Evaluating the Effect of Chronic Antihypertensive Therapy on Vasopressor Dosing in Septic Shock: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluating the Effect of Chronic Antihypertensive Therapy on Vasopressor Dosing in Septic Shock (NCT02884011), a registered phase not stated study. The primary outcome is Total Vasopressor Dose.

2. Clinical Question

The study asks whether chronic use of a β-blocker, an ACE-inhibitor, or both is related to vasopressor dosing during the first 48 hours of septic shock. The primary outcome is total vasopressor dose, expressed in mg and summarized using the median and inter-quartile range. The stated objective is to examine the effect of chronic medication use on dosing, not to evaluate a randomized treatment assignment.

This is a question about observed differences among medication-use groups. Because the study is retrospective and allocation is not stated, any comparison would be an association in the recorded data, not a randomized estimate of a medication’s causal effect. A clinically interpretable answer would require the group-specific dose summaries and an account of how differences between groups were handled. Those results and analysis details are not reported in the registry record.

3. Trial Design

The registry identifies NCT02884011 as a completed retrospective study sponsored by Rush University Medical Center. Its title is “Evaluating the Effect of Chronic Antihypertensive Therapy on Vasopressor Dosing in Septic Shock.” The listed condition is septic shock. Enrollment is 133; the study start is recorded as 2016-08 and primary completion as 2017-02.

The study describes four medication-use categories: no chronic antihypertensives, chronic β-blocker, chronic ACE-inhibitor, and both chronic β-blocker and ACE-inhibitor. The no-chronic-antihypertensives category is defined as not being on either a chronic β-blocker or ACE-inhibitor. The other categories are defined by the corresponding chronic medication use. These are exposure groups, not randomized treatment arms. The record does not state how people entered each category, whether medication use was verified in a particular way, or how other differences among groups were addressed.

The primary outcome is total vasopressor dose over 48 hours. The registry also lists outcomes concerning fluid within 6 hours, inotrope use, hydrocortisone use, cumulative vasopressor dose among patients receiving other antihypertensives, and vasopressor dose at 6, 12, and 24 hours. Numerical findings for these outcomes are not reported in the registry record. The record lists 8 outcome measures and 0 analyses.

Allocation is not stated, and the registry explicitly distinguishes this from a randomized comparison. Details such as eligibility criteria, recruitment or record-selection procedures, the analysis population, and the statistical analysis plan are not reported in the registry record. The completed status describes the study’s registry status; it does not itself indicate that results were posted.

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: retrospective study

Overall Study

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.

6. Primary Endpoint

The registry lists the primary outcome as Total Vasopressor Dose, measured over 48 hours.

The primary endpoint is total vasopressor dose during the first 48 hours of septic shock, measured in mg and summarized as a median with an inter-quartile range. It brings cumulative dosing across the specified vasopressors into a single outcome intended to compare dosing across the chronic medication categories. The registry names norepinephrine, epinephrine, phenylephrine, dopamine, and vasopressin. It states that epinephrine, phenylephrine, and dopamine are converted to norepinephrine equivalents using the listed equivalences: 100 mcg dopamine equivalent to 1 mcg norepinephrine, 1 mcg epinephrine equivalent to 1 mcg norepinephrine, and 2.2 mcg phenylephrine equivalent to 1 mcg norepinephrine.

As a general statistical consideration, a cumulative dose can represent treatment intensity over a defined interval, while a single time-point dose would represent a different aspect of dosing. Combining agents requires explicit conversion rules so that their contributions can be expressed on a common scale. The registry gives conversion rules for three agents but does not describe a conversion for vasopressin, nor does it provide the actual dose summaries or details of data handling.

The median describes the middle of an ordered set of observations; the inter-quartile range describes the spread of the central portion of that set. These summaries can be useful when dose values are asymmetric or include extreme observations. They do not, by themselves, quantify uncertainty in a comparison between groups. Group-specific numerical results and an inferential analysis are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a retrospective study and gives a median with inter-quartile range as the primary outcome summary. It lists 0 analyses. The specific statistical methods used to compare medication categories, if any, are not reported in the registry record. The explanations below describe general statistical concepts relevant to reading the stated outcome and design; they are not claims about methods actually used in this study.

