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The economics of preventing and treating pressure ulcers: a pilot study |
Thomson J S, Brooks R G |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology A potential prevention programme in patients with pressure ulcers. The prevention programme would consist of additional specialist preventative equipment and access to a specialist tissue viability nurse.
Type of intervention Secondary prevention; treatment.
Economic study type Cost-effectiveness analysis.
Study population Patients presenting with pressure ulcers (geriatric inpatients).
Setting Hospital. The economic analysis was conducted in Glasgow, UK.
Dates to which data relate Effectiveness data were taken from a 1994 published study covering a one-year period starting from 1 April 1990, alongside prevalence and incidence rates calculated based on a single study performed in the study hospital in 1995. The data collection dates for resource use data were not reported. The price year was not explicitly specified.
Source of effectiveness data Data on the prevalence and incidence of pressure ulcers were estimated by the authors using a point prevalence survey and incidence study at the study hospital. Information on preventable ulcers was identified from a single study published in 1994. The effectiveness of current care, as the comparator, was based on the authors' assumptions.
Link between effectiveness and cost data Costing for severe ulcer was performed on one patient in the infirmary (not in the geriatric unit) who presented with a severe ulcer (Grade 4) prior to the pilot study. The costing for the prevention programme was based on assumptions made by the authors.
Study sample Power calculations were used to determine the sample size. There were 638 patients in the study: 525 in the prevention group who did not have or develop pressure-related tissue injury, and 113 in the therapy group who were admitted with or developed a sore.
Study design This was a prospective cohort study, carried out in a single centre. The time frame of the study was 1 year with a mean length of stay of 3.9 days, ranging from two hours to 45 days. Loss to follow-up was not reported. The initiation of the pressure injury prevention and treatment programme was based on consultation with the sister or charge nurse and other members of the multidisciplinary intensive care unit (ICU) team.
Analysis of effectiveness The principle (intention to treat or treatment completers only) used in the analysis of effectiveness was not explicitly specified. The clinical outcome measure was the effectiveness rate of the prevention programme in terms of the percentage of patients who developed sores in the ICU and who did not already have a sore on admission (the incidence of pressure sores for those who did not already have a sore on admission to the ICU). The Acute Physiology and Chronic Health Evaluation System (APACHE II) was used to measure severity of illness on admission. Pearson's r test was used to test the correlation between APACHE II score and the incidence of pressure sores.
Effectiveness results The effectiveness rate of the prevention programme was 95%. Only 5% (n=31) of the patients who did not already have a sore on admission to the ICU developed sores in the ICU. The correlation between severity of illness on admission as measured by APACHE II score and the incidence of pressure sores was r=0.91, (p=0.029).
Clinical conclusions The active pressure injury prevention programme was effective in all but 31 (5%) of the study population who did not have a pressure sore on admission to the ICU. The multifactorial etiology of pressure injury and the complicated pathologies of critically ill patients make a certain proportion of pressure-related tissue trauma inevitable despite the most militant preventive efforts.
Methods used to derive estimates of effectiveness Estimates of effectiveness were also made by the authors.
Estimates of effectiveness and key assumptions The authors made the assumption that current care would not prevent any ulcers.
Measure of benefits used in the economic analysis The benefit measure was pressure ulcers avoided. The authors conducted a prevalence and incidence study at the study hospital in order to identify patients who developed pressure ulcers during their hospital stay. This would then indicate the number of pressure ulcers that might be avoided by an aggressive prevention programme. Weekly information was collected on patients in two wards over a 12 week period, using questionnaires provided by the Scottish Audit Study for Pressure Area Care.
