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 Effects of Growth Hormone Administration on Cardiovascular Risk in Cured Acromegalics With Growth Hormone Deficiency (NCT00182091), a randomized na study. The primary outcome is Change in High-sensitivity C-reactive Protein.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00182091 |
| Phase | NA |
| Condition | Acromegaly, Growth Hormone Deficiency, Pituitary Disease |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 75 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Massachusetts General Hospital |
| Results posted | Yes |
2. Clinical Question
Population
The main randomized comparison involved people with a history of acromegaly who were now growth hormone deficient and eligible to receive growth hormone. The study also included groups with a history of acromegaly and normal growth hormone levels, and with active acromegaly; these were described as non-interventional arms for the primary outcome.
Intervention
Recombinant human growth hormone was the active intervention. The study description says eligible growth hormone-deficient participants took part for 12 months.
Comparator
The randomized comparator was placebo, with saline listed as an intervention. The record names arms randomized to growth hormone and to placebo.
Primary question
The primary endpoint was change in high-sensitivity C-reactive protein from baseline to 6 months. The question was whether this cardiovascular risk marker changed differently between the randomized growth hormone and placebo groups.
The clinical context is growth hormone deficiency following cure of acromegaly. The study description explains that growth hormone levels after treatment for acromegaly may be normal or low, and that deficiency can follow damage to the pituitary or hypothalamic region from a tumor or its treatment. The research focus was cardiovascular risk-related measures, including blood markers, arterial stiffness, heart rate, and the heart’s response to changes in body position. The description also identifies hormone use, including estrogen or testosterone, as a possible source of differing effects.
The registry record does not report numerical results for the primary comparison. Therefore, the clinical question can be described from the endpoint and design, but the posted record does not establish the direction or size of any difference in change between the randomized groups.
3. Trial Design
The study is listed as randomized, single-masked, and parallel-group, with phase recorded as not applicable. Massachusetts General Hospital is the sponsor. The record lists enrollment of 75 and status as completed. The recorded start was 2004-08, and primary completion was 2009-12.
The central intervention comparison was between growth hormone-deficient participants with a history of acromegaly who were randomized to recombinant human growth hormone or placebo. The corresponding arm descriptions characterize both as interventional arms. Saline is listed as an intervention. The record also names AcroGHS and Active Acromegaly arms. The primary outcome description explicitly says these two arms were not interventional and therefore do not have outcome results for that endpoint.
The study description distinguishes growth hormone-deficient participants with a contraindication to receiving growth hormone from those without a contraindication. It says the former group and people with cured acromegaly and normal growth hormone levels were assessed on one occasion, while growth hormone-deficient participants without a contraindication participated for 12 months. The primary endpoint’s timeframe is baseline and 6 months. The record does not fully describe how all assessment schedules relate to every measure.
Random allocation supports a comparison of the assigned treatment groups, while a parallel design means participants are assigned to a group rather than crossing between interventions. The term single-masked indicates that masking was used for one party, but the identity of the masked party is not reported in the registry record. The allocation procedure, concealment details, and precise masking arrangements are also not reported. The overall enrollment figure should not be treated as the number analyzed for the primary endpoint: the record notes one non-completion in the growth hormone group and one placebo participant excluded from analysis, but does not provide a complete endpoint-specific analysis count.
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 | AcroGHD Randomized to Growth Hormone | AcroGHD Randomized to Placebo | AcroGHS | Active Acromegaly |
|---|---|---|---|---|
| STARTED | 15 | 15 | 25 | 20 |
| COMPLETED | 14 | 15 | 25 | 20 |
| NOT COMPLETED | 1 | 0 | 0 | 0 |
Reasons for not completing this period:
| Reason | AcroGHD Randomized to Growth Hormone | AcroGHD Randomized to Placebo | AcroGHS | Active Acromegaly |
|---|---|---|---|---|
| Withdrawal by Subject | 1 | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: In the Growth Hormone group, 1 study participant did not complete the study due to discomfort at injection sites. In the Placebo group, data from one study participant was excluded from analysis due to initiation of appetite suppressants to induce weight loss during the study, as prescribed by a physician at a bariatric clinic.
