Reducing Urinary Tract Infection Rates Using a Controlled Aseptic Protocol for Catheter Insertion: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Reducing Urinary Tract Infection Rates Using a Controlled Aseptic Protocol for Catheter Insertion (NCT03101371), a randomized phase 2 study. The primary outcome is Number of Participants With a Catheter Associated Urinary Tract Infection (CAUTI).

2. Clinical Question

The trial addressed whether changing catheter preparation and handling during insertion was associated with a difference in post-surgical catheter-associated urinary tract infections. The registry describes the protocol as intended to limit catheter exposure to the environment before, during, and after insertion. The comparison therefore concerns the complete insertion protocol as described, rather than povidone iodine alone.

The primary outcome was a count of participants with at least one qualifying infection during the observation period. The record states that infection was assessed with a rapid urine analysis test and defined by a urine culture result greater than 10^5 bacterial colony forming units per mL, regardless of symptoms. The specific details of eligibility, adherence to the protocol, and handling of participants who could not be assessed are not reported in the registry record.

This is a comparison of two randomized groups, but it was not masked. The posted figures can describe the outcomes recorded in each group and the uncertainty around their comparison. They do not, on their own, establish that the protocol caused a difference in infection risk or that the observed pattern will apply to other surgical settings.

3. Trial Design

The registry identifies NCT03101371 as a completed phase 2 study sponsored by the University of Colorado, Denver. The study began on 2017-10-10, and its primary completion date was 2019-02-15. The listed enrollment is 99. The posted outcome results give 45 participants in the standard-of-care arm and 45 in the aseptic-protocol arm; the registry record does not explain the relationship between those arm counts and the enrollment figure.

The design is randomized, open label, and parallel group. Random allocation means that the assigned catheter-insertion approach was determined by a random process; the method used to generate or conceal the allocation is not reported in the registry record. Open-label means masking was not used. The parallel structure indicates that the two groups received different insertion approaches during the trial rather than crossing between approaches.

The control arm used a non-treated catheter inserted directly from its package. The intervention arm used a povidone iodine-treated catheter and maintained the plastic sleeve on the catheter. Because these elements were combined, the comparison does not isolate the contribution of any one component.

The primary outcome was the number of participants with a catheter-associated urinary tract infection, assessed within 14 +/- 2 days after surgery. The registry lists six secondary outcomes: catheter-discontinuation method, patient satisfaction, extended hospital stay due to urinary tract infection, disruption of the closed drainage system during placement, readmission or additional care contacts for any reason, and antibiotic use at the time of surgery and after surgery. Numerical results are posted for some, but not all, of these secondary measures. Details of the intended analysis populations, missing-data procedures, and the original sample-size justification are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: 99 participants were randomized, however, 9 participants were excluded from analsysis due to early discontinuation for not meeting eligibility criteria (n=3), provider discretion (n=1), and lost to follow-up (n=5).

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With a Catheter Associated Urinary Tract Infection (CAUTI), measured over Within 14 +/- 2 days post-surgery.

The primary endpoint counts participants who had at least one catheter-associated urinary tract infection during the observation period. It is a participant-level binary outcome: each participant either met the registry definition at least once or did not. The outcome is not a count of infection episodes, and the record does not distinguish multiple episodes in one participant.

Participants were monitored for up to 14 days, with the primary timeframe listed as within 14 +/- 2 days after surgery. The registry states that assessment used a rapid urine analysis test and defines urinary tract infection as a urine culture result greater than 10^5 bacterial colony forming units per mL, regardless of symptoms. Thus, the endpoint uses a laboratory threshold rather than requiring symptoms in its definition.

This endpoint is relevant to the study question because it records whether an infection meeting the stated definition occurred after catheter placement. Counting participants makes the outcome interpretable as the frequency of people experiencing at least one event in each group. It does not describe infection severity, duration, or whether an infection led to further treatment unless those matters are captured separately by other outcomes. The registry lists extended hospital stay due to urinary tract infection as a secondary outcome, but details beyond the posted outcome description are not reported in the registry record.

As with any endpoint, the observed comparison depends on how consistently participants were monitored and how outcomes were determined. Further information about assessment procedures, missing observations, and adjudication is not reported in the registry record.

