-specific rate or as a primary outcome finding.
Serious adverse event counts do not, by themselves, show that an event was caused by a study procedure or exposure. The record does not report a causal assessment or detailed event descriptions. It also lists 0 other adverse events at risk and 0 affected in each group. These registry entries should be interpreted as reported categories, not as evidence that no unrecorded or unreported events occurred.
12. What the Result Does, and Does Not, Mean
The record supports a clear description of the research question and the primary measure: MRSA presence on gowns or gloves worn by health care workers during care interactions with residents grouped by MRSA history. It also documents a completed study with enrollment of 203 and a scheduled observation period over 6-25 care episodes in the 30 days after enrollment.
What the record does not support is a conclusion about the observed prevalence of positive swabs or a difference between the resident groups. It contains no group-specific primary outcome proportions, no contrast, no confidence interval and no p-value. Therefore, the magnitude and precision of any association cannot be assessed. The missing result is not evidence that the groups were the same, nor evidence that they differed.
The endpoint is also narrower than the study’s motivating concern. A positive gown or glove swab indicates MRSA on the sampled item; it does not by itself establish transmission to another resident, infection, or the effectiveness of a particular protective practice. The registry’s group definitions are based on resident history, not reported assignment to gowns, gloves or hand washing. The groups are not a like-for-like control comparison, and allocation is not stated.
For these reasons, the study goal and the posted outcome description should be distinguished from an intervention-effect claim. The registry explains why timing of protective practices mattered to the research question, but it does not post the outcome evidence needed to quantify any relationship or assess its uncertainty. The registry also does not report enough detail to evaluate repeated observations, missing measurements, or the population included in the primary analysis.
The serious adverse event figures provide a separate descriptive record. They should not be combined with the swab endpoint or treated as evidence about prevention efficacy. Overall, the entry documents the study’s scope and some safety counts, but it does not report the primary results required for an estimate of MRSA swab positivity or a causal conclusion about care practices.
13. Why This Trial Matters Statistically
This study raises a statistical issue that is important in infection-prevention research: the measured outcome may be a proxy for the event of greatest clinical interest. MRSA on a gown or glove is relevant to possible spread, but it is not itself a documented transmission or infection. Keeping the proxy and the clinical outcome distinct prevents an observed contamination measure from being interpreted more broadly than it supports.
The design description also matters. Residents were grouped by a history of MRSA, rather than by stated random assignment to different prevention strategies. A comparison between these groups is not equivalent to a randomized treatment comparison. This distinction affects the question the data can answer: observational group differences describe patterns across categories, while causal claims require an appropriate design and analysis that address alternative explanations.
Care-interaction measurements may also be repeated for residents or health care workers. As a general statistical principle, related observations should not automatically be treated as independent. The registry does not report how such dependence was handled, or even the realized number of interactions and swabs. Those details are necessary for understanding uncertainty around a proportion and for judging how much information the study’s measurements contain.
Finally, reporting the estimate alongside its denominator and uncertainty is essential. Without the number of positive swabs, the total number of swabs, and an interval or other inferential result, readers cannot evaluate either the frequency or precision of the primary outcome. The registry entry communicates the study’s purpose and measurement plan, but its absence of primary results limits statistical interpretation. This is a useful reminder that a well-motivated research question and a clearly named endpoint do not substitute for transparent outcome reporting.
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.
The main limitation of the registry record for interpreting this study is the absence of primary outcome results. No number of positive swabs, total number of swabs, group-specific proportion or comparison is reported. The record therefore does not allow readers to assess the observed outcome or its precision.
The listed groups differ by resident MRSA history and are not described as randomized treatment groups. Allocation is not stated, and the registry cautions that the groups are not a like-for-like control comparison. Consequently, any unreported difference in swab positivity could not be attributed to gowns, gloves or hand washing on the basis of this description alone.
The endpoint is limited to MRSA presence on gowns or gloves during care. It does not directly measure transmission to another resident or clinical infection. The registry does not state how many scheduled interactions were completed, how many swabs were obtained, or how repeated measurements from residents or health care workers were handled. The analysis population, missing-data procedures, statistical model and adjustment strategy are not reported in the registry record.
Other design details, including participant selection and the number of participating centers, are not reported in the registry record. The registry also does not provide a sample-size justification for the study’s own design. Its planning assumptions are described as illustrations, not as the study’s design or an account of observed power.
These limitations concern what can be learned from the posted record; they do not establish that the study lacked methods or analyses beyond what is registered. The available entry is insufficient to evaluate those unreported details.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Gown and Glove Use to Prevent the Spread of Infection in VA Community Living Centers — NCT01350479.
- Registry record last updated 2017-10-05; status last verified 2017-09.
- Results first posted 2017-03-15.
- 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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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT01350479 is a completed study titled “Gown and Glove Use to Prevent the Spread of Infection in VA Community Living Centers,” sponsored by the VA Office of Research and Development. Enrollment was 203. The study focused on MRSA and aimed to determine when protective practices are most important when caring for residents colonized with MRSA.
The primary outcome was the proportion of gown or glove swabs positive for MRSA during care interactions, scheduled over 6-25 episodes in the 30 days following resident enrollment. The listed resident groups were defined by MRSA history in the past year. They were not described as randomized treatment arms, and allocation is not stated.
The registry lists 1 outcome measure and 0 analyses. It does not report primary outcome counts, proportions, an effect estimate, confidence intervals or a p-value. It does report serious adverse event counts by group and top serious terms, but not a group-specific death count. The registry record therefore documents the study question, measurement plan and some safety information, while leaving the primary statistical findings unavailable.