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 Probiotics and Health-related Quality of Life in Individuals With Seasonal Allergies (NCT02349711), a randomized na study. The primary outcome is Change in Health-related Quality of Life Score From Baseline to the Peak Week of Allergy Season for Probiotic Versus Placebo, as Measured by MiniRQLQ.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02349711 |
| Phase | NA |
| Condition | Healthy |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 224 |
| Arms in the primary outcome | 2 |
| Lead sponsor | University of Florida |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns individuals with seasonal allergies. The registry record’s condition entry says Healthy, while its title and study description refer to seasonal allergies; this difference in wording is not resolved in the record. The registry reports enrollment of 224 and describes an intent-to-treat analysis of randomized participants, with missing outcome values excluded rather than imputed.
Intervention
The intervention was a mixture of Lactobacillus gasseri, Bifidobacterium bifidum, and Bifidobacterium longum. The detailed arm description says the supplement was taken as a capsule twice daily for 8 weeks. The brief summary describes participants receiving a daily probiotic or placebo for 8 weeks, so the dosing frequency is worded differently in those record entries.
Comparator
The comparator was placebo, described in the arm entry as a capsule taken twice daily for 8 weeks. The study is described as placebo-controlled and randomized. Its allocation is listed as randomized, its model as parallel, and its masking as triple; the brief summary separately calls it double-blind.
Primary question
The primary question was whether the change in MiniRQLQ score from baseline to the peak week of allergy season differed between the probiotic-mixture and placebo groups. The MiniRQLQ global score averages 14 questions and ranges from 0, not troubled, to 6, extremely troubled. The posted contrast is a mean difference in change scores, expressed in units on that scale.
The record describes a study lasting up to 8 weeks from randomization, with the intervention period described as 8 weeks. It also lists questionnaires assessing stress, physical activity, gastrointestinal symptoms, adverse events, and compliance. A subset was to provide stool and blood samples at baseline and week 6 to characterize microbial communities and immune function. The main posted numerical comparison concerns quality-of-life change, rather than those additional measurements.
3. Trial Design
The registry describes a randomized, parallel-group comparison of a probiotic mixture with placebo. It lists enrollment of 224 and a completed study. The recorded start was 2015-01 and primary completion was 2015-05. The record lists phase as NA. It gives University of Florida as the sponsor.
The two arm descriptions identify the probiotic mixture and placebo as dietary supplements. The detailed descriptions state that each was taken as a capsule twice daily for 8 weeks. The brief summary instead describes a daily probiotic or placebo for 8 weeks. These descriptions therefore differ in their wording about frequency, and the registry record does not clarify the difference. The study is described as randomized and placebo-controlled. The masking field says triple, while the brief summary says double-blind; the record does not explain this difference.
The primary outcome was change in health-related quality-of-life score from baseline to the peak week of allergy season, measured by MiniRQLQ. The primary outcome timeframe is described as up to 8 weeks from randomization. The posted group summaries include 80 for placebo and 81 for probiotic mixture. The registry’s population description says all randomized participants were considered for an intent-to-treat analysis, but also says no imputation was done and missing values excluded a participant from analysis. Thus, the analysis population can be smaller than the randomized population when measurements are missing.
Other planned assessments included serum total immunoglobulin E, constipation symptom score measured by the GSRS questionnaire, and regulatory T cells. The brief summary also lists stress, physical activity, gastrointestinal symptoms, adverse events, and compliance, and describes stool and blood sampling in a subset. The posted numerical primary comparison is the MiniRQLQ result; detailed estimates for the other outcomes 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: Before randomization, participants provided anthropometric measurements and demographic information. Out of the 224 participants who consented to participate, only 173 remained at randomization due to the participants no longer being interested or not coming to their study visits to be randomized.
