(CR-038) May Elevated Trans-epidermal Water Loss at Wound Closure Site Predict Wound Recurrence?

Akshay Kapoor, MBBS, MS, MCh – Associate Professor, Department of Burn & Plastic Surgery, AIIMS; Chandan Sen, PhD – Professor, University of Pittsburgh; Kanhaiya Singh, PhD; Mithun Sinha, PhD – Assistant Professor, School of Medicine; Shomita Steiner, PhD – University of Pittsburgh; Debarati Chattopadhyay, MS, MCH – Professor, Department of Burn & Plastic Surgery, AIIMS

Introduction: Clinically, wound closure is defined as sustained (2 weeks) coverage of wound without discharge. It does not address functionality of the repaired skin. Recent patient-based studies have shown that wounds may close in a way such that the criteria of coverage with no discharge are met but barrier function of the skin is not restored. Thus, such wounds do not achieve functional wound closure. Compromised barrier function in such structurally “closed” wounds is measured as high transepidermal water loss (TEWL) at the site of wound repair. The current study utilizes TEWL measurement of repaired skin at the site of wound closure using DermaLab TEWL open chamber unit (Cortex Technologies, Denmark) as a surrogate marker to study post-closure cutaneous functionality of human wounds.

Methods: A single-center, prospective, observational pilot study was performed to evaluate wound healing endpoint and recurrence by measuring TEWL post-closure at the site of wound repair. Patients with clinically-defined chronic wounds (such as pressure ulcers, diabetic ulcers, and trauma wounds) were enrolled. Non-invasive point-of-care TEWL measurements were obtained, from closed wound-site and contralateral healthy skin site, starting from confirmation of closure (post-closure, V0) continuing every 2 weeks for a maximum of five visits or until the wound recurred. Statistical analyses of the data involved logistic regression and likelihood ratio chi-square tests to assess differences in TEWL at visit 0 (V0) between the closed wound site and reference skin, with the TEWL score as the sole predictor of recurrence.

Results: Of the 72 subjects that completed the study, 44 (61%) showed no recurrence and 28 (39%) had wounds that recurred over a period of 12 weeks. A significant association was found between the V0 (post-closure) TEWL score and the odds of wound recurrence, both in univariate analysis (OR [95%CI] = 1.26[1.14,1.42] (p < 0.001) and after adjusting for covariates in multivariable analysis (OR [95%CI] = 1.34[1.19,1.61] (p < 0.001). The likelihood ratio chi-square analysis demonstrated that the V0 TEWL score may be a significant universal predictor of recurrence across all wound types studied. Cases of closed wounds with subsequent recurrence showed an overall higher post-closure V0 TEWL score, compared to those who did not have a wound recurrence, across visits. The TEWL score cut-off value predictive of recurrence was 24.1 g.m^–2.h^–1 (AUC = 0.967).

Discussion: The outcome of this study on a wide range of chronic wounds leads to the hypothesis that post-closure TEWL at the site of wound healing is a reliable biomarker of wound recurrence. It also raises the question whether the clinical endpoint of wound closure should include re-establishment of skin barrier function as additional criterion. The current standard of care wound closure endpoint calls for re-epithelialization of the wound with no discharge for two consecutive weeks disregarding the functional parameter of restoration of skin barrier function at the wound-site.