The economics of pressure relieving surfaces: an illustrative case study of the impact of high‐specification surfaces on hospital finances

Abstract

Pressure ulcers are associated with a significant economic burden that, in many cases, is recognised as being avoidable. The effectiveness of pressure relieving surfaces is well documented and acknowledged in clinical guidelines on the prevention and management of pressure ulcers. Whilst pressure relieving surfaces are more expensive than traditional hospital mattresses, judicious use, targeted to patients most at risk, can help to reduce the incidence and costs of pressure ulcers in hospital settings. This review paper includes a summary of pivotal clinical evidence on pressure relieving surfaces as well as a suggested approach for modelling their financial impact on hospital budgets. Simple financial modelling suggests that pressure relieving surfaces could lead to financial savings for a hospital when used appropriately.

INTRODUCTION

Health care payers are increasingly concerned with ensuring that health care funds are allocated efficiently. Demographic and epidemiological changes are placing ever greater demands on health care resources, forcing payer bodies to make difficult decisions about coverage and availability.

The management of pressure ulcers provides an illustrative case study of the challenges facing health care payer bodies. The development of pressure ulcers is positively associated with age (1) so demographic changes towards a more elderly population are expected to create further demand for wound care. The risk of developing pressure ulcers is further increased by other epidemiological and lifestyle trends such as the increasing rate of obesity (2) and physical inactivity or immobility associated with age (3).

Pressure ulcers occur in both community and hospital settings. The development of pressure ulcers in hospital settings is a particular concern. The development of a pressure ulcer, following admission for an unrelated cause, can result in extended hospital stays which are both costly and impact on hospital throughput. Estimates of the incremental length of stay as a result of developing a pressure ulcer vary significantly from 4 days reported in a study conducted in Australia (4) to almost 18 days from a study in the USA (5).

Many of the ulcers that develop in hospital settings are preventable through better patient management (6). A number of guidelines on the prevention and management of pressure ulcers are available from national and international bodies. Integral to these are recommendations relating to the appropriate use of pressure relieving surfaces. Pressure relieving surfaces is the term used to capture mattresses and mattress covers which are used in hospital settings to reduce friction, shear, temperature and moisture as well as pressure in patients at risk of developing a pressure ulcer. Pressure relieving surfaces range from simple mattress overlays to more advanced powered units which are designed to provide continuous pressure relief. Surfaces are often grouped into broad categories based on their mechanism of action, such as the typology suggested by Cullum et al. which grouped high‐tech surfaces into alternating pressure (AP) and continuous low‐pressure (CLP) surfaces (7). The acquisition costs of alternative surfaces differ significantly, reflecting the differences in complexity of the surfaces themselves.

The National Institute for Health and Clinical Excellence (NICE) produced guidance on the management of pressure ulcers for the health service in England and Wales (8). The guidance provides far‐reaching recommendations for practitioners in both primary and secondary care settings. The guideline acknowledges the role of pressure relieving surfaces in the management and prevention of pressure ulcers by providing recommendations on their use based on a systematic review conducted as part of the guideline development process. Table 1 provides the minimum recommended practice as presented in the recommendations. Although the recommendations stop short of providing detailed guidance on the use of specific systems, some attempt has been made to allocate patients to different surface types according to their ulcer status, based on the available evidence. However, practitioners may also want to consider other risk factors, such as obesity and mobility, which may also impact on the risk of ulcer progression.

Table 1.

Summary of the recommendations from NICE related to pressure relieving surfaces

Pressure ulcer grade	Minimum recommended management
At‐risk population	High‐specification foam mattress with pressure relieving properties as a minimum
Grade I/II	High‐specification foam mattress/surface with pressure relieving properties
Grade III/IV	Alternating pressure mattress or sophisticated continuous low air loss system

NICE, National Institute for Health and Clinical Excellence.

International guidelines from professional bodies, such as the European Pressure Ulcer Advisory Panel (9) include similar recommendations on pressure redistributing devices. Despite these guidelines, many avoidable pressure ulcers continue to develop due to inappropriate management of risk factors.

