Recovery Time in Thai Patients With Upper or Lower Respiratory Tract Infections Treated With Klacid MR: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Recovery Time in Thai Patients With Upper or Lower Respiratory Tract Infections Treated With Klacid MR (NCT01076153), a registered phase not stated study. The primary outcome is Average Time From Baseline to Recovery From Cough and Other Symptoms.

2. Clinical Question

This is a question about recovery following treatment in a clinical setting, not a randomized comparison of treatment against a control. Without a comparator, the record cannot establish how recovery time under Klacid MR differs from recovery time under another treatment or without treatment. It can describe the outcome as defined by the study, but the registry does not give the observed mean or its standard deviation. It also does not report an estimate of treatment effect, confidence interval, or p-value. The hypothesis therefore provides context for the study question, not a result demonstrating that recovery was faster.

3. Trial Design

The registry identifies this as a multicenter, post-marketing observational study. Its status is COMPLETED. The listed study period began in 2008-12, with primary completion in 2010-04. Abbott is named as the sponsor, and enrollment is listed as 760.

The study concerns Thai patients with upper or lower respiratory tract infections treated with clarithromycin modified release (Klacid MR). The record describes one group of patients receiving Klacid MR, rather than separate treatment and control groups. It does not describe random assignment; allocation is not stated. The study therefore does not provide a like-for-like control comparison. A before-and-after interpretation is also not supported by a reported baseline symptom score and follow-up score: the primary outcome is defined as time from baseline to recovery.

Treatment duration is described as 5 to 14 days. Participants were seen at baseline, and a medical appointment, either a visit or phone call, was made 6 to 14 days after the first visit. Symptoms were rated as resolved, improved, not changed, or worse, with associated dates recorded. Recovery was defined as disappearance of all signs and symptoms of infection.

The record lists 760 as enrollment and describes a per-protocol population of 694. It says 66 participants were excluded for protocol deviations, some with more than one deviation. The listed reasons include age less than 18 years, taking excluded drugs, and treatment duration outside the specified range, among other entries. The complete details of all deviations are not reported in the registry record. The available description does not establish whether the primary outcome was analyzed in any population other than the stated per-protocol population.

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: A total of 760 participants were enrolled in the study. 694 were analyzed as 66 participants had protocol deviations (some more than 1): Age less than 18 years (22), took excluded drugs (17), took Klacid more than 14 days (16), took Klacid less than 5 days (11), added 250 mg Klacid to Klacid MR (5), and used injectable drugs (3).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The per-protocol population consisted of 694 participants as 66 participants were excluded for protocol deviations (some more than 1): Age less than 18 years (22), took excluded drugs (17), took Klacid more than 14 days (16), took Klacid less than 5 days (11), added 250 mg Klacid to Klacid MR (5), and used injectable drugs (3).

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.

6. Primary Endpoint

The registry lists the primary outcome as Average Time From Baseline to Recovery From Cough and Other Symptoms, measured over Baseline to 14 days.

The primary endpoint is average time from baseline to recovery from cough and other symptoms, measured in days. It is a continuous outcome: each participant’s recovery time is represented as a duration, and the group-level summary is specified as a mean with standard deviation. The timeframe is baseline to 14 days.

The endpoint is intended to capture how long symptoms persist, rather than only whether symptoms are present at a single follow-up. Recovery was defined as disappearance of all signs and symptoms of infection. The symptoms assessed included, but were not limited to, cough, fever, and sore throat. At follow-up, symptoms could be rated as resolved, improved, not changed, or worse, and associated dates were recorded.

In general, a mean can describe the average duration across the participants included in an analysis, while a standard deviation describes variation in individual durations around that mean. These summaries can help characterize both typical recovery time and how much recovery times differ across participants. They do not, by themselves, show whether treatment caused a change. That interpretation requires an appropriate comparison or other design and analysis addressing alternative explanations.

