Outcomes and endpoints in clinical pressure ulcer prevention trials

Pressure ulcers are severe skin and tissue damages occurring in the context of severe illness, disability and care dependency. Evidence-based pressure ulcer prevention is the combination of ‘external evidence’ which is results of clinical trials and other research, ‘internal evidence’ which is individual clinical expertise and patient preferences and the consideration of legal and policy frameworks. Especially the limited number of high quality clinical trials is a major limitation in current pressure ulcer prevention science (Haesler et al. 2016). The quality and impact of clinical trials depend on a number of methodological criteria (e.g. randomization, concealed allocation etc.) but also on the choice of outcomes. The development of new pressure ulcers with a clinical trial is without doubt an important and relevant endpoint, but accurate and reliable measurements are not easy. What is more appropriate to measure: one ulcer per person or the number of ulcers? Are different anatomical locations comparable (e.g. heel vs. sacrum)? Is it appropriate to combine all categories into one endpoint (e.g. category 1 to 4)? Given the current understanding of pressure ulcer etiology and pathogenesis it is recommended to be as precise as possible in reporting clinical trial data, including meticulous documentation of observed pressure ulcer categories and anatomical locations (Kottner, Gefen 2012). In addition, severe pressure ulcers rarely occur in clinical trials which makes it even more challenging to draw appropriate conclusions about the effects of tested interventions. There are many other outcomes measured in pressure ulcer prevention trials: time to ulcer development, costs, pain, satisfaction, comfort etc. but these concepts and definitions are not comparable between trials. There is also a mismatch between outcomes reported in clinical trials and systematic reviews and meta-analyses. Agreement upon the most important outcomes and how to measure them is needed in clinical pressure ulcer prevention research.

References
Haesler E, Kottner J, Cuddigan J; 2014 International Guideline Development Group. The 2014 International Pressure Ulcer Guideline: methods and development. J Adv Nurs. 2016 Dec 17. [Epub ahead of print]

Kottner J, Gefen A. Incidence of pressure ulcers as primary outcomes in clinical trials: a comment on McInnes et al. (2012). Int J Nurs Stud. 2012;49(3):372-4.