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 Minimally Invasive Surgery (MIS) Database for the Purpose of Research (NCT00535990), a registered phase not stated study. The primary outcome is Post Operative Outcomes.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00535990 |
| Phase | Phase not stated |
| Condition | Morbid Obesity, Hernia, Colorectal Cancer |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 250 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Diego |
| Results posted | Yes |
2. Clinical Question
Population
The database concerns patients undergoing minimally invasive surgery procedures at UCSD. The registry record lists morbid obesity, hernia, colorectal cancer, and laparoscopy among the conditions. Enrollment is 250. It does not report further eligibility criteria or describe the characteristics of the enrolled participants.
Intervention
The research focus is surgical care involving minimally invasive procedures. The brief summary mentions laparoscopic, open, and robot-assisted procedures. The registry record does not specify which procedures individual participants received, or how treatment selection was made.
Comparator
No like-for-like control comparison is established. The registry record does not state an allocation method, and it explicitly identifies the record as not being a randomized comparison. Although different surgical approaches are mentioned, their use as comparison groups is not reported.
Primary question
The stated primary outcome concerns post-operative outcomes, including morbidity and mortality within 30 days, readmission within 30 days, surgical site infection and occurrences, reintervention, and specific surgical outcomes such as staple-line leak. Its timeframe is listed as 1 year. The record does not report outcome counts or analyses that answer how often these events occurred.
This is best understood as a research database intended to describe patterns of care, outcomes, and prognostic information, rather than as a trial estimating a randomized treatment effect. Its stated aim is to collect information about patients undergoing surgery at UCSD, with the hope of improving understanding of minimally invasive surgery and assisting the management of future patients. Those aims describe the purpose of collecting data; they are not evidence that any particular surgical approach has a benefit. The registry record does not set out a specific comparative hypothesis, define a control group, or report which factors would be used in a prognostic analysis. Consequently, the central question that can be read from the record is descriptive: what post-operative outcomes are recorded for the enrolled patients? The posted results do not provide the outcome findings needed to answer even that question. The record therefore identifies the intended population and outcome domains, but leaves the actual frequency and pattern of those outcomes unreported.
3. Trial Design
NCT00535990 is a completed research database sponsored by the University of California, San Diego. Its title and brief summary describe a database for collecting information on patients undergoing minimally invasive surgery procedures at UCSD. The stated purpose is to study patterns of care, outcomes, and prognostic information. Enrollment is 250. The recorded start is 2007-09, and primary completion is 2009-11.
The registry record does not establish a randomized treatment design. Allocation is not stated, and the record cautions that the arms are not a like-for-like control comparison. The summary refers to laparoscopic, open, and robot-assisted procedures, but does not specify how participants were classified by procedure, whether these were analysis groups, or whether any groups were compared. It is therefore not appropriate to interpret the record as a controlled comparison of surgical approaches.
One primary outcome measure is listed, titled “Post Operative Outcomes.” It is described as the number of participants and has a timeframe of 1 year. The outcome description names several components, including 30-day morbidity, 30-day mortality, 30-day readmission, surgical site infection, surgical site occurrences, surgical reintervention, and specific surgical outcomes such as staple-line leak. The record does not explain how these components were defined, whether each was analyzed separately, or how outcomes occurring at different time windows were combined.
The registry status is COMPLETED, but completion does not by itself mean that outcome findings were posted. The record lists zero analyses and contains no outcome analysis results. It does not report the recruitment or follow-up procedures, the analysis population, or the handling of participants with incomplete follow-up. A protocol, detailed statistical analysis plan, sample-size justification, or interim-analysis plan is not reported in the registry record. These omissions prevent a fuller reconstruction of the planned and executed study design.
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 | Surgical Intervention |
|---|---|
| STARTED | 250 |
| COMPLETED | 250 |
| NOT COMPLETED | 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 | Surgical Intervention |
|---|---|---|
| Participants analysed | 250 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 175 |
| Age, Categorical: >=65 years | Participants | 75 |
| Age, Continuous | years | 57 (25 to 86) |
| Sex: Female, Male: Female | Participants | 112 |
| Sex: Female, Male: Male | Participants | 138 |
6. Primary Endpoint
The registry lists the primary outcome as Post Operative Outcomes, measured over 1 year.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is titled “Post Operative Outcomes” and measures a number of participants. Its description covers several clinically distinct events: morbidity and mortality within 30 days, readmission within 30 days, surgical site infection, surgical site occurrences, surgical reintervention, and specific surgical outcomes such as staple-line leak. The listed timeframe is 1 year. The registry record does not clarify whether the one-year timeframe applies to all components, or whether the 30-day events are assessed as separate windows within that period.
