Statistical analysis of wound-healing rates for pressure ulcers.

To establish a functional model for determining wound-healing rates to use in the evaluation of efficacy of wound therapies, a review was conducted of statistical analysis methods from past wound-healing studies. Because most wounds do not usually close within the period of observation, that is, 12 weeks, evaluating time to 100% closure is not practical. Thus, a new, practical model for statistical analysis was formulated. A Gompertz-like function was applied to wound-healing rates of pressure ulcers, in the context of repeated measures for a nonlinear model. Photographing the wounds weekly, tracing their area with planimetry, and applying this new statistical model allows for the calculation of the expected rate of healing as a function of time. This approach yields a model useful for identifying prognostic factors, evaluating treatments, and improving our understanding of the variables that affect the wound-healing process.