7. Results Posted in the Registry

• Aseptic Protocol for Catheter Insertion: 13.3% (6/45) versus 15.6% (7/45) on control; risk difference -2.2 percentage points (95% CI -16.7 to 12.3), risk ratio 0.86 (0.31–2.35); unadjusted two-proportion z-test p = 0.764.

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.

Average Patient Satisfaction

• 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:
  • Aseptic Protocol for Catheter Insertion: mean 8.60 versus 8.17 on control; difference 0.43 (95% CI -0.49 to 1.35), standardized effect d = 0.19; z-test p = 0.359.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Aseptic Protocol for Catheter Insertion and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Extended Hospital Stay Due to a Urinary Tract Infection (UTI)

• 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:
  • Aseptic Protocol for Catheter Insertion: 2.2% (1/45) versus 0.0% (0/45) on control; risk difference 2.2 percentage points (95% CI -2.1 to 6.5); unadjusted two-proportion z-test p = 0.315.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Aseptic Protocol for Catheter Insertion and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Closed Drainage System Disrupted During Placement of Catheter

• 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:
  • Aseptic Protocol for Catheter Insertion: 93.3% (42/45) versus 93.3% (42/45) on control; risk difference 0.0 percentage points (95% CI -10.3 to 10.3), risk ratio 1.00 (0.90–1.12); unadjusted two-proportion z-test p = 1.000.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Aseptic Protocol for Catheter Insertion and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover different aspects of the perioperative and post-surgical experience: catheter-discontinuation method, patient satisfaction, extended hospital stay due to urinary tract infection, disruption of the closed drainage system during placement, readmission or other care contacts, and antibiotic use. Their breadth means they may provide context about implementation and related outcomes, but they do not measure the same endpoint as the primary infection count.

Numerical results are posted for patient satisfaction, extended hospital stay due to urinary tract infection, and disruption of the closed drainage system. Numerical results for the other listed secondary outcomes are not reported in the registry record. The posted pattern across the available secondary comparisons does not establish a consistent effect that can resolve the uncertainty in the primary result. These outcomes have distinct definitions and measurement scales, so they should not be combined into a single overall conclusion.

The patient-satisfaction comparison is a difference in mean scores, whereas the other posted secondary comparisons are event counts. A mean score describes an average and does not show the full distribution of individual responses. Event counts describe how many participants met an outcome definition. Each requires interpretation on its own scale and in light of its own precision.

The secondary comparisons are unadjusted, and the registry does not report a multiplicity plan. When several outcomes are examined, chance alone can produce apparently notable results among them. This general issue means that secondary findings carry less weight than a prespecified primary endpoint unless the analysis plan establishes how they will be interpreted. The registry record does not report whether these secondary analyses were prespecified in a particular hierarchy or whether any correction for multiple comparisons was intended. They are best regarded as descriptive or exploratory context rather than confirmation of the primary comparison.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Number of Participants Who Received the "Fill and Pull" Versus the "Pull and Void" Method of Catheter Discontinuation
• Average Patient Satisfaction
• Number of Participants With Extended Hospital Stay Due to a Urinary Tract Infection (UTI)
• Number of Participants With Closed Drainage System Disrupted During Placement of Catheter
• Number of Participants That Were Readmitted, Had Additional Clinic Visits or Went to the Emergency Department (ED) for Any Reason
• Number of Patients That Used Antibiotics at the Time of Surgery and Post-surgery

9. Statistical Interpretation

10. Statistical Methods Explained

The primary endpoint is binary at the participant level: an individual is counted if at least one qualifying catheter-associated urinary tract infection was recorded. The group summaries give the number of participants with the event and the number listed in each arm. For this kind of outcome, a risk difference expresses the difference between the event proportions in the two groups. A value of zero corresponds to no difference in those proportions; positive or negative values indicate which group has the larger observed proportion according to the comparison's stated ordering.

The posted primary comparison reports a risk-difference estimate, a confidence interval, and an unadjusted p-value. The estimate describes the observed contrast, while the confidence interval expresses uncertainty about the contrast under the method used to calculate it. The p-value assesses compatibility with a no-difference model; it is not a measure of the size or clinical importance of an effect. These statistics answer related but different questions, and none alone establishes causation.

The registry also includes relative measures for the primary outcome, but an interpretation of relative effects can be difficult when event counts are small. The absolute contrast remains useful for understanding the observed group difference in the outcome's original scale. The record does not report a sponsor analysis for this endpoint, so the posted comparison is the available registry estimate. Whether any adjustment for baseline characteristics was planned or performed is not reported in the registry record.

