Early-onset Obesity and Cognitive Impairment in Children With Pseudohypoparathyroidism: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Early-onset Obesity and Cognitive Impairment in Children With Pseudohypoparathyroidism (NCT02411461), a registered phase not stated study. The primary outcome is Intelligence Quotient.

2. Clinical Question

The study concerns whether intelligence quotient, measured with the Kaufman Brief Intelligence Test, 2nd Edition, differs among children with pseudohypoparathyroidism type 1a, healthy siblings, and obese patients. The registry describes the latter two groups as controls and identifies pseudohypoparathyroidism type 1a as the study group. Its stated background is that this condition is associated with childhood obesity and learning difficulties; the study description says investigators would examine eating behaviors and perform cognitive testing.

The record does not report group IQ results, an estimated difference, or a statistical test of the groups. It therefore documents the question and the outcome measure, rather than an answer about how the groups compared.

3. Trial Design

This is a completed study sponsored by Vanderbilt University Medical Center. The registry lists enrollment of 39 and gives a start date of 2014-12-01 and primary completion of 2017-01. It describes three groups: pseudohypoparathyroidism type 1a, healthy siblings, and obese patients. The first is designated the study group; the other two are designated control groups.

The registry characterizes the comparison as nonrandomized. Allocation is not stated, and the record cautions that the arms are not a like-for-like control comparison. Consequently, the group labels should not be read as evidence that participants were assigned to groups by chance or that the groups were otherwise comparable. The record does not report how participants entered each group or provide baseline characteristics that would allow readers to assess group similarity.

The brief study description says investigators would investigate eating behaviors and perform cognitive testing, comparing results with healthy siblings and other obese children. The listed primary outcome is intelligence quotient measured with the Kaufman Brief Intelligence Test, 2nd Edition. It is a continuous measure summarized as a mean with standard deviation, with a timeframe of one day.

The registry marks the study completed, but completion status alone does not establish that all planned assessments were obtained or analyzed. No outcome analysis is listed in the record. The protocol details, participant flow, group assignment process, and reasons for any missing measurements are not reported in the registry record. Without those details, the design can be described as a three-group observational comparison, but the strength and comparability of the group evidence cannot be assessed from the record alone.

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 Intelligence Quotient, measured over one day.

The primary endpoint is intelligence quotient, measured with the Kaufman Brief Intelligence Test, 2nd Edition. The registry describes the outcome as standard scores on a scale with mean 100 and standard deviation 15; higher scores indicate better function. The endpoint is recorded as a continuous measure, with the mean and standard deviation specified as the summary statistics and a timeframe of one day.

An IQ score is used in this study as a standardized way to assess cognitive function. Summarizing scores with a mean describes the group’s average measured score, while the standard deviation describes how spread out individual scores are around that average. These summaries address different features of the score distribution and should be read together when results are available.

The registry does not report the observed mean or standard deviation for any group, nor does it provide an estimated comparison. The scale’s stated reference properties explain how to interpret the measure, but they are not results from the children enrolled in this study. The record also does not report additional details about testing conditions, score availability, or the handling of incomplete assessments.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry specifies a continuous primary outcome summarized by its mean and standard deviation. These are complementary descriptive statistics. The mean represents the arithmetic average of the measured scores in a group. The standard deviation describes the spread of scores around that average; it does not describe uncertainty in the mean itself. To assess uncertainty in a mean or a comparison, an analysis would generally also report an inferential measure such as a confidence interval or a test result. No such outcome analysis is listed in this record.

What does a confidence interval add?

As a general statistical concept, a confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. Its width conveys precision: a wider interval indicates less precision than a narrower interval. A confidence interval for a group difference would help readers assess both the possible magnitude and uncertainty of that difference. The registry record does not report an interval or a group-difference estimate, so the precision of any comparison cannot be assessed.

Why does the comparison design matter?

In a randomized study, chance allocation is used to create comparison groups that are, on average, comparable in measured and unmeasured characteristics. That general rationale does not apply: the registry says the comparison is not randomized, allocation is not stated, and the arms are not a like-for-like control comparison. In a nonrandomized comparison, characteristics associated with group membership can also be associated with the measured outcome. This can make it difficult to distinguish a group association from other explanations. The record does not report baseline characteristics or an adjusted analysis that could help readers judge these issues.

