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 Evaluation of the Predictive Nature of the Postoperative CRP on Postoperative Recovery in Patients Undergoing Colorectal Resection (CRP-Track) (NCT02395380), a na na study. The primary outcome is C-reactive Protein Rate.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02395380 |
| Phase | NA |
| Condition | Colorectal Postoperative Complication |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 174 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Centre Hospitalier Departemental Vendee |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing colorectal resection. The registry record does not report further eligibility details for the population in the primary endpoint description.
Intervention
C-reactive protein dosage, recorded as the study intervention. The study objective also refers to procalcitonin and venous lactate as inflammatory markers.
Comparator
There is no randomized comparator arm. The endpoint description compares CRP below 172 mg/l at postoperative day 3 with recovery status at postoperative day 5.
Primary question
How well does CRP below 172 mg/l at postoperative day 3 identify the registry-defined composite of postoperative recovery by postoperative day 5?
The recovery endpoint is described using fever, absence of pain >2, intestinal gas transit, and patient autonomy for mobility and body care. The record names sensitivity, specificity, positive predictive value, and negative predictive value as the measures used to assess CRP levels at day 3 in relation to recovery at day 5.
The broader study objective was to evaluate the prognostic value of CRP, procalcitonin, and venous lactate for postoperative recovery and length of stay after colorectal surgery. The primary outcome description, however, focuses on the day-3 CRP threshold and the day-5 recovery endpoint. Results for the listed diagnostic measures, other inflammatory markers, and length of stay are not reported in the registry record. The clinical question is therefore identifiable, but its numerical answer cannot be read from the posted results.
3. Trial Design
The registry describes a completed, single-group study with an enrollment of 174. The study start date is 2015-07-06, and the primary completion date is 2017-03-11. Its listed intervention is C-reactive protein dosage, categorized as “other.” The record gives phase as NA, allocation as NA, and masking as none.
This design is not a randomized treatment comparison. In particular, the registry does not identify separate treatment groups whose outcomes could be interpreted as a like-for-like control comparison. The stated aim is prognostic: assessing whether inflammatory-marker measurements relate to subsequent recovery and length of stay. The primary outcome description narrows that aim to CRP below 172 mg/l at postoperative day 3 and a composite recovery endpoint at postoperative day 5.
The record does not report how participants were selected, how CRP was measured, or the timing and procedures for measuring the other markers. It also does not describe a protocol-defined analysis population or explain the difference between the enrollment total and the denominator listed in the safety information. Those details are not reported in the registry record, so they cannot be inferred from the design labels alone.
The study status is completed, but completion does not itself establish that all planned analyses or outcomes are available in the record. The registry lists one outcome measure and no analyses. The record does not report a statistical analysis plan, a sample-size justification, or details of any interim analyses. Consequently, the design can be characterized at a broad level, while important operational and analytical details remain unavailable.
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.
Before assignment: Of 174 enrolled participants, 168 met inclusion criteria
Overall Study
| Stage | C-reactive Protein Dosage |
|---|---|
| STARTED | 174 |
| COMPLETED | 168 |
| NOT COMPLETED | 6 |
Reasons for not completing this period:
| Reason | C-reactive Protein Dosage |
|---|---|
| CRP measuring missing | 5 |
| Unscheduled stoma | 1 |
Analysis population for the primary outcome, as defined in the registry: C-reactive Protein \< 172 mg/l overall postoperative recovery within 5 days.
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 | C-reactive Protein Dosage |
|---|---|---|
| Participants analysed | 168 | |
| Age, Continuous | years | 65.1 (SD 13.2) |
| Sex: Female, Male: Female | Participants | 76 |
| Sex: Female, Male: Male | Participants | 92 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as C-reactive Protein Rate, measured over 5 postoperative days.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “C-reactive Protein Rate,” is expressed as a percentage, and specifies a 95% confidence interval. Its description links CRP below 172 mg/l at postoperative day 3 with a composite measure of postoperative recovery at postoperative day 5. The listed recovery elements are fever, absence of pain >2, intestinal gas transit, and patient autonomy for mobility and body care.
The record names sensitivity, specificity, positive predictive value, and negative predictive value as the measures for evaluating the day-3 CRP threshold against day-5 recovery. In general, these measures describe different aspects of how a threshold classifies a later outcome. Sensitivity concerns identification of people meeting the outcome definition; specificity concerns identification of those who do not. Positive and negative predictive values describe the outcome status among people classified on either side of the threshold. These are general statistical definitions, not reported findings from this study.