What does the confidence interval communicate?

In general, a confidence interval gives a range of effect values compatible with the observed data and the chosen statistical method. A narrow interval indicates greater precision; a wide interval indicates less precision. If an interval for a difference includes zero, the data do not clearly distinguish a positive difference from a negative one at the corresponding confidence level. The primary interval spans zero, so the posted estimate does not precisely determine the direction of the underlying difference.

Confidence intervals are not guarantees that the true effect lies within a particular interval, and they do not assign probabilities to individual effect values. Their interpretation relies on the statistical model and assumptions used to construct them. The registry does not provide enough detail to assess every calculation assumption or whether an alternative analysis was prespecified.

Why can small event counts limit inference?

When the outcome occurs in relatively few participants, the observed group estimates can be sensitive to a small change in the number of recorded events. That can make the estimated difference uncertain even when the group sizes appear similar. This is a general feature of binary outcomes with low event counts, not evidence that the event assessment was incorrect in this trial. The primary outcome has 7 recorded events in the standard-of-care group and 6 in the aseptic-protocol group, so the estimate should be read alongside its broad uncertainty rather than as a stable, finely determined effect.

Different statistical procedures can behave differently with small counts, particularly when a group has very few or no events. The registry does not report the particular test or interval-construction method used for the posted primary comparison. It is therefore appropriate to interpret the reported estimate and uncertainty as posted, without assuming a specific model beyond the information in the record.

What does unadjusted mean?

An unadjusted comparison contrasts the groups without accounting for other measured variables in the estimate. Randomization is intended to support a fair comparison, but it does not ensure that every characteristic will be balanced in a particular trial. The registry does not report an adjusted primary analysis, baseline covariate adjustment, or the analysis population used. The posted primary p-value is explicitly unadjusted, so it should not be interpreted as the result of a documented adjusted model.

The posted secondary comparisons are also unadjusted. Looking at multiple outcomes increases the chance that at least one result may appear unusual by chance. General statistical practice may use a prespecified strategy to address multiple comparisons, but the registry record does not report such a strategy. This is one reason to give greater weight to the primary outcome and to treat secondary findings cautiously.

How should planning calculations be understood?

The sample-size planning illustrations are based on the observed effect, not on the trial's original design. They use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is set to the stated fraction of the observed effect. These assumptions define a hypothetical planning exercise; they do not describe a reported protocol calculation.

For a binary endpoint, the planning figures are participants per arm. The values are highly dependent on the effect chosen for planning. Smaller effects require more participants to distinguish them from no difference with the same target power, because a smaller signal is harder to separate from random variation. The illustrations should therefore be read as conditional planning scenarios, not as a claim about what the trial should have enrolled or what its actual operating characteristics were.

11. Confidence Intervals and Precision

The primary comparison is imprecise. The point estimate is based on 7 participants with an event in the standard-of-care group and 6 in the aseptic-protocol group, with 45 participants listed in each group. The confidence interval for the risk difference spans zero and extends to values on both sides of no difference. It therefore does not identify the direction of the underlying difference with confidence, and it leaves room for a range of effect sizes.

A confidence interval is useful because it shows how much uncertainty surrounds an estimate, rather than focusing only on whether a p-value crosses a conventional threshold. Here, the interval is compatible with no difference as well as with effects in either direction. This means the study result should not be read as proving equality or as establishing a meaningful benefit or harm. The data provide limited precision for the primary comparison.

The low number of recorded primary events is relevant to that uncertainty. With relatively few events, each recorded outcome can have appreciable influence on the estimated group contrast. This is a general property of event-count data. It does not by itself indicate bias, but it cautions against treating a small numerical difference as a precise estimate of an underlying effect.

The same general principle applies to secondary outcomes: confidence intervals are important where reported, and the magnitude and precision of an estimate matter in addition to a p-value. Several registry-listed secondary outcomes do not have numerical comparisons reported in the record. The registry also does not report a prespecified precision target for the primary endpoint. As a result, the degree of precision intended at the design stage is not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures for the binary primary outcome are participants per arm, not total events. They are hypothetical calculations based on the observed effect and the stated planning assumptions: a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set to the stated fraction of the observed effect. The registry does not report the original trial sample-size assumptions or justification.

