A post-hoc analysis of reduction in diabetic foot ulcer size at 4 weeks as a predictor of healing by 12 weeks.

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 > or = 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 > or = 50% PAR (P < or = 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 > or = 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.