The last paper describes an incidence study. Please, read the following paper:
Anrys C, Van Tiggelen H, Verhaeghe S, Van Hecke A, Beeckman D. Independent risk factors for pressure ulcer development in a high-risk nursing home population receiving evidence-based pressure ulcer prevention: Results from a study in 26 nursing homes in Belgium. Int Wound J. 2019 Apr;16(2):325-333. doi: 10.1111/iwj.13032. Epub 2018 Nov 9. PMID: 30412652; PMCID: PMC7949181.