The 80% power column gives the number of participants per arm estimated to yield an 80% chance of detecting the chosen effect under those assumptions, if that effect were the true one. The 90% power column describes the corresponding planning target with a 90% chance. Power is a property of a study design for a specified effect and model; it is not the probability that a particular result is correct.

The planning scenarios use 100%, 75%, and 50% of the observed effect. As the selected effect becomes smaller, the participant requirement increases: a smaller difference is harder to distinguish from random variation while maintaining the same significance level and target power. For the primary outcome, the planning figures are 3,928 participants per arm for 80% power and 5,257 for 90% power when planning for 100% of the observed effect; 7,094 and 9,497 when planning for 75%; and 16,211 and 21,702 when planning for 50%.

These are planning illustrations, not observed power. They should not be interpreted as the trial's original target, nor as evidence that the trial failed or succeeded on a design criterion. They inherit uncertainty from the observed effect used as their starting point, which is itself imprecise in this trial.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.156; treatment proportion p₁ = 0.133; average p̄ = 0.144.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.4972 = 0.9744.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.4969 = 0.4182.
4. n = (0.9744 + 0.4182)² / (-0.0222)² = 3,927.2, rounded up to 3,928 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.155555555555556                          # control proportion
p1 <- 0.133333333333333                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(3101371)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 3,928 (80% power), 5,257 (90% power)
 75% of observed effect: n per arm = 7,094 (80% power), 9,497 (90% power)
 50% of observed effect: n per arm = 16,211 (80% power), 21,702 (90% power)
power.prop.test: 3927.2 
Simulated power at n = 3,928 per arm: 0.803 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and six secondary outcomes. It also indicates no reported analyses for the trial. The posted comparison statistics therefore do not come with a registry-reported analysis plan detailing which tests were prespecified, how outcomes were ordered, or how multiplicity was handled. A plan for controlling the chance of false-positive findings across multiple comparisons is not reported in the registry record.

This matters because examining several outcomes creates multiple opportunities for an apparently unusual result to arise by chance. A p-value for an individual secondary comparison does not account for the fact that other outcomes were also considered. Without a reported multiplicity strategy, secondary p-values should be treated as unadjusted and exploratory. The primary result remains the principal basis for interpreting the trial's stated question, while secondary results can provide context but should not be treated as independent confirmatory evidence.

Missing-data methods are not reported in the registry record. The outcome descriptions indicate the intended observation period, but do not explain whether all randomized participants had complete outcome assessments, how incomplete follow-up was handled, or whether participants were included according to original assignment. The analysis population is not reported in the registry record. The posted arm summaries list 45 participants in each group, but those counts alone do not establish how missing outcomes or protocol deviations were treated.

Other details that would help assess the analysis include the statistical test, any adjusted model, the handling of protocol adherence, and the approach to participants with uncertain outcome status. These details are not reported in the registry record. Their absence limits evaluation of whether the posted estimates match a prespecified analysis and how sensitive the findings might be to alternative assumptions.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for 0 participants in the standard-of-care arm and 0 participants in the aseptic-protocol arm. Deaths are reported as 0 in each group. For other adverse events, the posted counts are 2 in the standard-of-care group and 3 in the aseptic-protocol group; each group lists 45 participants at risk.

These counts describe events recorded in the registry and should not be interpreted as establishing a safety difference. With few recorded events, the comparison is imprecise, and the registry record does not provide detailed event descriptions or a comparison analysis for adverse events. It also does not state whether the listed other adverse events were considered related to the catheter protocol. The absence of reported serious events does not establish that no serious event could occur, and the recorded other-event counts do not establish that the protocol caused those events.

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

The posted primary data show 7 participants with a catheter-associated urinary tract infection in the standard-of-care group and 6 in the aseptic-protocol group. The unadjusted p-value is 0.764, and the confidence interval for the group difference spans zero. The observed count is slightly lower in the aseptic-protocol group, but the comparison is too imprecise to establish the direction or size of an underlying difference.

This does not mean the two approaches are equivalent. Demonstrating equivalence would require a suitable design, a prespecified equivalence margin, and an analysis addressing that question; those details are not reported in the registry record. Nor does the result establish that the aseptic protocol prevents infection or that it has no effect. It describes the outcomes recorded in this randomized comparison, with substantial uncertainty.

