Risk assessment tools for the prevention of pressure ulcers
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
The objective of this review is to answer the following question: Does the use of structured, systematic pressure ulcer risk assessment tools, in any health care setting, reduce the incidence of pressure ulcers?
Background
Pressure ulcers (also known as bed sores, pressure sores and decubitus ulcers) are localised areas of tissue damage caused by excess pressure, shearing or friction forces, that occur in people who do not have the ability to reposition themselves in order to relieve pressure on bony prominences. This ability is often diminished in the very old, the malnourished, and those with acute illness (Robertson 1990). Indeed, it is suggested that approximately 18% of hospitalised patients have a pressure ulcer (EPUAP 2002), and, although some of these pressure ulcers may be present on admission, most pressure ulcers occur during a hospital stay for the management of acute illness (Bridel 1996). Pressure ulcer incidence rates range between 2.2% to 66% in the UK, and 0% to 65.6% in the USA and Canada (Kaltenthaler 2001). These figures are influenced by the location and condition of the patient group (hospital versus community setting, general hospital patients versus those with fractured neck of femur) with the highest incidence noted among elderly orthopaedic patients (Bridel 1996; Hanson 1993; Richardson 1981; Versluysen 1986). Interestingly, a review of data from a six‐year national incidence study in the USA, found that the incidence in 1999 was 8% and in 2004 was 7%, demonstrating little change in overall figures (Whittington 2004).
Pressure ulcers impact negatively on quality of life as it is known that individuals with pressure ulcers frequently experience pain, combined with fear, isolation and anxiety regarding wound healing (Fox 2002). Importantly, it has also been shown that pressure ulcers are associated with an increased risk of death (Allman 1997). One study identified that the risk of dying for elderly patients with a pressure ulcer was three times greater than for those without a pressure ulcer (Berlowitz 1990) although it is probable that pressure ulcers are usually a consequence of poor health rather than a cause of death. Further work supports this demonstrating an odds ratio of 3.64 (p<0.001) (Bo 2003) and 4.19 (p<0.001) (Alarcon 1999) respectively of death in acutely ill elderly people with pressure ulcers.
Pressure ulcers are a significant financial burden to health care systems. Bennett (Bennett 2004) suggests that the total annual cost for pressure ulcer management in the UK is £1.4 to 2.1 billion, which is equivalent to 4% of the total UK health care expenditure. Similar findings have been noted in the Netherlands where pressure ulcers have been found to be the third most expensive health problem (Haalboom 2000). It has been suggested that the length of hospital stay is two to three times greater for those with a pressure ulcer, than for similar cases without (30.4 days compared to 12.8 days) (Allman 1997).
Globally, the exact economic impact of pressure ulcers has yet to be established. However, it is known that pressure ulcers are common (EPUAP 2002) and affect patients in both community (Margolis 2002) and hospital settings (Clark 1991). Although individuals of any age can develop pressure ulcers, they are more common in certain patient groups such as the elderly (Whittington 2000), and those in orthopaedic settings (Versluysen 1986), though other medical conditions can predispose individuals to their development (Schoonhoven 2002). Changing demographics and the rise in the number of elderly in the future means that the number of pressure ulcers is likely to increase in the years ahead. Therefore, it is reasonable to suggest that pressure ulcer prevention strategies that can reduce prevalence and incidence rates, will have a positive impact on patients and the health service as a whole (Thompson 1999).
Pressure ulcer risk assessment is a component of the assessment process used to identify individuals at risk of developing a pressure ulcer (EPUAP 1998). Risk assessments generally use checklists that alert practitioners to the most common risk factors that predispose individuals to pressure ulcer development. These checklists are often developed into risk assessment tools, for example, the Norton Scale (Norton 1975), the Waterlow risk assessment scale (Waterlow 1985) and the Braden scale (Braden 1987). There are currently almost 40 risk assessment scales in use, most of which are based on the seminal work of (Norton 1975), or have been designed in response to a review of the literature (Defloor 2004).
Use of a risk assessment tool is recommended by many international pressure ulcer prevention guidelines (AHCPR 1992; EPUAP 1998A; NICE 2001; Rycroft‐Malone 2000). The ideal risk assessment tool should be both reliable and valid, and sensitive and specific (NPUAP 1998). The tool must accurately identify those individuals who are at risk, as well as those not at risk ‐ and do this consistently (Defloor 2005). To date, there is little empirical evidence available concerning the reliability and validity of existing tools (Cullum 1995; Defloor 2004; Defloor 2005; Haalboom 1999; McGough 1999; Schoonhoven 2002A; Pancorbo 2006). This has far‐reaching implications for practice, where clinical decisions ‐ such as the use, or not, of pressure ulcer preventative strategies ‐ are often made on the basis of the results of risk assessment. Therefore, it is likely that some patients are receiving interventions that they do not require, and conversely, others are not receiving interventions that they do need (Defloor 2005). This inappropriate allocation of resources compounds the increasing burden of pressure ulcers, and adds to spiralling health care costs.
