ABSTRACT
BACKGROUND: Wound healing trajectories (percent healing vs time) provide a dynamic picture of the decrease in wound burden over the entire continuum of the healing process. Trajectories can be robustly compared using survival statistics methodology. Improvement in healing can be determined by shifting the curve from "impaired" healing toward "ideal" healing. Although this concept of shifting the curve "to the left" has been demonstrated in acute incisional healing depicted by the gain in tensile strength, and in other chronic wounds, it has not been utilized for chronic pressure ulcers. METHODS: Wound healing trajectories were constructed for 211 patients enrolled in 8 separate randomized clinical trials for grade III and IV pressure ulcers. Trajectories were constructed for patients achieving ≥90% or more healing within 112 days and those who achieved less than <90% wound closure. Kaplan-Meier curves were constructed for all patients receiving an experimental treatment and for those receiving placebo vehicles. RESULTS: Different trajectories were achieved for the faster healing patients. Eighty-one percent of patients reached 90% healing within 112 days; 80% of those in treatment groups and 85% of those in placebo groups. Linear regression suggested that all patients entered into the clinical trials would achieve 90% healing by 18 weeks. Only 17% of the patients achieved total healing (100% wound closure) within the 112-day study period. Linear regression suggested that it would take 110 weeks to achieve total healing in all patients. CONCLUSION: Wound healing trajectories provide a more complete description of treatment efficacy than do fixed endpoints, such as the number of patients achieving 100% closure at one defined time point. Since more successful healers have different trajectories than less successful healers, shifting the trajectory to the left from "impaired" toward "ideal" healing may provide a better endpoint to determine treatment efficacy.
ABSTRACT
Outcome measures of venous ulcer healing are not uniformly accepted. Stringent criteria of 100% closure fail to provide information of healing over the entire span of repair. Wound-healing trajectories (plot of percentage of wound closure versus time of wound treatment) were constructed for 232 patients treated in eight clinical trials at two independent wound care/research centres. Trajectories were constructed for ulcers that totally healed (100% closure) and those that did not (<100% closure) over a 20-week period. Kaplan-Meier survival plots determined the percentage of patients achieving total healing versus time of treatment. The wound-healing trajectories were almost identical for patients achieving complete ulcer healing, as were the trajectories for patients with less than 100% closure. The trajectories for the ulcers healing completely were significantly different from those with <100% closure. Only 60% of all patients achieved 100% closure by 20 weeks. Using linear regression, it was predicted that it would take 31 weeks for all patients to achieve total healing. Total healing is an inadequate outcome measure for healing of venous stasis ulcers. Clinical trials using this measure would require excessive time periods. As wound-healing trajectories for patients treated at two centres mimic one another, shifting the wound-healing trajectory from one of impaired healing to one of a more ideal healing course may be considered a better outcome measure for determining healing of venous stasis ulcers.