This paper reviews some of the key evidence on the use of pressure relieving surfaces and considers the economic implications of adopting an effective portfolio of surfaces to manage patients at risk of developing a pressure ulcer.

METHODS

Clinical and economic evidence on pressure relieving surfaces was identified through a targeted literature search of published sources. Although no attempt was made to undertake a systematic literature search, efforts were made to review the most rigorous and well‐designed studies of pressure relieving surfaces as well as any review papers which had adopted systematic searching principles.

Clinical and economic studies identified in the search were reviewed for relevance. The findings presented by relevant studies are summarised below.

In addition to this, an illustrative example of the financial implications of adopting a more aggressive approach to managing patients at risk of developing pressure ulcers was developed for the purposes of this study. The example is intended to show the potential financial impact of providing a range of surfaces for patients at risk of developing a pressure ulcer in an average sized district hospital in the UK. The example is intended to be illustrative although attempts have been made to ensure that it is based on the best available evidence.

RESULTS

Clinical evidence on pressure relieving surfaces

A number of studies have considered the effectiveness of pressure relieving surfaces in preventing pressure ulcers, including comparisons with standard mattresses as well as comparisons between different pressure relieving surfaces. However, the evidence base remains relatively small and is characterised by difficulties in interpretation of the findings. For example, the definitions of surface types vary across study settings, particularly in relation to what is considered to be a ‘standard’ foam mattress. Interpretation of the evidence is further complicated by changes in the definitions over time and in some cases, a lack of clarity in reporting. In addition to this, disentangling the effectiveness of the pressure relieving surface from other aspects of best practice, such as manual turning, creates further problems when attempting to attribute any effect to the surface.

However, despite these challenges a number of well‐designed studies have sought to compare alternative surfaces. Some of the most rigorous clinical studies of pressure relieving devices have been conducted in the UK, such as the Prevention of Pressure Ulcer Study (PPUS‐1) trial reported by Russell and colleagues (10). This prospective, randomised study included over 1100 patients aged over 65 in elderly care, rehabilitation or orthopaedic wards in UK hospitals. Participants were randomised to either a standard hospital mattress or a viscoelastic polymer foam mattress. There was relatively little specific guidance on what constitutes a standard hospital mattress meaning that a range of services was used. The findings report that 22% of patients on standard mattresses developed a pressure ulcer compared to 15% on the pressure relieving surface. Estimates of the relative risk of developing an ulcer were in excess of 1·36 (depending on definition of an ulcer adopted). Whilst the absence of a specific definition of standard hospital mattresses could be a cause for criticism of the study, this may actually increase the external validity of the findings to a broad audience of health care providers in the UK.

A second study conducted by Nixon and colleagues (11) compared alternating pressure overlays with alternating pressure mattresses. The PRESSURE (Pressure RElieving Support Surfaces: a Randomised Evaluation) study recruited almost 2000 patients from 11 hospital‐based research centres. Participants were aged over 55 and were recruited from vascular, orthopaedic, general medical and elderly care wards. Few differences in clinical endpoints were identified between overlays and mattress replacements. No significant differences were identified in the incidence of ulcers and the time to healing was similar in both arms. Pressure relieving mattresses were associated with a shorter length of stay which helped to inform the development of an economic evaluation of the trial findings (reported below). The authors recommend that time to ulceration should be considered as an outcome measure for future studies of pressure relieving surfaces.

In addition to these two large‐scale studies, a number of other comparative and non comparative studies of pressure relieving mattresses have been published. A recent systematic review by McInnes et al. (12) attempted to summarise the available evidence on pressure relieving surfaces and undertake meta‐analysis of the findings. The review adopted rigorous principles, considering only evidence generated in randomised controlled trials. A total of 52 studies were deemed to meet the inclusion criteria. The studies cover a total population of over 10 000 patients; however, the studies were heterogeneous and the sample sizes vary significantly across studies. The findings report the risk of developing a pressure ulcer on a particular surface type relative to an alternative surface. A summary of the relative risks is provided in Table 2.

