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 Intensive Glycemic Control for Congestive Heart Failure Exacerbation (NCT00812253), a randomized phase 2 study. The primary outcome is Hospital Length of Stay.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00812253 |
| Phase | Phase 2 |
| Condition | Congestive Heart Failure, Diabetes Mellitus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 74 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Kathleen Dungan |
| Results posted | Yes |
2. Clinical Question
Population
Patients with congestive heart failure and diabetes mellitus. The registry describes these conditions and states that patients with heart failure often have high blood glucose. The posted primary outcome does not specify a separate analysis population.
Intervention
Intravenous insulin. The registry identifies this as a drug intervention; it does not provide further details about the intravenous regimen in the arm description.
Comparator
Subcutaneous insulin, described as basal bolus insulin given by 4 injections per day. The trial used parallel groups and no masking.
Primary question
How did hospital length of stay, measured in days, compare between the intravenous and subcutaneous insulin groups? The posted results report the median and interquartile range for each group, but a two-arm comparison is not estimable from the posted primary endpoint results.
The clinical question is about the distribution of hospital stay in the two assigned groups, not a direct comparison of blood glucose values. Length of stay is a time measure that can reflect the course of a hospitalization, but it can also be affected by factors beyond the measured treatment contrast. The registry record does not report details of eligibility criteria, the insulin targets, or the reasons a patient might leave hospital. Those details should not be inferred from the trial title or from the outcome alone.
The comparison is randomized, but the registry describes no masking. Random allocation can support a fair comparison in principle; lack of masking means participants and care teams knew the assigned group. The record does not say how that might have affected inpatient decisions or outcome assessment. The primary results give group medians and interquartile ranges, not a reported treatment-effect estimate or a sponsor-reported significance test. The available primary results therefore describe the observed group summaries without establishing a precise between-group effect.
3. Trial Design
This is a randomized, parallel-group Phase 2 trial with no masking. The registry lists an enrollment of 74 and identifies intravenous insulin and subcutaneous insulin as the interventions. The subcutaneous regimen is described as basal bolus insulin given by 4 injections per day; the intravenous arm has no further regimen description. The sponsor is Kathleen Dungan. The trial status is completed, with a start date of 2009-01 and a primary completion date of 2013-09.
Parallel groups mean that participants are assigned to one of the interventions rather than crossing between both interventions as part of the stated design. Randomization refers to the assignment process, while the lack of masking means the registry does not describe the treatment assignment as concealed from participants or study personnel after assignment. The registry record does not report the method used to generate or conceal the allocation sequence, the randomization ratio, or any stratification factors.
The primary outcome is hospital length of stay, reported as a median with an interquartile range. Posted group summaries include 26 participants in the intravenous insulin group and 39 in the subcutaneous insulin group for this endpoint. The registry enrollment count and endpoint-specific group counts are different kinds of information; the record does not explain the difference. It also does not report an analysis population definition or reasons for participants not appearing in endpoint summaries.
Secondary outcomes named in the record include hospital readmission, heart rate variability, change in quality of life, brain natriuretic peptide, and cardiac output. Results are posted for quality of life and cardiac output, but the record does not give posted results for the other named secondary outcomes. There are no reported analyses listed for the posted secondary results. Details of the protocol, sample-size justification, interim analyses, and the prespecified statistical analysis plan are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Intravenous Insulin (IV) | Subcutaneous Insulin |
|---|---|---|
| STARTED | 32 | 42 |
| COMPLETED | 26 | 39 |
| NOT COMPLETED | 6 | 3 |
Reasons for not completing this period:
| Reason | Intravenous Insulin (IV) | Subcutaneous Insulin |
|---|---|---|
| Withdrawal by Subject | 3 | 2 |
| Protocol Violation | 1 | 1 |
| Lost to Follow-up | 2 | 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.