Direct costs Costs were not discounted, which seems appropriate given the short time frame of the study. Some quantities were reported separately from the costs. Cost items were reported separately. Direct costs associated with care of pressure ulcers and the costs of a hospital-based prevention programme were estimated. Costs were estimated following prior observation of one patient with a severe (Grade 4) ulcer at the study hospital. Specific costs included in the analysis consisted of nursing staff time for wound dressing and patient turning, specialist tissue viability nursing time, material costs, pharmaceuticals, dietary supplements, and pressure relieving equipment costs (including maintenance, laundry, and a finance charge of 12% of the purchase price). A tissue viability nurse provided estimates of nursing staff time required for wound dressing and patient turning. Costs were estimated from the perspective of the Scottish National Health Service. The date of the price data was not explicitly specified. Overhead costs were not included in the cost analysis. The cost analysis also did not cover the costs of transportation for patients, relatives and friends; and the costs of educating and training staff (especially nurses) in the appropriate prevention and treatment of pressure ulcers.
Indirect Costs Costs were not discounted, which appears appropriate given the short time frame of the study. Costs of leisure and working time lost by patients as a result of additional hospitalisation for pressure ulcer treatment were estimated. The perspective adopted in the cost analysis was that of society (societal valuation of the time lost due to additional hospitalization). The value of leisure time lost was assumed to be 43% of average earnings based on UK Department of Transport calculations. It was assumed that 4 hours per day of leisure time would be lost for each additional day of treatment for patients who developed pressure ulcers, whilst in hospital. Leisure time loss was estimated for total hospital stay for patients admitted to hospital with a pressure ulcer. The date of the price data was not explicitly specified. Indirect cost analysis did not cover intangible costs such as pain, distress, loss of dignity, and the possibility of losing normal social support networks due to an increased length of in-patient stay.
Sensitivity analysis One-way sensitivity analysis was performed on time limits for nursing activities using lower and upper time limits.
Estimated benefits used in the economic analysis Based on the population at the study hospital and the effectiveness rate from the study published in 1994, it was estimated that 42.75% (42 cases, four of which were expected to have been severe without the prevention programme) of all ulcers developing on a daily basis could be avoided. The authors made the assumption that current care would not prevent any ulcers.
Cost results Total annual costs of current care at the study hospital were estimated to range between 749,403 and 851,211, whilst costs for the prevention programme were estimated to range between 443,697 and 508,711. This represents a potential reduction in overall costs of between 305,706 and 342,510 per annum.
Synthesis of costs and benefits A synthesis of costs and benefits was not performed by the authors as the introduction of a prevention programme would reduce both the incidence of pressure ulcers and costs.
Authors' conclusions The pilot study indicated that it is possible to undertake economic analysis to evaluate interventions to improve the management of pressure ulcers.
CRD COMMENTARY - Selection of comparators The reason for the choice of the comparator (current care) is clear.
Validity of estimate of measure of benefit The internal validity of the estimate of benefit cannot be guaranteed given the conservative assumption made by the authors regarding the ineffectiveness of the current care in preventing new cases of pressure ulcers, and the fact that, as the authors acknowledged, the incidence study was conducted over a period of less than 1 year which may have led to underestimation of the number of pressure ulcers.
Validity of estimate of costs Some quantities were reported separately from the costs and adequate details of the methods of cost estimation were provided. The base price year used in the analysis was not reported. As noted by the authors other costs should be included in a full economic appraisal including travel costs for patients and families, and training for staff.
Other issues The results of the analysis may not be generalisable to other settings or countries. Appropriate comparisons were not made with other studies, perhaps, because this pilot study aimed to establish the feasibility of the economic appraisal in the context in question. As acknowledged by the authors, a cost-utility analysis may have been a more appropriate framework for the context in question.
Implications of the study Future well-designed randomized controlled trials in the framework of a cost-utility analysis are required to estimate both the potential benefits and cost implications associated with management strategies for treatment and prevention of pressure ulcers.
Bibliographic details Thomson J S, Brooks R G. The economics of preventing and treating pressure ulcers: a pilot study. Journal of Wound Care 1999; 8(6): 312-316 Indexing Status Subject indexing assigned by NLM MeSH Aged; Cost Savings; Cost-Benefit Analysis; Health Care Costs /statistics & Humans; Incidence; Pilot Projects; Pressure Ulcer /economics /epidemiology /prevention & Prevalence; Primary Prevention /economics /methods; control; numerical data AccessionNumber 21999007769 Date bibliographic record published 30/09/2000 Date abstract record published 30/09/2000 |
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