Congenital Sucrase-Isomaltase Deficiency (CSID) Genetic Prevalence Study (GPS): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Congenital Sucrase-Isomaltase Deficiency (CSID) Genetic Prevalence Study (GPS) (NCT01914003), a registered phase not stated study. The primary outcome is Prevalence of CSID Genetic Variants.

2. Clinical Question

This is a prevalence question in a selected group, not a randomized comparison of treatments. The symptom criteria define the population in which the variants were assessed; they do not establish that any symptom was caused by a variant. The study description says the population was enriched for children with chronic, idiopathic symptoms. Therefore, a result from this group would address variant prevalence among those children, not prevalence among all children. The registry record reports 53 participants enrolled and a primary outcome timeframe of 1 year. It does not provide the primary outcome count, a prevalence estimate, or the results needed to assess how precisely the question was answered.

3. Trial Design

The study, titled the Congenital Sucrase-Isomaltase Deficiency (CSID) Genetic Prevalence Study, was a multicenter study. Its official title describes assessment of known CSID genetic variants and functional sucrase activity by a 13C-sucrose breath test in children with chronic diarrhea or chronic abdominal pain. The registry record lists 53 participants enrolled, a start date of 2013-05, a primary completion date of 2015-05, and a status of completed.

The registry describes two categories: participants with one or more known CSID mutations and controls without any known CSID mutations. These are mutation-status groups, not treatment arms. The record does not state the allocation method and cautions that the groups are not a like-for-like control comparison. The available information does not establish whether the groups were comparable in symptom history or other characteristics, nor does it describe how participants were selected within the eligible symptom group.

The primary outcome is titled “Prevalence of CSID Genetic Variants.” It is expressed as a number of participants, with a timeframe of 1 year, and applies to children 18 years of age or younger whose primary symptom was chronic idiopathic diarrhea or chronic abdominal pain without constipation. The brief study description says the gene was assessed for a panel of known CSID mutations and that functional deficiency would also be assessed using a breath test. However, the registry lists one outcome measure and does not report a breath-test outcome or a primary genetic-variant result.

The registry record does not report a protocol-level statistical plan, participant flow, detailed eligibility criteria beyond the primary outcome description, or the timing of individual assessments. No randomized treatment comparison is described. The study is best read as a descriptive prevalence investigation in a symptom-selected population, while recognizing that the posted record does not contain the outcome data needed to quantify that prevalence.

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

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 Prevalence of CSID Genetic Variants, measured over 1 year.

The primary endpoint concerns the prevalence of known CSID genetic variants among children in the study’s defined symptom group. The registry labels the outcome as a number of participants and specifies a 1 year timeframe. Its description limits the population to children 18 years of age or younger with chronic idiopathic diarrhea or chronic abdominal pain without constipation.

In general, prevalence describes how common a characteristic is within a defined population. Counting participants with a known variant can help describe that characteristic, provided the eligible population and the relevant denominator are clear. The registry record does not report the primary count or an accompanying prevalence estimate, so the endpoint cannot be quantified from the posted results. A count alone would also need to be interpreted within the study’s selected population; it would not automatically describe all children.

The study’s official title refers to functional sucrase activity assessed by a 13C-sucrose breath test. The brief description also mentions functional deficiency assessment. The registry record does not report a breath-test measure or result, so that aspect cannot be interpreted alongside the genetic endpoint. The endpoint’s stated purpose is descriptive: to characterize known variants in the specified group, rather than to estimate a treatment effect or establish that a genetic finding caused an individual child’s symptoms.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is described as a count of participants with known CSID genetic variants. A count is a descriptive statistic: it records how many people meet an outcome definition. For a prevalence question, that count is normally interpreted relative to a clearly defined population or denominator. The registry gives the outcome’s target population and timeframe but does not report the primary count or a prevalence estimate. No numerical prevalence conclusion can therefore be drawn from the posted outcome record.

What does a prevalence estimate describe?

In general, prevalence describes the frequency of a condition or characteristic in a defined population. Its meaning depends on how that population was selected and how the characteristic was defined. Here, the target population is children 18 years of age or younger with chronic idiopathic diarrhea or chronic abdominal pain without constipation, and the genetic target is a panel of known CSID variants. This is a symptom-selected group. Any estimate would apply first to that group, rather than automatically to a broader population. The registry record does not provide enough information to assess whether the study participants represent all children meeting those symptom criteria.

Why does the group definition matter?

The mutation group is defined by one or more known CSID mutations; the control group is defined by not having any known CSID mutations. This is a classification based on genetic status, not assignment to an intervention. In general, a comparison between groups can be affected by differences in who enters each group, how characteristics are measured, and whether other relevant factors differ. The registry says allocation was not stated and cautions that the groups are not a like-for-like control comparison. No adjusted analysis or group-characteristic information is reported, so a causal interpretation would not be justified.