Overall Study
| Stage | Placebo | Probiotic Mixture |
|---|---|---|
| STARTED | 87 | 86 |
| COMPLETED | 84 | 84 |
| NOT COMPLETED | 3 | 2 |
Reasons for not completing this period:
| Reason | Placebo | Probiotic Mixture |
|---|---|---|
| Withdrawal by Subject | 2 | 1 |
| Lost to Follow-up | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: Because this was an intent-to-treat study, all data from all randomized participants was considered for analysis. No imputation was done, so missing values excluded a participant from the analysis. While data from a participant may be missing, they were considered to have "completed" the study if they completed all study visits.
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 | Placebo | Probiotic Mixture | Total |
|---|---|---|---|---|
| Participants analysed | 87 | 86 | 173 | |
| Age, Continuous | years | 27.6 (SD 13.1) | 26.0 (SD 10.8) | 26.8 (SD 12.0) |
| Sex: Female, Male: Female | Participants | 65 | 54 | 119 |
| Sex: Female, Male: Male | Participants | 22 | 32 | 54 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Health-related Quality of Life Score From Baseline to the Peak Week of Allergy Season for Probiotic Versus Placebo, as Measured by MiniRQLQ, measured over up to 8 weeks from date of randomization.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | Standard Error |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in the MiniRQLQ global score from baseline to the peak week of allergy season. MiniRQLQ is a health-related quality-of-life questionnaire for allergic rhinitis symptoms. The record describes a global score formed as an average of 14 questions, with values from 0, not troubled, to 6, extremely troubled, and says the score includes all domains. This makes the endpoint a continuous measure: it can express not only whether a participant’s score changed, but the size and direction of that change.
Using change from baseline focuses the comparison on how scores shifted during the study period rather than on a single follow-up score alone. The primary question compares those changes between the probiotic-mixture and placebo groups at the peak week of allergy season. A negative change represents a decrease on a scale where higher values indicate being more troubled. The posted group estimates are least-squares means, with standard errors, and the between-group estimate is a mean difference.
Quality of life is relevant to the study’s stated topic because the outcome captures participants’ reported experience across the questionnaire’s domains. It is distinct from biological measures such as serum IgE or regulatory T cells, which are listed as secondary outcomes. The registry record does not report a threshold for a clinically important MiniRQLQ change or explain how the peak week was selected. Consequently, the posted score contrast can be interpreted as a difference in measured changes, but its clinical importance cannot be determined from the record alone.
7. Results Posted in the Registry
- Probiotic Mixture: mean -0.68 versus -0.19 on control; difference -0.48 (95% CI -0.86 to -0.11), standardized effect d = -0.40; z-test p = 0.011.
Mean difference: Probiotic Mixture
95% CI: -0.86 to -0.11
Recalculated from the posted summary statistics
8. Statistical Interpretation
The posted least-squares mean change was -0.195 for placebo and -0.677 for the probiotic mixture. The reported mean difference for probiotic mixture relative to placebo was -0.483, with a confidence interval from -0.855 to -0.110. On the MiniRQLQ scale, a negative change is a decrease in reported trouble. The negative contrast therefore describes a greater average decrease in the probiotic group’s score than in the placebo group over the specified measurement period. This is a description of the posted result, not a conclusion about treatment effectiveness.
The registry reports an unadjusted p value of 0.011. It indicates how compatible the observed contrast is with a null model of no difference under the analysis assumptions; it does not measure the probability that the null model is true, nor does it establish whether the size of the contrast matters to participants. No adjusted p value is reported in the registry record. The confidence interval gives a range of values compatible with the reported analysis and conveys uncertainty around the estimated mean difference.
The group estimates are summaries of change, not final MiniRQLQ scores. They do not show how individual participants’ scores varied, how many improved or worsened, or whether the pattern was similar across questionnaire domains. The standard errors describe uncertainty in the estimated group means; they are not standard deviations of individual scores. The posted comparison uses least-squares means, but the registry record does not report the full model specification, covariates, or handling of repeated measurements. The point estimate and interval should therefore be read as the registry’s reported summary rather than as a complete account of the analysis.