In general, post-operative outcomes are used to describe events after surgery and to characterize the course of care. Reporting the number of participants with events can make the frequency of complications or other outcomes understandable, provided the event definitions, follow-up period, and denominator are clear. Because this outcome combines multiple event types, separate reporting would be important for interpretation: mortality, readmission, infection, and reintervention do not represent the same event or necessarily share the same observation window. The registry record does not explain whether participants could contribute to more than one component, or whether a composite endpoint was intended.
No primary outcome counts or analysis estimates are reported. Thus, the endpoint description establishes what the database intended to capture, but it does not establish how many participants experienced any listed outcome. The endpoint's value as an outcome measure cannot be judged from a description alone; its observed findings and operational definitions are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a completed database project with enrollment of 250, but it does not post analyzed findings for its primary outcome. There is one outcome measure and zero analyses listed. The outcome description names post-operative events, while the results needed to quantify those events are absent. Completion status should therefore be read as the recorded status of the project, not as evidence that a particular clinical result was demonstrated.
The record's stated purpose is to examine patterns of care, outcomes, and prognostic information in patients undergoing minimally invasive surgery procedures at UCSD. Its summary mentions laparoscopic, open, and robot-assisted procedures. However, no treatment allocation is stated, and the record warns that any arms are not like-for-like control groups. The data cannot be interpreted as a randomized comparison between surgical approaches. The registry record also does not report adjusted or unadjusted estimates, confidence intervals, p-values, or the number of participants experiencing the primary outcome. Without those findings, there is no statistical estimate of outcome frequency or precision to interpret.
The primary measure has a broad description that includes several event categories and both 30-day language and a listed timeframe of 1 year. The record does not clarify whether all components were assessed over the same period, how events were defined, or whether they were reported individually or combined. These details matter because the meaning of a participant count depends on what counts as an event and how long participants were observed. They also matter if participants can experience multiple types of event.
The safety entry reports 0 serious events among 250 at risk and 0 other events among 250 at risk in the group titled Surgical Intervention. The deaths value is null, which is not a reported count of zero. These safety figures are distinct from the primary post-operative outcome measure, and the registry record does not explain the relationship between the safety categories and the listed outcome components. Zero reported events in a registry entry should not be taken to mean that every relevant event was actively assessed and ruled out; the amount and completeness of safety reporting are not described.
Accordingly, the strongest statistical reading is limited: the registry documents an intended data-collection project and a set of planned outcome domains, but does not provide clinical outcome analyses. It does not support an estimate of comparative effect, a causal conclusion, or a precise description of the frequency of post-operative events. The absence of posted analyses is not evidence that outcomes were absent. Any interpretation beyond the project purpose and the explicitly posted counts would require information that is not reported in the registry record.
9. Statistical Methods Explained
The statistical information in this record is sparse. It lists one primary outcome measure, gives its unit as participants, and identifies its parameter as a number of participants with an event. It lists zero analyses. No outcome counts, effect estimates, standard errors, confidence intervals, or p-values are reported. The explanations below describe general statistical ideas relevant to this kind of outcome; they do not imply that a particular method was used in this database project.
What does a participant count represent?
In general, a binary outcome classifies each participant according to whether an event occurred or did not occur during a defined observation period. The event count is interpretable only alongside the number of participants assessed and the event definition. If follow-up is incomplete, a denominator based on everyone enrolled can differ from a denominator based on participants whose outcome status is known. The registry record does not report the number assessed for each post-operative outcome or how incomplete follow-up was handled. Although the outcome is described as a number of participants, no such outcome counts are posted.
Why do event definitions and follow-up windows matter?
General statistical interpretation depends on a clear definition of what qualifies as an event and when it is counted. The primary outcome description includes several different events, and the registry timeframe is 1 year, while some components are explicitly described as 30-day outcomes. A 30-day event and an event assessed over a year answer different questions. The record does not state whether the one-year timeframe applies to every component, whether outcomes were combined, or whether each component was tabulated separately. It also does not report definitions for morbidity, surgical site occurrences, or the specific surgical outcomes.
What can a confidence interval tell a reader?
In general, a confidence interval describes statistical uncertainty around an estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, while neither width nor inclusion of a particular value alone establishes clinical importance or causation. A confidence interval cannot be interpreted when the underlying estimate and interval are not reported. No confidence interval for a post-operative outcome appears in the registry record. There is therefore no posted precision estimate to assess.
What does the design allow statistically?
General comparisons between treatment groups require a defensible definition of those groups and a design or analysis that addresses how participants came to receive each treatment. Random assignment can support causal comparisons under appropriate conduct and analysis, whereas nonrandomized comparisons may reflect differences between patients or care settings. This record does not state allocation, is identified as not being a randomized comparison, and warns that arms are not like-for-like controls. The registry record does not report a method for adjusting for differences between groups. The mention of laparoscopic, open, and robot-assisted procedures is not enough to establish a comparative analysis.