What does a median with an inter-quartile range describe?

As a general statistical explanation, the median is the midpoint of ordered observations: half the values fall at or below it and half at or above it, allowing for ties and the details of the dataset. The inter-quartile range describes the interval spanning the middle half of the observations. Together, these summaries describe a group’s location and spread without requiring a symmetric distribution. They do not show every observed value, and they do not alone quantify uncertainty about a difference between groups.

For a group comparison, a reader would need the summaries for each medication category and a clearly defined contrast. A difference between medians is not automatically the same as a difference in means, and an unadjusted contrast does not account for other group characteristics. The record contains no primary dose summaries or inferential comparison, so neither the size nor the precision of a contrast can be assessed from the posted results.

Why does the outcome combine vasopressor agents?

The primary endpoint combines named vasopressors into total dose and expresses certain agents as norepinephrine equivalents. As a general measurement principle, a conversion rule places different agents onto a common scale, making a combined measure possible. The record specifies the conversion equivalences for dopamine, epinephrine, and phenylephrine. It names norepinephrine and vasopressin as included agents, but does not state a vasopressin conversion rule or describe the handling of missing dose measurements, treatment changes, or patients who received no vasopressor.

A cumulative outcome over 48 hours captures dosing across that stated interval. It may depend on both the intensity and duration of treatment, so it is not interchangeable with a dose at a single time point. The registry’s secondary outcomes include vasopressor dose at 6, 12, and 24 hours, which address different time windows. Their numerical values and precise calculation details are not reported in the registry record.

What does over-dispersion mean for dose data?

As a general statistical explanation, over-dispersion means that observations vary more than a particular model assumes. Clinical dose data can, in principle, include many low values and a smaller number of high values; such a pattern can make a model that assumes more uniform variation poorly calibrated. Over-dispersion matters because underestimated variability can make confidence intervals too narrow and significance tests too optimistic. This is a general concern, not a description of the observed dose distribution in this study: the registry does not report the distribution or any model diagnostics.

Median and inter-quartile range summaries do not require a normal distribution in the way that some mean-based procedures do, but those summaries still do not constitute a test or model. The registry does not report whether a nonparametric procedure, regression model, transformation, robust method, or other approach was used. It also does not report whether the comparison accounted for baseline characteristics.

How should uncertainty be assessed?

As a general statistical explanation, a confidence interval gives a range of values compatible with the data under a specified analysis procedure and its assumptions. Its width conveys precision: a wider interval reflects less precise estimation than a narrower interval. A p-value addresses compatibility of data with a particular null model; it does not give the probability that a hypothesis is true, nor does it communicate the size or clinical importance of an effect.

No confidence intervals, p-values, test statistics, or effect estimates for the primary outcome are reported in the registry record. Therefore the statistical precision of any difference cannot be evaluated. A report of descriptive summaries alone, if it were available, would not replace uncertainty estimates for a contrast.

What do the planning assumptions mean?

As a general explanation, a sample-size calculation is conditional on assumptions about the target effect, variability, allocation, significance threshold, and statistical method. The record characterizes its planning illustrations as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect set as a stated fraction of the observed effect. Such a calculation is a planning illustration, not an observed study finding and not observed power. The record does not report the trial’s own sample-size justification or design rationale.

The stated illustration describes participants per arm for 80% power for non-time-to-event outcomes; time-to-event illustrations describe the total number of events. These hypothetical planning quantities should not be mistaken for the study’s actual group counts or for evidence that the observed analysis had a particular probability of detecting an effect. The registry does not report a primary effect estimate from which to assess the illustrations’ relevance.

What can be inferred from the design?