The intervention was a combined protocol: povidone iodine treatment of the catheter and maintenance of the plastic sleeve. The study therefore does not isolate the effects of those components. The open-label design also means that participants and study personnel were not masked, though the registry record does not report whether knowledge of assignment affected outcome assessment.

The endpoint was defined by a urine culture threshold regardless of symptoms and observed within a limited post-surgical timeframe. The result does not directly address infections outside that period, other infection definitions, or outcomes not recorded in the registry. Patient satisfaction and other secondary outcomes add context but, because they are distinct outcomes and their analyses are unadjusted, they do not eliminate uncertainty in the primary comparison.

The most appropriate reading is therefore narrow: the posted data do not provide strong statistical evidence of a difference in the primary outcome, and the interval indicates limited precision. The findings should not be stretched into a general conclusion about every catheter-insertion setting or every element of aseptic practice.

17. Why This Trial Matters Statistically

This trial illustrates why randomized design and statistical precision answer different questions. Randomization provides a framework for comparing assigned approaches, but the amount of information in the outcome data still matters. The primary outcome has few recorded events, and the confidence interval spans values consistent with differences in either direction. A non-small p-value cannot by itself establish that the approaches are equivalent or that the observed estimate is exact.

The endpoint also makes the role of definition clear. The registry counts participants with at least one event and defines infection using a culture threshold regardless of symptoms. That operational definition supports a specific comparison, but it is not interchangeable with every possible definition of urinary tract infection. The observation period and measurement approach shape what the result can address.

Another statistical lesson is the importance of distinguishing a primary endpoint from a set of secondary outcomes. Several secondary domains are listed, but not all have numerical results posted, and the registry does not report a multiplicity strategy. Considering each finding in isolation can overstate what exploratory comparisons establish. The primary outcome should carry the greatest weight for the stated question, while secondary findings should be interpreted cautiously.

Finally, planning calculations based on an observed effect can illustrate how strongly sample-size needs depend on the effect chosen, but they cannot reconstruct the trial's original design rationale. These planning scenarios are especially uncertain when the observed estimate is imprecise. The original sample-size justification is not reported in the registry record.

18. 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 registry record leaves several design and analysis details unavailable. Eligibility criteria beyond the description of surgical patients receiving a catheter, allocation-generation and concealment procedures, adherence to the assigned protocol, and the analysis population are not reported in the registry record. The stated enrollment and the posted group counts are not reconciled in the record, so the relationship between those figures cannot be clarified from the posted information.

The study was open label. The record does not explain whether outcome assessors were independent of treatment assignment or whether knowledge of the insertion approach could have influenced measurement or follow-up. The infection definition includes a culture threshold regardless of symptoms, but the record does not provide further detail about culture collection, adjudication, or handling of uncertain results.

Information on missing outcome data, protocol deviations, and statistical methods is limited. The registry does not report the method used to generate the primary confidence interval or the exact test underlying the unadjusted p-value. It does not report a prespecified multiplicity approach, an adjusted analysis, or the original sample-size justification. These omissions restrict assessment of robustness and of the relationship between the posted comparisons and the planned analyses.

The primary event counts are small, producing limited precision for the group comparison. The intervention also bundles catheter treatment and sleeve handling, so the study cannot identify the contribution of each component. Finally, numerical results are not reported for all listed secondary outcomes. These limitations constrain both statistical interpretation and the range of conclusions that can be drawn from the registry record.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Reducing Urinary Tract Infection Rates Using a Controlled Aseptic Protocol for Catheter Insertion — NCT03101371.
• Registry record last updated 2020-03-10; status last verified 2020-03.
• Results first posted 2020-02-18.
• 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.

22. Record Summary

NCT03101371 is a completed, randomized, open-label, parallel-group phase 2 trial sponsored by the University of Colorado, Denver. It compared standard catheter insertion with an aseptic protocol using a povidone iodine-treated catheter and maintaining the plastic sleeve.

The primary endpoint was participants with at least one catheter-associated urinary tract infection within 14 +/- 2 days after surgery. The posted result was 7 participants in the standard-of-care group and 6 in the aseptic-protocol group, with 45 listed in each arm. The unadjusted p-value was 0.764, and the confidence interval spans no difference.

The primary comparison is imprecise and does not establish either a difference or equivalence. Some secondary results and adverse-event counts are posted, but analysis-plan, missing-data, and multiplicity details are not reported in the registry record.