ReviewEnteral nutritional support in prevention and treatment of pressure ulcers: A systematic review and meta-analysis
Introduction
The European Pressure Ulcer Advisory Panel (EPUAP) defined pressure ulcers as “an area of localised damage to the skin and underlying tissue caused by pressure, shear, friction and/or a combination of these things” (EPUAP, 2004). The severity of ulcers is graded from I to IV (see Table 1). In-patient pressure ulcer prevalence ranges from 3 to 66%, across a range of patient groups including the elderly and those with a fractured neck of femur (Versluysen, 1986, Ek et al., 1991, O’Dea, 1995, Bours et al., 1999, Whitfield et al., 2000, Tannen et al., 2004). Community based prevalence rates are similar (Tannen et al., 2004), with estimates ranging from 3 to 54% across different patient groups (Preston, 1991, Joy and Halling, 1998, Thomas et al., 1998, Bours et al., 1999, Haalboom, 2000).
Pressure ulcers are associated with an increased risk of morbidity and mortality. There is a four- to six-fold increase in risk of death (Allman et al., 1986). From a quality of life perspective, pain, exudate, body image and healing are the issues of greatest concern to patients (Fox, 2002). Furthermore, local and systemic infections are common, requiring extended hospitalisation (Stratton et al., 2003). The economic consequences are substantial, with the annual cost of treating pressure ulcers estimated in the region of £750 million (€1065 million) in the UK and US$ 3 billion (€2.4 billion) in the USA (Stratton et al., 2003).
Multivariate analyses indicate that low body mass index, low body weight, reduced feeding activity and food intake are independent risk factors for pressure ulcer development (Berlowitz and Wilking, 1989, Weiler et al., 1990, Ek et al., 1991, Bergstrom and Braden, 1992, Thomas, 1997, Green et al., 1999). Furthermore, malnutrition increases the risk of (Thomas, 2001), and impairs the healing of (Stratton et al., 2003, Harris and Fraser, 2004), pressure ulcers, due to reduced nutrient availability for tissue maintenance and repair, resulting in loss of the cushioning effect of fat mass, reduction of skin resistance, physical weakness, decreased mobility and oedema (Stratton et al., 2003). The majority of newly hospitalised patients with stage III/IV pressure ulcers (Guenter et al., 2000), and 46% of patients with leg or foot ulcers living at home (Wissing and Unosson, 1999), are reported to be malnourished.
Several studies have examined the effect of nutritional support on the development of pressure ulcers in at-risk patients (Delmi et al., 1990, Hartgrink et al., 1998, Bourdel-Marchasson et al., 2000, Houwing et al., 2002, Houwing et al., 2003). However, there have been few studies of the effects of nutritional support in patients with established pressure ulcers (Myers et al., 1990, Breslow et al., 1993). The role of nutritional support using disease-specific formulas developed specifically for patients with pressure ulcers is currently unclear. Such formulas contain additional quantities of a number of individual nutrients that are important in the wound healing process (including protein, arginine and Vitamin C; Taylor et al., 1974, Barbul et al., 1990, Breslow et al., 1993, Kirk et al., 1993, Scholl and Langkamp-Henken, 2001).
In 2003, a Cochrane review of eight randomised controlled trials (RCTs) concluded that although there was insufficient evidence “elderly people suffering from acute illness appear to develop fewer pressure ulcers when given two daily supplement drinks” (Langer et al., 2003). The Cochrane review was based on evidence from RCTs only, did not include meta-analysis, missed some relevant information (Ek et al., 1991) within the review period (up to September 2002) and only assessed PU incidence and time to complete healing as outcome measures and not other clinically relevant parameters (e.g. dietary intake and quality of life).
Therefore, the aim of this systematic review was to determine the effect of enteral nutritional support on pressure ulcer incidence, pressure ulcer healing, quality of life, complications, mortality, nutritional status (dietary intake, body weight) and any other clinically relevant outcome measures, specifically comparing nutritional support (oral nutritional supplements (ONS) or enteral tube feeding (ETF)) versus routine care, enteral formulas of different composition and ETF versus parenteral nutrition. Meta-analysis of quantitative outcomes was also to be undertaken where possible (i.e. where consistent, numerical measures were reported).
Section snippets
Materials and methods
The review was planned, conducted and reported following published guidelines. These include those issued by the Cochrane Collaboration (Cochrane, 2004a, Cochrane, 2004b), the UK National Health Service Centre for Reviews and Dissemination (CRD) (CRD, 2000, CRD, 2001) and the QUORUM guidelines (Moher et al., 1999). A flow chart (Fig. 1) illustrates the principle stages and processes undertaken.
Overall search findings
A total of 916 studies were identified by the search strategy (Fig. 1). Following evaluation of the title/abstract, 36 papers were deemed potentially relevant and obtained in full. Upon reading the full text of these 36 papers, 15 (Chernoff et al., 1990, Delmi et al., 1990, Peck et al., 1990, Breslow et al., 1991, Breslow et al., 1993, Ek et al., 1991, Henderson et al., 1992, Bourdel-Marchasson et al., 1997, Bourdel-Marchasson et al., 2000, Mitchell et al., 1997, Craig et al., 1998, Hartgrink
Discussion
This systematic review shows that enteral nutritional support, and in particular high protein ONS, are associated with a significant reduction (by 25%) in pressure ulcer development compared to routine care (e.g. usual diet and usual pressure ulcer care). ONS and ETF may also aid pressure ulcer healing in at-risk patient groups but these trends require confirmation with further study. Prevention of pressure ulcers is associated with benefits for both the patient, who may be spared a common,
Acknowledgements
This study was conducted using an educational grant supplied by Numico. Thanks to Abacus International, UK, for research support, and to Statwood, UK, for statistical support.
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