Cath Lab Digest

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Abstract: Percent area reduction (PAR) after 4 weeks of diabetic foot ulcer (DFU) treatment has been suggested as a clinical monitoring parameter to distinguish DFUs that will heal within 12 weeks from those that will not despite standard wound care. The purpose of this post-hoc analysis of control DFU treatment outcomes from two published, randomized, controlled studies was to assess the relationship between PAR during early standard wound care and ulcer closure by week 12. The proportion of DFUs healed after 12 weeks was 57% (39 out of 69; 95% confidence interval [CI], 44% to 68%) in study A and 52% (38 out of 73; 95% CI, 40% to 64%) in study B for wounds with ≥50% PAR by week 4 and 5% (three out of 64; 95% CI, 1% to 13%) and 2% (one out of 44; 95% CI, 0.1% to 12%), respectively, for DFUs with <50% PAR at week 4. Regardless of baseline size category, DFUs with <50% PAR at 4 weeks were less likely to heal by 12 weeks than DFUs with ≥50% PAR (P ≤ 0.001). Using pooled data, PAR at weeks 1 to 3 also varied between ulcers that did and did not heal after 12 weeks but sensitivity and specificity was highest on week 4. These findings confirm that percent reduction in wound size is an early predictor of treatment outcome and that protocols of care should be re-evaluated if ≥50% PAR is not achieved. Studies to assess DFU healing before and after 4 weeks of standard wound care are needed to further refine these guidelines of care.

Potential Conflicts of Interest: Dr. Snyder, Dr. Dauphinée, and Dr. Stavosky disclose they have received monetary compensation as consultants for Advanced BioHealing, Inc. Mr. Cardinal is an employee of Advanced BioHealing, Inc.

Please address correspondence to: Robert J. Snyder, DPM, CWS, Wound Healing Center, University Hospital and Medical Center, 7301 N. University Drive, Suite 305, Tamarac, FL 33321; email: drwound@aol.com. Financial support for data analysis and manuscript development was provided by Advanced BioHealing, Inc., La Jolla, CA.

     Diabetic foot ulcers (DFUs) are among the most common complications of diabetes mellitus, with an annual incidence of 1% to 4% and lifetime risk of 15% to 25%.^1-5 The morbidity associated with DFUs is high — >85% of lower-extremity amputations are precipitated by a DFU^6,7 and approximately 15% of DFUs result in lower-extremity amputation.^4,8 Delayed healing of DFUs can decrease patient mobility, reduce quality of life,⁹ and increase the risk of amputation.⁶

     A meta-analysis¹⁰ of the control groups from nine DFU treatment studies showed that with standard good wound care 24% of ulcers heal after 12 weeks of care and 31% after 20 weeks of care. These results illustrate that even with good standard wound care DFUs remain difficult to heal. Prognostic indicators of wound closure can alert clinicians to reassess the therapeutic approach and consider more advanced interventions if necessary. In a retrospective analyses of 27,630 patients from a group of more than 150 wound care clinics in the US, investigators found negative prognostic factors for neuropathic DFU healing include baseline ulcer area >2 cm2, ulcer duration >2 months, and ulcer grade ≥3 (on a 6-point scale).¹¹

     In 2003, Sheehan et al,¹² studying healing rates of DFU, confirmed what had previously been observed in other chronic wounds: percent area reduction (PAR) after 4 weeks of treatment is a robust predictor of healing.