Table 2.

Relative risk of developing a pressure ulcer according to surface type

Comparison	Relative risk
CLP versus standard foam	0·41
LAL versus standard foam	0·33
AP versus standard foam	0·31

CLP, continuous low pressure; LAL, low air loss; AP, alternating pressure.

The findings suggest that more advanced surfaces can reduce the development of pressure ulcers relative to standard foam surfaces by over 60%, with alternating pressure surfaces providing the greatest reduction in risk. Whilst these findings suggest that advanced surfaces offer significant clinical benefits, some caution should be taken in interpreting the evidence. The review considered studies published over a period of almost 30 years during which definitions of what constitutes a standard foam surface and an advanced surface may have changed considerably. Whilst every effort was made in the analysis to include all relevant studies and control for potential confounding effects wherever possible, the direct comparisons between surface types may suffer as a result of this.

The available clinical evidence suggests that there are some advantages to the use of pressure relieving surfaces although identification of the attributable effect is complicated by differences in study design, population studies and interventions considered.

Economic evidence on pressure relieving surfaces

A number of authors have sought to develop economic evaluations of alternative types of pressure relieving surfaces. Iglesias and colleagues (13) conducted an economic evaluation alongside the PRESSURE trial which suggested that alternating pressure mattresses are more likely to be cost effective and acceptable to patients than alternating mattress overlays. However, the study did not consider alternative forms of pressure relieving surfaces.

Fleurence (14) developed a decision analytic model that considered the cost effectiveness of high‐tech devices, namely alternating pressure mattress replacements and alternating pressure overlays, relative to standard foam mattresses. The study considered both prevention and treatment of pressure ulcers of varying degrees of severity A number of scenarios were considered whereby patients were admitted to hospital at risk of developing a pressure ulcer or with an existing ulcer. The findings suggest that alternating pressure overlays may be the most cost‐effective means of preventing the development of pressure ulcers in patients at risk upon admission. However, alternating pressure mattresses are likely to be the most cost‐effective means of managing patients with a pre‐existing superficial or severe pressure ulcer.

Both of these studies are to be commended on the quality of the economic evaluations and together, they provide a convincing case for the use of high‐tech surfaces over standard foam mattresses where there is an elevated risk of developing a pressure ulcer. However, neither makes any attempt to discriminate between different types of high‐tech surfaces on the basis of cost effectiveness evidence.

Legood and McInnes' (15) summary of the published economic evidence on pressure relieving surfaces came to similar conclusions. Whilst they identified good quality evidence on the high‐tech surfaces compared with standard foam mattresses they concluded that ‘the most relevant comparison—high‐tech versus high‐specification foam mattresses—was absent from the research literature’. Future evaluations of pressure relieving surfaces should aim to address this point which is of critical importance to health care decision makers given the significant differences in the acquisition prices of pressure relieving surfaces. Clinicians and health service managers are aiming to ensure that the best possible care is delivered within available budgets. In order to do so, evidence on the relative merits of individual surface types, their cost effectiveness and their impact on health service budgets are all necessary. The case study below attempts to investigate how these issues might be addressed using simple financial modelling techniques applicable to health service decision makers.

Financial implications of pressure relieving surfaces: an illustrative case study

Recommendations on the management of pressure ulcers suggest that hospitalised patients at risk of developing a pressure ulcer should have access to pressure relieving surfaces.

Whilst there is only limited economic evidence available on the relative value of pressure relieving surfaces, a reasonable investment in prevention could be justified if it resulted in a reduction in the number of pressure ulcers and avoided the costs associated with treatment.