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 | AcroGHD Randomized to Growth Hormone | AcroGHD Randomized to Placebo | AcroGHS | Active Acromegaly | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 15 | 15 | 25 | 20 | 75 | |
| Age, Continuous | years | 47 (SD 12) | 47 (SD 11) | 47 (SD 12) | 46 (SD 14) | 46 (SD 12) |
| Sex: Female, Male: Female | Participants | 9 | 8 | 18 | 10 | 45 |
| Sex: Female, Male: Male | Participants | 6 | 7 | 7 | 10 | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Change in High-sensitivity C-reactive Protein, measured over baseline and 6 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | mg/liter |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in high-sensitivity C-reactive protein, measured in mg/liter, from baseline to 6 months in the growth hormone and placebo arms. High-sensitivity C-reactive protein is a blood marker used in cardiovascular risk assessment. As a continuous endpoint, it represents a measured quantity rather than a count of events or a yes-or-no outcome.
Analyzing change focuses on how the measured value shifts over the stated follow-up interval. In a randomized comparison, the relevant treatment question is whether the average change differs between assigned groups. A group’s change on its own does not answer that comparative question: both groups could change, or neither could, and the contrast between their changes is the quantity of interest.
The registry describes the endpoint using a mean and standard deviation. The mean represents the group’s average change, while the standard deviation describes variability among individual measurements around that average. These summaries can help characterize the group response and its spread, but do not by themselves show the uncertainty in the between-group contrast. That requires an estimate of the contrast and an uncertainty measure, such as a confidence interval.
The registry record does not include the actual group means, standard deviations, treatment contrast, confidence interval, or p-value for this endpoint. It therefore does not permit an assessment of the observed direction, size, or precision of the primary result. The use of this biomarker also does not mean that the endpoint directly measures cardiovascular events; it is a risk marker, not an event count.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a randomized comparison and a primary endpoint, but numerical results for that endpoint are not reported in the registry record. No between-group estimate, group-level change, confidence interval, or p-value is available in the record details. Consequently, the direction and magnitude of the primary comparison cannot be described, and its statistical precision cannot be evaluated.
This distinction matters because knowing the endpoint and design is not equivalent to knowing the result. The endpoint is average change in high-sensitivity C-reactive protein from baseline to 6 months, and the principal randomized contrast is growth hormone versus placebo. Without the result summaries, it is not possible to say whether the average change was higher or lower in either arm, whether the groups were similar, or whether the estimated contrast was compatible with a range of effects.
A confidence interval, if reported, would communicate the uncertainty around an estimated treatment contrast. Its width would indicate how precisely the contrast was estimated, and its bounds would show which values are reasonably compatible with the data under the analysis. A p-value, if reported, would describe how unusual results at least as incompatible with a specified null hypothesis would be under that model. Neither measure alone expresses clinical importance. No such numerical inferential result is included in the registry record.
The enrollment figure is 75, but it is not a substitute for the number contributing data to the primary endpoint. The endpoint description reports that one growth hormone participant did not complete the study because of discomfort at injection sites. It also reports that data from one placebo participant were excluded after that participant began appetite suppressants to induce weight loss, as prescribed by a physician. The record does not give the full number analyzed by arm or explain whether other observations were missing. It would be inappropriate to infer a complete-case count or an analysis population from the enrollment figure alone.
The registry lists four outcome measures and three named secondary outcomes: change in total fat mass, total abdominal adipose tissue, and visceral abdominal adipose tissue. It lists no analyses. Numerical findings for those measures are not included in the record details, so they cannot support interpretation of the primary endpoint or provide corroborating evidence.
Planning illustrations based on a fraction of the observed effect are not results from the trial and do not establish observed power. The record gives the general planning assumptions—two-sided significance level 0.05, equal allocation, and a normal approximation—but no observed effect or illustration values. Those assumptions therefore cannot be used to reconstruct the primary result or its uncertainty. The appropriate reading is limited: the registry describes a randomized, masked comparison and an endpoint, but the posted data available in the record do not show the primary outcome estimate.
