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 Exercise in Obese Diabetic Patients With Chronic Kidney Disease (NCT01036490), a randomized na study. The primary outcome is Change in Proteinuria.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01036490 |
| Phase | NA |
| Condition | Chronic Kidney Disease |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 36 |
| Arms in the primary outcome | 2 |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns patients with type 2 diabetes, obesity, and chronic kidney disease. The registry describes this population as generally physically inactive and identifies heart, kidney, diabetes, body-composition, and quality-of-life outcomes as areas of interest. Enrollment was 36.
Intervention
The intervention was named Exercise and described as a structured exercise program. The registry does not report the specific exercise activities, intensity, frequency, supervision, or adherence information, so the intervention cannot be characterized more precisely from this record.
Comparator
The comparison group was named Control and described only as the Control group. Further details about what participants in that group were asked to do, or what care they received, are not reported in the registry record.
Primary question
The primary outcome was change in proteinuria, measured in mg/g creatinine, from baseline to 12 weeks. The registry presents the change as a median with an inter-quartile range. The question is whether the observed change differed between the exercise and control groups; the posted result does not, by itself, establish why any difference occurred or how it relates to longer-term kidney outcomes.
3. Trial Design
The registry describes a randomized, parallel-group trial with no masking. The study is marked completed, with a start date of 2010-07-01 and a primary completion date of 2014-12-31. The listed phase is NA. The sponsor is the VA Office of Research and Development. These registry entries identify the broad design and status but do not explain how randomization was generated or implemented.
Enrollment was 36. The posted primary outcome results list 14 participants in the Exercise group and 18 in the Control group. The secondary eGFR results list the same group sizes. These are the sizes attached to those outcome results, not a description of the analysis population or an account of missing observations. The registry does not report whether every randomized participant contributed data to each analysis, or how any missing outcome data were handled.
The intervention is called Exercise, and the registry's summary describes a structured exercise program. It does not give the program's content, dose, duration, monitoring, or adherence. The control arm is described only as Control group. Consequently, the contrast is clear at the level of the assigned group labels but not in terms of the exact activities or care received by each group.
The primary outcome timeframe is 12 weeks minus baseline. The registry also lists changes in albuminuria and estimated glomerular filtration rate (eGFR) among the secondary outcomes. The record does not report the allocation ratio as a design specification, stratification factors, eligibility criteria, or the analysis population. Those omissions limit how fully the design and the intended scope of the comparison can be reconstructed.
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
| Stage | Exercise | Control |
|---|---|---|
| STARTED | 18 | 18 |
| COMPLETED | 14 | 18 |
| NOT COMPLETED | 4 | 0 |
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 | Exercise | Control | Total |
|---|---|---|---|---|
| Participants analysed | 18 | 18 | 36 | |
| Age, Continuous | years | 65 (SD 8.7) | 67 (SD 7.5) | 66 (SD 8.0) |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 18 | 18 | 36 |
| Body mass index | kg/m^2 | 36.2 (SD 4.8) | 37.4 (SD 4.2) | 37 (SD 4.5) |
6. Primary Endpoint
The registry lists the primary outcome as Change in Proteinuria, measured over 12 weeks minus baseline.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | mg/g creatinine |
| Endpoint classification | not reduced to a single comparison |
Proteinuria is the amount of protein in urine. The primary outcome is the change in proteinuria, measured in mg/g creatinine, from baseline to 12 weeks. The registry reports a median change and an inter-quartile range for each group. Creatinine is part of the stated measurement unit; no further details of the urine collection or laboratory procedure are reported in the registry record.
As a general statistical explanation, protein loss in urine can be used as a measure of kidney-related status, and measuring change compares follow-up values with baseline values. A negative change represents a decrease in the measured quantity. The median describes the middle of the observed group values, while the inter-quartile range describes the spread of the middle portion of those values. These summaries can be useful when values are skewed or affected by unusually high or low observations, though the registry does not state why this summary was selected.
A change measure does not show the starting levels on its own. The registry does not provide baseline proteinuria values or a confidence interval for the difference between groups on this endpoint. The posted group medians therefore describe the observed changes but do not quantify the precision of a direct between-group effect estimate. The time window is also limited to the stated 12-week assessment; longer-term proteinuria and kidney outcomes are not reported as part of this primary result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary outcome is change in proteinuria over 12 weeks. The Exercise group had a median change of -34.0 mg/g creatinine, with an inter-quartile range from -236.0 to 247.0. The Control group had a median change of -133.0 mg/g creatinine, with an inter-quartile range from -406.0 to -75.0. Both medians are negative, while the group medians and the spreads of the observations differ. The ranges indicate that individual changes varied considerably, especially in the Exercise group.