A recovery endpoint can make a prognostic question more concrete by setting a later clinical status against an earlier marker measurement. However, the registry record does not explain the precise rule for combining the listed recovery elements, such as whether each element must be met or how any exceptions are handled. It also does not report the observed percentage estimates or their confidence interval. Thus, the endpoint and its intended timing are described, but the numerical performance and some operational details of the composite are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted results do not provide numerical estimates for the primary endpoint. Although the record describes a day-3 CRP threshold of below 172 mg/l and names sensitivity, specificity, positive predictive value, and negative predictive value, it does not report the values for those measures. It also does not report the stated 95% confidence interval. Accordingly, the registry record does not establish how accurately the threshold classified recovery in this study, nor how precise any such estimate was.
The study objective refers more broadly to CRP, procalcitonin, and venous lactate in relation to postoperative recovery and length of stay. The primary endpoint description is limited to the CRP threshold and recovery status. Numerical results for procalcitonin, venous lactate, or length of stay are not reported in the registry record. The available description should not be read as evidence that those markers were or were not associated with outcomes.
In general, an estimate of diagnostic or prognostic performance needs to be considered together with its uncertainty. A confidence interval indicates a range of values compatible with the observed data under the analysis assumptions; a wider interval usually reflects less precision than a narrower one. Here, no estimate or interval is posted, so the degree of uncertainty cannot be assessed from the registry record. The planned form of an endpoint is not a substitute for its observed result.
The single-group design also shapes interpretation. It can address whether a measurement is associated with a later outcome within the studied group, if such analyses are reported. It does not, by itself, estimate the effect of assigning one treatment rather than another. The record describes a prognostic assessment, not a randomized comparison of interventions, and no causal treatment effect can be inferred from the design information.
The registry lists an enrollment of 174, while its serious adverse event information gives 168 at risk. These are different recorded quantities; the record does not explain the relationship between them or identify the analysis denominator for the primary endpoint. The enrollment total should therefore not be substituted for an unreported endpoint denominator. Without the outcome counts and analysis population, the reported endpoint cannot be reconstructed from the registry record.
Overall, the record makes the intended question and measurement timing understandable, but it does not provide the numerical findings needed to answer that question. The absence of posted estimates is not evidence that the threshold performed well or poorly. It means that the accuracy and precision of the proposed prognostic classification are not reported in the registry record.
9. Statistical Methods Explained
The methods description identifies a threshold-based prognostic question: CRP below 172 mg/l at postoperative day 3 is related to a composite recovery status at postoperative day 5. It names four diagnostic measures and specifies a percentage endpoint with a 95% confidence interval. The registry record does not provide the estimates, counts, or detailed analysis procedures underlying those measures.
What do sensitivity and specificity describe?
In general, sensitivity and specificity evaluate classification against a defined outcome. Sensitivity asks how often a classification rule identifies people who meet the outcome definition. Specificity asks how often it classifies people who do not meet that definition. They answer complementary questions: a rule can identify many people with the outcome while also classifying many people without it as positive, or it can be more selective while missing some people with the outcome. The balance depends on the threshold and the outcome definition.
For this study, the registry identifies the CRP threshold and the day-5 recovery outcome but does not post the cross-classification counts. Without those counts, neither sensitivity nor specificity can be checked or interpreted quantitatively. The registry also does not explain whether the endpoint’s component criteria were all required, how each component was assessed, or how incomplete components were handled. Those operational details matter because the same marker threshold can yield different classifications if the outcome definition changes.
What do predictive values add?
In general, positive predictive value describes the proportion of people classified as positive who meet the outcome definition; negative predictive value describes the proportion classified as negative who do not meet it. These measures directly relate a classification to the observed outcome in the study population. Unlike sensitivity and specificity, predictive values depend on how common the outcome is in the population being assessed. Therefore, estimates from one group may not carry over unchanged to a population with a different outcome frequency. This is a general property of predictive values, not a claim about the frequency of recovery in this study.
The registry names positive and negative predictive value but does not report either estimate or the outcome frequency needed to understand their context. No conclusion about the practical classification performance of the threshold can be drawn from the endpoint description alone.
Why does the confidence interval matter?
In general, a confidence interval expresses statistical uncertainty around an estimate. It communicates how much precision the data provide under the assumptions of the calculation. The interval does not guarantee that the true value lies within its limits, and it does not correct for bias, measurement problems, or an unsuitable analysis. A confidence interval is most useful when read alongside the point estimate, the number of observations contributing to it, and the analysis method.