In order to explore the potential economic implications of adopting high‐specification surfaces, an illustrative case study is presented below. The case study considers a medium‐sized hospital with 500 beds, operating at an 80% occupancy rate. Based on an average length of hospital stay of 5 days [reflecting the mean for all elective stays in the UK (16)], this generates a total of 29 220 admissions per year. The financial implications of pressure ulcers developed in this setting are explored using an interactive model developed with the support of KCI Inc. The model is used to explore the illustrative example presented above but it has been developed to allow it to be adapted to incorporate data on local prevalence, incidence and costs of pressure ulcers, thus producing a bespoke analysis for any given setting.

Prevalence and incidence of pressure ulcers

Initially, we assume that all patients are admitted on standard foam mattresses. Estimates of the incidence and prevalence of pressure ulcers on standard foam mattresses are presented in Table 3. Estimates of prevalence and incidence are derived from a large‐scale, multi‐national observational study of pressure ulcers. (17)

Table 3.

Estimates of the prevalence of pressure ulcers at admission

	Existing pressure ulcers (%)	At risk [new pressure ulcers (%)]
Prevalence	19·0	8·0
Grade 1	62·4	100·0
Grade 2	30·1	0·0
Grade 3	4·3	0·0
Grade 4	3·2	0·0

Applying these data to the admissions in our hypothetical scenario suggests that the hospital will treat 7890 pressure ulcers within the year, 5552 of which are prevalent and 2338 are incident cases.

Costs of managing pressure ulcers

The cost of managing pressure ulcers is derived from a previously published study, which generated bottom–up estimates of the resources involved in managing a pressure ulcer according to ‘good clinical practice’ and allocated appropriate unit costs (18). The costs have been inflated to prices of 2008. The average cost of managing a pressure ulcer, stratified by the grade of ulcer is reported in Table 4.

Table 4.

Estimated cost of treating pressure ulcers according to severity

Grade of pressure ulcer	Cost per patient *
Grade I	£ 1064
Grade II	£4402
Grade III	£7313
Grade IV	£10 551

^*Source: Bennett et al. Original figures inflated using inflation indices from the Office of National Statistics.

For the purpose of this analysis, the cost of managing an incident ulcer occurring during a hospital stay was taken to be equivalent to the cost of managing a grade I ulcer. However, it is recognised that an incident pressure ulcer may develop beyond grade I during the hospitalisation and as such could cost significantly more than this.

Applying these costs to the number of pressure ulcers reported above means that the cost of managing pressure ulcers occurring in this hospital is estimated to be in excess of £19 million per year.

Effectiveness of pressure relieving surfaces

Allocating a proportion of the at‐risk patients to high‐specification mattresses has the potential to reduce the number of pressure ulcers that develop and their associated costs. The rate of pressure ulcer development according to surface type, as derived from sources of clinical evidence discussed above is presented in Table 5.

Table 5.

Probability of developing a pressure ulcer according to surface type

Surface type	Probability of developing a pressure ulcer (%)	Source
Standard foam	21·8	Russell et al. 2003
Constant low pressure	8·9	McInnes et al. 2008
Alternating pressure	6·8	McInnes et al. 2008

Cost of pressure relieving surfaces

The cost of alternative types of pressure relieving surfaces is presented in Table 6. Average costs are based on an assumed duration of use of 3 years and list prices for each type of surface.

Table 6.

Cost of pressure relieving surfaces

Surface type	Average cost
Standard foam	£383 *
Constant low pressure	£1810 †
Alternating pressure	£2500 ‡

^*Average list price of Softform (MSS, Cardiff, UK), Pentaflex (Huntleigh, Lund, Sweden), Tempur (TempurMed, Lexington, KY, US), TheraRest (KCI, San Antonio, TX, US).

^†Average price of Duo (HillRom, Batesville, IN, US), Breeze (Huntleigh), AtmosAir 4000 (KCI), AtmosAir 9000 (KCI), RIK Fluid overlay (KCI), TheraKair Visio (KCI).

^‡Average price of Nimbus3 (Huntleigh), AlphaXcell (Huntleigh), Primo (HillROM), ProfiCARE (KCI).