The registry reports a two-sided t-test for the primary comparison and a p-value of 0.04. That is the sponsor-reported result attached to the comparison. The record does not provide a direct between-group estimate for the primary outcome, an interval estimate, or further details of the test calculation. Because the arm summaries are medians and inter-quartile ranges, the reported test result should be read alongside those summaries rather than as a complete description of the size and precision of the group contrast. The test result alone does not indicate the clinical importance of a difference.
The secondary eGFR summaries show a mean change of 0.2 mL/min/1.73m^2 for Exercise, with a standard deviation of 4.7, and a mean change of -3.4 mL/min/1.73m^2 for Control, with a standard deviation of 8.9. An unadjusted recalculation gives a mean difference of 3.6, with an interval from -1.192 to 8.392 and an unadjusted p-value of 0.141. The interval spans values on either side of no difference, so the estimate is imprecise and compatible with a range of possible effects. The sponsor-reported two-sided test for eGFR has a p-value of 0.15.
These results address different measures and should not be treated as interchangeable. Proteinuria is the primary endpoint; eGFR is a secondary outcome. The primary p-value is below a conventional threshold often used in statistical testing, but the registry does not report the analysis plan or whether this threshold was prespecified. The secondary eGFR result does not provide clear statistical evidence of a group difference in the unadjusted recalculation, and its interval is broad. Neither result establishes a durable change in kidney function or a clinical outcome beyond the stated follow-up.
The posted results are group-level summaries from a randomized study, but the record leaves important uncertainties about missing observations, analysis populations, and outcome procedures. The results can be interpreted as the estimates and test results recorded for this trial; they should not be extended beyond its participants, intervention description, outcome measures, and follow-up timeframe.
9. Statistical Methods Explained
The registry reports change scores for the primary outcome and for eGFR. A change score compares a follow-up measurement with a baseline measurement for the same outcome. Here the stated primary timeframe is 12 weeks minus baseline. As a general statistical explanation, a group summary of change can show the typical direction and variation of observed change within each arm, while a between-group comparison addresses whether the changes differ across the randomized groups.
What do the primary summaries describe?
The primary endpoint is summarized by a median and inter-quartile range. The median is the central observed value when observations are ordered. The inter-quartile range gives the span between the middle quarters of the observations, describing the spread of the central part of the data. These summaries do not show every participant's value, and they are not the same as a confidence interval for a group difference. The registry reports no interval estimate for the primary contrast, so its precision cannot be judged from an interval for that comparison.
The Exercise median change is -34.0 mg/g creatinine, with an inter-quartile range from -236.0 to 247.0. The Control median change is -133.0 mg/g creatinine, with an inter-quartile range from -406.0 to -75.0. The extensive spread in the observed values means the medians alone do not capture all variation in individual responses. No additional distributional summaries or participant-level data are reported.
How should the reported tests be read?
The registry lists a two-sided t-test for the primary comparison and reports p = 0.04. A two-sided test evaluates evidence for a difference in either direction rather than testing only for a difference in one prespecified direction. As a general explanation, a p-value describes how unusual data at least as incompatible with a specified no-difference model would be if that model and the test assumptions held. It is not the probability that the no-difference model is true, and it does not measure the size or clinical importance of an effect.
The primary summaries are medians and inter-quartile ranges, while the listed test is a t-test. A t-test is generally framed as a comparison of means. The record does not explain how the test was applied to the primary data, whether another calculation was used, or how the summary and test were reconciled. The test statistic, degrees of freedom, confidence interval, and analysis details are not reported in the registry record. This limits assessment of the primary test beyond the stated method and p-value.
For eGFR, the registry gives means and standard deviations for both groups. A recalculated unadjusted mean difference is 3.6 mL/min/1.73m^2, with an interval from -1.192 to 8.392 and p = 0.141. A confidence interval is an interval estimate that represents uncertainty about an estimated effect under the method used. As a general explanation, a wide interval indicates less precision than a narrow interval. The registry does not state the confidence level for this recalculated interval, so a confidence percentage should not be inferred from the posted figures alone. The interval includes zero, which is consistent with no difference as well as with effects in either direction within the interval.
What does the planning illustration mean?
The eGFR planning illustration is based on the observed effect, not on the trial's own design. It uses a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For 100% of the observed effect, the illustration gives 66 participants per arm for 80% power and 89 participants per arm for 90% power. For 75% of the observed effect, it gives 118 participants per arm for 80% power and 157 participants per arm for 90% power. For 50% of the observed effect, it gives 264 participants per arm for 80% power and 354 participants per arm for 90% power.
As a general explanation, planning power concerns the probability that a future study would detect a specified effect under the assumed design and statistical model. These figures are planning illustrations, not observed power and not a reconstruction of the rationale for the trial's enrollment. The registry does not report its original sample-size justification. Because the planning figures use the observed eGFR effect, they depend on an estimate from this trial that is itself imprecise; they should not be treated as a stable estimate of the sample size needed for a definitive study.
