Background

Condition

Pressure ulcers are defined by the United States National Pressure Ulcer Advisory Panel (NPUAP) and the European Pressure Ulcer Advisory Panel (EPUAP) as “localized injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure, or pressure in combination with shear.”1 Pressure ulcers are a common condition, affecting an estimated 1.3 to 3 million adults in the United States (U.S.).2 In 2006, there were more than 500,000 hospital stays in which pressure ulcers were reported. Estimates of pressure ulcer prevalence range from 0.40 to 38 percent in acute care hospitals, 2 to 24 percent in long-term nursing facilities, and 0 to 17 percent in home care settings.24 The variation in estimates is due in part to differences in how ulcers are assessed and defined and in the populations evaluated. The prevalence of facility-acquired pressure ulcers was 6 percent in 2008 and 5 percent in 2009.4

Pressure ulcers are often associated with pain and can contribute to decreased function or lead to complications such as infection.5 In some cases, pressure ulcers may be difficult to treat despite surgical and other invasive treatments. In the inpatient setting, pressure ulcers are associated with increased length of hospitalization and delayed return to function.6 In addition, the presence of pressure ulcers is associated with poorer general prognosis and may contribute to mortality risk.6 Between 1990 and 2001, pressure ulcers were reported as a cause of death in nearly 115,000 people, and listed as the underlying cause in more than 21,000 people.7 Estimates of the costs of treatment for pressure ulcers vary, but range between $37,800 and $70,000 per case.6,8

Most current grading systems for pressure ulcers, including the commonly utilized NPUAP/EPUAP system, assign one of four stages, based on the depth of the ulcer and tissue involvement, with higher stages indicating greater severity (Table 1).1 In this system, stage 1 is defined as superficial erythema without skin breakdown, stage 2 as partial thickness ulceration, stage 3 as full thickness ulceration, and stage 4 as full thickness with involvement of muscle and bone. When a full thickness (at least stage 3) ulcer has overlying purulent material or eschar so that it is not possible to determine the depth or extent of tissue involvement, the ulcer is classified as unstageable. Another category, suspected deep tissue injury, refers to skin changes suggesting an injury to the tissues underneath the skin’s surface, and most commonly occur in the heel area.

Table 1. National Pressure Ulcer Advisory Panel/European Pressure Ulcer Advisory Panel pressure ulcer classification.

Table 1

National Pressure Ulcer Advisory Panel/European Pressure Ulcer Advisory Panel pressure ulcer classification.

Risk factors for pressure ulcers include older age, cognitive impairment, physical impairments and other comorbidities that affect soft tissue integrity and healing (such as urinary incontinence, edema, impaired microcirculation, hypoalbuminemia, and malnutrition).5,9 Given the negative impact and burdens associated with pressure ulcers, interventions that can prevent occurrence or reduce severity could have an important impact on quality of life and health status. Such an approach may also be more efficient than interventions for treating ulcers that have already developed. According to one estimate, treatment costs may be as much as 2.5 times the cost of prevention.10

A number of diverse interventions are available as potential preventive interventions for pressure ulcers. However, research indicates that many patients at high risk of pressure ulcers do not receive preventive interventions.11 Because patients vary in their propensity to develop pressure ulcers and the underlying reasons for being at increased risk, methods for accurately assessing risk could help more efficiently target the use or intensity of preventive interventions. A number of risk assessment instruments and preventive interventions are available.1214

The purpose of this report is to review the comparative clinical utility and diagnostic accuracy of risk assessment instruments for evaluating risk of pressure ulcers, and to evaluate the benefits and harms of preventive interventions for pressure ulcers. People at risk for pressure ulcers are cared for in diverse settings, including acute care hospitals, long-term care facilities, and the community at large. This report therefore also reviews how effectiveness varies in specific patient subgroups and in different settings.

Prevention Strategies

Recommended prevention strategies for pressure ulcers generally involve the use of risk assessment tools to identify people at higher risk for developing ulcers in conjunction with interventions for preventing ulcers.1,15,16 Use of preventive interventions is based in part on assessed risk, with higher-risk patients receiving more intensive interventions. Pressure ulcers are associated with a number of risk factors, including older age, black race, lower body weight, physical or cognitive impairment, poor nutritional status, incontinence, and specific medical comorbidities that affect circulation such as diabetes or peripheral vascular disease.

A number of instruments have been developed to assess risk for pressure ulcers. The three most widely used instruments are the Braden Scale (six items, total scores range from 6 to 23), the Norton Scale (five items, total scores range from 5 to 20), and the Waterlow Scale (11 items, total scores range from 1 to 64) (Table 2).5,1719 All three scales include items related to activity, mobility, nutritional status, incontinence, and cognition, though they are weighted differently across studies.18

Table 2. Commonly used scales for risk assessment of pressure ulcers.

Table 2

Commonly used scales for risk assessment of pressure ulcers.

