Objective: A previous study suggested that the frequency with which patients visit wound care clinics influences the rate of chronic wound healing but high bias was present with regard to wound care centre selection. The objective of this retrospective cohort study was to confirm this finding by using a very large sample size of diabetic foot ulcers (DFUs) from the US Wound Registry.
Method: Patients who visited the clinic more than once for a new DFU were eligible for study inclusion. No exclusion was made with regard to Wagner grade, wound severity, or patient comorbidity. A Cox regression was conducted to analyse time to heal within 1 year using covariates known or suspected to influence wound healing, including visit frequency.
Results: In terms of relative effect size, covariates that impeded wound healing the most were wound age and visit frequency with lower visit frequencies associated with lower probabilities of wound healing. Compared with DFUs (n=39,750) seen at a frequency of 7.5 times or more per 4 weeks, wounds seen at intervals of 2 weeks or less had a hazard ratio of 0.098 [(95% confidence interval: 0.09-0.11]. Using a separate breakpoint of ≥2 versus < 2 per 4 weeks specifically for the estimate of overall effect size, Cohen's w was 0.14-a small-to-medium effect size.
Conclusion: Our findings confirm previous work and have implications for clinical practice and analysis of uncontrolled studies.
Keywords: clinic visit frequency; diabetic foot ulcers; wound healing; wound registry.