# C1 Esterase Inhibitor Activity Is Reduced in the Acute Phase Following Burn Injury: A Prospective Observational Study

- **DOI:** [10.1093/jbcr/irz109](https://doi.org/10.1093/jbcr/irz109)
- **Rating:** Limited (2.8 out of 5)
- **Verdict:** Serial C1 inhibitor profiling reveals a novel burn-associated trajectory, but unadjusted severity confounding prevents strong mechanistic or prognostic conclusions.
- **Framework version:** v5.9
- **Pipeline version:** v0.4
- **Evaluation date:** 2026-09-18
- **Evaluation page:** https://www.nabu.science/paper/10.1093%2Fjbcr%2Firz109

## Key claims

1. These findings suggest that C1 esterase inhibitor may play a critical role in regulating vascular permeability in the acute phase following the burn injury.
   - Support: Tentative
   - Type: Primary finding
   - Basis: vascular permeability was not directly measured in this observational cohort
   - Location: Abstract, pp. 3–4; Conclusions, p. 20
2. C1 esterase inhibitor activity after burn dropped acutely on days 1 and 2 but increased immediately until days 3 to 5.
   - Support: Supported
   - Type: Secondary
   - Basis: serial measurements directly show the reported early decline and recovery
   - Location: Abstract, p. 3; Results, p. 12; Figure 2
3. C1 esterase inhibitor activity on admission showed significant inverse correlation with the volume of infusion per body weight required in the first 24 hours after injury and %TBSA burned.
   - Support: Supported
   - Type: Secondary
   - Basis: unadjusted correlations support direction but cannot separate burn severity from related clinical factors
   - Location: Abstract, p. 3; Results, p. 14; Figure 5
4. C1 esterase inhibitor activity on admission was significantly lower in the non-survivors than in the survivors during the 28-day evaluation period.
   - Support: Tentative
   - Type: Secondary
   - Basis: severe prognostic confounding and a potentially inappropriate group test undermine the significance claim
   - Location: Abstract, p. 3; Results, p. 14; Table 2; Figure 4

## Strengths

- **Novel serial biomarker trajectory documented** Serial measurements show reduced C1 esterase inhibitor activity on days 1 and 2, recovery by days 3–5, and elevation after one week. This adds a detailed temporal profile to the limited prior burn literature.
  - Dimension: contribution
  - Location: Results, p. 12; Figure 2
- **Prospective protocol supports descriptive analysis** The cohort was enrolled prospectively, treated under a unified resuscitation protocol, and sampled at prespecified intervals using named commercial assays.
  - Dimension: methodological rigour
  - Location: Methods, pp. 7–10
- **Relevant evidence base supports trajectory** The discussion connects the clinical observations to prior burn studies, sepsis research, hereditary angioedema biology, and animal thermal-injury experiments.
  - Dimension: positioning
  - Location: Introduction, pp. 5–6; Discussion, pp. 15–20

## Limitations

- **Independent groups tested as paired** The Methods and Figure 4 legend report a Wilcoxon signed-rank test for survivors versus non-survivors. Because these are independent groups, the reported significance of this central comparison may be invalid.
  - Dimension: methodological rigour
  - Location: Methods, Statistical analysis, p. 11; Figure 4 legend, p. 32
- **Mortality association remains severely confounded** Non-survivors were substantially older and had higher APACHE II and SOFA scores and more full-thickness burn area. No adjusted analysis separates C1 inhibitor activity from these prognostic differences.
  - Dimension: methodological rigour
  - Location: Table 2, p. 30; Results, p. 14
- **Mechanistic interpretation exceeds measurements** The study did not directly measure vascular permeability or test C1 inhibitor replacement, yet the abstract and conclusion assign the inhibitor an important regulatory role. The therapeutic proposal therefore remains hypothesis-generating.
  - Dimension: reporting
  - Location: Abstract, pp. 3–4; Discussion, pp. 18–20; Conclusions, p. 20

## Reliability checks

Concerns (4 of 4 checks).

- **Internal coherence:** Concern. The statistical test reported for the independent survivor and non-survivor groups is a paired-sample test, so the central mortality-group P value may be invalid. A minor abstract-to-table P-value discrepancy does not alter the direction or nominal significance of the result.
- **Research conduct:** Clean. Institutional approvals and written informed consent are declared, and the funding source is disclosed. No text-grounded research-conduct concern was identified.
- **Reference integrity:** Clean. 40 of 40 checkable references verified
  - 41 references in manuscript
  - 1 have no canonical index record — counted, but not index-checkable
  - 1 reference confirmed by manual review
  - References not verified automatically are resolved manually within 24 hours.

## Post-publication record

- **Status:** Clean
- **Summary:** No retraction or expression of concern found in Crossref (includes Retraction Watch).
- **Last checked:** 2026-10-17