Fifty percent area reduction after 4 weeks of treatment is a reliable indicator for healing—analysis of a single-center cohort of 704 diabetic patients

Abstract

Introduction The aim of the study was to investigate whether an area reduction greater than 50% within the first 4 weeks of treatment is associated with a higher long-term probability of healing. Patients and Methods We treated diabetic foot ulcers according to a comprehensive interdisciplinary wound care protocol. Follow-up was documented through a special wound documentation system. Data were entered into SPSS for statistical analysis to calculate the probability of healing according to the Kaplan–Meier method. Results were expressed as median (minimum–maximum), and the percentage of area reduction (PA) was defined as [(area 4 weeks/area baseline)×100)/area baseline. Patients were divided into responders when PA reached at least 50% and nonresponders when PA was less than 50%. Healing was defined as PA=100%. Results In total, 704 patients were included into the analysis. Median time of follow-up was 71 (2–365) days. Wound duration was 31 (1–4018) days, and the initial wound size was calculated to be 1.18 (0.1–99) cm 2. In 27.8%, there was a positive probing to bone; in 64.5%, both pedal pulses were not palpable. Major amputation rate was 2.8% and minor amputation rate was 10.2%. The overall probability of healing was 35% after 12 weeks, 41% after 16 weeks, and 73% after 1 year. The surrogate visit (4 weeks) was performed after a median of 27 (14–42) days without a difference between responders and nonresponders. There were 334 (47%) responders and 370 (53%) nonresponders. Responders had a significantly higher probability of healing compared with nonresponders (12 weeks: 52.3% vs. 18.4%, P=.0001; 16 weeks: 46.7% vs. 26.5%, P=.0001; 1 year: 82.5% vs. 64.9%, P=.0001). Conclusions The calculation of the percentage of area reduction after 4 weeks of treatment is a valid tool to estimate the probability of healing. In clinical practice, a reevaluation of the treatment schedule is recommended for wounds that do not reach 50% area reduction within the first 4 weeks of therapy.