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Clinical activity-based cost effectiveness of traditional versus modern wound management in patients with pressure ulcers |
Ohura T, Sanada H, Mino Y |
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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 Three alternative strategies for the management of pressure ulcers were examined. The strategies were:
wound treatment with modern dressings that maintain a moist environment in combination with a standardised wound management algorithm (MC/A);
wound treatment with traditional dressings (ointment and gauze) in combination with a standardised wound management algorithm (TC/A);
wound treatment with traditional dressings (ointment and gauze) without a standardised wound management algorithm (TC/NoA).
Potential materials used with modern and traditional dressings were listed.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients with Stage II and III pressure ulcers.
Setting The setting was a hospital. The economic study was carried out in Japan.
Dates to which data relate The effectiveness and resource use data were gathered from August 2001 to April 2002. The price year was not reported (Note: correspondence with the authors has indicated that "the clinical test data were gathered from August 2001 to April 2002...." and "the cost calculation was based on costs recorded during this period".
Source of effectiveness data The effectiveness evidence was derived from a single, multi-centred study.
Link between effectiveness and cost data The costing was performed prospectively on the same sample of patients as that used in the effectiveness study.
Study sample Power calculations were not reported. Of the 91 patients initially enrolled, 8 dropped out (for reasons that were not described). Therefore, the final study sample comprised 83 patients. There were 29 patients (18 Stage II and 11 Stage III) in the MC/A group, 34 patients (13 Stage II and 21 Stage III) in the TC/A group, and 20 patients (10 Stage II and 10 Stage III) in the TC/NoA group. The mean age was 76.8 years (age range: 41 - 96). There were 48 male patients (58%). The average Pressure Sore Status Tool (PSST) score at enrolment was 26.9 in the MC/A group, 29.8 in the TC/A group, and 31.5 in the TC/NoA group.
Study design This was a prospective cohort study that was carried out in 13 centres. The maximum length of follow-up was 12 weeks. It appears that no loss to follow-up was observed. Prevention measures were the same in all three groups, and always included special mattresses. The staff involved in the study underwent extensive training to ensure in-study consistency. In addition, quality control conditions were maintained.
Analysis of effectiveness The analysis of the clinical study was limited to those patients who did not drop out of the study. The primary outcome measure used was the change in PSST, which identified the rating of pressure ulcers and their level of severity at baseline and at final assessment. The PSST score comprised 13 characteristics of pressure ulcers, each rated on a 5-grade scale (maximum score 65; minimum score 13, no ulcer). The study groups were comparable at baseline in terms of age, size of ulcers, first day PSST score, and the estimated risk of developing pressure ulcers.
Effectiveness results The reduction in PSST score in the whole sample was 11.1 points with MC/A, 6.9 points with TC/A, and 9.0 points with TC/NoA.
Statistical significance was observed between the MC/A and TC/A groups, (p=0.046).
When Stages II and III ulcers were analysed separately, the MC/A managed patients showed better results but no statistically significant difference was observed, probably due to the lack of power of the reduced sample size.
Clinical conclusions The effectiveness analysis showed that the MC/A strategy was more effective than the TC/A strategy in reducing pressure ulcer PSST scores. A trend toward better outcomes with the TC/A strategy than with the TC/NoA strategy was also observed.
Measure of benefits used in the economic analysis The summary benefit measure was the change in PSST. This was derived directly from the effectiveness study.
Direct costs Discounting was not relevant because of the short timeframe of the study (12 weeks). The unit costs were not presented separately from the quantities of resources used. The health services included in the economic evaluation were materials (dressings, supplementary materials, and pharmaceutical agents) and staff time (physicians, nurses, assistant nurses, and care-workers). General pressure ulcer care was included in the three protocols. The cost/resource boundary of the study was that of the hospital. The costs were estimated directly from the participating institution using an activity-based costing methodology. When cost estimates were not available, representative market prices were used. A specific formula was used to calculate labour costs on the basis of monthly wages. Resource use was derived from patient-level, prospectively collected data, which were gathered from August 2001 to April 2002 and the costs were also from this period.
Statistical analysis of costs A statistical analysis was performed to test the significance of differences in the estimated costs.
Indirect Costs The indirect costs were not included in the economic evaluation.
Currency Japanese yen (Y) and US dollars ($). The conversion rate was Y 120.00 = US$ 1.00.
Sensitivity analysis Sensitivity analyses were not carried out.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The average total costs in the whole sample were Y 87,715 ($730.96) with the MC/A strategy, Y 131,283 ($1,094.03) with the TC/A strategy, and Y 200,584 ($1,671.53) with the TC/NoA strategy.
The difference between the MC/A and TC/NoA strategies was statistically significant.
Similar trends were also observed in the sub-group of Stage II ulcers, but the differences did not reach statistical significance because of the small sample size. However, significant differences between the MC/A and TC/NoA strategies were noted in the sub-group of Stage III ulcers.