Population: Baseline population consists of patients with available study data.
| Characteristic | Unit | Intravenous (IV) Insulin | Subcutaneous (SQ) Insulin | Total |
|---|---|---|---|---|
| Participants analysed | 26 | 39 | 65 | |
| Age, Continuous | years | 61 (SD 10) | 63 (SD 12) | 62 (SD 11) |
| Sex: Female, Male: Female | Participants | 8 | 13 | 21 |
| Sex: Female, Male: Male | Participants | 18 | 26 | 44 |
| Region of Enrollment: United States | participants | 26 | 39 | 65 |
| Preserved ejection fraction: Preserved Ejection Fraction | participants | 6 | 11 | 17 |
| Preserved ejection fraction: Reduced Ejection Fraction | participants | 20 | 28 | 48 |
| HbA1c | Percentage of hemoglobin | 8.4 (SD 2.0) | 7.7 (SD 1.4) | 8.0 (SD 1.7) |
6. Primary Endpoint
The registry lists the primary outcome as Hospital Length of Stay, measured over Days.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | days |
| Endpoint classification | Time-to-Event Analysis |
The primary endpoint is hospital length of stay, defined in the registry as the duration of hospitalization in days. The posted summary uses the median and interquartile range for each treatment group. The median is the middle of an ordered set of observed stays; the interquartile range describes the central spread of those stays. These summaries are useful when an outcome is skewed or when a few unusually long stays could make a mean less representative of a typical observation. That is a general statistical reason to summarize time spent in hospital with a median and interquartile range, not a statement about the investigators’ documented rationale.
Length of stay can describe an important part of the inpatient course and may be easier to interpret than a laboratory measure alone. It is not a direct measure of glucose control, cardiac function, or quality of life. It can also reflect discharge practices and other clinical or organizational factors. The registry record does not report how discharge decisions were made or whether any particular factors were accounted for in analysis.
The intravenous insulin group had a median stay of 7 days, with an interquartile range from 5 to 11 days. The subcutaneous insulin group had a median stay of 8 days, with an interquartile range from 5 to 12 days. The posted primary results do not include an estimable two-arm comparison for this median-time endpoint. The summaries therefore describe the observed group distributions, but they do not provide a reported estimate of the difference between groups or its uncertainty.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
For hospital length of stay, the posted median was 7 days in the intravenous insulin group, with an interquartile range of 5 to 11 days. In the subcutaneous insulin group, the median was 8 days, with an interquartile range of 5 to 12 days. These values are descriptive summaries. The registry record indicates that a two-arm comparison for this median-time endpoint is not estimable from the posted results. No sponsor-reported hazard ratio or other primary comparative estimate is available in the record. As a result, the primary outcome cannot be summarized as a quantified treatment contrast with an uncertainty interval.
The secondary results include an unadjusted recalculation for change in quality of life at 30 day. The estimated mean difference, comparing subcutaneous with intravenous insulin, is -0.2 units on the scale, with an interval from -13.38 to 12.98. The unadjusted p value is 0.976. The interval includes zero and spans values on either side of zero, so the posted summary is compatible with a range of differences rather than a narrowly estimated contrast. The registry does not identify a sponsor-reported analysis for this result.
For cardiac output at 72 hours, the unadjusted recalculated mean difference is -1.7 liter/min, with an interval from -7.162 to 3.762. The unadjusted p value is 0.542. This interval also includes zero and covers values in both directions. The estimate is based on endpoint-specific groups of 13 and 11 participants, so the posted result is limited in precision. The data do not establish that the groups had identical outcomes; rather, the estimate and interval leave uncertainty about the size and direction of a difference.
These secondary comparisons are unadjusted recalculations from posted summary statistics, not sponsor-reported analyses. Their p values should not be read in isolation, especially because multiple outcomes are involved and no multiplicity adjustment is reported. Nor should the secondary endpoints be used to replace the primary endpoint: the posted primary summaries do not give a comparative estimate. Taken together, the registry record offers descriptive primary results and two imprecise secondary comparisons, not a definitive quantified account of the between-group effect on hospital stay.
The distinction between a point estimate and its uncertainty matters. A point estimate is one summary of the observed contrast, whereas an interval expresses the range of values compatible with the data under the calculation’s assumptions. General statistical interpretation: a wide interval signals limited precision, and an interval that includes zero does not by itself show equivalence. Equivalence requires a prespecified margin and an appropriate analysis; such details are not reported in the registry record.