The registry describes the study as intent-to-treat, but also says missing values were not imputed and that a participant with missing data was excluded from the analysis. This means the outcome calculation did not include missing measurements through an imputation procedure. The record does not report the number or pattern of missing primary-outcome values, or whether missingness differed between groups. This limits assessment of how well the analyzed participants represent all randomized participants.
Three secondary outcomes are listed, and the study summary mentions further assessments. The unadjusted p value should be understood in that setting: the registry record does not report a multiplicity adjustment or a prespecified hierarchy for interpreting multiple outcomes. It also does not report a clinically important difference threshold. The result provides evidence about the observed score contrast and its statistical precision, but does not by itself establish the practical importance, persistence, or generalizability of the difference.
9. Statistical Methods Explained
The primary outcome is continuous, so its group summaries describe average changes in a numerical score. The registry identifies the reported parameter as a least-squares mean and its dispersion as a standard error. A least-squares mean is a model-based estimate of a group mean. It can account for terms included in the fitted model, but the registry record does not describe which terms were included. The term should therefore not be taken to imply a particular adjustment or covariate set.
What does a standard error describe?
A standard error expresses the precision of an estimated mean, rather than the spread of individual participant scores. Smaller standard errors generally correspond to more precise estimates under the model. The posted standard errors are 0.139 for placebo and 0.130 for the probiotic mixture. They help characterize uncertainty in each group estimate, but do not show the full range of participant experiences. Individual-level distributions are not reported in the registry record.
How should the mean difference be read?
The posted comparison gives a mean difference of -0.483 for probiotic mixture relative to placebo. It is the contrast between the groups’ estimated changes, on the MiniRQLQ scale. Because more negative change means a larger decrease in score, the negative estimate indicates that the average score reduction was greater in the probiotic arm in this analysis. The group means and mean difference are reported values; no additional calculation is needed to interpret their direction. The contrast is an average and does not imply that every participant experienced a change of that size or in that direction.
What does the confidence interval add?
A confidence interval describes uncertainty around an estimated contrast under the analysis method. The reported interval extends from -0.855 to -0.110. Both endpoints are below zero, so the interval is compatible with a negative mean difference across the values it contains. It does not state that the true effect has a particular probability of lying inside this specific interval. It also does not incorporate uncertainty about unreported design choices, missing-data assumptions, or selective reporting.
What does the p value say?
The registry reports an unadjusted p value of 0.011. A p value summarizes how unusual an observed result, or a more extreme one, would be under a specified null hypothesis and statistical model. It is not a measure of effect size or a probability that the intervention has no effect. The record does not provide the full test specification or a multiplicity-adjusted p value. The term unadjusted is important because the record lists multiple outcomes and does not state that this result was adjusted for testing them.
Why can over-dispersion matter in general?
In general, over-dispersion means that variation in the data is greater than a model assumes. When a model underestimates variation, standard errors can be too small and intervals too narrow. This concept is especially relevant to outcomes whose variability is not well described by the assumed distribution. The primary endpoint in this trial is a continuous questionnaire score, and the registry record does not report an over-dispersion assessment or a diagnostic result. This general issue should not be read as evidence that over-dispersion occurred in this analysis.
What is not described about the model?
The registry provides the model-based group estimates and the comparison, but does not report the model formula, covariates, assumptions checks, or details of the test used to produce the interval and p value. It also does not report whether any interim analyses occurred or describe a statistical analysis plan. Those elements are not reported in the registry record, so the model cannot be independently reconstructed from the posted summary statistics alone.
How does missingness affect the analysis?
The registry states that all randomized participants were considered for an intent-to-treat analysis, no imputation was done, and missing values excluded a participant from analysis. In general, an analysis that omits missing outcomes uses the measurements that are available; its interpretation can depend on why values are missing and whether missingness is related to group or outcome. The record does not report missing-value counts or reasons, so the impact of missingness cannot be evaluated from the posted results.
What should be made of the planning calculations?
The sample-size planning figures are illustrative calculations based on the observed effect and specified assumptions, not a report of the trial’s original design calculations. In general, planning calculations relate a target effect, variability assumptions, significance level, allocation, and desired power to a required sample size. Here, the registry record does not report the trial’s original sample-size justification or its original design assumptions. The planning calculation assumptions that are reported are described with the sample-size reading.
