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 Levofloxacin-containing Therapies In Second Line Helicobacter Pylori Eradication (NCT02596620), a randomized na study. The primary outcome is Percentage of Participants With Successful Eradication of H. Pylori.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02596620 |
| Phase | NA |
| Condition | Helicobacter Pylori Infection |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 164 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Chang Gung Memorial Hospital |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes patients with Helicobacter pylori infection after failure of standard triple therapy. The specific characteristics of the enrolled population, including eligibility details and baseline clinical or bacterial factors, are not reported in the registry record. The investigators also described an aim to examine factors that might influence salvage-regimen efficacy, but no such factor analyses are posted.
Intervention
One randomized group received sequential therapy over 10 days. Esomeprazole and amoxicillin were used for the first 5 days, followed by esomeprazole, levofloxacin and metronidazole for the next 5 days. The recorded regimen lists esomeprazole 40 mg twice daily, amoxicillin 500 mg as 2 tablets twice daily, levofloxacin 500 mg once daily and metronidazole 250 mg as 2 tablets three times daily during the relevant treatment days.
Comparator
The other randomized group received 10-day triple therapy with esomeprazole 40 mg twice daily, amoxicillin 500 mg as 2 tablets twice daily and levofloxacin 500 mg once daily. The comparison concerns these complete regimens, including their different schedules and drug combinations, rather than the isolated effect of one medicine.
Primary question
The primary question is what percentage of participants in each group had successful H. pylori eradication, assessed 4 weeks after eradication treatment. Success was defined by negative results on both rapid urease testing and histology, or by a negative urea breath test. The posted results give a percentage and a 95% confidence interval for each group, but do not report a formal two-arm comparison estimate or test.
3. Trial Design
This was a randomized, parallel-group trial recorded as single masked. The registry record does not say who was masked, how masking was maintained, or whether masking applied to participants, clinicians, outcome assessors, or another group. Allocation is recorded as randomized, but details of sequence generation and allocation concealment are not reported in the registry record. The phase is recorded as NA.
The study compared sequential therapy with triple therapy in patients being treated after failure of standard triple therapy. The registry lists enrollment as 164 and reports 81 participants for each treatment group in the primary outcome results. These figures describe the record as posted; the registry does not explain the relationship between the enrollment figure and the outcome denominators.
The study start is recorded as 2013-10, and primary completion as 2015-10. Its status is completed. Chang Gung Memorial Hospital is listed as the sponsor. The registry identifies Helicobacter pylori infection as the condition and lists Nexium, Amolin, Cravit and Flagyl as drug interventions. Generic drug names and the regimen schedules are also included in the arm descriptions.
The stated aim was to compare the eradication efficacy of the two 10-day regimens after standard triple-therapy failure and to determine which clinical and bacterial factors might influence salvage-regimen efficacy. Although that broader aim is described, the posted results contain one primary outcome and no posted secondary outcomes. Details of the planned statistical analysis, including any adjustment variables or analysis populations, 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.
Before assignment: We excluded those patients who had taken antibiotics, bismuth, proton-pump inhibitors, or non-steroidal anti-inflammatory drugs within the previous 4 weeks, were allergic to the medications used, had a history of previous gastric surgery or serious concomitant illness, or were currently pregnant.
Overall Study
| Stage | Sequential Therapy | Triple Therapy |
|---|---|---|
| STARTED | 82 | 82 |
| COMPLETED | 81 | 81 |
| NOT COMPLETED | 1 | 1 |
Reasons for not completing this period:
| Reason | Sequential Therapy | Triple Therapy |
|---|---|---|
| Lost to Follow-up | 1 | 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 | Sequential Therapy | Triple Therapy | Total |
|---|---|---|---|---|
| Participants analysed | 82 | 82 | 164 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 70 | 68 | 138 |
| Age, Categorical: >=65 years | Participants | 12 | 14 | 26 |
| Gender: Female | Participants | 46 | 42 | 88 |
| Gender: Male | Participants | 36 | 40 | 76 |
| Region of Enrollment: Taiwan | participants | 82 | 82 | 164 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With Successful Eradication of H. Pylori, measured over Negative results of H.pylori 4 weeks after eradication.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of eradication |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the percentage of participants with successful eradication of H. pylori. The registry defines success as either negative results on both rapid urease testing and histology, or a negative urea breath test, at 4 weeks after eradication treatment. The reported outcome is therefore a binary classification summarized as a group percentage: each participant is classified as meeting or not meeting the stated success definition.
This endpoint is used to describe whether the infection was detected by the specified follow-up tests after treatment. Combining the two stated routes to success allows the endpoint definition to accommodate either paired negative results from rapid urease testing and histology or a negative breath test. The record does not report how participants were assigned to a testing route, how discordant results were handled, or whether testing was complete for everyone in the outcome denominator.