9. Statistical Methods Explained
The registry reports the primary endpoint as a median with an interquartile range. A median gives the central observation in an ordered distribution. The interquartile range runs from the first quartile to the third quartile and summarizes the middle portion of the data. General statistical explanation: these summaries are often useful for outcomes with an asymmetric distribution, because the median is less sensitive than the mean to extreme observations. They do not, by themselves, estimate a treatment-group difference or show how uncertain that difference is.
The posted primary summaries are 7 days (interquartile range 5 to 11) for intravenous insulin and 8 days (interquartile range 5 to 12) for subcutaneous insulin. The registry record says a two-arm comparison is not estimable for this median-time endpoint. The record does not provide a sponsor-reported hazard ratio, a test statistic, or an interval for the primary comparison. A difference between two medians should not be calculated and presented as though it were the trial’s reported analysis. The primary endpoint therefore remains descriptive in the available results.
For continuous secondary outcomes, the posted summaries use group means and standard deviations. A mean is the arithmetic average, while a standard deviation describes spread around the mean. General statistical explanation: a mean difference expresses the contrast between group averages in the outcome’s original units. It is useful when the mean is a suitable summary and the assumptions behind the calculation are reasonable. A standard deviation describes individual variability; it is not the same as the standard error, which reflects uncertainty in an estimated mean.
The quality-of-life comparison is an unadjusted recalculation from posted summaries. The reported contrast is the subcutaneous group mean minus the intravenous group mean: -0.2 units on a scale, with an interval from -13.38 to 12.98 and an unadjusted p value of 0.976. The cardiac-output comparison is also an unadjusted recalculation: -1.7 liter/min, with an interval from -7.162 to 3.762 and an unadjusted p value of 0.542. These are not analyses reported by the sponsor in the registry. The record lists no reported analyses for these secondary outcomes, and it does not state whether the recalculation assumptions match the trial’s planned analysis.
A confidence interval is generally an interval calculated by a method that, under its assumptions, has a stated long-run coverage property. The registry record does not state the confidence level for the recalculated intervals, so no level should be assumed from the posted information. In each secondary comparison, the interval covers zero and values on either side of it. General statistical explanation: this means the results do not narrowly pin down the direction or size of the difference. It is not proof that the groups are equal. A nonsignificant p value likewise does not establish equivalence or absence of an effect.
The planning illustrations are not observed power and are not the trial’s sample-size justification. They use an observed effect as a starting point, with a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. The effect to detect is set to a stated fraction of the observed effect. These assumptions describe the calculation, not a reported protocol decision. The registry record does not report the trial’s own sample-size calculation or its assumptions.
For quality of life, the illustration for detecting 100% of the observed effect gives 243,236 participants per arm for 80% power and 325,624 participants per arm for 90% power. Planning for 75% of the observed effect gives 432,420 participants per arm for 80% power and 578,887 participants per arm for 90% power. Planning for 50% of the observed effect gives 972,943 participants per arm for 80% power and 1,302,495 participants per arm for 90% power.
For cardiac output, the illustration for detecting 100% of the observed effect gives 287 participants per arm for 80% power and 384 participants per arm for 90% power. Planning for 75% of the observed effect gives 510 participants per arm for 80% power and 682 participants per arm for 90% power. Planning for 50% of the observed effect gives 1,146 participants per arm for 80% power and 1,535 participants per arm for 90% power. These are planning illustrations based on the observed estimates; the registry record does not report that these sample sizes were used or planned for the trial.
General explanation: planning calculations can become very large when the observed effect used as a target is small relative to the variability in the outcome. They are sensitive to the estimated effect, the assumptions about allocation and statistical model, and the chosen power target. With limited endpoint-specific data, the observed effect may itself be imprecise. For that reason, these figures should not be interpreted as evidence about the probability that the completed trial detected an effect.
The recalculated comparisons are labeled unadjusted. That means the posted p values are not reported as adjusted for testing multiple outcomes. General statistical explanation: testing multiple outcomes can raise the chance of at least one small p value when all null hypotheses are true. A multiplicity strategy can address that issue, but the registry record does not report one. No adjustment should be assumed, and the p values should be treated as exploratory rather than as a complete account of confirmatory inference.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies several secondary outcomes, while the posted results include two secondary comparisons. It does not report a multiplicity adjustment or explain how confirmatory and exploratory outcomes were distinguished. The recalculated secondary p values are unadjusted. General statistical explanation: when several outcomes are tested, the chance of at least one apparently small p value can increase, even if none of the underlying effects is real. Methods such as adjusting significance thresholds or controlling a family-wise error rate can address that issue, but no such method is documented in the registry record.