Similar results were observed when the total costs were broken down into the two main components, materials and labour.
The author estimated that, in a typical hospital of 300 beds, with an occupancy rate of 90% and an ulcer prevalence of 5.8%, the savings of managing patients with MC/A compared with TC/NoA could be up to Y 2,483,118 ($20,692.65) per year.
Synthesis of costs and benefits The average cost-effectiveness ratios were calculated to combine the costs and benefits of the management protocols under evaluation. The ratio was expressed as the PSST units difference per yen spent (V).
When the whole sample of patients was considered, V was 0.127 with the MC/A strategy, 0.052 with the TC/A strategy, and 0.045 with the TC/NoA strategy.
The difference between the MC/A and TC/NoA strategies was statistically significant, (p=0.044).
In the sub-group of patients with Stage II ulcers, V was 0.173 with the MC/A strategy, 0.12 with the TC/A strategy, and 0.090 with the TC/NoA strategy. None of the differences in the Stage II ulcer subset reached statistical significance.
In the sub-group of patients with Stage III ulcers, the values of V were 0.081 (MC/A), 0.032 (TC/A), and 0.025 (TC/NoA), respectively. All differences in the Stage III subset were statistically significant.
Authors' conclusions For the management of patients with pressure ulcers in Japan, the strategy of modern wound dressings combined with a wound management algorithm (MC/A) was more effective and more cost-effective than traditional dressing protocols, with or without a standardised wound care algorithm.
CRD COMMENTARY - Selection of comparators The selection of the comparators appears to have been appropriate, as the three protocols under evaluation represented three alternative management strategies currently implemented at the study centres. You should decide whether they represent valid comparators in your own setting.
Validity of estimate of measure of effectiveness The effectiveness evidence came from a prospectively conducted cohort study. The lack of random allocation of the patients to study groups could have introduced some bias and confounding factors. However, the study groups were comparable and were well balanced at baseline. Limited information on the follow-up was provided, and the authors did not provide any explanation for the drop-out of 8 patients. The main limitation to the internal validity of the study was the small sample size, and the fact that no power calculations had been performed in the preliminary phase of the study to determine an appropriate size for the sample. A positive aspect of the study was the multi-centre design.
Validity of estimate of measure of benefit The summary benefit measure was specific to the interventions considered in the study and would be difficult to compare with the benefits of other health care interventions. The impact of the protocols on the patients' quality of life was not investigated.
Validity of estimate of costs The authors did not state explicitly which perspective was adopted in the study. It appears that the costs relevant to the hospital have been included in the analysis. Information on the unit costs, quantities of resources used, and price year was not provided, thus limiting the possibility of replicating the study and reflating the results of the analysis in other settings. The source of the data was clearly reported, and standard statistical analyses of the costs were performed to determine the significance of cost-differences. However, the cost estimates were specific to the study setting and no sensitivity analyses were performed. The authors stressed that all relevant resources involved with the provision of care for the management of pressure ulcers were included in the analysis.
Other issues The authors did not compare their findings with those from other studies. It was stated that the analysis focused on the Japanese setting, thus caution is required when extrapolating the current results to other settings. However, the costing approach used in the study could be easily used in other economic evaluations. Sensitivity analyses were not performed, which limits the external validity of the analysis. The study referred to patients with Stage II and III pressure ulcers and this was reflected in the authors' conclusions. The authors calculated the average cost-effectiveness ratios for the MC/A, TC/A and TC/NoA strategies, but an incremental analysis would have suggested that MC/A was the dominant strategy.
Implications of the study The study results suggested that using the MC/A strategy instead of traditional dressings would result in substantial savings in the costs of managing pressure ulcers. In addition, owing to the projected rising number of bedridden elderly people in Japan, it is likely that such savings could potentially increase over time.
Source of funding Supported by ConvaTec, Bristol-Myers Squibb Company, Princeton (NJ), USA.
Bibliographic details Ohura T, Sanada H, Mino Y. Clinical activity-based cost effectiveness of traditional versus modern wound management in patients with pressure ulcers. Wounds 2004; 16(5): 157-163 Other publications of related interest Lyder CH, Shannon R, Empleo-Frazier O, et al. A comprehensive program to prevent pressure ulcers in the long-term care: exploring costs and outcomes. Ostomy/Wound Management 2002;48:52-62.
Xakellis GC, Chrischilles EA. Hydrocolloid versus saline gauze dressing in treating pressure ulcers: a cost-effectiveness analysis. Archives of Physical Medicine and Rehabilitation 1992;73:463-6.
Indexing Status Subject indexing assigned by NLM MeSH Algorithms; Comparative Study; Cost-Benefit Analysis; Costs and Cost Analysis; English Abstract; Health Care Costs; Humans; Occlusive Dressings /economics; Pressure Ulcer /economics /therapy AccessionNumber 22004000743 Date bibliographic record published 31/05/2005 Date abstract record published 31/05/2005 |
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