The observed percentages are 91.4% for sequential therapy and 81.5% for triple therapy. Their reported 95% confidence intervals are 85.1% to 97.6% and 72.8% to 90.1%, respectively. These estimates describe the groups’ posted outcomes; they do not, on their own, provide a formal estimate or test of the difference between regimens. The endpoint is limited to the stated assessment at 4 weeks and does not describe longer-term eradication or other outcomes.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary results are 91.4% successful eradication in the sequential-therapy group, with a 95% confidence interval from 85.1% to 97.6%, and 81.5% in the triple-therapy group, with a 95% confidence interval from 72.8% to 90.1%. The point estimates are descriptive summaries of the outcome in each reported group. The confidence intervals convey uncertainty around those group estimates.
The registry record does not provide a two-arm effect estimate, such as a difference in eradication percentages, and it does not report a confidence interval or hypothesis test for a between-group contrast. The comparison is therefore not accompanied by a direct inferential result in the posted record. A reader should distinguish the separate group estimates from an analysis that directly quantifies the contrast between them. No recalculated comparison is reported for this endpoint.
The intervals are not guarantees about the true group percentages, and they do not establish how likely one regimen is to have a better outcome than the other. General statistical interpretation: a confidence interval is a range generated by a method that, under its assumptions and repeated use, is intended to capture the underlying parameter at the stated rate. It is not a range containing every individual participant’s outcome. The registry does not describe the method used to construct these intervals, so the precise assumptions behind them are not available.
The values apply to the outcome definition and follow-up specified in the record: testing 4 weeks after eradication treatment, using the listed criteria for success. They should not be extended to different follow-up periods, different patient groups, or other outcomes. The registry’s stated interest in clinical and bacterial factors does not establish that subgroup or predictor results were analyzed or posted; no such results are listed.
The record also does not report a formal statistical analysis plan, an adjusted comparison, or a sample-size justification. The absence of those details means that the precision and inferential basis of the reported comparison cannot be fully assessed from the registry record. The posted figures support a descriptive account of the two groups, but not a definitive conclusion about the size or statistical significance of a treatment contrast.
9. Statistical Methods Explained
What does a group percentage represent?
The primary endpoint classifies participants as having successful eradication or not having successful eradication under the registry definition. A group percentage expresses the share meeting that definition among the participants included in that group’s outcome denominator. Here, the posted percentages are 91.4% for sequential therapy and 81.5% for triple therapy. These are observed summaries, not predictions for every future patient or guarantees about an individual result.
The registry reports 81 participants for each group’s primary outcome. It does not state whether the outcome analysis included everyone as randomized, only those with available test results, or another analysis population. Nor does it explain how missing test results were handled. Those details matter because the denominator and missing-outcome assumptions can affect a percentage estimate.
What does a confidence interval add?
Each percentage is accompanied by a 95% confidence interval: 85.1% to 97.6% for sequential therapy and 72.8% to 90.1% for triple therapy. General statistical explanation: a confidence interval communicates the uncertainty of an estimate under a particular statistical method. A narrower interval generally indicates greater precision than a wider interval, when the methods and quantities being compared are suitable for that interpretation. An interval is not a range of individual responses, and a 95% confidence level does not mean there is a 95% probability that this particular fixed interval contains the true value.
The record does not describe how the intervals were calculated. It is therefore not possible to verify from the posted information which interval procedure was used or what assumptions were applied. The intervals shown are for each group’s percentage. They are not a confidence interval for the difference between groups.
Why is a direct comparison different?
A comparison between the regimens would quantify the contrast using a specified measure, such as a difference in percentages or a ratio, and would ordinarily report uncertainty for that contrast. The record gives neither a direct contrast estimate nor its confidence interval or test result. Seeing separate group estimates does not substitute for that analysis. A formal comparison also depends on a chosen analysis method and, where relevant, adjustment or stratification choices. Those choices are not reported in the registry record.
General statistical explanation: separate confidence intervals are not themselves a test of the difference between groups. Their appearance can help readers understand the precision of the separate estimates, but a direct inferential claim requires the contrast and its uncertainty to be analyzed as such. No new contrast should be inferred by subtracting or otherwise combining the posted percentages.
What can be inferred from the trial structure?
Randomized allocation is recorded, and the trial is described as parallel-group and single masked. Randomization is generally intended to support a fair comparison by balancing, on average, measured and unmeasured characteristics at assignment. Its practical protection depends on implementation, including sequence generation and allocation concealment, neither of which is described. Parallel-group design means participants are assigned to one regimen group rather than crossing between regimens, but details of follow-up and adherence are not reported.