Missing-data handling is not reported in the registry record. The available endpoint-specific group sizes differ across outcomes, but the record does not explain whether that reflects missing observations, outcome eligibility, measurement timing, or another reason. It does not describe imputation, complete-case analysis, or sensitivity analyses. The primary endpoint’s analysis population is also not specified. The registry enrollment figure should not be treated as the number analyzed for every endpoint.
The record does not report whether results were analyzed by assigned group, according to treatment received, or using another analysis population. It also does not provide reasons for excluded or unavailable outcomes. These omissions limit the ability to assess how missing data or departures from assigned treatment could influence the posted estimates.
The trial is randomized and unmasked, but the registry record does not describe the allocation-generation or concealment procedures, or how outcome assessment was handled. No interim analyses or statistical analysis plan details are reported. These details matter when interpreting whether reported outcomes and analyses were planned in advance and how fully they account for uncertainty. Their absence in the registry record should not be replaced by assumptions about what the protocol may have specified.
11. 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 |
|---|---|---|---|
| Intravenous (IV) Insulin | 0 | 26 | 0.0% |
| Subcutaneous (SQ) Insulin | 0 | 39 | 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 |
|---|---|
| Intravenous (IV) Insulin | 9 of 26 |
| Subcutaneous (SQ) Insulin | 3 of 39 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Intravenous (IV) Insulin | Subcutaneous (SQ) Insulin |
|---|---|---|---|
| Hypoglycemia | Endocrine disorders | 9 of 26 | 3 of 39 |
The adverse-event figures show no serious adverse events recorded as affecting participants in either group: 0 among 26 at risk in the intravenous insulin group and 0 among 39 at risk in the subcutaneous insulin group. The registry also reports other adverse events affecting 9 participants in the intravenous group and 3 in the subcutaneous group, with the at-risk counts given as 26 and 39, respectively. These are descriptive counts, not adjusted comparisons.
The registry record does not provide serious adverse-event terms, and it does not report death counts. A missing death count should not be read as a count of zero. The record also does not give event timing, severity grading for other adverse events, exposure duration, or definitions of the event categories in the information available for these results.
General statistical explanation: when event counts are limited, observed counts can be imprecise and may not reveal the full range of possible risk differences. The figures do not establish that one intervention is safer, nor do they rule out uncommon harms. They describe what was recorded in the registry results and should be interpreted in light of the missing safety-analysis details.
12. What the Result Does, and Does Not, Mean
The registry record supports a descriptive account of the posted results. For hospital length of stay, it reports a median of 7 days in the intravenous insulin group and 8 days in the subcutaneous insulin group, with overlapping interquartile ranges. It does not provide an estimable two-arm comparison for this primary endpoint. Therefore, the record does not quantify the primary between-group effect or its uncertainty through a reported comparative estimate.
The two posted secondary outcomes have unadjusted recalculated estimates with intervals that include zero and extend in both directions. These results are imprecise and do not establish equivalence, prove no effect, or identify a reliable direction of difference. The secondary estimates do not substitute for a comparative analysis of the primary outcome. The posted summaries also do not provide results for every secondary outcome named in the registry.
Randomization is a feature of the design, but interpretation depends on the conduct and analysis details as well as on the estimates. The registry record does not report an analysis population, missing-data methods, a multiplicity approach, or the trial’s statistical analysis plan. It describes no masking. These gaps mean readers cannot determine from this record alone how some design and analysis choices were handled.
General statistical explanation: an estimate is not a guarantee of the true effect, and a wide interval can be compatible with substantially different underlying effects. A nonsignificant result does not demonstrate that groups are the same; demonstrating equivalence or noninferiority requires a defined margin and a suitable planned analysis. Such a margin and analysis are not reported in the registry record.
