A time-dependent survival analysis for early prognosis of chronic wounds by monitoring wound alkalinity |
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Authors: | Le Quynh Hoang Suvra Pal Zhaoli Liu Jon Senkowsky Liping Tang |
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Affiliation: | 1. Department of Bioengineering, University of Texas at Arlington, Arlington, Texas, USA;2. Department of Mathematics, The University of Texas at Arlington, Arlington, Texas, USA;3. College of Nursing and Health Innovation, The University of Texas at Arlington, Arlington, Texas, USA;4. Texas Health Physician's Group, Arlington, Texas, USA |
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Abstract: | The objective is to determine whether monitoring wound alkalinity between visits may help prognosticate chronic wound healing. The alkalinity of 167 wounds during the first 3 visits was assessed using disposable DETEC® pH. Wounds grouped by frequency of alkaline results were compared by % wound size reduction during each visit and 120-day healing probability. The Cox proportional hazards model for time-dependent variables was used to generate non-healing probability curves, where variables are binary (alkaline/non-alkaline, infection/no infection), categorical (wound type), and continuous (wound area); the response is time to complete wound healing; and the event of interest is complete wound healing in 120 days. Results show that wounds with frequent alkaline results have significantly smaller % size reduction per visit. Logistic regression shows an increase in 120-day healing probability with fewer alkaline results. Survival analysis shows that the instantaneous healing rate of non-alkaline or non-alkaline transitioning wounds is 1.785, 2.925, and 5.908 times that of alkaline or alkaline-transitioning wounds for 1, 2, and 3 alkalinity measurements, respectively. Furthermore, the concordance statistic of each survival model shows that goodness of fit increases with more alkalinity measurements. Overall, frequent wound alkalinity assessments may serve as a novel way to prognosticate wound healing outcomes. |
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Keywords: | logistic model pH prognosis survival analysis wound healing |
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