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Healing pressure ulcers with collagen or hydrocolloid: a randomized, controlled trial |
Graumlich J F, Blough L S, McLaughlin R G, Milbrandt J C, Calderon C L, Agha S A, Scheibel L W |
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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 The use of topical type I collagen dressing (daily) for the treatment of Stage II or III pressure ulcers.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised individuals with at least one Stage II or III pressure ulcer, as defined by the National Pressure Ulcer Advisory Panel. The patients had to be older than 18 years of age and be resident in nursing facilities. There were extensive exclusion criteria, including hypersensitivity to collagen, concomitant investigational therapy, osteomyelitis, cellulitus, malnutrition, burn ulcers and diabetic foot ulcers.
Setting The setting was an institution. The economic study was carried out in Illinois, USA.
Dates to which data relate The effectiveness and resource use data related to 2000 to 2001. The price year was not stated, but may be inferred to relate to the study year.
Source of effectiveness data The effectiveness data were derived from a single study.
Link between effectiveness and cost data The costing was not undertaken on the same patient sample as that used in the effectiveness study. Instead, it was based on standardised treatment protocols.
Study sample The sample size was determined using power calculations for categorical variables. The sample size was determined with 80% power and a two-sided alpha of 0.05, with the assumption that a 24% difference in healing rates was clinically important. The estimated sample size was 128 patients, based on 58 patients per group after allowing for a 10% dropout rate. Nursing home nurses determined whether the patient was eligible. Eighty patients were assessed for eligibility. Fifteen of these were excluded (1 refused consent, 6 multiple debridements, 5 healed before baseline, 3 ulcers were Stage I). The final sample size was therefore 65 patients, with 30 allocated to hydrocolloid and 35 allocated to collagen. The mean age of the patients was 80.6 (+/- 12.2) in the hydrocolloid group and 82.0 (+/- 9.9) years in the collagen group.
Study design The study was a multi-centre randomised controlled trial. The patients were allocated to the groups by block randomisation, stratified by the presence of diabetes mellitus. Follow-up was for 8 weeks. Two patients were lost to follow-up, both from the hydrocolloid group. The outcome assessors were blinded to the treatment assignment.
Analysis of effectiveness The analysis of effectiveness was conducted on an intention to treat basis. The primary health outcome was the proportion of ulcers healed within 8 weeks of randomisation. The secondary outcomes were the area healed per day and linear healing of the wound edge. Efficacy was assessed using ulcer photography. There were no significant differences between the groups at baseline, although this might have been because of a lack of power to detect such differences. The authors acknowledged that ulcer duration and area appeared different at baseline.
Effectiveness results The healing rate was 51% in the collagen group and 50% in the hydrocolloid group. This gave a difference in healing rates of 1% (95% confidence interval: -26 - 29; p=0.893). The secondary outcomes were not significantly different, (p>0.5).
There were no adverse events that were judged to be related to the study interventions.
Clinical conclusions The authors concluded that there were no significant differences in healing outcomes with collagen in patients otherwise eligible for hydrocolloid treatment.
Modelling The cost per ulcer dressing was determined using the authors' standardised treatment protocols. This was extrapolated by multiplying by the number of dressing changes per week and the duration of treatment (8 weeks).
Measure of benefits used in the economic analysis No summary measure of health benefit was used. In effect, a cost-consequences analysis was performed.
Direct costs The resource use quantities were not reported separately from the costs. The costs included those to a nursing home facility. These were the acquisition cost of the ulcer dressings, the labour cost and the cost of ancillary supplies per dressing change. The labour costs were estimated from a survey of nursing homes. The acquisition costs were based on wholesale prices. The other resource use was modelled according to the authors' standardised treatment protocols. Discounting was not relevant as the study period was less than one year. The study reported the average cost per patient. The date to which the price data referred was not stated.
Statistical analysis of costs The costs were treated as point estimates. This ignores any uncertainty or variability in the costs.
Indirect Costs The indirect costs were not included in the analysis.
Sensitivity analysis The authors stated that sensitivity analyses were undertaken, but no further details were given. They stated that no sensitivity analyses favoured collagen.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The average cost per patient of treating Stage II or III pressure ulcers for 8 weeks was $627.56 with collagen and $222.36 with hydrocolloid. The costs of adverse events were not relevant as none were recorded.
Synthesis of costs and benefits Authors' conclusions Collagen is more expensive than hydrocolloid for treating pressure ulcers, but demonstrates no additional clinical benefits.
CRD COMMENTARY - Selection of comparators The choice of the comparator was justified as it is a standard treatment in the study setting. You should determine whether hydrocolloid dressings are widely used to treat pressure ulcers in your own setting.
Validity of estimate of measure of effectiveness A randomised controlled trial was appropriate for addressing the study question. The authors did not describe whether the study sample was representative of the study population, but this is likely to have been the case. The patient groups were shown to have no statistically significant differences at analysis, although this might have been because of a lack of power to detect such differences (the final sample size was lower than that required by the power calculation). The authors stated that the patient groups did not appear balanced at analysis, so they conducted adjusted post-hoc analyses to examine the potential differences between these groups.
Validity of estimate of measure of benefit The authors did not derive a summary measure of health benefit. Therefore, the study was, in effect, a cost-consequences analysis.
Validity of estimate of costs It is not possible to ascertain whether the study included all the costs relevant to the perspective adopted, because resource use was based on authors' standardised treatment protocols rather than actual practice. The use of actual treatment patterns in the same study sample as the effectiveness analysis would have reduced uncertainty about the appropriateness of the costs used. The costs and the quantities were not reported separately, which may limit the generalisability of the study results. However, the unit costs for each resource were clearly reported. The authors gave no details about the sensitivity analyses they conducted. Labour costs and time were derived from a survey in the authors' setting, although details of the methodology of the survey were not provided. Other costs were based on wholesale prices in the authors' setting. The authors acknowledged that the study costs may not be generalisable beyond an Illinois setting. You must consider whether the costs in the study setting are comparable to those in your own setting.
Other issues The authors made appropriate comparisons of their findings with those from other studies. The issue of generalisability to other settings, such as inpatient or home care, was addressed. The authors do not appear to have presented their results selectively and their conclusions reflected the scope of the analysis. The authors acknowledged that the method of blinding the outcome assessors prevented the use of exudate and slough as study outcomes. They also acknowledged that the study had insufficient statistical power to detect equivalence between the treatments.
Implications of the study The principal finding was that hydrocolloid is the preferred choice. However, the authors suggested that further research, to assess the cost-effectiveness of collagen in comparison with hydrocolloid in deep Stage III pressure ulcers, is required. They also suggested that future trials should stratify by initial ulcer depth or stage.
Bibliographic details Graumlich J F, Blough L S, McLaughlin R G, Milbrandt J C, Calderon C L, Agha S A, Scheibel L W. Healing pressure ulcers with collagen or hydrocolloid: a randomized, controlled trial. Journal of the American Geriatrics Society 2003; 51(2): 147-154 Indexing Status Subject indexing assigned by NLM MeSH Aged; Aged, 80 and over; Collagen /economics /therapeutic use; Colloids /economics /therapeutic use; Costs and Cost Analysis; Female; Humans; Male; Pressure Ulcer /drug therapy /economics; Single-Blind Method AccessionNumber 22003000318 Date bibliographic record published 31/05/2005 Date abstract record published 31/05/2005 |
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