The findings are limited to the outcomes and summaries posted for this trial. They do not establish a general conclusion about insulin treatment, and they should not be turned into medical advice. The safest statistical reading is that the primary endpoint is summarized descriptively, the secondary comparisons are uncertain and unadjusted, and important analysis details are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically instructive because the primary endpoint is a time measure reported with medians and interquartile ranges, while the posted results do not provide a comparative estimate. Group summaries can show the observed distributions at a broad level, but they cannot by themselves answer how precisely the groups differ. The gap between descriptive results and an inferential comparison is especially important when readers are tempted to interpret a small difference between medians as a treatment effect.
The record also illustrates why outcome-specific denominators matter. The number of participants represented in a result varies by endpoint, and the registry does not explain those differences. Without a stated analysis population and missing-data methods, readers cannot fully assess how the available observations relate to the randomized groups or the enrolled population.
The secondary outcomes highlight the distinction between a recalculated estimate and a sponsor-reported analysis. Their intervals allow differences in either direction, and their unadjusted p values do not account for testing multiple outcomes. General statistical explanation: a point estimate, its interval, and the wider analysis context all matter; a p value alone does not describe the size or precision of an effect.
The planning illustrations are another useful distinction. They are based on observed effects and stated calculation assumptions, not on the trial’s own design justification or its observed power. Very large illustrative sample sizes can arise when the estimated target effect is small, but they should not be treated as evidence that a completed trial was or was not adequately powered. The trial’s own sample-size justification is not reported in the registry record.
Overall, this record shows why transparent reporting of comparative estimates, uncertainty, analysis populations, missing data, and multiplicity procedures is important for clinical interpretation. Those details help readers distinguish a descriptive pattern from a well-supported estimate of a between-group effect.
14. 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.
Several limitations are specific to the posted results for this trial. The primary endpoint is described through group medians and interquartile ranges, but a two-arm comparison is not estimable in the registry record. This prevents a direct assessment of the primary contrast and its precision from the posted results. A visual difference between group medians should not be treated as a formal comparative result.
The available secondary comparisons are recalculated from posted summaries and are not listed as sponsor-reported analyses. The registry record does not provide a statistical analysis plan, analysis population, missing-data methods, or multiplicity procedure. It also does not explain why endpoint-specific participant counts vary. These omissions make it difficult to assess whether the available summaries reflect all randomized participants or how incomplete outcome data were addressed.
The study is described as unmasked, and the record does not provide details about allocation concealment, outcome assessment, treatment targets, or the intravenous regimen. The subcutaneous regimen is described, but the record offers no parallel detail for the intravenous intervention. These gaps limit assessment of how comparable the interventions were in practice and how outcome measurement or care decisions may have been influenced by awareness of assignment.
Some outcomes named as secondary do not have posted results in the registry record. Safety reporting is also limited: serious adverse-event counts are posted, but event terms are not, and death counts are not reported. The record does not give event timing or further details needed to interpret adverse-event categories. The planning illustrations are not the trial’s design justification and do not resolve these limitations.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Intensive Glycemic Control for Congestive Heart Failure Exacerbation — NCT00812253.
- Registry record last updated 2018-01-02; status last verified 2017-12.
- Results first posted 2014-08-07.
- 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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18. Record Summary
NCT00812253 is a completed randomized Phase 2 parallel-group trial comparing intravenous insulin with subcutaneous insulin in patients with congestive heart failure and diabetes mellitus. The registry describes no masking and lists an enrollment of 74. The subcutaneous regimen is described as basal bolus insulin given by 4 injections per day.
The primary outcome is hospital length of stay, reported as a median of 7 days (interquartile range 5 to 11) for intravenous insulin and 8 days (interquartile range 5 to 12) for subcutaneous insulin. A two-arm comparison for the median-time endpoint is not estimable from the posted results. Secondary results are posted for change in quality of life and cardiac output; both are unadjusted recalculations with intervals that include zero. Other named secondary outcomes do not have posted results in the record.
Analysis populations, missing-data handling, multiplicity methods, the trial’s sample-size justification, and the statistical analysis plan are not reported in the registry record. Serious adverse events are recorded as affecting 0 participants in each group; the record also lists other adverse events and does not report death counts.