Why can over-dispersion matter?
As a general statistical concept, over-dispersion occurs when outcome variation is greater than a model assumes. If variability is underestimated, standard errors can be too small and intervals too narrow; if variability is high, estimates may be imprecise. The eGFR standard deviations differ between the groups, and the group sizes are not equal in the posted results. The registry does not report a variance-model assessment or adjustments for unequal variability. For the primary outcome, the wide inter-quartile ranges also signal substantial variation, but do not by themselves establish the appropriate statistical model.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| t-test, 2 sided | not reported | 0.040 |
The sponsor's primary analysis is reported as a two-sided t-test with p = 0.04. The registry also reports the primary outcome as medians and inter-quartile ranges, but does not give a between-group estimate, interval estimate, or detailed test output. There is no recalculated primary comparison in the posted analysis, so the primary result should be described using the sponsor's reported test together with the arm summaries. The record does not explain how the t-test relates to the median-based summaries.
For eGFR, the sponsor reports a two-sided test with p = 0.15. A simple unadjusted recalculation from the posted group means and standard deviations gives a mean difference of 3.6 mL/min/1.73m^2, an interval from -1.192 to 8.392, and p = 0.141. The recalculated p-value is close to the sponsor's reported value, and the posted record does not flag a discrepancy. This recalculation is not an adjusted analysis and may not reproduce any details unavailable in the registry record.
The sponsor's result remains the trial's reported analysis. The recalculation offers a transparent, unadjusted comparison from the posted summary statistics; it does not replace the sponsor analysis, establish the prespecified method, or address missing data and analysis-population questions that the registry does not answer.
11. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises when multiple outcomes, comparisons, timepoints, or analyses are tested. As a general statistical explanation, the more tests that are considered, the greater the chance of finding an apparently notable result by chance if each is interpreted in isolation. This concern is often addressed through a prespecified hierarchy, adjustment procedures, or cautious interpretation of secondary analyses. The registry names albuminuria and eGFR as secondary outcomes, with each label appearing twice, and identifies six outcome measures overall. A multiplicity strategy, outcome hierarchy, and any adjustment for multiple testing are not reported in the registry record.
The primary comparison has a reported p-value, but the registry does not state whether the test, direction, or analysis was prespecified in a statistical analysis plan. It also does not report interim analyses or how they may have affected interpretation. These items are not reasons to assume a problem occurred; they are information gaps that limit independent assessment of the testing strategy.
Missing-data handling is also not described. The record gives group sizes for the posted results and indicates that values were missing or not estimable for a two-arm comparison for another endpoint. It does not state how many observations were unavailable for each outcome, why data were unavailable, whether imputation was used, or whether analyses included all randomized participants. The analysis population is not reported in the registry record. Therefore, the posted outcome group sizes should not be taken as proof of a particular intention-to-treat, per-protocol, or other analysis population.
The record does not explain whether changes were calculated only for participants with measurements at both baseline and follow-up, how deviations from the assigned group were handled, or whether any covariates were included. Those details can affect what an estimate represents. Without them, the safest interpretation is limited to the group summaries and tests that are explicitly reported, rather than assuming a particular missing-data method or analysis strategy.
12. 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 |
|---|---|---|---|
| Exercise | 0 | 18 | 0.0% |
| Control | 0 | 18 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Exercise | 0 of 18 |
| Control | 0 of 18 |
The registry reports zero serious adverse events among 18 participants at risk in the Exercise group and zero among 18 participants at risk in the Control group. It also reports zero other adverse events among 18 participants at risk in each group. These are counts recorded for the specified groups; they do not establish that no adverse effects occurred outside the categories or observation captured in the registry.
As a general statistical explanation, a zero count in a study does not demonstrate that the underlying risk is zero. Safety estimates are more uncertain when the amount of information is limited, and counts alone do not describe event timing, duration, severity, or relationship to the intervention. The registry does not provide a list of serious event terms, and deaths are not reported in the registry record.
The figures should therefore be read as the adverse-event counts posted for this study, not as proof that the exercise program is free of risk or that the groups have equivalent safety. The registry record does not provide enough detail to assess how adverse events were collected, classified, or followed over time.
13. What the Result Does, and Does Not, Mean
The primary result describes changes in proteinuria over the stated 12-week period and reports a two-sided p-value of 0.04. The group summaries show different median changes, with substantial variation within the groups. This is evidence about the recorded comparison in this trial, not a complete estimate of the magnitude and precision of a between-group difference: no primary contrast estimate or interval is reported.
The secondary eGFR data offer a separate view of kidney function, but the unadjusted recalculated estimate is imprecise. Its interval includes zero and a range of effects on either side. This does not prove that there is no difference; it indicates that the available summary data do not pin down the size or direction of a difference with precision. The sponsor's reported eGFR test is also not conventionally statistically significant, but p-values alone do not determine whether an effect is clinically important.