10. Confidence Intervals and Precision
The reported mean difference is -0.483, and its confidence interval runs from -0.855 to -0.110. The interval is entirely below zero, which is consistent with the negative direction of the estimated contrast. Its width conveys uncertainty: values closer to zero and values representing a larger negative contrast are both compatible with the reported analysis. The interval should be considered alongside the point estimate rather than treating the estimate as exact.
Confidence intervals are useful because they show a range of effect sizes that are reasonably compatible with the data and the analysis method. They do not show the distribution of individual responses, nor do they establish that the effect is clinically important. The record gives no threshold for interpreting a MiniRQLQ change as clinically meaningful. Whether the interval contains values that would be considered important to patients cannot therefore be resolved from the registry record.
The group standard errors are 0.139 for placebo and 0.130 for the probiotic mixture. These describe precision of the estimated means, not participant-to-participant variability. The registry also reports an unadjusted p value of 0.011, but does not report an adjusted result. The interval and p value reflect the analysis as posted and do not account for uncertainty from unreported model choices or missing-data patterns.
Precision is not the same as certainty about generalization. The registry record does not report the number or pattern of missing primary-outcome measurements, the full statistical model, or a clinically important difference threshold. These omissions matter when judging how stable and practically interpretable the numerical contrast may be. The interval supports a statistical reading of the estimated difference, while leaving those other questions open.
11. 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.
| Effect to detect | Participants per arm, 80% power | Participants per arm, 90% power |
|---|---|---|
| 100% of the observed effect | 99 | 132 |
| 75% of the observed effect | 175 | 234 |
| 50% of the observed effect | 393 | 525 |
The planning figures are participants per arm, not total event counts. They are illustrative calculations based on the observed effect, using a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. For 100% of the observed effect, the planning figures are 99 participants per arm for 80% power and 132 participants per arm for 90% power. For 75% of the observed effect, they are 175 participants per arm for 80% power and 234 participants per arm for 90% power. For 50% of the observed effect, they are 393 participants per arm for 80% power and 525 participants per arm for 90% power.
The 80% power column gives the calculated number of participants per arm under which the assumed effect would be detected at the stated significance level in 80% of repeated studies, if the planning assumptions hold. The 90% power column gives the corresponding planning number for 90% power. These are planning targets, not guarantees about a particular study. They are not observed power.
The effect fractions describe planning for a smaller effect than the observed estimate. Smaller effects need more participants to detect under otherwise unchanged assumptions, as reflected in the larger planning figures for 75% and 50% of the observed effect. The curve should be read as a display of this planning relationship, not as additional trial outcome evidence. The registry’s own original sample-size assumptions and justification are not reported in the registry record; these calculations should not be mistaken for the trial’s original design plan.
12. 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 z1−α/2 = 1.960) and the desired power (z1−β = 0.842 for 80% and 1.282 for 90%).
Formula
n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.
Worked calculation for this trial
- Observed difference Δ = -0.483; pooled standard deviation σ = 1.206.
- n = 2 × (1.96 + 0.842)2 × 1.2062 / -0.4832 = 98.0, rounded up to 99 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
delta <- -0.4826 # observed difference in means
sigma <- 1.20600219656235 # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^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 (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")
# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2349711)
n <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n)) # difference in sample means
s2 <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1)) # pooled sample variance
tstat <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))
Output from running the code
100% of observed effect: n per arm = 99 (80% power), 132 (90% power)
75% of observed effect: n per arm = 175 (80% power), 234 (90% power)
50% of observed effect: n per arm = 393 (80% power), 525 (90% power)
power.t.test: 99
Simulated power at n = 99 per arm: 0.799 (20000 replicates)The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-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.