For descriptive database work, event counts can still be useful when the population, observation period, event definitions, and completeness of outcome ascertainment are made clear. The posted record does not report those details sufficiently to interpret outcome frequencies. It also does not report which variables were collected for prognostic analysis, how a prognostic model might have been specified, or whether any model was fitted. No method should be attributed to the project without those details.
What is reported about planning and power?
The registry record includes general assumptions for a sample-size planning illustration: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. The assumptions also distinguish between participant counts per arm for most outcomes and total event counts for time-to-event analyses. These are planning conventions, not evidence that the project used a two-arm design or that it had an observed treatment effect. No numerical sample-size estimates or observed effect values are reported. The record does not report a sample-size justification for the database project, and these assumptions do not establish observed power.
In general, power is a design-stage probability calculated under specified assumptions; it is not a measure of whether a result is true. A post hoc power calculation based on an observed estimate would not replace reporting the estimate and its uncertainty. Here, there are no posted outcome estimates to interpret, and the planning illustration cannot supply missing results. The record does not report interim analyses, a prespecified analysis plan, or a method for handling multiple outcomes. These methods should not be inferred from the outcome list or from the general planning assumptions.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome description contains several event categories: morbidity, mortality, readmission, surgical site infection, surgical site occurrences, reintervention, and specific surgical outcomes such as staple-line leak. The registry record lists one outcome measure but does not say whether these components were analyzed separately, combined into a composite, or treated as descriptive fields in the database. It also does not report a hierarchy of outcomes or an adjustment for multiple statistical tests. The statistical plan for multiplicity is not reported in the registry record.
In general, testing many outcomes can increase the chance of at least one apparently notable result arising by chance. Whether adjustment is appropriate depends on the purpose and prespecification of the analyses. For a descriptive database, transparent reporting of all planned and analyzed outcomes can be as important as any formal adjustment. No outcome analyses are posted, so the record does not permit an assessment of how many comparisons were conducted or whether multiplicity influenced interpretation.
Missing-data handling is also not described. The record does not report participant-level follow-up completeness, missing outcome counts, reasons for missingness, or any imputation or sensitivity-analysis methods. In general, missing outcome status can affect both the denominator and the interpretation of observed event frequencies; treating unobserved outcomes as if no event occurred can be misleading. No such assumption can be attributed to this project from the posted record.
The analysis population is not reported in the registry record. It is unclear whether outcome summaries, if conducted, would include all enrolled participants, only participants with available follow-up, or another defined group. The record also does not explain how participants receiving different surgical approaches would be grouped for analysis. These omissions limit reproducibility and the ability to assess the scope of any result.
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 |
|---|---|---|---|
| Surgical Intervention | 0 | 250 | 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 |
|---|---|
| Surgical Intervention | 0 of 250 |
The safety entry lists a group titled Surgical Intervention. It reports 250 participants at risk for serious events and 0 affected, and 250 at risk for other events and 0 affected. These are the posted counts for those categories. The deaths value is null; it should be read as not reported, not as a zero death count. No top serious-event terms are listed.
In general, an at-risk count identifies the population used for a safety summary, while an affected count records participants with events under the registry's categories. These figures do not by themselves describe how events were defined, how long participants were followed for safety, or how completely events were collected. The registry record does not provide those details, nor does it explain how these safety categories correspond to the primary outcome's list of post-operative events.
The posted zero counts should therefore be interpreted narrowly as the values entered in the safety record. They are not a substitute for the missing primary outcome results and do not establish that every listed complication was assessed or that none occurred. The record does not report additional detail on severity, timing, relatedness, or individual event types. Because the deaths entry is null, no conclusion about the death count can be drawn from that entry.
12. What the Result Does, and Does Not, Mean
This record establishes that the University of California, San Diego sponsored a completed research database project with enrollment of 250. Its stated focus was collecting information about patients undergoing minimally invasive surgery procedures, with an interest in patterns of care, outcomes, and prognostic analysis. The primary outcome description identifies a broad set of post-operative events and gives a timeframe of 1 year, with several components explicitly referring to 30-day outcomes.
It does not establish the frequency of those outcomes. The registry record lists one outcome measure but no analyses, and it does not post event counts for morbidity, mortality, readmission, infection, surgical site occurrences, reintervention, or specific surgical outcomes. It also does not provide estimates or confidence intervals that would show the precision of any outcome estimate. The posted safety counts are limited to their own categories and do not fill this gap.