9. Statistical Methods Explained
The main statistical structure is a comparison of a continuous outcome between randomized parallel groups. The endpoint is change in high-sensitivity C-reactive protein between baseline and 6 months, summarized using the mean and standard deviation. In general, a mean is useful for describing the average level of change in a group, while a standard deviation describes how dispersed individual changes are around that group average. Neither quantity alone is the treatment effect: the treatment effect for a two-group question is the contrast between the groups’ average changes.
What does a between-group contrast represent?
In general, a between-group contrast compares outcomes under the randomized assignments. For a change endpoint, analysts may compare the average changes directly, or use a model that accounts for baseline measurements. These approaches can differ in their assumptions and interpretation. The statistical analysis plan and the actual model used are not reported in the registry record, so it is not possible to determine which approach was used. The record also does not give the numerical contrast.
Randomization is intended to make treatment assignment independent of participants’ baseline characteristics, on average across repeated applications of the random allocation process. It helps make the assigned groups comparable without relying solely on measured characteristics. In a particular trial, randomization does not guarantee identical group composition, especially when the groups are small. The record identifies random allocation but does not describe the sequence-generation method, allocation concealment, or any stratification factors.
A standard deviation is not the same as a standard error or a confidence interval. In general, the standard deviation describes participant-to-participant variability; the standard error describes uncertainty in an estimated group quantity; and a confidence interval expresses a range of values compatible with the estimate and its assumptions. A precise estimate generally has a narrower confidence interval than an imprecise one. Since the registry record does not provide a contrast or interval, precision cannot be assessed for this endpoint.
What do a p-value and confidence interval add?
In general, a p-value evaluates how compatible the data are with a specified null model, conditional on the analysis assumptions. It is not the probability that the null hypothesis is true, nor does it measure the size or importance of an effect. A confidence interval adds information about effect size and uncertainty by showing a range of values consistent with the data under the method used. Interpretation should consider the estimate and interval together rather than relying on a significance label alone. The registry record does not report either measure for the primary comparison.
For continuous outcomes, distributional assumptions may matter. A normal approximation is one possible approach to estimating uncertainty for a mean contrast, particularly when its assumptions are reasonable. The planning description names a normal approximation for its illustrations; it does not establish that the outcome analysis used that method. The record does not state whether the outcome distribution was checked, transformed, or analyzed with a robust or other alternative method.
In general, skewed measurements or influential observations can make a mean-based analysis sensitive to a small number of values. High-sensitivity C-reactive protein can be described by the registry as a mean and standard deviation, but the record does not provide distributional summaries or diagnostic information. It is therefore not possible to assess skewness, outliers, or the suitability of a particular model from the posted record.
How should the planning illustrations be read?
The stated planning framework assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. These are assumptions for planning illustrations based on the observed effect, not evidence that the original trial was designed using those assumptions. The trial’s own sample-size justification is not reported in the registry record.
In general, a sample-size calculation estimates how many participants would be needed to achieve a chosen probability of detecting an effect of a specified size under stated assumptions. Such an illustration is conditional on those assumptions and the effect size used. It is not observed power, and it does not replace an estimate with a confidence interval. Because no observed effect or illustration values are included in the record details, no numerical planning result can be interpreted.
Over-dispersion is a general concern when observed variation exceeds what a model assumes. For continuous outcomes, an incorrect variance assumption can affect standard errors and therefore confidence intervals and tests. For this trial, the record does not report an over-dispersion assessment or a model-based variance analysis. That limitation should not be mistaken for evidence that over-dispersion occurred.
Multiple outcomes can create multiplicity: when many hypotheses are examined, the chance of at least one apparently unusual result can increase if each is tested without adjustment. General approaches include defining one primary endpoint in advance, controlling an error rate across a family of tests, or treating secondary findings as exploratory. The registry identifies a primary endpoint and three secondary outcome titles, but no analysis results or multiplicity adjustment are reported in the registry record. It is therefore not possible to say how multiple testing was handled.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures, including the primary endpoint of change in high-sensitivity C-reactive protein and three secondary outcomes concerning total fat mass, total abdominal adipose tissue, and visceral abdominal adipose tissue. It lists no analyses. The analysis plan, hierarchy among secondary outcomes, and any adjustment for multiple comparisons are not reported in the registry record.