How should uncertainty be understood?

In general, a confidence interval describes a range of values compatible with the data under a specified statistical method. It conveys precision as well as the estimate itself: a more informative interval gives readers a sense of how much uncertainty remains. The registry record does not report a confidence interval for the genetic endpoint, and it does not provide the primary count from which readers could assess the result. A statistical test or p-value would answer a different question about compatibility with a specified null hypothesis; neither is reported for the primary endpoint.

The registry describes the primary outcome as a count, which is a binary-outcome setting at the participant level: each person either meets the defined outcome or does not. In general, binary data can be summarized with counts and proportions. If observations are clustered, for example by site, methods may need to account for that dependence; the registry identifies the study as multicenter but does not report whether or how site was handled analytically. There is no basis in the record to assert that a particular model, adjustment, or variance method was used.

What does the planning illustration mean?

In general, sample-size calculations are prospective planning tools. The registry’s planning description specifies a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; it says the effect to detect is a stated fraction of the observed effect. Those assumptions describe an illustration, not a report of the trial’s design justification or an observed statistical result. The registry does not report that these assumptions formed the study’s original protocol or sample-size rationale. Planning sample sizes are not observed power, and they do not establish whether the study had adequate precision for its prevalence question.

For an outcome measured over time, the event timing and follow-up structure may influence the appropriate method. The primary outcome’s timeframe is stated as 1 year, but the registry does not describe participant-level follow-up, censoring, or a time-to-event analysis. The outcome is described as a participant count, not as a time-to-event measure. No inference about an unreported analysis should be made from the timeframe alone.

The study title refers to functional sucrase activity assessed with a 13C-sucrose breath test. In general, a functional measure and a genetic classification address related but distinct constructs: one concerns measured activity, while the other concerns the presence of variants. A relationship between them would require reported measurements and an analysis. The registry record does not include breath-test results or a statistical analysis relating activity to genetic status. Thus, the title identifies an intended study element, but does not supply evidence about its results.

Finally, a completed registry status indicates that the study is recorded as completed; it does not communicate the statistical quality, completeness, or precision of the reported results. The record lists no analyses and does not document the inferential methods, missing-data approach, or analysis population. Those details are necessary for a full appraisal of how the primary question was statistically answered.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("CSID Mutations", "Control")
n      <- c(27, 26)
events <- c(27, 0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  CSID Mutations  27  27  100.0  87.2  100.0  87.5  100.0  87.7  99.9
ARM  Control  26  0  0.0  0.0  13.2  0.0  12.9  0.1  12.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the prevalence of CSID genetic variants, and reports no analyses. It does not describe a prespecified hierarchy of outcomes, adjustments for multiple testing, or any broader analysis plan. The number of outcome measures listed alone does not establish whether multiple comparisons were considered in the study. Any multiplicity strategy is not reported in the registry record.

Missing-data handling is also not reported. The record does not say whether genetic assessments were available for every enrolled participant, how incomplete assessments were treated, or whether any participants were excluded from a particular analysis. It does not provide a primary analysis population or participant flow. The reported enrollment of 53 therefore cannot be assumed to equal the number included in the primary outcome analysis.

The record gives safety counts for the two mutation-status groups, but these are not a substitute for a primary-outcome analysis population. It also does not say whether the breath test was completed by all participants or how missing breath-test measurements were handled. These gaps limit assessment of potential bias and of the applicability of any result. The registry record does not report whether sensitivity analyses were conducted to examine the effects of missing data.

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.

The registry safety entries report zero serious events among 27 at risk in the CSID Mutations group and zero among 26 at risk in the Control group. The entries for other events also report zero affected in each group, with the same respective at-risk counts. These figures describe the events recorded in the registry’s safety fields; they are not the study’s primary genetic-variant outcome.

A zero event count means that no affected participants are recorded for that entry. In general, a zero count does not prove that the underlying event risk is zero, and its interpretation depends on how events were collected and how long participants were observed. The registry record does not report the safety-collection procedures or a detailed safety analysis. It lists no serious-event terms. Death counts are not reported, which should not be read as a reported zero.

The two groups are mutation-status categories, and the record cautions that they are not a like-for-like control comparison. These safety counts should not be used to infer that one group was safer or to make a causal comparison. They are limited descriptive entries in the registry record.

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

The study addresses a clinically specific descriptive question: how many children with chronic idiopathic diarrhea or chronic abdominal pain without constipation had known CSID genetic variants. The registry identifies the target population, the mutation-status group definitions, and the intended focus on genetic prevalence. It also identifies functional sucrase activity by breath test as part of the study’s stated scope.

