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))x100)/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.