The registry specifies the endpoint and its measurement approach but does not report the observed mean, standard deviation, or a treatment-effect estimate. It also does not report how recovery dates were handled when recovery was not observed during the stated timeframe. Those details are important to interpret the endpoint fully.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is a continuous outcome: time from baseline to recovery, measured in days. The registry specifies a mean and standard deviation as the summary statistics. In general, a mean is the arithmetic average of the measured durations in an analysis population. A standard deviation describes how dispersed those individual durations are around the mean. Neither statistic is reported numerically for this study in the registry record, so the center and spread of the observed recovery times cannot be assessed from the listed result.

What does the mean describe?

For a continuous outcome, a mean can be a useful description when the average duration is meaningful for the study question. It does not show the range of individual experiences, and it can be influenced by unusually long or short durations. The standard deviation adds information about variability, but it does not show the shape of the distribution. A confidence interval, if reported, would address uncertainty in an estimated mean or contrast. No confidence interval is reported in the registry record.

These statistical summaries are distinct from a treatment comparison. A mean recovery time in a group describes that group; to estimate a difference associated with treatment, the analysis ordinarily needs a comparator and a defined contrast. This registry describes a treated group and no control group. It does not report an effect estimate comparing Klacid MR with another intervention or with no treatment. The study’s hypothesis about shortening recovery time is not itself an estimate of that effect.

How should the recovery definition be read?

The endpoint defines recovery as the disappearance of all signs and symptoms of infection. Symptoms were rated at baseline and at a later medical appointment, which could be a visit or phone call 6 to 14 days after the first visit. Ratings included resolved, improved, not changed, or worse, and dates were recorded. The primary timeframe is baseline to 14 days. These descriptions clarify what the investigators intended to measure, but the registry does not report the individual-level timing data or the resulting group summary.

In general, when the outcome is time until an event, statistical methods may need to account for participants whose event time is not observed during follow-up. This can involve censoring or other explicit rules for incomplete observation. The record does not report how recovery times were handled when recovery was not observed within the timeframe, nor does it identify a time-to-event analysis. The endpoint is described as a mean of a continuous measure, so methods used for time-to-event outcomes should not be assumed to have been applied.

What does the study design allow?

This is described as a multicenter, post-marketing observational study. Treatment assignment is not reported, and the record does not describe a comparator. In general, observational data can characterize outcomes among people receiving care in the settings studied. Without a suitable comparison strategy, however, such data do not isolate the effect of treatment from other factors related to who receives treatment and how the illness progresses. The registry does not report an adjusted analysis or a statistical model that could be evaluated for this purpose.

The primary-outcome description identifies a per-protocol population of 694 and notes that 66 participants were excluded for protocol deviations, some more than once. In general, a per-protocol analysis focuses on participants meeting specified study criteria. Its interpretation depends on what criteria were applied and how exclusions relate to the outcome. The record gives examples of deviation categories but does not report the complete details of all deviations or a comparison of included and excluded participants. No separate all-enrolled analysis is reported in the registry record.

The registry lists 760 enrolled participants and 2 outcome measures, but lists 0 analyses. These entries do not supply an analysis plan, statistical model, handling of missing observations, or multiplicity approach. Those elements are not reported in the registry record. No analysis should be inferred from the stated outcome summary alone.

General statistical note: over-dispersion matters when observed variability is greater than a model assumes. A model that understates variability can produce confidence intervals that are too narrow and tests that appear more precise than warranted. Whether over-dispersion is relevant depends on the outcome and model. Because no model or numerical outcome distribution is reported, there is no basis to assess over-dispersion for this study.

