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This was an NIHR-funded study to develop and evaluate a new pressure ulcer assessment tool, called PURPOSE-T. The tool, developed as part of a five year NIHR research programme, is used by following a manual and assesses eight risk factors: mobility; skin; previous pressure ulcer; sensory perception; perfusion (blood flow); nutrition; moisture; and diabetes. Field testing by nurses showed very good agreement between tests and between assessors. This tool, drawing on new research, has many advantages over the various current assessment tools, which show numerous inconsistencies. PURPOSE-T is already being used by early adopter Trusts and could help to reduce the incidence of pressure ulcers.

Why was this study needed?

Pressure ulcers are areas of damaged skin and tissue, caused when an area of skin is placed under pressure. Typically they occur in a person confined to bed or a chair by an illness, and so are sometimes called bedsores or pressure sores. They can lead to extended hospital stays and reduced quality of life. There are an estimated 180,000 new cases each year in the NHS, with an annual cost for prevention and treatment of between £1.4 and £2.1 billion.

There are over 40 pressure ulcer risk assessment scales available. They vary in how they were developed – for example, informed by literature review, expert opinion or adaptation of an existing scale – and are inconsistent in their coverage of risk factors. Many were developed thirty to forty years ago. It is therefore timely to re-examine which risk factors should be considered in pressure ulcer risk assessment, and how these should be assessed.

The NIHR funded this work to develop and test an up-to-date pressure ulcer risk assessment tool – called the “Pressure Ulcer Risk Primary or Secondary Evaluation Tool”, abbreviated to “PURPOSE-T”.

What did this study do?

The development and testing of the tool comprised five phases: 1) a systematic review, 2) a consensus study, 3) the development of a conceptual framework and theoretical cause pathway, 4) design and pre-testing of the tool and 5) clinical evaluation.

The systematic review identified and clustered pressure ulcer risk factors into domains. The consensus process then used the review of risk factors to develop draft assessment indicators for the development of the tool. In step three, the development of a conceptual framework and theoretical cause pathway helped the team to further understand direct and indirect causal factors for pressure ulcer development. The first draft of the PURPOSE-T tool was built on evidence from steps 1, 2 and 3. Initial pre-testing of the tool was conducted over three sessions and focussed on improving usability. Finally, clinical evaluation of the tool was through field testing of 230 patients by both expert and community or ward-based nurses.

This was a very thorough process to design, test and evaluate a risk assessment tool. The findings should be considered reliable.

What did it find?

  • The systematic review identified 15 risk factor domains, three of which were classified as “primary” domains. They were: 1) mobility and activity, 2) skin and pressure ulcer status and 3) perfusion – the delivery of blood through capillaries – with diabetes a notable risk factor in this domain.
  • PROSPECT-T assesses pressure ulcer risk across eight risk factors: mobility; skin (examination of 13 sites); previous pressure ulcer; sensory perception; perfusion; nutrition; moisture; diabetes.
  • Clinical evaluation field testing of PROSPECT-T showed very good test–retest agreement for the tool and agreement between different users, with percentage agreement ranging from 79.1% to 94.2%.
  • PURPOSE-T was found to have a number of advantages compared to other risk assessment tools, including: 1) A screening stage for all patients allows rapid identification of those obviously not at risk, which may save time in clinical practice; 2) interventions are suggested in response to specific risk factors; 3) pain – recognised to be a key predicator of pressure ulcer development ­– has been incorporated as a risk factor; 4) primary and secondary prevention are distinct, so patients with an existing pressure ulcer or ulcer scarring are allocated to a secondary prevention pathway.

What does current guidance say on this issue?

The 2014 NICE guideline on pressure ulcers recommends that all adults admitted to hospitals, or those with a risk factor receiving NHS care in community settings (for example, poor mobility or cognitive impairment), should have their risk of developing a pressure ulcer assessed. Ideally a validated scale should be used to support clinical judgement (for example, the Braden scale, the Waterlow score or the Norton risk-assessment scale).

NHS England state that all pressure ulcers should be recognised as patient safety incidents and reported through the National Reporting and Learning System (NRLS) for the purposes of national learning.

What are the implications?

The PURPOSE-T risk assessment tool uses a manual and is intended for use by qualified nurses. It has already been implemented in early adopter Trusts, both acute and community, and the authors state that it is ready for wider implementation across the NHS.

The development of PURPOSE-T was exemplary, based on a systematic review of the risk factor evidence, and involved international and interdisciplinary experts, in partnership with service users. The tool offers a number of advantages over current assessment procedures..

Further and ongoing evaluation of PURPOSE-T is needed. Reliability of the tool across different patient populations needs to be assessed, as well as the impact the tool has on decision-making and pressure ulcer incidence in practice. The authors of the study hope that the development of an electronic version of PURPOSE-T will facilitate continued refinement of the tool. They are also keen that a lay version of the tool is developed, so that patients and carers can use it for self-assessment. Use of the tool in the NHS will allow a larger dataset to test how well it predicts pressure ulcers developing in routine care.


Nixon J, Nelson EA, Rutherford C, et al. Pressure UlceR Programme Of reSEarch (PURPOSE): using mixed methods (systematic reviews, prospective cohort, case study, consensus and psychometrics) to identify patient and organisational risk, develop a risk assessment tool and patient-reported outcome Quality of Life and Health Utility measures. Programme Grants Appl Res. 2015;3(6).

This project was funded by the National Institute for Health Research Programme Grants for Applied Research programme (Grant Reference Number RP-PG-0407-10056).


NHS England. Serious Incident Framework 2015/16- frequently asked questions. London: NHS England; 2015.

NHS Improving Quality. Pressure ulcers. Leeds: NHS England; 2015.

NICE. Pressure ulcers: prevention and management. CG179. London: National Institute for Health and Care Excellence; 2014.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

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The Braden scale was developed in 1987 and looks at the following criteria: sensory perception; moisture; activity; mobility; nutrition; and friction and shear.

The Waterlow score was developed in 1985 and assesses the following areas: build/weight for height; skin type/visual risk areas; sex and age; malnutrition screening tool; continence; and mobility. Additional areas are assessed in special risk patients: tissue malnutrition; nerve damage; major surgery or trauma.

The Norton risk-assessment scale was the first to be developed, in 1962, and considers five domains: physical condition; mental condition; activity; mobility; continence.

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