Reliability of photographic analysis of wound epithelialization assessed in human skin graft donor sites and epidermolysis bullosa wounds

BACKGROUND In many clinical trials on cutaneous healing, wound closure is the primary endpoint and single most important outcome parameter, making precise assessment of this time point one of utmost importance. The assessment of wound closure can be performed either by subjective clinical inspection or with a variety of methodologies anticipated to provide more objective data. The aim of this study was to examine intra- and interrater variability of blinded photographic analysis of wound closure of human partial thickness wounds, as well as the reliability of remote photographic analysis of wounds with that of direct clinical assessment. METHODS Two plastic surgeons, a dermatologist, and a maxillofacial surgeon constituted our rater panel. High-resolution images of patient wounds derived from two randomized controlled clinical trials (EU Clinical Trials Register numbers EudraCT 2009-017418-56 (registered 12 January 2010) and EudraCT 2010-019945-24 (registered 13 July 2010)) were individually assessed by the blinded, experienced study raters. The reliability of photographic image analysis was tested using intraclass and interclass correlation. The validity of photographic image analysis was correlated with clinical assessments of documented time to heal from the study centers' files. RESULTS The results demonstrated that the mean intraclass correlation coefficient of all four examiners was excellent (r = 0.79; 95% confidence interval (CI), 0.61, 1.00)). The interrater correlation coefficient was good (r = 0.67; 95% CI, 0.57, 1.00)) and therefore acceptable. The agreement between remote visual assessment and clinical assessment at the time of healing was good (r = 0.64; 95% CI, 0.52, 0.76)) with an overall difference of about 1 day. CONCLUSIONS Remote photographic analysis of cutaneous wounds is a feasible instrument in clinical open-label studies to evaluate time to wound closure. We found that it was a reliable method of measuring wound closure that correlated satisfactorily with clinical judgment, bolstering the potential relevance in the current era of evolving application and dependency in the field of telemedicine. TRIAL REGISTRATION EU Clinical Trials Register EudraCT numbers 2009-017418-56 (date of registration: 12 January 2010) and 2010-019945-24 (date of registration: 13 July 2010).