The endpoint description specifies a 95% confidence interval, but the registry record does not post its limits or the estimate it would accompany. It also does not describe the interval calculation. Thus, neither the magnitude nor the precision of the endpoint estimates can be assessed. No interval should be reconstructed without the relevant counts and methods.
What does the threshold comparison mean?
In general, converting a continuous laboratory measurement into categories makes a threshold-based classification easier to describe, but it discards information about differences within each category. A person just below a cutoff and a person much farther below it receive the same threshold classification; similarly, values on the other side of the cutoff are grouped together. This general feature does not establish whether the selected threshold is suitable. The registry identifies below 172 mg/l as the threshold for the primary question but does not report why it was selected or whether other thresholds were considered.
The threshold is measured at postoperative day 3, and the recovery outcome is assessed at postoperative day 5. That ordering supports a prognostic framing in which an earlier measurement is related to a later status. It does not by itself show that the marker causes recovery, or that changing the marker would change the outcome. Establishing causal effects would require a different question and an appropriate design and analysis.
The broader study objective mentions CRP, procalcitonin, venous lactate, recovery, and length of stay. The record does not explain whether these measures were analyzed jointly, separately, or under a prespecified model. It does not report adjusted estimates, model assumptions, handling of continuous measurements, or validation procedures. Those methods are not reported in the registry record and should not be inferred from the endpoint’s statistical labels.
Finally, the registry lists no analyses. The stated outcome and named measures indicate what the record intended to assess, but they do not provide an analysis result. In the absence of counts, estimates, confidence limits, and analysis details, the available methodological description supports a clear explanation of the question, not a numerical assessment of predictive performance.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and no analyses. The study’s brief description refers to CRP, procalcitonin, venous lactate, postoperative recovery, and length of stay, while the primary endpoint description specifies a CRP threshold and day-5 recovery. The record does not explain how these broader objectives relate to any planned secondary outcomes or analyses.
Multiplicity concerns arise in general when several outcomes, markers, thresholds, or statistical comparisons are examined. Repeated testing can increase the chance of finding an apparently notable result by chance. A prespecified analysis plan can explain which tests are primary and how multiple comparisons are handled. No multiplicity strategy or statistical analysis plan is reported in the registry record, so it is not possible to determine whether any adjustment was planned or used.
The registry record does not report how missing CRP measurements, incomplete recovery assessments, or other unavailable observations were handled. It does not identify the analysis population for the primary endpoint, describe exclusions, or state whether participants were analyzed according to a particular rule. Although enrollment is listed as 174, the denominator for the primary endpoint is not reported in the registry record; the safety denominator should not be assumed to be the endpoint denominator.
Details about interim analyses, missing-data assumptions, and sensitivity analyses are also not reported in the registry record. These omissions limit assessment of how robust a numerical result would be to incomplete data or alternative analytical choices. Since no primary estimates are posted, these issues cannot be explored from the reported results.
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 |
|---|---|---|---|
| C-reactive Protein Dosage | 0 | 168 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| C-reactive Protein Dosage | 1 of 168 |
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 |
|---|---|
| C-reactive Protein Dosage | 0 of 168 |
The registry’s serious adverse event information lists 168 participants at risk and 0 affected in the C-reactive protein dosage group. It separately lists 1 death. These are the recorded figures; the registry does not provide further details about the event, its timing, its cause, or its relationship to study procedures.
The count of 0 affected for serious adverse events should not be read as meaning that no death occurred, because the record lists a death separately. Nor does the listed death establish that it was caused by the study intervention or related to CRP measurement. Such a relationship is not reported in the registry record. The record also does not explain how the safety denominator relates to the enrollment of 174 or to the population used for the primary endpoint.
These figures describe what the registry records, but they do not support a comparative safety assessment. The study is listed as single-group, with no randomized treatment-control comparison. No rates should be calculated from the counts without a stated analysis population and appropriate context. The registry does not list top serious adverse event terms, so additional event descriptions are not available in the record.
12. What the Result Does, and Does Not, Mean
The registry record describes a specific prognostic question: whether CRP below 172 mg/l at postoperative day 3 identifies the listed composite recovery status by postoperative day 5. It also identifies sensitivity, specificity, positive predictive value, negative predictive value, and a 95% confidence interval as relevant statistics. These details define the intended assessment, but the numerical findings for those measures are not reported in the registry record.
As a result, the posted information does not show how many participants met the recovery endpoint, how many had CRP below the threshold, or how often the threshold classification agreed with later recovery status. It does not provide an estimate of the threshold’s predictive performance or the precision of any estimate. The listed enrollment cannot fill this gap because the endpoint denominator is not reported.
