Natural history study of recessive dystrophic epidermolysis bullosa wounds and patient reported outcomes using mobile application home photography.

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare, blistering genetic disease where wounding and wound pain are the most reported problems by patients. The natural history of RDEB wounds, specifically spontaneous wound closure between chronic open vs. recurrent wounds, has not been prospectively studied, thus limiting the design of clinical trial endpoints. We conducted a prospective observational study in which participants used a mobile application to upload weekly photographs of multiple target wounds for up to 6 months and reported associated wound pain and itch (Photo Cohort, N = 69 wounds). We also utilized a separate dataset of placebo-treated wounds from a previously completed trial (Validation Cohort, N = 57 wounds) to validate the 12-week definition of wounds and to determine their rate of spontaneous wound closure. We reveal that chronic open wounds were larger, more painful, and only 17% of were observed to have spontaneous wound closure during follow up. In contrast, 100% (P < 0.001) of recurrent wounds were observed to have spontaneous closure during the photo observation. These differences were confirmed in the Validation Cohort. The median time to wound closure for chronic open wounds was 14.6 vs. 8 weeks for recurrent wounds. Additionally, recurrent wounds had a 29-fold greater likelihood to close spontaneously. In conclusion, chronic open wounds have a lower rate of spontaneous wound closure and are associated with more pain and itch. Wound type is the most significant predictor of spontaneous wound closure and should be the key consideration in the selection of wounds in RDEB clinical trials.