A simple index to predict healing in venous leg ulcers: a secondary analysis from four randomised controlled trials

Objective: To investigate whether the use of a simple baseline measurement predicts venous leg ulcer healing at 12 and 24 weeks. Method: This was a secondary analysis of a cohort of four randomised controlled trials (RCTs) of treatments adjuvant to compression. Self-reported ulcer duration, and measured ulcer length and width, to calculate estimated ulcer area, were used to obtain a Margolis index score. The score created three prognostic strata for likelihood to heal within 24 weeks, and the number of participants healed and time-to-healing were compared. Results: There were a total of 802 participants across the four RCTs-408 (50.9%) in two 12-week trials and 394 (49.1%) in two 24-week trials. The mean age of participants was 63.7 +/- 17.6 years, and 372 were female (46.4%). The Margolis index score at baseline was 0 for 320 participants (predicted normal healing); 1 for 334 participants; and 2 for 148 participants (both 1 and 2 predicted slow-to-heal). Overall, 248 (77.5%) of those participants who scored 0 at baseline healed within 24 weeks, compared with 182 (54.5%) of participants who scored 1, and 30 (20.3%) participants who scored 2. The median time-to-healing was 40 (24-62) days, 57 (35-100) days and 86.5 (56-151) days, respectively. The area under the receiver operating characteristic curve was 0.69 and 0.77, respectively, for the 12 and 24 week trials. Conclusion: A simple baseline index identifies participants with normal or slow-to-heal wounds and could be used to demonstrate prognostic balance between treatment groups in trials. This approach could also be used in clinical practice to assist with managing expectations and for early identification of patients who may best benefit from adjuvant treatments.