The posted record does not report the primary genetic count, a prevalence estimate, or a breath-test result. As a result, it cannot establish how common known variants were among the participants, how precisely prevalence was estimated, or how genetic status related to functional sucrase activity. It also cannot show whether genetic status explained any participant’s symptoms. Those questions require outcome data and analyses that are not reported in the registry record.

The study should not be interpreted as a randomized treatment trial. Its two groups are defined by whether known mutations were present, and the registry cautions that they are not a like-for-like control comparison. Differences between these groups, if reported, would not automatically show that mutation status caused an outcome. The information available does not describe a causal analysis or adjustment for other factors.

The safety entries record zero serious and zero other affected participants in each group, but those entries have limited scope and do not resolve the missing primary outcome. Likewise, completed status establishes the registry’s study status but does not supply results that are absent from the record. The main statistical message is that the study question and design are identifiable, while the numerical evidence needed to answer the main question is not reported.

14. Why This Trial Matters Statistically

Prevalence studies depend on a well-defined population and a clearly specified characteristic. This study identifies both: children 18 years of age or younger with chronic idiopathic diarrhea or chronic abdominal pain without constipation, and known CSID genetic variants. That specificity helps define the question and prevents a symptom-selected estimate from being casually treated as prevalence in all children.

The distinction between genetic status and functional activity is also statistically important. The study title refers to genetic variants and functional sucrase activity by a 13C-sucrose breath test. These are distinct types of measurement. Reporting both, together with an analysis of their relationship, could address whether known variants correspond to functional findings in this selected population. The registry record does not report those results, so that potential relationship remains unassessed in the posted information.

The study also illustrates why group labels matter. “CSID Mutations” and “Control” describe mutation status, not randomized treatment assignment. The registry explicitly cautions that the groups are not a like-for-like control comparison. A statistical comparison between categories must therefore be interpreted in light of how the groups arose and what information is available about their characteristics.

Finally, a completed study record without its main outcome count or analysis leaves a gap between a clearly articulated research question and an interpretable result. A prevalence estimate needs its count, denominator, and an account of uncertainty to convey both magnitude and precision. Those elements are not reported for the primary outcome. The record is useful for identifying the intended population and outcome, but it does not allow readers to judge the principal finding.

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 primary limitation for interpretation is that the registry record does not report the primary genetic-variant count or prevalence estimate. It also does not give an uncertainty interval or inferential analysis. The main study question therefore cannot be answered numerically from the posted results.

The population is restricted to children with chronic idiopathic diarrhea or chronic abdominal pain without constipation. The brief description characterizes this as an enriched population. Any result would be specific to the selected group, and the registry does not provide details sufficient to evaluate how participants were recruited or how representative they were of children meeting the symptom criteria.

The mutation-status groups are not described as randomized, and allocation is not stated. The registry warns that they are not a like-for-like control comparison. No group characteristics or adjusted analyses are reported, limiting the interpretation of any potential contrast between groups. The official title and study description refer to functional breath testing, but no breath-test result is reported.

The record lists one outcome measure and no analyses. It does not report a statistical analysis plan, missing-data procedures, analysis populations, participant flow, or multiplicity methods. The stated timeframe is 1 year, but details of follow-up and assessment timing are not reported. These omissions prevent a full assessment of completeness, bias, precision, and statistical methods.

The safety entries contain zero affected participants for the listed serious and other event categories, but the record does not detail safety ascertainment. Death counts are not reported. These entries should be treated as limited registry summaries rather than evidence that no events occurred outside the recorded information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Congenital Sucrase-Isomaltase Deficiency (CSID) Genetic Prevalence Study (GPS) — NCT01914003.
• Registry record last updated 2017-11-06; status last verified 2016-08.
• Results first posted 2016-10-10.
• 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

The registry record identifies NCT01914003 as the completed Congenital Sucrase-Isomaltase Deficiency (CSID) Genetic Prevalence Study. It reports 53 participants enrolled, with a start date of 2013-05 and a primary completion date of 2015-05. The study focused on children with chronic idiopathic diarrhea or chronic abdominal pain without constipation and assessed known CSID genetic variants. Its official title also refers to functional sucrase activity measured by a 13C-sucrose breath test.

The primary outcome is the number of participants with CSID genetic variants over a 1 year timeframe. Groups are defined by presence or absence of known mutations; the record cautions that they are not a like-for-like control comparison. Safety entries report zero serious and zero other affected participants in both groups. The primary genetic result, breath-test findings, analyses, and missing-data methods are not reported in the registry record.