Renal Hemodynamics, Energetics and Insulin Resistance: A Follow-up Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Renal Hemodynamics, Energetics and Insulin Resistance: A Follow-up Study (NCT05530356), a registered phase not stated study. The primary outcome is Glomerular Filtration Rate.

2. Clinical Question

The clinical question is therefore about longitudinal characterization of kidney function and related biological measures in an existing youth-onset cohort, rather than the effect of an assigned therapy. The broader aims include kidney energetics, oxidative metabolism in a subset, arterial stiffness, and exploratory brain and cognitive measures. These aims give the follow-up study a wider scope than its named primary endpoint. They do not establish that every participant underwent every assessment, nor do they identify a treatment contrast that can be interpreted causally.

3. Trial Design

The registry describes a prospective follow-up study of participants previously enrolled in Renal-HEIR. Its stated focus is youth-onset type 2 diabetes and the transition from adolescence to young adulthood, with obese and lean control groups included. The study status is completed, and the registry lists enrollment of 57. The listed start date is 2022-09-30 and the primary completion date is 2024-06-19.

The groups are described as lean controls, obese youth without type 2 diabetes, and obese youth with type 2 diabetes. All are identified as previously enrolled in the Renal-HEIR study. Allocation is not stated, and the record explicitly cautions that the arms are not a like-for-like control comparison. These features matter: the group labels describe participant categories, not random assignment to study conditions. Differences between categories could reflect characteristics other than diabetes status, and the registry record does not report an analysis that adjusts for such differences.

The primary outcome is a one-time measure of glomerular filtration rate collected at a single visit following screening. Timing varied by participant, up to 7 months after screening. The record also lists 7 outcome measures, but does not provide primary-outcome results or analysis estimates. It names Pulse Wave Velocity as a secondary outcome.

The protocol description includes functional MRI, PET assessment of kidney oxidative metabolism in a subset of participants at least 18 years of age with youth-onset type 2 diabetes and/or obesity, and SphygmoCor assessment of peripheral arterial stiffness. It also describes repeat biopsies 3-years after an initial biopsy for eligible participants with youth-onset type 2 diabetes, molecular analysis of tissue from J-wire endovascular biopsies, and exploratory brain imaging and cognitive assessment. These are stated study aims; the registry record does not establish which assessments were completed by each participant. The record lists drugs and procedures, but does not describe a randomized therapeutic intervention.

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 Glomerular Filtration Rate, measured over One-time measure collected at a single visit following screening; timing varied by participant, up to 7 months after screening.

The primary endpoint is glomerular filtration rate, measured by iohexol clearance and reported in mL/min/1.73m^2. Glomerular filtration rate is a measure of how much fluid is filtered by the kidneys over time, adjusted to a standard body surface area. In this study, it provides a quantitative measure of kidney function that can be examined across the participant groups and in the context of the follow-up study’s broader focus on kidney physiology.

The registry specifies that the endpoint is a mean with standard deviation as the dispersion measure. A mean describes the central value of a group’s measurements; a standard deviation describes the spread of measurements around that mean. These summaries can characterize the distribution of the measured outcome, but they do not by themselves establish whether group differences are statistically distinguishable or clinically important.

The outcome description states that GFR is measured by iohexol clearance. The visit is described as a one-time measure after screening, with timing varying by participant, up to 7 months after screening. Thus, the primary endpoint is not described as a repeated series of GFR values over the follow-up period. The study’s broader aim is to define changes in kidney function as participants transition toward young adulthood, but the registry record does not report primary-outcome values, group means, standard deviations, confidence intervals, or a comparison estimate. The reason this measure is used in the study is its role as a quantitative kidney-function assessment; the record does not report a separate rationale for choosing it as the primary endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a continuous primary outcome summarized as a mean and standard deviation. It does not report an analysis method, estimates, or inferential results. The concepts below explain how such methods are generally read; they should not be mistaken for methods documented as having been used in this study.

What does a mean and standard deviation describe?