Comparing the study group with healthy siblings and with obese patients involves two different reference groups. Each can address a different descriptive contrast, but neither is automatically an interchangeable control for the other. The registry does not specify a hierarchy among these contrasts or report results for them. It also does not give enough detail to determine whether the planned analysis treated the groups jointly, compared them separately, or adjusted for participant characteristics.

What can the sample-size illustrations establish?

The planning assumptions describe illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not evidence that the study’s actual design used those assumptions. Because the registry does not report an observed effect or an outcome analysis, the illustrations cannot supply an estimate of the study’s group differences. The record does not report the trial’s own sample-size justification.

Why is the standard deviation relevant?

As a general concept, the spread of individual measurements affects how precisely a group mean or difference in means can be estimated. Greater variability can make a mean less precise when other design features are held constant. The endpoint’s standard deviation is therefore relevant to interpreting results and planning a future study. The scale’s reference standard deviation is part of the measure’s stated scoring context; it is not the observed standard deviation for these groups. No group-specific standard deviations are reported in the registry record.

What is missing from the analysis record?

The registry lists one outcome measure and zero analyses. It does not report a model, a group contrast, a confidence interval, a test statistic, or a p-value for intelligence quotient. It also does not report whether assumptions were checked, whether transformations or covariate adjustments were used, or how any incomplete observations were handled. These omissions prevent a reproducible interpretation of an endpoint result because no result or analysis is recorded. General statistical principles can explain how such methods work, but they cannot fill in methods or findings that are not reported.

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("Pseudohypoparathyroidism Type 1a", "Healthy Siblings", "Obese Patients")
n   <- c(16, 8, 15)
m   <- c(85.9, 104.3, 103.2)
sp  <- c(17.2, 8.9, 11.5)
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  Pseudohypoparathyroidism Type 1a  16  85.900  17.200  76.735  95.065
CARM  Healthy Siblings  8  104.300  8.900  96.859  111.741
CARM  Obese Patients  15  103.200  11.500  96.832  109.568

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no analyses. It therefore does not report a set of tested hypotheses, a prespecified testing sequence, or a method for controlling multiplicity. Multiplicity becomes relevant when several outcomes, group contrasts, or analyses are considered, because repeated testing can increase the chance of a seemingly notable finding under a null hypothesis. That is a general statistical concern; the record does not establish which comparisons were planned or performed.

The description of three groups raises the possibility of more than one pairwise comparison, but the record does not specify a primary contrast or state how comparisons were to be handled. It would be inappropriate to infer that every possible contrast was tested, or that any particular adjustment was used. No p-values or analysis results are listed.

The registry does not report missing outcome data, completion of cognitive testing by group, reasons for unavailable measurements, or an analysis population. It also does not describe an intention-to-treat population or another rule for inclusion in the endpoint analysis. The enrollment entry and completed status do not establish how many participants contributed endpoint measurements. These details are not reported in the registry record.

In general, missing data can affect interpretation when the likelihood of a measurement being absent is related to a participant’s characteristics or outcome. The impact depends on why values are missing and on the analysis assumptions. Without information about missingness and analysis populations, the extent or direction of any such concern cannot be assessed for this study.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry reports serious adverse events and other adverse events separately for the three listed groups. For pseudohypoparathyroidism Type 1a, the serious-event count is 0 among 16 at risk, and the other-event count is 0 among 16 at risk. For Healthy Siblings, the serious-event count is 0 among 8 at risk, and the other-event count is 0 among 8 at risk. For Obese Patients, the serious-event count is 0 among 15 at risk, and the other-event count is 0 among 15 at risk. The registry also reports 0 deaths in each group.

These entries should be read as the counts recorded in the registry, not as evidence about the primary cognitive outcome. The record does not describe event definitions beyond the serious and other categories, ascertainment procedures, or the duration and completeness of safety follow-up. A zero recorded count does not, on its own, provide information about how completely events were sought or whether the groups had comparable observation. No serious adverse-event terms are listed.

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

The record establishes that the study was designed to assess intelligence quotient in children with pseudohypoparathyroidism type 1a and compare the results with healthy siblings and obese patients. It defines the measure, gives its scoring context, identifies the group labels, and records safety counts. These registry entries describe the research question and available registry entries.