Two systematic reviews have been previously conducted exploring the effectiveness of pressure ulcer risk assessment tools in the prevention of pressure ulcers. The first review searched for studies published between 1962 and 1995 (Cullum 1995), the second searched between 1962 and 1999 (McGough 1999). Both reviews restricted the inclusion criteria to studies published in the English language. The conclusions from these reviews were that there was no evidence that using pressure ulcer risk assessment scales reduced the incidence of pressure ulcers. However, these reviews are now out of date, and restricted to publications in English, it is necessary to conduct an up‐to‐date review no language restrictions in order to clarify the role of pressure ulcer risk assessment tools in clinical practice.
Objectives
The objective of this review is to answer the following question: Does the use of structured, systematic pressure ulcer risk assessment tools, in any health care setting, reduce the incidence of pressure ulcers?
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials (RCTs) comparing the use of structured, systematic, pressure ulcer risk assessment tools with no structured pressure ulcer risk assessment, or with unaided clinical judgement, or RCTs comparing the use of different structured pressure ulcer risk assessment tools will be considered for this review.
Types of participants
Studies involving people of any age, in any healthcare setting will be eligible.
Types of interventions
RCTs which make the following comparisons will be eligible for inclusion in this review:
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Pressure ulcer risk assessment using a specific structured, systematic pressure ulcer risk assessment tool compared with no structured pressure ulcer risk assessment tool;
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Comparisons between two different pressure ulcer risk assessment tools.
Types of outcome measures
Primary outcome measure
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the proportion of participants developing new pressure ulcers (for the purpose of this review a pressure ulcer will be defined as a break in the continuity of the skin, caused by pressure, shearing or friction forces (Nixon 1999)).
Secondary outcome measure
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the severity of new pressure ulcers;
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time to ulcer development;
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pressure ulcer prevalence;
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sensitivity, specificity and ease of use of the various risk assessment tools.
Studies will only be eligible for inclusion if they report the primary outcome. Studies which report only secondary outcomes will not be eligible
Search methods for identification of studies
The following databases will be searched:
MEDLINE (January 1966 to present)
EMBASE (1974 to present)
CINAHL (1982 to present)
The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library latest issue)
The Wounds Group Specialised Register
The following search strategy will be used in CENTRAL to identify relevant studies and will be adapted were necessary to allow for the variations in indexing between databases:
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#1 MeSH descriptor Pressure Ulcer, this term only
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#2 MeSH descriptor Skin Ulcer, this term only
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#3 decubitus or decubital
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#4 skin near/3 breakdown*
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#5 bedsore* or (bed next/1 sore*)
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#6 decubitus next (ulcer* or sore*)
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#7 pressure* next (wound* or sore* or ulcer* or injur* or damag*)
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#8 (#1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7)
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#9 MeSH descriptor Risk Assessment, this term only
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#10 (anderson or braden or norton or knoll or waterlow or medley or maelor or arnold or gosnell) near (score* or scale* or tool* or assess*)
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#11 risk near/2 assess*
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#12 (assess* or predict*) next (tool* or score* or scale*)
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#13 MeSH descriptor Nursing Assessment explode all trees
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#14 (knoll or norton or waterlow) next (modif*)
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#15 birty* next para
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#16 cubbin near jackson
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#17 braden next dupa
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#18 douglas next ward
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#19 (wound* next assess*) near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#20 (bed next sore*) near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#21 decubit* near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#22 (pressure next ulcer*) near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#23 (pressure next sore*) near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#24 bedsore* near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#25 (pressure next injur*) near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#26 (pressure next damag*) near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#27 (pressure next wound*) near (tool* or score* or scale* or scoring or instrument* or equipment* or device*)
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#28 (( #9 AND # ) OR #10 OR #11 OR #12 OR #13 OR #14 OR #15 OR #16 OR #17 OR #18 OR #19 OR #20 OR #21 OR #22 OR #23 OR #24 OR #25 OR #26 OR #27)
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#29 (#8 AND #28)
Citations in all retrieved and relevant publications identified by these strategies will be searched for further studies. Experts in the wound care field, namely, council members of the European Pressure Ulcer Advisory Panel, The European Wound Management Association, The National Pressure Ulcer Advisory Panel and the World Union of Wound Healing Societies, will be contacted to identify any studies not located through the primary search. There will be no restrictions on articles on the basis of language or date of publication.