Single masking indicates that masking was recorded, but the registry does not identify who was masked or how this was done. Without that information, readers cannot assess the likely role of masking in outcome assessment or other trial procedures. The endpoint includes laboratory or diagnostic test results, but the record does not say whether outcome assessors were masked.
How should planning calculations be read?
General statistical explanation: a sample-size calculation for a future study depends on assumptions about the target effect, variability or event rate, significance level, power, allocation, and analysis method. A planning illustration is not a result observed in this trial and is not evidence that the trial had a particular probability of detecting an effect. The record describes planning assumptions for an illustration based on a fraction of the observed effect, with a two-sided significance level of 0.05, equal allocation and a normal approximation. It does not report a sample-size justification from the trial’s own design in the registry record. Any planning figures should therefore be read as hypothetical design illustrations, not as observed power or as proof that the trial was adequately powered.
In this record, the endpoint is a count-based binary outcome, but the posted results do not provide a formal two-group analysis. The number of outcome measures is recorded as one, and no analyses are listed. The statistical plan, including any planned interim analyses, is not reported in the registry record. These omissions constrain how much can be said about the analytic process beyond the descriptive results.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome measure and no posted secondary outcomes. It records no analyses. The trial description mentions examining clinical and bacterial factors that might influence salvage-regimen efficacy, but the registry record does not report analyses of those factors or any other secondary results. It also does not report a multiplicity plan. Without a stated set of planned tests and a correction strategy, the handling of multiple comparisons cannot be assessed; the record does not establish that such testing was performed.
Missing-data handling is not reported in the registry record. The primary outcome is based on test results 4 weeks after eradication treatment, but the record does not state whether all randomized participants completed testing, how unavailable or indeterminate results were classified, or whether any imputation was used. The posted outcome groups each list 81 participants, while overall enrollment is recorded as 164; the registry does not explain the accounting between these figures. No assumption about missing outcomes or participant flow should be inferred from that difference.
The analysis population is also not reported. The record does not say whether the percentages are based on an intention-to-treat population, a per-protocol population, or another definition. It does not describe exclusions, treatment adherence, withdrawals, or protocol deviations. These details are important for interpreting a randomized trial because different analysis populations can answer different questions and can be affected differently by missing outcomes or post-randomization exclusions.
Overall, the posted record supports a descriptive reading of the primary percentages, but leaves the handling of missing observations, analysis populations and multiplicity unspecified.
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 |
|---|---|---|---|
| Sequential Therapy | 0 | 81 | 0.0% |
| Triple Therapy | 0 | 81 | 0.0% |
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 |
|---|---|
| Sequential Therapy | 19 of 81 |
| Triple Therapy | 9 of 81 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Sequential Therapy | Triple Therapy |
|---|---|---|---|
| Nausea/vomiting | Gastrointestinal disorders | 7 of 81 | 4 of 81 |
| Abdominal pain | Gastrointestinal disorders | 5 of 81 | 2 of 81 |
| Dizziness | General disorders | 4 of 81 | 1 of 81 |
| Headache | General disorders | 3 of 81 | 1 of 81 |
| Diarrhea | Gastrointestinal disorders | 2 of 81 | 1 of 81 |
| Other | General disorders | 2 of 81 | 1 of 81 |
The posted safety figures list no serious adverse events in either group: 0 among 81 participants at risk in the sequential-therapy group and 0 among 81 at risk in the triple-therapy group. These are the serious-event counts recorded in the registry results. The record lists no top serious adverse-event terms. Death counts are not reported in the registry record.
The registry separately records other adverse events affecting 19 participants in the sequential-therapy group and 9 in the triple-therapy group, with 81 participants at risk in each group. These are counts, not a formal comparison of event rates. The record does not provide an inferential analysis of these figures, definitions for the “other” category, event severity details beyond the category label, or further information about timing and follow-up.
General statistical explanation: observing zero serious events in a group does not establish that the underlying risk is zero. Rare events may not occur in a study even when a nonzero risk exists, and interpretation depends on the size and follow-up of the group and on how events were collected. The registry record does not provide enough safety-analysis detail to assess those matters fully. The counts should be read as the posted adverse-event summaries, not as proof of equivalent safety or as a basis for a treatment recommendation.
12. What the Result Does, and Does Not, Mean
The registry reports successful eradication percentages of 91.4% for sequential therapy and 81.5% for triple therapy, with a 95% confidence interval for each group. These results describe the participants and endpoint as recorded: patients treated after failure of standard triple therapy, assessed by the specified tests 4 weeks after treatment. They provide a view of the observed outcomes in each randomized group.
The record does not report a formal estimate of the between-group contrast, its uncertainty, or a hypothesis test. Accordingly, the posted percentages alone do not establish the magnitude or statistical significance of a difference between regimens. They also do not show whether a difference, if present, is clinically important. No new comparative value should be calculated from the separate group summaries.