Any sample-size figures presented as planning illustrations are not observed power. They describe hypothetical planning under stated assumptions, not the probability that this completed study detected an effect. The registry record does not report a sample-size justification or the statistical plan used for the study.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Klacid MR (Total Number Recovered)", "Klacid MR (URTI, Recovered)", "Klacid MR (LRTI, Recovered)", "Klacid MR (URTI and LRTI, Recovered)")
n   <- c(658, 491, 148, 19)
m   <- c(7.06, 6.76, 7.82, 9.05)
sp  <- c(2.65, 2.11, 3.75, 3.08)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Klacid MR (Total Number Recovered)  658  7.060  2.650  6.857  7.263
CARM  Klacid MR (URTI, Recovered)  491  6.760  2.110  6.573  6.947
CARM  Klacid MR (LRTI, Recovered)  148  7.820  3.750  7.211  8.429
CARM  Klacid MR (URTI and LRTI, Recovered)  19  9.050  3.080  7.565  10.535

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and 0 analyses. The primary outcome is average time from baseline to recovery from cough and other symptoms; a secondary outcome is the number and type of adverse events. The record does not report a prespecified testing hierarchy, multiplicity adjustment, or a plan explaining how conclusions were to be drawn across outcomes. That information is not reported in the registry record.

In general, when several outcomes or statistical tests are considered, the chance of a false-positive finding can increase if each is treated as an independent opportunity for significance. A prespecified hierarchy or adjustment can address that issue, but it is not appropriate to assume one was used without documentation. Here, no analyses or p-values are listed, so the registry does not permit an assessment of multiplicity in the reported results.

Missing-data handling is also not reported in the registry record. The primary endpoint relies on symptom ratings and associated dates, with an appointment 6 to 14 days after baseline and an endpoint timeframe of baseline to 14 days. The record does not state how absent follow-up, incomplete symptom ratings, or recovery not observed during the timeframe were treated. It does not report whether any imputation, censoring rule, or sensitivity analysis was used.

The population description identifies a per-protocol population of 694 and states that 66 participants were excluded for protocol deviations, with some participants having more than one deviation. Examples include age less than 18 years, taking excluded drugs, and treatment duration outside the specified range. The complete list of deviation details and the analysis population used for each outcome are not reported in the registry record. No comparison of participants included and excluded from the per-protocol population is given. These omissions limit assessment of possible selection effects and the robustness of any outcome summary.

12. Safety Results

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

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’s adverse-event summary lists the Klacid MR group with 760 at risk for serious adverse events and 0 affected. For other adverse events, it lists 760 at risk and 5 affected. The record does not report deaths. These are the event entries available in the registry record; they should be read as descriptive counts rather than as a comparison between treatments.

The summary does not identify the specific serious or other adverse-event terms. No serious-event terms are listed, and the registry does not provide detail about the type, timing, severity, duration, or assessed relationship of the other adverse events to treatment. It also does not report a comparator group against which these entries could be interpreted.

In general, an adverse-event count is not by itself an estimate of treatment-attributable risk. Interpretation depends on how events were defined and collected, the period of observation, completeness of reporting, and whether similar participants were observed under a comparison condition. The record gives an at-risk count for each category, but does not provide those additional details. The absence of a reported death value should not be read as a confirmed zero; deaths are not reported in the registry record.

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

The registry documents a post-marketing observational study of Thai patients with upper or lower respiratory tract infections treated with Klacid MR. It specifies recovery time as the primary outcome, defines recovery as disappearance of all signs and symptoms of infection, and describes symptom ratings and follow-up timing. These details help clarify what the investigators intended to measure.

The result needed to describe the observed recovery time is not reported in the registry record. The record gives no numerical mean or standard deviation for the primary outcome and no confidence interval, p-value, or treatment-effect estimate. Consequently, it is not possible from this record to assess the average recovery time observed in the analyzed population or the precision of such an estimate.

The registry describes one treated group and no comparator. The study’s hypothesis that Klacid MR shortens symptom recovery time is a stated expectation, not a demonstrated comparison. A recovery-time description in a treated group cannot alone establish what would have happened to comparable patients under another treatment or without the study treatment. The record also does not report an adjusted analysis that might account for differences in patient characteristics or other care.

The record identifies 760 enrolled participants and a per-protocol population of 694, with 66 participants excluded for protocol deviations. Some participants had more than one deviation. This distinction matters because an analysis restricted to a per-protocol group may not describe all enrolled participants equally well, and the registry does not provide results for both populations or details sufficient to assess the effect of exclusions.