13. Multiplicity, Missing Data and Analysis Populations
The registry lists three secondary outcomes: serum total IgE, constipation symptom score measured by the GSRS questionnaire, and regulatory T cells. The study summary also mentions assessments of stress, physical activity, gastrointestinal symptoms, adverse events, and compliance. The primary outcome is the MiniRQLQ change score. Because multiple outcomes are part of the study, the interpretation of an unadjusted p value depends partly on whether a testing strategy was specified. A multiplicity adjustment, testing hierarchy, or other strategy is not reported in the registry record.
The posted primary comparison has an unadjusted p value of 0.011. No adjusted p value is reported in the registry record. The record also does not describe interim analyses or state whether there was a prespecified statistical analysis plan. It is therefore not possible to determine from the posted information how multiplicity was handled in the trial’s planned analysis. The unadjusted result should not be treated as if a correction for multiple outcomes had been applied.
The population description uses intent-to-treat language, saying data from all randomized participants were considered. It also states that no imputation was done and that missing values excluded a participant from the analysis. This is not an analysis in which missing outcomes were filled in with estimated values. The record does not report how many primary-outcome measurements were missing, why they were missing, or whether the pattern differed by group. Without those details, the possible effect of missingness on the estimated contrast cannot be assessed.
The analysis population may consequently differ from the full randomized population for this outcome, despite the stated intent-to-treat approach. The registry record does not describe additional sensitivity analyses for missing data or provide alternative estimates under different assumptions. Nor does it report a sample-size justification or details of the original analysis plan. These uncertainties affect assessment of robustness, but they do not change the numerical estimates that the registry posts.
14. 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 |
|---|---|---|---|
| Placebo | 0 | 87 | 0.0% |
| Probiotic Mixture | 0 | 86 | 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 |
|---|---|
| Placebo | 0 of 87 |
| Probiotic Mixture | 0 of 86 |
The serious adverse event figures list zero serious events among 87 at risk in the placebo group and zero among 86 at risk in the probiotic-mixture group. The other adverse event figures also list zero events in each group, with the same at-risk counts. No serious adverse event terms are listed. These are event counts as reported in the registry, not percentages, and no rates should be inferred from them.
The deaths field is null for both groups, so deaths are not reported in the registry record; a null entry should not be read as a reported zero. The adverse-event at-risk figures differ from the primary-outcome group counts, and the record does not explain the difference. The adverse-event figures describe the recorded categories during the reported observation period; they do not establish that no events occurred outside the categories or reporting process represented in the registry.
Zero reported events in these summaries does not establish that an intervention is free of risk. The record does not provide event narratives, exposure-adjusted rates, or detailed information about ascertainment and follow-up. These figures should be read narrowly as the posted adverse-event counts and at-risk group sizes, without extrapolating beyond them.
15. What the Result Does, and Does Not, Mean
The posted primary result describes a difference in average MiniRQLQ change between the probiotic-mixture and placebo groups. The estimated difference is -0.483, with a confidence interval from -0.855 to -0.110. As higher MiniRQLQ scores indicate being more troubled, the negative direction corresponds to a greater average reduction in the probiotic group’s score in the posted comparison. This is an interpretation of the reported score contrast, not a statement that the intervention works or does not work.
The result does not establish how much individual participants changed, whether a majority changed in the same direction, or whether effects were consistent across the MiniRQLQ domains. It also does not establish that the difference is important to participants: the registry record does not report a clinically important change threshold. The confidence interval describes statistical precision under the analysis, while practical importance requires context that is not included in the record.
The record’s intention-to-treat wording is qualified by its statement that missing values were not imputed and led to exclusion from analysis. The extent and pattern of missingness are not reported, so the influence of those exclusions is unknown. The registry also does not provide the full statistical model, a multiplicity adjustment, or the original sample-size justification. These limitations make it difficult to assess every aspect of robustness from the registry information alone.
The trial compared a specific mixture with placebo during a defined seasonal-allergy study period. The record does not establish whether results apply to other probiotic formulations, populations, settings, or longer periods. The posted primary estimate is therefore best understood as a result for this trial’s measured MiniRQLQ change and the analysis described in the registry, not as a general claim about probiotics or all people with seasonal allergies.