The four categories are defined by chronic medication use, while allocation is not stated. As a general statistical matter, retrospective comparisons can be affected by confounding: characteristics associated with medication use may also be associated with dosing. Adjusted analyses can address measured covariates under assumptions, but cannot automatically remove unmeasured confounding. The registry does not report covariate adjustment, missing-data methods, or an analysis population. No specific modeling strategy or causal interpretation can therefore be attributed to this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and several secondary outcomes, including fluid within 6 hours, inotrope use, hydrocortisone use, cumulative vasopressor dose among patients receiving other antihypertensives, and dose at 6, 12, and 24 hours. When many outcomes or contrasts are examined, the chance of at least one apparently notable finding can increase. As a general statistical principle, a prespecified testing hierarchy or multiplicity adjustment can help manage that issue, but the registry record does not report whether either was planned or used.

The record lists 0 analyses, and numerical results for the listed outcomes are not reported. A multiplicity procedure, primary-versus-secondary testing hierarchy, or specification of which pairwise contrasts were intended is not reported in the registry record. It is therefore not possible to assess how the study handled multiple testing or to interpret an individual finding within a testing plan.

Missing-data handling is also not reported in the registry record. The record does not describe how incomplete dose measurements, missing medication histories, or unavailable outcome data were treated. It does not state whether participants were excluded for missing information, whether any imputation was used, or how missingness was assessed. As a general statistical consideration, conclusions can depend on why data are missing and on the method used to handle them; that issue cannot be evaluated without the study’s reporting.

The analysis population is not reported in the registry record. In particular, the record does not describe whether all enrolled participants were included in each outcome analysis or whether analysis eligibility depended on treatment receipt, timing, or data availability. The registry’s enrollment count does not by itself identify the number contributing data to the primary outcome. No protocol-defined population or analysis plan should be inferred from the record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports serious adverse events and other adverse events separately for the four medication categories. For serious adverse events, the affected count is 0 in each group; for other adverse events, the affected count is also 0 in each group. The reported at-risk counts are 51 for no chronic antihypertensives, 46 for β-blocker, 17 for ACE-inhibitor, and 19 for both β-blocker and ACE-inhibitor.

Deaths are listed separately: 21 in the no-chronic-antihypertensives group, 26 in the β-blocker group, 6 in the ACE-inhibitor group, and 11 in the group taking both. These are registry counts, not a comparative analysis. The record does not describe the relationship between deaths and adverse-event categories, the observation period for the death entries, or an analysis adjusting for group differences.

As a general statistical consideration, a zero event count in a registry field means that no affected events were entered for that field and group; it does not establish that an exposure has no safety risks. The counts do not show event ascertainment procedures, completeness of reporting, or uncertainty around event rates. Because the study is retrospective and nonrandomized, these figures should not be interpreted as a randomized comparison of safety.

12. What the Result Does, and Does Not, Mean

The registry record establishes a retrospective investigation of chronic antihypertensive medication categories and vasopressor dosing in septic shock. It identifies the primary outcome as total vasopressor dose over 48 hours and describes the four medication-use categories. It also names several secondary outcomes and provides adverse-event counts. These details explain the study’s intended question, but they are not a report of the primary comparison’s results.

The record does not report group-specific primary outcome values or analyses. It therefore does not support a conclusion about whether total vasopressor dose differed across medication categories, the magnitude or direction of any difference, or the precision of an estimate. The listed 0 analyses makes especially important the distinction between a registered objective and a reported statistical finding. Study completion does not fill that gap.

Even if dose differences were reported, a retrospective comparison between medication-use groups would not by itself establish that chronic medication use caused those differences. The registry does not report random allocation, and allocation is not stated. As a general statistical principle, differences in underlying characteristics between groups can influence outcomes. The record does not provide information about adjustment for such characteristics or about unmeasured confounding.

The safety entries also have a limited meaning: 0 serious events and 0 other events are recorded in each group, while deaths are separately listed. These entries cannot stand in for a complete safety assessment or resolve the absence of primary outcome findings. The registry does not describe event ascertainment, missingness, or comparative safety methods.

Accordingly, the record is useful for identifying the study design, intended endpoint, exposure categories, and stated outcome framework. It does not permit an estimate of the association between chronic antihypertensive use and vasopressor dose, nor does it establish benefit, harm, or a causal effect. Those questions would require reported outcome data and sufficient detail on analysis and limitations.

