Association of hemoglobin A_1c and wound healing in diabetic foot ulcers

OBJECTIVE This study evaluated the association between hemoglobin A_1c (A1C) and wound outcomes in patients with diabetic foot ulcers (DFUs). RESEARCH DESIGN AND METHODS We conducted a retrospective analysis of an ongoing prospective, clinic-based study of patients with DFUs treated at an academic institution during a 4.7-year period. Data from 270 participants and 584 wounds were included in the analysis. Cox proportional hazards regression was used to assess the incidence of wound healing at any follow-up time in relation to categories of baseline A1C and the incidence of long-term (‡90 days) wound healing in relation to tertiles of nadir A1C change and mean A1C change from baseline, adjusted for potential confounders. RESULTS Baseline A1C was not associated with wound healing in univariate or fully adjusted models. Compared with a nadir A1C change from baseline of 20.29 to 0.0 (tertile 2), a nadir A1C change of 0.09 to 2.4 (tertile 3) was positively associated with long-term wound healing in the subset of participants with baseline A1C <7.5% (hazard ratio [HR] 2.07; 95% CI 1.08–4.00), but no association with wound healing was seen with the mean A1C change from baseline in this group. Neither nadir A1C change nor mean A1C change were associated with long-term wound healing in participants with baseline A1C ‡7.5%. CONCLUSIONS There does not appear to be a clinically meaningful association between baseline or prospective A1C and wound healing in patients with DFUs. The paradoxical finding of accelerated wound healing and increase in A1C in participants with better baseline glycemic control requires confirmation in further studies.