The study objective also concerns inflammatory markers beyond CRP and length of stay, but results for those topics are not reported in the registry record. The primary endpoint description should not be treated as a report of all objectives or as evidence that an unreported analysis was positive or negative.
The result, as posted, does not establish that CRP predicts recovery accurately or inaccurately. It does not establish a causal effect of CRP or of measuring CRP, and it does not compare treatment strategies. In general, a marker’s association with a later outcome is distinct from evidence that acting on the marker changes outcomes. The single-group design and absence of posted numerical results preclude those broader conclusions.
The defensible interpretation is limited: the registry documents a completed single-group study, an intended day-3 CRP threshold, a day-5 composite recovery endpoint, and named diagnostic performance measures. The estimates needed to judge the observed relationship and its uncertainty are not reported in the registry record. Readers should distinguish that missing numerical answer from a finding of no association.
13. Why This Trial Matters Statistically
This study raises a useful statistical question about the timing and interpretation of prognostic markers: can an earlier measurement help classify a later recovery outcome? The registry makes that temporal structure explicit by relating CRP at postoperative day 3 to recovery at postoperative day 5. It also identifies several distinct performance measures rather than treating a threshold as informative on its own.
Statistically, that distinction matters. Sensitivity and specificity describe classification relative to the outcome definition, while predictive values describe the observed outcome among people placed in each classification group. In general, these measures answer different questions and may have different implications across populations. A threshold’s meaning therefore depends both on how the endpoint is defined and on the group in which it is evaluated.
The record also illustrates why estimates and uncertainty are essential. Naming a confidence interval does not reveal the size or precision of an effect; the numerical estimate and interval must be available for interpretation. Here, the registry describes the measures but does not report their results. That limits what can be learned from the posted record, regardless of the study’s completed status.
The study objective is broader than the primary endpoint description, mentioning multiple inflammatory markers and length of stay. This makes transparent outcome reporting particularly important: readers need to know which questions were analyzed, what methods were used, and which results were observed. The registry lists no analyses, and those details are not reported in the registry record.
The statistical contribution that can be assessed is therefore the framing of the prognostic question, not the performance of the threshold. The distinction between a clearly stated estimand and an available estimate is central to interpreting registry results responsibly.
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.
A key limitation of the available record is that it defines the primary question without reporting the numerical diagnostic estimates. The sensitivity, specificity, positive predictive value, negative predictive value, and 95% confidence interval are named, but their values are not reported in the registry record. The endpoint denominator and the underlying outcome and classification counts are also not reported, preventing independent verification of the estimates.
The endpoint description identifies several recovery components but does not state how they are combined into the composite outcome. The record also does not specify how the pain criterion was assessed or how missing component measurements were handled. These details affect the meaning and reproducibility of a composite endpoint and are not reported in the registry record.
The design is single-group, with allocation listed as NA and masking as none. There is no randomized comparator arm, so the record cannot support a treatment comparison. The relationship between enrollment of 174 and the 168 participants listed as at risk for serious adverse events is not explained, and neither figure establishes the primary endpoint analysis population.
The brief study objective mentions procalcitonin, venous lactate, and length of stay, but the record lists only one outcome measure and no analyses. It does not report results for those broader topics, a statistical analysis plan, adjustment for multiple comparisons, the handling of missing data, or interim analyses. These omissions limit both evaluation of the intended breadth of the study and assessment of the methods used. They should be treated as unreported details, not filled in by assumption.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluation of the Predictive Nature of the Postoperative CRP on Postoperative Recovery in Patients Undergoing Colorectal Resection (CRP-Track) — NCT02395380.
- Registry record last updated 2026-04-20; status last verified 2026-04.
- Results first posted 2026-04-20.
- 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
The registry record describes NCT02395380, “Evaluation of the Predictive Nature of the Postoperative CRP on Postoperative Recovery in Patients Undergoing Colorectal Resection (CRP-Track).” The listed sponsor is Centre Hospitalier Departemental Vendee. The study is completed, with a start date of 2015-07-06, a primary completion date of 2017-03-11, and enrollment of 174.
It is described as a single-group study with phase and allocation listed as NA and masking listed as none. The intervention is C-reactive protein dosage. The primary endpoint relates CRP below 172 mg/l at postoperative day 3 to a composite postoperative recovery endpoint at postoperative day 5, with sensitivity, specificity, positive predictive value, and negative predictive value named as measures.
The registry record does not report the numerical primary endpoint results, its confidence interval, or any analyses. It lists 168 at risk and 0 affected for serious adverse events, and separately lists 1 death. Further details about the death are not reported in the registry record.