The record does not establish that one surgical approach is better or worse than another. It does not state treatment allocation and cautions that this is not a randomized comparison with like-for-like control arms. The mention of laparoscopic, open, and robot-assisted procedures describes the scope in the brief summary, not a demonstrated comparative analysis. Without reported group definitions, outcome results, or an analysis addressing differences between patients, a causal interpretation is not supported.
In general, a research database can support descriptive and prognostic work when collection, outcome definitions, follow-up, and analysis are clearly documented. That general potential should not be confused with results that are actually posted. The registry record does not report the variables collected for prognostic analysis, any fitted model, or any validation of predictions. It also does not report the completeness of follow-up or how missing outcomes were handled.
The appropriate conclusion is narrow: the registry documents the purpose and scope of a surgical research database, but the posted results do not answer how frequently the specified outcomes occurred or what factors predicted them. The absence of reported analyses is not evidence of no events or no association. Additional findings and methods are not reported in the registry record.
13. Why This Trial Matters Statistically
This record is statistically informative in part because it illustrates the distinction between registering a data-collection project and reporting an analyzed clinical result. A completed status and an enrollment count describe aspects of project conduct, but neither supplies the outcome estimates needed to evaluate event frequency or precision. The registry record lists the subject of the primary measure, yet lists no analyses.
The outcome description also highlights why endpoint structure matters. It brings together multiple post-operative events, including outcomes with an explicitly stated 30-day window and a measure timeframe of 1 year. In general, event definitions and timing determine what a count means. When the relationship among components and observation windows is unclear, readers cannot tell whether the measure represents separate descriptive outcomes or a combined endpoint. The record does not resolve that distinction.
The design description is another important statistical boundary. The project concerns surgery approaches, but the registry record does not establish randomized allocation and warns that arms are not like-for-like controls. This makes it especially important not to interpret the existence of different procedures as evidence of a treatment comparison. Descriptive patterns in a database and causal effects from a controlled comparison are different statistical quantities.
Finally, the record shows why safety counts need context. A zero entry is a reported value for a particular category and denominator, not a complete account of outcome ascertainment. Definitions, duration of observation, and completeness of reporting affect interpretation. The deaths entry is null rather than a count of zero. Taken together, these points make the record useful for identifying the intended research scope and the information needed for interpretation, while leaving clinical outcome conclusions unresolved.
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 registry record provides limited detail for evaluating either the conduct or statistical interpretation of the project. It does not report eligibility criteria, participant characteristics, recruitment procedures, or the distribution of procedures received. Although the brief summary mentions laparoscopic, open, and robot-assisted procedures, it does not say how patients were selected for them or whether they formed defined groups for analysis.
The primary outcome is broad, combining several post-operative domains in its description. Its timeframe is listed as 1 year, but the record also specifies 30-day morbidity, mortality, and readmission. It does not clarify the assessment window for the other components, define the events, or explain whether outcomes were assessed separately or combined. No primary outcome counts or analysis results are reported.
Important statistical methods are not reported in the registry record. These include the analysis population, handling of missing outcomes, any adjustment for differences between groups, multiplicity procedures, and the statistical plan. A sample-size justification for this database project is not reported. The general assumptions listed for a planning illustration do not give numerical estimates and do not establish that the project was designed as a two-arm comparison.
The safety record is also limited: it gives zero affected participants in the serious and other event categories, but does not provide event definitions, safety follow-up details, or a reported death count. The deaths entry is null. The record does not explain how safety reporting relates to the primary outcome measure.
These limitations restrict the conclusions to the project purpose, enrollment, stated outcome domains, and posted safety entries. They prevent assessment of outcome frequency, precision, comparative effects, or prognostic performance.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Minimally Invasive Surgery (MIS) Database for the Purpose of Research — NCT00535990.
- Registry record last updated 2021-12-06; status last verified 2021-11.
- Results first posted 2021-12-06.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00535990 is a completed research database sponsored by the University of California, San Diego, with enrollment of 250. The recorded start is 2007-09, and primary completion is 2009-11. Its stated purpose is to collect information on patients undergoing minimally invasive surgery procedures at UCSD and to examine patterns of care, outcomes, and prognostic information.
The registry record lists one primary outcome measure, “Post Operative Outcomes,” described as a number of participants and assigned a timeframe of 1 year. Its components include 30-day morbidity, 30-day mortality, 30-day readmission, surgical site infection, surgical site occurrences, surgical reintervention, and specific surgical outcomes such as staple-line leak. The record lists zero analyses and reports no primary outcome results.
The safety entry lists zero serious events and zero other events among 250 at risk in the Surgical Intervention group. The deaths value is null, not a reported count of zero. Allocation is not stated, and the record identifies the study as not being a randomized comparison with like-for-like control arms. The registry record does not report a detailed statistical analysis plan, handling of missing data, or a sample-size justification for the project.