For a continuous measure such as glomerular filtration rate, a mean is the arithmetic center of the observed values. The standard deviation describes how dispersed those values are around the mean. A small spread indicates that measurements cluster more closely around the average; a larger spread indicates greater variability. These summaries are most informative when considered together and alongside the number of participants contributing data. The registry record does not report group-specific GFR means, standard deviations, or analysis sample sizes, so those features cannot be assessed for this study.

Descriptive summaries are not the same as a comparison test. A difference in means can be estimated, and a confidence interval can express the range of effect estimates compatible with the data under the assumptions of the analysis. A confidence interval also conveys precision: a narrower interval indicates greater precision than a wider interval. No GFR confidence interval or difference estimate is reported in the registry record. No p-value is reported either. Without an estimate and its uncertainty, the magnitude and precision of any group contrast are unknown.

Why does the group structure matter?

The record lists three participant categories, but allocation is not stated and the record says the arms are not a like-for-like control comparison. In general, random assignment can help balance both measured and unmeasured characteristics between groups. When participants are categorized by pre-existing characteristics instead, group differences may have several possible explanations. An observed difference would not, on its own, establish that the category caused the difference. The registry record does not report a model, covariate adjustment, or causal analysis that would address this issue.

In general, a group comparison should be interpreted with attention to the sampling process, the amount of missing data, and the analytic population. The enrollment figure alone is not necessarily the number with an observed primary outcome. Participants may have different amounts of available data for different assessments, particularly in a study that describes PET in a subset and biopsies for eligible participants. The registry record does not report outcome-specific denominators or the handling of missing measurements.

How should the planning illustrations be understood?

The stated 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 framed as a stated fraction of the observed effect. These are planning assumptions, not a report of the trial’s own design or a guarantee of a particular result. The registry record does not report a sample-size justification for the study itself. Any sample-size illustration should be interpreted as a hypothetical planning exercise rather than observed power. Power is a design concept concerning the chance of detecting an effect under specified assumptions; it cannot be inferred from a completed study’s enrollment alone.

In general, planning based on an observed effect can be sensitive to the estimate chosen as the starting point. A smaller assumed effect generally requires more information to detect with the same target power, while a larger assumed effect requires less. The registry record’s stated assumptions do not provide a basis for claiming that the study was adequately powered for its primary endpoint, nor does the record report the effect estimate on which any illustration is based. Sample-size planning also does not replace reporting the observed estimate and its uncertainty.

What can the event counts establish?

Adverse-event counts are descriptive. A count of participants with an event does not indicate severity for events outside the serious category, event timing, recurrence, or whether investigators judged an event related to a procedure. A comparison of counts across these groups would also need to account for the different numbers listed at risk and the nonrandom group structure. The registry record does not report such a comparison or an event-rate analysis. General statistical methods for event data may include rates or risk comparisons, but no such analysis should be attributed to this record.

Overall, statistical interpretation depends on more than naming an endpoint and listing enrollment. The record would need outcome summaries, analysis denominators, an analysis plan, and uncertainty estimates to support a quantitative interpretation of the primary endpoint. Those items are not reported in the registry record. The available information supports a description of the planned measurement and study aims, not a conclusion about the size, direction, or precision of an outcome contrast.

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("Lean Control", "Obese Control", "Type 2 Diabetes")
n   <- c(9, 15, 33)
m   <- c(135, 147, 149)
sp  <- c(20, 30, 32)
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  Lean Control  9  135.000  20.000  119.627  150.373
CARM  Obese Control  15  147.000  30.000  130.387  163.613
CARM  Type 2 Diabetes  33  149.000  32.000  137.653  160.347

11. Multiplicity, Missing Data and Analysis Populations

The record lists 7 outcome measures and identifies glomerular filtration rate as the primary outcome. It names Pulse Wave Velocity as a secondary outcome and describes additional aims involving kidney energetics, oxidative metabolism, biopsies, brain imaging, and cognition. The registry record does not report how multiplicity across outcomes or analyses was handled. It does not specify an adjustment procedure, a hierarchy for testing secondary outcomes, or whether exploratory results were to be treated differently from confirmatory results.