Multiplicity matters when several outcomes or comparisons are tested. In general, examining more hypotheses without accounting for the collection of tests can increase the chance of a false-positive finding somewhere among them. A clearly designated primary endpoint can help focus interpretation, while secondary results may be treated as supportive or exploratory depending on a prespecified plan. No such detailed plan is reported, and no secondary numerical results are available in the record details.
The endpoint description identifies two participant-level data issues. One participant in the growth hormone group did not complete the study because of discomfort at injection sites. Data from one participant in the placebo group were excluded from analysis after initiation of appetite suppressants to induce weight loss, as prescribed by a physician. The record does not state how missing measurements were handled, whether any imputation was used, or whether analyses followed intention-to-treat or another population definition.
In general, missing-data methods rely on assumptions about why measurements are missing and how missing values relate to observed information. Excluding participants or measurements can affect comparability if the reasons for missingness are related to treatment or outcome. The limited descriptions do not establish the direction or size of any such effect. The complete analysis population, participant flow by outcome, and sensitivity analyses are not reported in the registry record.
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 |
|---|---|---|---|
| AcroGHD Randomized to Growth Hormone | 0 | 15 | 0.0% |
| AcroGHD Randomized to Placebo | 0 | 15 | 0.0% |
| AcroGHS | 0 | 25 | 0.0% |
| Active Acromegaly | 0 | 20 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| AcroGHD Randomized to Growth Hormone | 0 of 15 |
| AcroGHD Randomized to Placebo | 0 of 15 |
| AcroGHS | 0 of 25 |
| Active Acromegaly | 0 of 20 |
The adverse-event record lists four groups: AcroGHD randomized to growth hormone, AcroGHD randomized to placebo, AcroGHS, and Active Acromegaly. For each group, the posted figures show 0 serious adverse events and 0 other adverse events. The corresponding numbers at risk are 15, 15, 25, and 20, respectively. These figures describe the registry’s listed event counts and at-risk groups; they do not provide detailed event narratives.
Zero reported events should be read as an event count in the registry record, not as proof that no symptoms or health problems occurred. The record does not give a definition of the adverse-event collection period, detail how events were solicited, or provide information about severity other than the serious-versus-other categories. It also does not identify any serious adverse-event terms.
Deaths are recorded as not reported for these groups. That is different from a reported count of zero deaths. The figures therefore allow a narrow description of the posted serious and other adverse-event counts, but they do not establish comprehensive safety inferences or permit comparison of event rates beyond the information explicitly listed.
12. What the Result Does, and Does Not, Mean
The registry record describes a randomized study of recombinant human growth hormone versus placebo among growth hormone-deficient people with a history of acromegaly. Its primary endpoint was change in high-sensitivity C-reactive protein from baseline to 6 months. This identifies the intended comparison and the measure used to address a cardiovascular risk-related question.
However, the numerical primary outcome result is not reported in the registry record. Without group summaries and a between-group estimate, the record cannot show whether the marker changed in either direction, whether the groups differed, or how large any difference might have been. Without an uncertainty estimate, it also cannot show how precisely the contrast was measured. No conclusion about the effect of growth hormone on this endpoint follows from the design description alone.
Even if a numerical difference were available, a biomarker endpoint would not by itself establish a difference in cardiovascular events. The primary measure is a risk marker, and the record details do not include cardiovascular event results. Nor does an endpoint based on average change describe every participant’s experience. A mean can conceal substantial individual variability, which is one reason dispersion and uncertainty are important.
The study description includes additional cardiovascular-related measures, and the registry lists changes in fat mass and adipose tissue as secondary outcomes. The numerical results for those measures are not reported in the record details. The named non-interventional groups also do not provide randomized treatment comparisons for the primary outcome. Comparisons involving those groups would need to be interpreted differently from the randomized growth hormone-placebo contrast.