Allocating at‐risk patients to appropriate surfaces: the clinical and financial implications

Now let us assume that some of the population at risk of developing a pressure ulcer are re‐allocated to a high‐specification surface rather than all patients being managed on standard foam mattress. Table 7 provides a summary of the expected costs and outcomes based on alternative portfolios of surfaces used to manage individuals at risk of developing a pressure ulcer.

Table 7.

Impact of re‐allocating at risk patients to advanced pressure relieving surfaces

Patients on standard foam	85%
Patients on constant low pressure	10%
Patients on alternating pressure	5%
Number of pressure ulcers avoided	48
Additional cost of surfaces	£3314
Pressure ulcer treatment costs avoided	£64 199
Net impact (cost savings)	£60 885

Based on this illustrative analysis, the adoption of high‐specification surfaces for only a small proportion (15%) of the population at risk of developing pressure ulcers can lead to the avoidance of 48 pressure ulcers. The additional acquisition cost of the high‐specification surfaces is £3314. However, the cost savings resulting from the avoidance of pressure ulcers is estimated to be £64 199. Therefore, the net impact to the health service is £60 885 suggesting that allocating a proportion of at‐risk patients to high‐specification surfaces is an effective use of health service resources.

Limitations of the case study

Clearly, the findings presented above are illustrative. The analysis combines data from a number of sources to generate an estimate of the impact on hospital finances and this inevitably introduces some degree of uncertainty into the analysis. For example, the effectiveness data are derived from multiple studies which may not be directly comparable and did not always clearly report the exact nature of the surfaces included.

Secondly, it should be acknowledged that the predicted ‘savings’ for the hospital resulting from adopting high‐specification surfaces may not be realisable in practice, that is the financial predictions may not be cash‐releasing. For example, many of the savings in terms of practitioner time are likely to result in re‐allocation of staff rather than result in cash savings. However, these efficiency savings should not be disregarded as they present the opportunity to re‐allocate staff to activities that may be more productive or generate additional revenues for a hospital. Furthermore, estimates of the cost of treating a pressure ulcer used in the analysis include both primary and secondary care costs so any savings may accrue to multiple organisations across the local health economy, rather than the hospital. However, health care planners are increasingly conscious of matters of efficiency, and the avoidance of extended stays and the potential impact on throughput is to be welcomed.

CONCLUSION

Best practice guidelines for the management of pressure ulcers include a series of recommendations on the use of pressure relieving surfaces to help prevent the development of pressure ulcers. The clinical and economic evidence on pressure relieving surfaces is far from definitive. However, a number of well‐designed studies have shown that pressure relieving surfaces can help to reduce the development of pressure ulcers in at‐risk patients in hospital settings. Based on this, the emerging clinical opinion is that judicial use of pressure relieving surfaces in hospital settings is recommended.

Pressure relieving surfaces are significantly more costly than standard foam mattresses. As such, it is important that health care payers consider whether these surfaces represent an efficient use of health care resources. The economic evidence that is available supports the use of high‐specification surfaces over standard foam mattresses in patients at risk of developing a pressure ulcer. Furthermore, the illustrative case study presented herein suggests that selective use of pressure relieving surfaces in the at‐risk population can lead to reductions in the number of ulcers occurring and the costs associated with treatment. The case study is intended to acknowledge that not all patients admitted to hospitals will require a high‐specification surface but rather that such surfaces are best targeted to those individuals with pre‐existing risk factors.

This review has identified that further research is warranted in two particular areas. Firstly, direct comparisons of high‐specification surfaces would help to ensure that resources are allocated efficiently. Secondly, health care professionals working in wound management are encouraged to work with payers to help establish how patients can be assessed for their risk of developing pressure ulcers upon admission and allocated to an appropriate surface. Addressing these points offers the potential to reduce patient morbidity whilst simultaneously improving health service efficiency.

ACKNOWLEDGEMENTS

The review and development of the financial model were supported by KCI Europe.