Multiplicity is a general statistical concern when several outcomes or comparisons are examined. Each additional test can create another opportunity for a chance finding. A prespecified primary outcome can help clarify which question is central, but it does not by itself explain how results from other outcomes should be interpreted. Because the registry record reports zero analyses and no outcome estimates, there are no reported tests to evaluate for multiplicity.

Missing-data handling is not reported in the registry record. The enrollment is listed as 57, but the number contributing GFR measurements and the number included in each other assessment are not reported. The record also does not state whether participants with incomplete measurements were excluded, whether missing values were imputed, or whether analyses used all available observations. This is relevant because the description includes assessments limited to a subset or to eligible participants.

The analysis populations are not reported in the registry record. No intention-to-treat, per-protocol, or other population is defined, and the record does not explain how participants were selected for any analysis. These omissions prevent assessment of whether the analyzed participants represented all enrolled participants or particular subgroups. They also prevent evaluation of how exclusions or incomplete follow-up might affect reported estimates. Since no primary-outcome estimates are posted, there is no basis for assessing the impact of missing data on the GFR result.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists serious adverse event counts for three groups: Lean Control, Obese Control, and Type 2 Diabetes. The number at risk is listed as 9, 15, and 33, respectively, and the serious adverse event count is 0 in each group. Deaths are listed as 0 in each group. These entries mean that the registry reports no serious adverse events or deaths in the listed groups; they do not establish that no other safety events occurred.

For other adverse events, the registry lists 0 among 9 Lean Control participants, 1 among 15 Obese Control participants, and 2 among 33 Type 2 Diabetes participants. These are counts, not adjusted comparisons or estimates of event risk. They do not establish that group membership or a study procedure caused an event. The registry record does not describe the events in the serious-event term list, and it does not provide event timing, duration, severity details for other events, or investigator attribution.

Safety counts should be interpreted in the context of the listed number at risk, the study’s nonrandom group structure, and the registry’s reporting scope. A zero count in a group does not prove that an event is impossible, and the listed counts do not show whether all events were captured in the same way across groups. No statistical comparison or formal safety analysis is reported in the registry record.

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

The registry record establishes that this completed study was designed as a prospective follow-up of people previously enrolled in Renal-HEIR, including participants with youth-onset type 2 diabetes and obese and lean controls. It identifies glomerular filtration rate measured by iohexol clearance as the primary outcome. It also describes a broad set of related kidney, vascular, tissue, brain, and cognitive aims. These details define what the study set out to investigate.

The record does not report the primary outcome values, group summaries, a difference between groups, or uncertainty around any estimate. It therefore does not establish whether GFR was higher or lower in any group, how large a group contrast might be, or how precise an estimate might be. The completion status and enrollment listing do not answer those outcome questions. No statistical analyses are reported in the registry record.

The listed group categories are not randomized treatment arms. Allocation is not stated, and the record cautions that they are not a like-for-like control comparison. Even if group outcome estimates were available, the group structure would require careful interpretation: a difference could be associated with diabetes status, obesity, or other group characteristics, and the registry record does not report an adjustment strategy that would separate these explanations.

The study’s stated aims include measures that may be collected in subsets or among eligible participants. This means the results for different assessments would not necessarily represent identical participant groups. The registry record does not report outcome-specific participant numbers or missing-data methods. Any interpretation of the planned measures would need those details along with the actual estimates.

The adverse-event entries describe counts but do not provide causal assessments or a comparative safety analysis. Overall, the registry supports a description of the study’s scope, groups, primary endpoint, and reported safety counts. It does not support a conclusion about the direction or magnitude of kidney-function differences, the precision of any comparison, or the effect of a treatment.