They do not establish the average intelligence quotient in any group. No group means, standard deviations, differences, confidence intervals, or test results are reported. The registry lists no analyses. Consequently, the record cannot show the magnitude or precision of a group comparison, whether any difference was compatible with chance variation, or whether the groups had similar score distributions.

Nor can the study description establish that a group difference, if reported in another source, was caused by the condition. The comparison is nonrandomized, allocation is not stated, and the registry cautions that the groups are not like-for-like controls. Group differences could reflect factors that the registry does not describe. Baseline characteristics and adjusted analyses are not reported in the registry record.

The endpoint’s scale properties should not be confused with observed findings. The stated reference mean and standard deviation describe the scoring scale, while higher scores are defined as better function. They do not indicate how participants in this study scored. Similarly, completed status means the registry identifies the study as completed; it does not confirm that outcome measurements were complete or that an analysis was reported.

The appropriate reading is therefore limited: this is a completed, nonrandomized, three-group study with a defined cognitive endpoint, but the registry record contains no endpoint results. No conclusion about group differences or treatment effects follows from the record.

14. Why This Trial Matters Statistically

This study is statistically notable for the structure of its comparison. The research question places children with pseudohypoparathyroidism type 1a alongside two different control groups: healthy siblings and obese patients. Those reference groups may provide distinct descriptive contexts, but the record explicitly cautions that the arms are not a like-for-like control comparison. This makes careful attention to group comparability central to interpreting any reported score differences.

The endpoint is a continuous cognitive measure, and the record identifies both the mean and standard deviation as relevant summaries. This encourages a distinction between a group’s average score and the variability of scores among its members. Both would be needed to understand the distribution of observed measurements; an inferential estimate would be needed to characterize uncertainty in a comparison.

The record also illustrates why registration status and outcome reporting are not the same thing. The study is marked completed and its endpoint is defined, yet no analyses are listed and no endpoint results are reported. Readers can identify the intended outcome and broad comparison design, but cannot evaluate the observed findings or their precision.

Finally, the planning assumptions associated with sample-size illustrations should be kept separate from the actual study’s reported analysis. They describe a hypothetical planning framework, not observed power and not evidence of a result. The record does not report the study’s own sample-size justification. Together, these features make transparent outcome reporting and clear description of group comparability particularly important for statistical interpretation.

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 registry record does not report intelligence quotient results or any statistical analysis. This is the principal limitation for interpreting the study: the endpoint is defined, but the observed group summaries, comparisons, and their uncertainty are unavailable in the record.

The comparison is nonrandomized, allocation is not stated, and the registry warns that the arms are not a like-for-like control comparison. No baseline characteristics are reported to help assess how the groups differed before testing. The record also does not describe recruitment, eligibility details, or how participants came to be in each group.

Although the registry identifies the outcome as a one-day assessment, it does not report testing completion, missing measurements, participant flow, or the analysis population. It is therefore not possible to establish how much of the enrolled group contributed to the outcome or how incomplete assessments, if any, were handled. The record does not report outcome-assessment procedures beyond naming the Kaufman Brief Intelligence Test, 2nd Edition.

The statistical plan is not described in sufficient detail to identify the intended group contrasts, covariate adjustment, handling of multiple comparisons, or analytic assumptions. The planning assumptions do not substitute for a reported protocol or analysis. Safety entries are recorded, but ascertainment and follow-up details are not reported in the registry record. These gaps limit conclusions about both the endpoint and the context in which it was measured.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Early-onset Obesity and Cognitive Impairment in Children With Pseudohypoparathyroidism — NCT02411461.
• Registry record last updated 2019-11-13; status last verified 2019-10.
• Results first posted 2018-06-08.
• 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

NCT02411461 is a completed study sponsored by Vanderbilt University Medical Center. The registry lists enrollment of 39, a start date of 2014-12-01, and primary completion in 2017-01. The study compares children with pseudohypoparathyroidism type 1a with healthy siblings and obese patients; it is described as nonrandomized, with allocation not stated and arms that are not a like-for-like control comparison.

The primary outcome is intelligence quotient measured with the Kaufman Brief Intelligence Test, 2nd Edition, summarized as a mean and standard deviation. The registry lists one outcome measure and no analyses, and does not report endpoint results. Adverse-event entries report zero serious events, zero other events, and zero deaths in each listed group.