A variety of diverse interventions are available for the prevention of pressure ulcers. Categories of preventive interventions include support surfaces (including mattresses, integrated bed systems, overlays, and cushions), repositioning, skin care (including lotions, dressings, and management of incontinence), and nutritional support.15,16 Each of these broad categories encompasses a variety of interventions. The term “support surfaces” refers to devices “for pressure redistribution designed for management of tissue loads, micro-climate, and/or other therapeutic functions.”26 Criteria for classifying support surfaces have historically included the material used (e.g., foam, air, gel, beads, water), whether the support surface is static or dynamic (e.g., alternating-air or low-air-loss overlays, mattresses, or bed systems) and whether the support surface requires power.27 More recent proposals are to reclassify support surfaces as “reactive” (a powered or nonpowered support surface with the capacity to change its load distribution properties only in response to applied load) or “active” (a power supported surface that can alter when and where load is applied to a person who sits or lies upon it and does not require a high applied load to redistribute body weight).26,27 However, most published trials used older and often poorly standardized methods for describing and classifying support surfaces. In this report, we broadly classified support surfaces as static, alternating air, or low-air-loss.

The use of preventive interventions varies according to the level of assessed risk, as well as according to specific patient characteristics or differences in settings. For example, a nutritional supplement may be of limited use in a patient who is not malnourished, and skin care needs may differ for people with incontinence compared with those without. Some interventions that require substantial nursing resources or specialized equipment may not be as feasible for community settings. Preventive interventions may also be used in combination or as part of complex multi-component interventions including repositioning, nutritional support, skin care, and support surfaces.

Scope of Review and Key Questions

This topic was nominated for review by the American College of Physicians, which intends to develop a guideline on prevention and management of pressure ulcers. This report focuses on pressure ulcer risk assessment and prevention approaches (i.e., prediction of and prevention of ulcers in people without ulcers at baseline). Treatment of pressure ulcers is addressed in a separate report.28

The analytic framework and key questions used to guide this report are shown below (Figure 1). The analytic framework shows the target populations, interventions, and health outcomes we examined, with numbers corresponding to the key questions.

Figure 1 is an analytic framework that depicts the events that individuals experience while undergoing risk assessment and implementation of preventive interventions for pressure ulcers. The figure illustrates how an asymptomatic patient population undergoes risk assessment, and how patients found to be at high risk are enrolled in preventive intervention designed to reduce outcomes of pressure ulcer incidence and severity. The patient population of interest is adults in various settings without pressure ulcers. Risk assessment stratifies these patients into high and low risk. High-risk patients receive preventive interventions. The outcomes of interest are pressure ulcer incidence and severity. The figure also depicts the possibility of harms or adverse events occurring as a result of preventive interventions.

Figure 1

Analytic framework. Note: The numbers in the analytic framework correspond to the numbers of the Key Questions.

The following key questions are the focus of our report:

Key Question 1.

For adults in various settings,* is the use of any risk-assessment tool effective in reducing the incidence or severity of pressure ulcers, compared with other risk-assessment tools, clinical judgment alone, and/or usual care?

Key Question 1a.

Do the effectiveness and comparative effectiveness of risk-assessment tools differ according to setting*?

Key Question 1b.

Do the effectiveness and comparative effectiveness of risk-assessment tools differ according to patient characteristics, and other known risk factors for pressure ulcers, such as nutritional status or incontinence?

Key Question 2.

How do various risk-assessment tools compare with one another in their ability to predict the incidence of pressure ulcers?

Key Question 2a.

Does the predictive validity of various risk-assessment tools differ according to setting*?

Key Question 2b.

Does the predictive validity of various risk-assessment tools differ according to patient characteristics?

Key Question 3.

In patients at increased risk of developing pressure ulcers, what are the effectiveness and comparative effectiveness of preventive interventions in reducing the incidence or severity of pressure ulcers?

Key Question 3a.

Do the effectiveness and comparative effectiveness of preventive interventions differ according to risk level as determined by different risk assessment methods and/or by particular risk factors?

Key Question 3b.

Do the effectiveness and comparative effectiveness of preventive interventions differ according to setting*?

Key Question 3c.

Do the effectiveness and comparative effectiveness of preventive interventions differ according to patient characteristics?

Key Question 4.

What are the harms of interventions for the prevention of pressure ulcers?

Key Question 4a.

Do the harms of preventive interventions differ according to the type of intervention?

Key Question 4b.

Do the harms of preventive interventions differ according to setting*?

Key Question 4c.

Do the harms of preventive interventions differ according to patient characteristics?

Key Question 1 focuses on direct evidence showing that using a risk assessment tool is associated with reduced pressure ulcer incidence or severity. An implicit assumption with this key question is that results of the risk assessment will inform the use of preventive interventions. Because direct evidence on the effects of risk assessment tools on clinical outcomes may be limited, the remainder of the key questions addresses the indirect chain of evidence necessary to assess strategies for prevention of pressure ulcers. Optimal prevention strategies require accurate identification of people at risk as well as effective interventions to reduce risk. Therefore, Key Question 2 addresses the diagnostic accuracy of risk assessment instruments, and Key Questions 3 and 4 evaluate the benefits and harms associated with various preventive interventions, compared with usual care and/or other interventions. Each key question also has sub-questions that address how estimates of diagnostic accuracy or clinical benefits vary in different patient groups defined by various risk factors or in different care settings.

Footnotes

*

Including acute care hospital, long-term care facility, rehabilitation facility, operating room, home care, and wheelchair users in the community.

Such as the Braden Scale, the Norton Scale, the Waterlow Scale, or others.

Such as age, race or skin tone, physical impairment, body weight, or specific medical comorbidities (e.g., diabetes and peripheral vascular disease).