Fifty Percent Area Reduction After Four Weeks of Treatment is a Reliable Indicator for Healing—Analysis of a Single-Center Cohort of 704 Diabetic Patients

Abstract

Conclusion: Calculating wound area reduction after 4 weeks is a valid tool to estimate the probability that a diabetic foot wound will heal. A 50% wound area reduction after 4 weeks of therapy indicates likely healing of a diabetic foot wound. Summary: Subjective and wound-based parameters can be used to document healing of diabetic foot wounds. The only objective wound-based parameters for healing are wound size and ultimate complete wound closure. The authors sought to investigate whether an area reduction >50% with 4 weeks of treatment was associated with long-term probability that a diabetic foot wound would heal. The authors treated diabetic foot wounds according to an institutional, interdisciplinary wound care protocol. Follow-up was documented using a wound care documentation system and data were analyzed. The probability of healing was assessed with the Kaplan-Meier method, with results expressed as percentage of area reduction. Patients were classified as responders to the protocol when the percentage of wound area reduction reached at least 50% after 4 weeks of treatment, and nonresponders when the percentage area reduction was <50% at 4 weeks. Healing was defined as a percentage area reduction of 100%. The analyses included 704 patients with a median follow-up of 71 days (range, 2-365 days). Wound duration was 31 days (range, 1-4018 days). Initial wound size was 1.18 cm2 (range, 0.1-99 cm2). Bone was involved in the base of the wound in 28%, and in 64.5% both pedal pulses were not palpable. Major amputation rate was 2.8%, and minor amputation rate was 10.2%. Overall probability of healing was 35% after 12 weeks, 41% after 16 weeks, and 73% after 1 year. There were 334 responders (47%) and 370 nonresponders (53%). Responders had a significantly higher probability of healing compared with nonresponders (12 weeks: 52% vs 18%, P = .0001; 16 weeks: 47% vs 27%, P = .0001; 1 year: 83% vs 65%, P = .0001). Comment: The data suggest that diabetic foot wounds more prone to heal will exhibit a greater healing response early in the course of their treatment. The practical point is that if the wound has not decreased by 50% in area after 4 weeks, an alternative form of wound therapy should be considered.