14. Why This Trial Matters Statistically

This study is statistically notable for the distinction between a broad biological research program and the narrow information available for its primary endpoint in the registry record. The study aims to characterize kidney function during the transition from adolescence to young adulthood, while also examining energetic, vascular, tissue, brain, and cognitive measures. Such breadth can support multiple scientific questions, but it also makes clear reporting of priorities and analysis populations important.

The primary outcome is a continuous physiological measure, and the record specifies a mean and standard deviation as its summary format. For readers to assess the evidence, those summaries would need to be accompanied by the number of participants measured and an estimate of the relevant group contrast with an uncertainty interval. The registry record does not report those results. This illustrates why a defined endpoint and a completed status are not substitutes for outcome reporting.

The observational group structure also matters statistically. Participants are grouped by characteristics rather than by stated random allocation, and the record explicitly cautions against treating the arms as like-for-like. This limits how far a group contrast could be taken as evidence of cause and effect, even if a contrast were reported. Analysis methods and participant characteristics would be essential context for assessing the strength of an association.

Finally, the description includes subset and eligibility-based assessments alongside a primary endpoint, while the record does not report outcome-specific denominators or missing-data procedures. Those details are central to understanding who contributes information to each estimate. The study therefore highlights a general reporting principle: statistical interpretation depends on the measured outcomes, their uncertainty, the analysis populations, and the design—not only on the stated aims or completion status.

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 main limitation for statistical interpretation is that the registry record does not report primary-outcome results or analyses. There are no GFR group means, standard deviations, confidence intervals, comparison estimates, or p-values. The record lists zero analyses. As a result, the magnitude, direction, and precision of any group difference cannot be assessed from the registry information.

The registry lists enrollment of 57, but does not report how many participants contributed a GFR measurement or the analysis denominator for any outcome. The primary measure is described as one-time, with timing varying by participant, up to 7 months after screening. The record does not explain whether this variation was accounted for in analysis or how missing measurements were handled. The analysis populations are also not reported.

The groups are not described as randomized, allocation is not stated, and the record warns that they are not a like-for-like control comparison. This limits causal interpretation of any group difference. The record does not report baseline summaries or an adjustment model that might help readers assess differences in participant characteristics. It also does not report a sample-size justification for the study or a statistical plan.

The broad study description includes measures limited to subsets or eligible participants, but does not specify which assessments were completed by which participants. The registry lists 7 outcome measures without describing a multiplicity strategy. It also does not report whether the exploratory brain and cognition aims were analyzed or how their results would be distinguished from confirmatory analyses.

Safety reporting is limited to counts at risk and counts with serious and other adverse events. Event descriptions, timing, attribution, and comparative analyses are not reported. These limitations apply to interpretation of the registry record and do not establish what may be available in other study materials.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Renal Hemodynamics, Energetics and Insulin Resistance: A Follow-up Study — NCT05530356.
• Registry record last updated 2026-08-24; status last verified 2026-07.
• Results first posted 2026-08-24.
• 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 describes NCT05530356, titled “Renal Hemodynamics, Energetics and Insulin Resistance: A Follow-up Study,” sponsored by University of Colorado, Denver. The listed study status is completed, with enrollment of 57. The recorded start date is 2022-09-30, and the primary completion date is 2024-06-19.

The study follows participants previously enrolled in Renal-HEIR, including lean controls, obese youth without type 2 diabetes, and obese youth with type 2 diabetes. Its primary outcome is glomerular filtration rate measured by iohexol clearance, expressed in mL/min/1.73m^2, as a one-time measure following screening. The registry specifies a mean and standard deviation but does not report outcome values or analyses.

The broader aims include kidney energetics and oxidative metabolism, arterial stiffness, biopsy-based molecular work, and exploratory brain imaging and cognitive assessment. The record lists 7 outcome measures and zero analyses. Serious adverse events and deaths are listed as 0 in each group; other adverse events are listed as 0, 1, and 2, respectively. Allocation is not stated, and the registry cautions that the groups are not a like-for-like control comparison.