The safety entries report 0 serious adverse events and 5 other adverse events among 760 at risk for each category, while deaths are not reported in the registry record. These counts lack a comparator and detailed event descriptions, so they do not establish comparative safety or treatment causation.

Thus, the record supports a description of the study question, setting, endpoint definition, and stated population. It does not support a conclusion about the magnitude or precision of recovery time, whether treatment shortened recovery, or a comparative safety effect.

14. Why This Trial Matters Statistically

This study illustrates why a clearly stated clinical question and a design capable of addressing that question are both important. The investigators’ hypothesis concerns whether Klacid MR shortens symptom recovery time. The registry, however, describes a post-marketing observational study with a treated group and no comparator. That design can describe outcomes among treated patients, but the registry does not identify a comparison that would separate treatment-associated differences from the natural course of infection or other influences.

The endpoint also shows why operational definitions matter. Recovery was defined as disappearance of all signs and symptoms of infection, while symptoms could be rated as resolved, improved, not changed, or worse at follow-up. A broad endpoint definition can be clinically interpretable, but its analysis depends on how dates and incomplete observations are handled. Those analysis details are not reported in the registry record.

The difference between enrollment and the stated per-protocol population is another useful statistical consideration. The record reports 760 enrolled and a per-protocol population of 694, with protocol deviations cited as the reason for exclusions. Exclusion rules can shape the population represented by an analysis. Without outcome results for the enrolled population, complete deviation details, and information about missing data, readers cannot judge how those exclusions affect the recovery-time summary.

Finally, statistical precision cannot be judged from a study description alone. The registry specifies a mean and standard deviation as the intended summary, but does not report their observed values or a confidence interval. The result is therefore not merely uncertain; the numerical endpoint result is absent from the registry record. This case underscores the distinction between a registered hypothesis, a defined outcome, and a reported analysis. Each is necessary for a complete statistical interpretation, but they are not interchangeable.

15. 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 principal limitation for interpreting the primary question is that the registry record does not report the numerical recovery-time result. The mean and standard deviation are specified as the outcome summaries, but neither value is listed. No confidence interval or treatment-effect estimate is reported, so neither the observed average nor its precision can be assessed.

The study is observational and no comparator is described. Allocation is not stated, and the registry does not report an analysis designed to estimate a comparative treatment effect. The findings therefore cannot establish whether recovery under Klacid MR was faster than under another treatment or without treatment.

The primary outcome depends on symptom resolution and dates recorded during follow-up. Although the record defines recovery and describes follow-up timing, it does not report how incomplete observations or recovery not observed within the timeframe were handled. It also does not report the analysis model, any adjustment for other factors, or a sensitivity analysis.

The record reports a per-protocol population of 694 and says 66 participants were excluded for protocol deviations, some more than once. It gives examples of deviations, but the complete details of all reasons are not reported in the registry record. Results for an all-enrolled population and information comparing included with excluded participants are not reported.

Finally, the safety summary provides counts but little event detail. Specific event types, timing, treatment relationship, and deaths are not reported in the registry record. These limitations constrain both outcome interpretation and assessment of how broadly the results might apply.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Recovery Time in Thai Patients With Upper or Lower Respiratory Tract Infections Treated With Klacid MR — NCT01076153.
• Registry record last updated 2011-07-12; status last verified 2011-06.
• Results first posted 2011-06-29.
• 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.

19. Record Summary

This completed, multicenter post-marketing observational study evaluated recovery time among Thai patients with upper or lower respiratory tract infections treated with Klacid MR. The registry lists enrollment of 760 and identifies Abbott as the sponsor. The listed study period began in 2008-12, with primary completion in 2010-04.

The primary outcome was average time from baseline to recovery from cough and other symptoms, measured in days over baseline to 14 days. Recovery was defined as disappearance of all signs and symptoms of infection. The record describes a per-protocol population of 694 and exclusions for protocol deviations.

No comparator is described. The numerical primary-outcome result and inferential analyses are not reported in the registry record. Safety entries list 0 serious adverse events and 5 other adverse events among 760 at risk for each category; deaths are not reported.