13. Why This Trial Matters Statistically

This study raises a statistical question that is relevant to clinical research: how to compare a continuous, cumulative treatment measure across groups defined by prior medication use. The registry specifies a 48-hour dose endpoint, a median and inter-quartile range summary, and conversions for selected vasopressors. Those choices make the definition of the outcome central to interpretation. A combined dose measure depends on the conversion rules and on how the observation interval and component agents are handled.

The retrospective design also highlights the distinction between association and causation. Group membership reflects chronic medication use rather than a stated randomized assignment. As a general statistical matter, an observed comparison can be confounded when group characteristics are related to both exposure and outcome. A clear analysis would need to explain how measured differences were handled and what limitations remain. Such analysis details are not reported in the registry record.

The record’s lack of numerical analyses is itself statistically important. Without group summaries, effect estimates, uncertainty intervals, or tests, readers cannot evaluate magnitude, precision, or compatibility with a null comparison. The primary objective alone does not tell whether an effect was observed. The distinction between planned outcomes and posted findings is essential when assessing an incomplete registry record.

The record also illustrates why multiplicity, missing data, and analysis populations matter. Multiple time points and secondary endpoints can produce multiple possible comparisons, while incomplete outcome data can alter who contributes to each result. These issues cannot be assessed from the posted information because corresponding methods are not reported.

Finally, adverse-event counts need context. The zero affected counts are reported alongside separate death counts, but without event definitions or comparative analyses, they are not a comprehensive safety conclusion. Taken together, the study’s statistical importance lies in the questions its design and registry entries raise, and in the need for transparent outcome reporting before an effect can be evaluated.

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 central limitation of the registry record is that it contains no numerical primary-outcome results and lists 0 analyses. The primary endpoint is defined, but group medians, inter-quartile ranges, estimates comparing groups, and measures of uncertainty are not reported. The listed secondary outcomes likewise have no numerical findings in the registry record. This prevents assessment of effect size, direction, precision, or statistical compatibility with a null comparison.

The study is described as retrospective, and allocation is not stated. The medication categories are not randomized arms, so group differences may reflect characteristics beyond chronic medication use. The record does not report participant eligibility criteria, baseline characteristics, covariate adjustment, or methods to address confounding. A causal interpretation is not justified by the registry description alone.

Details of outcome collection and calculation are incomplete. Although the primary outcome timeframe, summary measure, unit, named vasopressors, and some conversion equivalences are stated, handling of vasopressin and missing dose data is not reported in the registry record. The record also does not explain dose timing, the analysis population, or the handling of participants with incomplete follow-up.

Other important analysis details are not reported, including a statistical analysis plan, sample-size justification, multiplicity strategy, missing-data method, and whether any interim analyses occurred. The registry does not identify which participants contributed to each outcome. The serious and other adverse-event fields report zero affected events in all groups, but event ascertainment and completeness are not described. Death counts are listed separately without a reported comparative analysis.

These limitations concern what can be concluded from the registry record; they do not establish that unreported methods or results were absent from other study materials. Those details are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Evaluating the Effect of Chronic Antihypertensive Therapy on Vasopressor Dosing in Septic Shock — NCT02884011.
• Registry record last updated 2025-01-03; status last verified 2024-11.
• Results first posted 2025-01-03.
• 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.

18. Record Summary

NCT02884011 is a completed retrospective study sponsored by Rush University Medical Center. The listed condition is septic shock, and enrollment is 133. The study start is recorded as 2016-08, with primary completion recorded as 2017-02.

The primary outcome is total vasopressor dose in mg over 48 hours, summarized using the median and inter-quartile range. The comparison concerns four chronic medication-use categories: no chronic antihypertensives, β-blocker, ACE-inhibitor, and both β-blocker and ACE-inhibitor. Secondary outcomes include fluid, inotrope and hydrocortisone use, and vasopressor measures at specified times.

The registry lists 8 outcome measures and 0 analyses. Primary and secondary numerical outcome results, analysis methods, missing-data procedures, and the analysis population are not reported in the registry record. Adverse-event fields list 0 serious and 0 other events for each category; deaths are recorded separately. The posted information defines the study question and design but does not provide an analyzed estimate of the primary comparison.