16. Why This Trial Matters Statistically
This trial illustrates why the numerical contrast, its uncertainty, and the endpoint’s meaning should be read together. A mean difference conveys the average separation in change between groups, while a confidence interval shows the range of estimates compatible with the analysis. A p value addresses a statistical null model, not clinical importance. Keeping these questions distinct prevents a single statistic from carrying more meaning than it can support.
The endpoint is a patient-reported quality-of-life measure, not a laboratory marker. That distinction matters because participant experience and biological outcomes answer different questions. The registry lists serum total IgE and regulatory T cells among secondary outcomes, but the posted primary result is the MiniRQLQ contrast. The primary result should not be conflated with unreported secondary findings.
The record also highlights the importance of clear reporting. Its population entry says Healthy while its title and summary concern seasonal allergies; its masking field says triple while the summary calls the study double-blind; and the brief dosing description differs from the detailed arm entries. Such wording differences do not change the posted effect estimate, but they complicate reconstruction of the study context. Missing-data handling, multiplicity, and the full model are also not described in detail.
Finally, planning calculations based on an observed effect are not the same as a trial’s original design rationale. They can illustrate how a smaller target effect generally requires more participants under stated assumptions, but they cannot establish whether the completed study was designed with adequate power. That original justification is not reported in the registry record. Taken together, these distinctions support a careful statistical reading without extending beyond what the record documents.
17. 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 has limitations specific to interpreting this trial. It gives different descriptions of masking: the masking field says triple, while the brief summary says double-blind. The detailed arm descriptions state twice-daily capsules, while the brief summary describes a daily probiotic or placebo. The record does not resolve these wording differences. Its condition entry says Healthy even though the title and summary concern individuals with seasonal allergies.
The population description says the analysis was intent-to-treat, but also states that no imputation was performed and missing outcome values excluded a participant from the analysis. The record does not state how many primary-outcome observations were missing, why they were missing, or whether missingness differed between arms. The posted group counts for the outcome are 80 for placebo and 81 for probiotic mixture, while the adverse-event at-risk counts are 87 and 86, respectively; the record does not explain the distinction.
The reported outcome summary does not include the full model specification, covariates, diagnostic checks, analysis plan, or details of any interim analyses. A multiplicity adjustment is not reported, despite secondary outcomes and other assessments being listed. The record also does not report a clinically important MiniRQLQ threshold, detailed results for the secondary outcomes, or the trial’s original sample-size justification. These omissions limit independent assessment of the analysis and the practical meaning of the primary estimate.
The study describes a specific mixture and seasonal assessment period. The registry record does not provide enough information to establish applicability beyond the study population and intervention as described. These limitations concern what can be concluded from the registry record; they do not alter the posted estimates.
18. Related Tutorials
19. Related Statistical Calculators
20. Sources
- ClinicalTrials.gov: Probiotics and Health-related Quality of Life in Individuals With Seasonal Allergies — NCT02349711.
- Registry record last updated 2017-06-09; status last verified 2017-05.
- Results first posted 2016-08-31.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
21. Record Summary
The registry describes a completed randomized, parallel, placebo-controlled study of a probiotic mixture in individuals with seasonal allergies. Enrollment was 224, and the listed sponsor was University of Florida. The intervention and placebo were described as capsules taken for 8 weeks, although the record differs in its wording about dosing frequency and masking.
The primary outcome was change in MiniRQLQ global score from baseline to the peak week of allergy season. The posted least-squares mean changes were -0.195 for placebo and -0.677 for the probiotic mixture. The mean difference was -0.483, with a confidence interval from -0.855 to -0.110 and an unadjusted p value of 0.011.
The registry lists secondary biological and symptom outcomes, but their detailed results are not reported in the registry record. It reports zero serious and other adverse events in the listed groups; deaths are not reported. Missing primary-outcome values were not imputed and were excluded from analysis. The full statistical model, multiplicity approach, and original sample-size justification are not reported in the registry record.