The findings do not describe longer-term eradication, recurrence, or outcomes beyond the primary endpoint unless separately reported; no such secondary outcomes are posted. Nor do the results establish which clinical or bacterial factors influenced outcomes, despite that being part of the investigators’ stated aim. Details about participant characteristics, adherence, missing test results and the analysis population are not reported in the registry record, limiting assessment of how broadly the group estimates apply.
Randomization is an important design feature, but the available record does not describe how randomization was implemented or who was masked. Such details help assess the risk of bias and the strength of a causal interpretation. The posted summary is therefore best understood as descriptive evidence from a randomized comparison with important analytic details unavailable, rather than as a complete account of the trial’s inferential findings.
These results are not medical advice and do not establish that either regimen works or does not work. They report the outcome percentages and safety counts entered in the registry. Treatment decisions require broader clinical evidence and individual clinical judgment, neither of which is addressed by these statistics.
13. Why This Trial Matters Statistically
This trial raises a common statistical question in clinical research: how should two active regimens be compared when the registry posts a result for each group but not a direct estimate of their contrast? The distinction matters because separate percentages answer a descriptive question about each group, while a comparative estimate answers how far apart the outcomes are under a specified statistical model.
The primary endpoint is a binary outcome summarized as a percentage, with a 95% confidence interval for each group. That format makes both the observed result and its uncertainty visible. It also illustrates why uncertainty around each group estimate should not be mistaken for uncertainty around the treatment contrast. A direct contrast and its interval would be needed to assess the comparative precision using the trial’s chosen method.
There is also a useful lesson in interpreting registry completeness. The trial is described as randomized, parallel and single masked, yet key details about randomization, masking, analysis populations, missing outcomes and statistical methods are not reported in the registry record. A design label supplies important context, but it does not replace the implementation and analysis details needed to evaluate bias and uncertainty.
Finally, the stated interest in clinical and bacterial factors is not matched by posted secondary results. The record lists one primary measure and no analyses. That gap illustrates why a stated research aim and a reported statistical result are not interchangeable. The available figures support description of the primary outcome, while leaving the intended broader analyses and formal comparison undocumented.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
Several trial-specific limitations constrain interpretation of the posted results. The registry does not provide a formal between-group estimate or test for the primary endpoint, despite presenting results for both randomized groups. Consequently, the statistical uncertainty around the contrast and the method used to compare regimens are unavailable.
Important design and analysis details are not reported in the registry record. These include the method for generating and concealing random allocation, the identity of the masked party, the analysis population, and the handling of missing outcome tests. The outcome denominators and overall enrollment are both recorded, but their relationship is not explained. The registry also does not describe adherence, withdrawals, exclusions or protocol deviations.
The primary endpoint is assessed 4 weeks after treatment. The posted result therefore does not address durability beyond that time point. No secondary outcomes are posted, and no analyses are listed, including analyses of the clinical or bacterial factors mentioned in the trial aim. A statistical analysis plan, multiplicity approach, interim-analysis plan and trial-specific sample-size justification are not reported in the registry record.
The safety summary is limited to the recorded counts of serious and other adverse events. Event definitions, collection procedures, follow-up details and an inferential safety comparison are not reported. The absence of serious events in the posted groups should not be taken as evidence that serious events cannot occur.
These limitations concern what can be evaluated from the registry record. They do not establish that the unreported procedures or analyses were absent from the full trial conduct; their status is not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Levofloxacin-containing Therapies In Second Line Helicobacter Pylori Eradication — NCT02596620.
- Registry record last updated 2017-02-28; status last verified 2017-01.
- Results first posted 2016-11-04.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry describes NCT02596620, titled “Levofloxacin-containing Therapies In Second Line Helicobacter Pylori Eradication.” It is recorded as a completed, randomized, parallel-group, single-masked trial sponsored by Chang Gung Memorial Hospital. The phase is listed as NA; the recorded study start is 2013-10 and primary completion is 2015-10.
The comparison was between 10-day sequential therapy and 10-day levofloxacin-containing triple therapy after standard triple-therapy failure. The primary outcome was successful H. pylori eradication, assessed 4 weeks after treatment using the registry’s specified test criteria. The posted percentages were 91.4% for sequential therapy and 81.5% for triple therapy, with group-specific 95% confidence intervals. No formal two-arm comparison is posted.
The registry lists no secondary outcome results or analyses. It records 0 serious adverse events in each group, other adverse events affecting 19 participants in the sequential group and 9 in the triple group, and no reported death counts. Details of missing-data handling, analysis populations and the statistical plan are not reported in the registry record.