The safety record lists zero serious and zero other adverse events in each of the four named groups, while deaths are not reported. These entries are limited to the registry’s recorded categories and do not establish that no adverse experiences occurred. Overall, the available record supports a description of the research question, design, endpoint, and reported event counts, but not a conclusion about efficacy, clinical benefit, or the numerical primary result.
13. Why This Trial Matters Statistically
This trial raises several important statistical issues in a compact clinical setting. The randomized comparison targets a treatment contrast, while the primary endpoint is a continuous biomarker measured over time. Interpreting such a study requires separating the group averages from the between-group difference, and separating an estimated difference from its uncertainty. The registry record names the outcome and summaries but does not include the numerical result needed for those steps.
The study also includes non-interventional groups alongside randomized treatment arms. That distinction matters because randomized comparisons can support a different kind of inference from comparisons across groups that were not randomized to the intervention. The record explicitly states that the AcroGHS and Active Acromegaly arms were not interventional arms and do not have results for the primary endpoint. Treating all listed groups as if they formed one randomized comparison would misrepresent the design.
Missing observations and exclusions are relevant even when the number described is small: interpretation depends not only on how many values are absent, but also on why they are absent and how the analysis handled them. Here, the record describes a non-completion in the growth hormone group and an exclusion in the placebo group, without giving the full analysis population or missing-data method.
Multiplicity is another issue because the record lists a primary outcome and secondary outcomes, yet does not report the analysis plan or any adjustment strategy. Finally, planning illustrations based on the observed effect should not be mistaken for observed power or for the study’s original design rationale. Together, these issues show why a registry entry can establish a trial’s question and structure while remaining insufficient for a complete statistical interpretation of its results.
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.
The principal limitation for interpreting this trial from the registry record is the absence of numerical primary-outcome results. The record identifies the endpoint, unit, summary measure, and timeframe, but does not report the group means, standard deviations, treatment contrast, confidence interval, or p-value. The direction, magnitude, and precision of the primary comparison therefore cannot be assessed.
The participant-level information is incomplete. The outcome description notes one growth hormone participant who did not complete the study because of injection-site discomfort and one placebo participant whose data were excluded after starting appetite suppressants to induce weight loss, as prescribed by a physician. It does not provide a complete flow of participants through the primary analysis, explain the handling of missing measurements, or identify the analysis population.
The statistical analysis plan is not reported in the registry record. This includes the model for the primary endpoint, any baseline adjustment, assumptions or diagnostics, handling of multiple outcomes, and any sensitivity analyses. The registry lists no analyses. The planning framework is described, but no observed effect or planning values are available in the record details, and the trial’s own sample-size justification is not reported.
Masking is recorded as single, but the masked party is not identified. Details of random sequence generation, allocation concealment, and the timing or completeness of outcome assessments are also not reported. The study description indicates different assessment schedules for some groups, while the primary endpoint is specified at baseline and 6 months; fuller scheduling details are unavailable.
The adverse-event record reports event counts but not deaths, which are not reported. It does not include detailed event terms or collection procedures. These limitations restrict interpretation of both the primary outcome and safety information; they should not be filled by assumptions about the study’s conduct or analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of Growth Hormone Administration on Cardiovascular Risk in Cured Acromegalics With Growth Hormone Deficiency — NCT00182091.
- Registry record last updated 2020-09-02; status last verified 2020-08.
- Results first posted 2012-05-28.
- 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
NCT00182091 is a completed randomized, single-masked, parallel study sponsored by Massachusetts General Hospital. The record lists enrollment of 75, phase as not applicable, a start of 2004-08, and primary completion of 2009-12.
The main interventional comparison was growth hormone versus placebo among people with growth hormone deficiency after cure of acromegaly. The primary endpoint was change in high-sensitivity C-reactive protein, in mg/liter, from baseline to 6 months, summarized as a mean and standard deviation. AcroGHS and Active Acromegaly were identified as non-interventional arms for that endpoint.
The registry record does not report numerical primary or secondary outcome results, analysis methods, or a full analysis population. It describes one non-completion in the growth hormone group and one placebo exclusion. Adverse-event entries list zero serious and zero other events in each named group; deaths are not reported.