Data collection and analysis
Study selection
Titles and, where available, abstracts of the studies identified by the search strategy will be assessed by two authors independently for their eligibility (as identified in the selection criteria) for inclusion in the review. Full versions of potentially relevant studies will be obtained and screened against the inclusion criteria by two authors independently. Any differences in opinion will be resolved by discussion and, where necessary, reference to the Wounds Group Editorial base.
Data extraction
Details of eligible studies will be extracted and summarised using a data extraction sheet. Specifically, the following information will be extracted:
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Author
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Title
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Source
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Date of study
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Country
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Care setting
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Inclusion and exclusion criteria
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Sample size
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Participant baseline characteristics by group
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Design details
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Study type
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Allocation
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Intervention details
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Concurrent interventions
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Is risk assessment part of a wider assessment programme/package
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Frequency of risk assessment
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Length of follow up
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Patient length of stay
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Which health professional administered the tool
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Outcome measures
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Verification of diagnosis
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Analysis
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Loss to follow up
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Results
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Conclusions
Two authors will extract data independently; any differences in opinion will be resolved by discussion and, where necessary, reference to the Wounds Group Coordinating Editor. If data are missing from reports, attempts will be made to contact authors to obtain the missing information.
Validity assessment
The validity of individual studies will be appraised critically, by two authors independently, to check methodological rigour, using the quality assessment suggested elsewhere (Verhagen 1998; Khan 2001). The quality items to be assessed are adequacy of the randomisation process, adequacy of the allocation concealment, intention‐to‐treat analysis (ITT), and blinding of investigators, participants and outcomes assessment. Each item will be assessed separately rather than combined in a scoring system.
1.Adequacy of the randomisation process:
Trials will be awarded the following grades for adequacy of the randomisation process:
A = Adequate sequence generation is reported using random number tables, computer random number generator, coin tossing, or shuffling.
B = Did not specify one of the adequate reported methods in (A) but mentioned randomisation method.
C = Using a system involving dates, names, or admittance numbers for the allocation of patients. These studies are known as quasi‐randomised and will be excluded from the review.
2.Adequacy of allocation concealment
Trials will be awarded the following grades for allocation concealment:
A = Adequate: a randomization method described that would not allow an investigator/participant to know or influence an intervention group before an eligible participant entered the study, such as central randomisation; serially numbered, opaque, sealed envelopes.
B = Unclear: trial states that it is 'randomized', but no information on the method used is reported or a method is reported that was not clearly adequate.
C = Inadequate: inadequate method of randomization used, such as alternate medical record numbers or unsealed envelopes; or any information in the study that indicated that investigators or participants could influence the intervention group.
3. Blinding
The following points will be graded as 'yes' for present, 'no' for absent, and 'not stated' if the relevant information is not stated in the trial report:
a. Blinding of care providers.
b. Blinding of participants.
c. Blinding of outcome assessor.
d. Blinding of data analysis.
4. Intention‐to‐treat analysis (Hollis 1999)
A ‐ Yes: Specifically reported by authors that ITT was undertaken and this was confirmed on study assessment, or not stated but evident from study assessment that ITT was undertaken
B ‐ Unclear. Described as ITT analysis, but unable to confirm on study assessment, or not reported and unable to confirm by study assessment.
C ‐ No: Lack of ITT confirmed on study assessment (Patients who were randomised were not included in the analysis because they did not receive the study intervention, they withdrew from the study or were not included because of protocol violation) regardless of whether ITT reported or not
Synthesis
Initially a structured narrative summary of the studies reviewed will be conducted. For dichotomous outcomes, relative risk plus 95% confidence intervals will be calculated. For continuous outcomes, weighted mean difference plus 95% confidence intervals will be calculated.
Clinical heterogeneity will be explored by examining potentially influential factors, e.g. care setting or patient characteristics. Statistical heterogeneity will be assessed using the I2 test (Higgins 2003). This examines the percentage of total variation across studies due to heterogeneity rather than to chance. Values of I2 over 75% indicate a high level of heterogeneity.
Statistical pooling will be carried out on groups of studies which are considered to be sufficiently similar. In the absence of heterogeneity (I2 = 0% or for low levels of heterogeneity I2 less than 25%) a fixed‐effect model will be used; if there is evidence of heterogeneity (I2 more than 25%), a random effects model will be used. If it is inappropriate to pool studies they will be presented in a narrative summary only. Results will be presented by care setting, patient group and type of risk assessment.