As a general explanation, statistical evidence and clinical importance are different questions. Statistical tests assess compatibility of observed data with a model, while clinical interpretation also depends on the size of the effect, its precision, the measure's relevance, and the duration of follow-up. The registry does not report a clinically important threshold for proteinuria or eGFR, nor does it describe longer-term outcomes in the posted results.
The results do not show whether any change persisted beyond the stated timeframe, whether it affected other health outcomes, or whether it was attributable to a specific part of the exercise program. The exercise intervention and control condition are not described in enough detail to support those inferences. The study's results also cannot be assumed to apply to people outside the described population or to different exercise programs.
In short, the record documents a primary test result and a set of group summaries, alongside incomplete secondary information and limited analysis details. It does not establish a treatment recommendation, a long-term effect, or the absence of risk. The findings are best understood within the limits of the trial's stated population, measurements, and timeframe.
14. Why This Trial Matters Statistically
This trial is statistically instructive because its primary result combines median-based summaries with a reported t-test. The medians and inter-quartile ranges make the observed spread visible, while the test result is a single inferential summary. The registry does not explain how the test was implemented, so readers cannot fully connect the reported p-value to the displayed distributional summaries or assess the assumptions behind it.
The trial also illustrates the difference between a reported p-value and a well-characterized effect estimate. For the primary outcome, the record gives no between-group estimate or interval, leaving the magnitude and precision of the contrast uncertain. For eGFR, the recalculated estimate and interval make uncertainty more explicit: the interval includes no difference and also allows effects in either direction. Statistical interpretation benefits from estimates and intervals alongside tests, not from p-values alone.
A further lesson is the distinction between planning calculations and observed trial evidence. The posted sample-size illustration uses the observed eGFR effect under stated assumptions. Such calculations can help frame future planning, but they are not the trial's original design justification and are not observed power. Because the observed estimate is uncertain, planning directly from it can also carry uncertainty into future sample-size choices.
Finally, the limited reporting on multiplicity, missing data, analysis populations, and intervention details shows why registry results need context. These omissions do not erase the recorded results, but they restrict what can be concluded about their robustness and generalizability. Clear reporting of analysis choices and outcome completeness is essential for judging what a trial's statistical results mean.
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 enrollment was 36, and the outcome results list 14 participants in the Exercise group and 18 in the Control group. The record does not report a sample-size justification, so it is not possible to determine whether the study was designed to estimate the primary effect with a particular level of precision. The planning illustration is based on the observed eGFR effect and should not be mistaken for the trial's own design rationale.
The primary result lacks a reported between-group estimate and interval. The test is identified as a two-sided t-test, while the endpoint summaries are medians and inter-quartile ranges; the record does not explain this choice or provide enough test details to evaluate it. Baseline endpoint values and participant-level distributions are not reported, limiting assessment of the change summaries and possible imbalance at baseline.
Descriptions of the exercise program and control condition are sparse. The registry does not report the exercise regimen, adherence, supervision, or relevant co-interventions. Masking is listed as none. The record does not describe allocation concealment or other procedures used to maintain random assignment.
Information on missing data, analysis populations, and handling of protocol deviations is not reported. The registry also does not give a multiplicity plan, interim-analysis information, or a statistical analysis plan. Secondary outcome reporting is incomplete, with values missing or not estimable for a two-arm comparison for another endpoint. Deaths are not reported in the registry record. These limitations restrict evaluation of robustness, safety, and generalizability beyond the posted summaries.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Exercise in Obese Diabetic Patients With Chronic Kidney Disease — NCT01036490.
- Registry record last updated 2018-07-06; status last verified 2018-06.
- Results first posted 2016-04-27.
- 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.
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19. Record Summary
NCT01036490 is a completed randomized, parallel-group trial comparing Exercise with Control in patients described as having type 2 diabetes, obesity, and chronic kidney disease. The registry lists no masking and an enrollment of 36. The primary endpoint is change in proteinuria, measured in mg/g creatinine, from baseline to 12 weeks.
The registry reports group medians and inter-quartile ranges for the primary outcome and a sponsor-reported two-sided t-test with p = 0.04. Secondary eGFR results include group means and standard deviations; an unadjusted recalculation gives a mean difference of 3.6, with an interval from -1.192 to 8.392 and p = 0.141, compared with the sponsor-reported p-value of 0.15. The record also gives zero serious and other adverse events in each group, while deaths are not reported in the registry record.
Important details about the intervention, analysis populations, missing data, multiplicity, and the primary effect estimate are not reported. The results therefore describe the posted trial comparisons but do not establish longer-term effects or resolve the uncertainty around the size of the primary contrast.