Cost-utility analysis comparing free and pedicled TRAM flap for breast reconstruction Thoma A, Khuthaila D, Rockwell G, Veltri K

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1 Cost-utility analysis comparing free and pedicled TRAM flap for breast reconstruction Thoma A, Khuthaila D, Rockwell G, Veltri K 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 the free TRAM (transverse rectus abdominis myocutaneous) flap versus the unipedicled TRAM flap in postmastectomy reconstruction. Type of intervention Treatment. Economic study type Cost-utility analysis. Study population The hypothetical study population comprised 45-year-old women with an expected life span of 78.6 years following mastectomy for cancer. Setting The setting was secondary care. The economic analysis was conducted in Ontario, Canada. Dates to which data relate The effectiveness and cost data were gathered from studies published between 1989 and The price year was Source of effectiveness data The effectiveness data were derived from a review of the literature. Modelling A decision analytic model was used to compare the costs and utilities for unipedicled and free TRAM flaps. Following the surgery, there were two "chance" events, success or complications. The seven complications reported in the literature were hernia, abdominal wall weakness, total flap loss, partial skin necrosis, fat necrosis, haematoma and infection. Short-term complications were modelled and the time horizon of the model was until death at the expected life expectancy of Outcomes assessed in the review The outcomes assessed in the review and used as model inputs were the probability of surgery success, and the probabilities of various complications of free TRAM and unipedicled TRAM flaps. Page: 1 / 5

2 Study designs and other criteria for inclusion in the review Randomised controlled trials, comparative studies, cost-effectiveness studies and cost studies were all included in the review. Sources searched to identify primary studies The Cochrane Library and MEDLINE were searched. Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Number of primary studies included Twelve primary studies were included in the analysis. Methods of combining primary studies Investigation of differences between primary studies Results of the review The probability of success was after a free TRAM flap and after an unipedicled TRAM flap. The probabilities of each complication after a free TRAM flap were: for hernia; for abdominal wall weakness; for total flap loss; for partial skin necrosis; for fat necrosis; for haematoma; and for infection. The probabilities of each complication after an unipedicled TRAM flap were not reported. The probabilities reported in the decision tree were different to those reported in the table of literature estimates. It was not clear how these related to each other. Measure of benefits used in the economic analysis The benefit measure was the number of quality-adjusted life-years (QALYs) saved. Utility estimates were obtained Page: 2 / 5

3 from experts' opinion. A questionnaire was sent to 58 plastic surgeons, of which 33 responded. The questionnaire utilised a visual analogue scale. The benefits were not discounted. Direct costs The perspective of the Ministry of Health for the province of Ontario was adopted. Only the direct medical costs were included. These were for the surgeons and anaesthetists, the operating room and hospital. The surgeons and anaesthetists' fees were derived from the Ontario Ministry of Health Schedule of Benefits (OMHSB). The operating room and hospital costs were obtained from Budgeting Services at St. Joseph's Healthcare. The resource quantities and the costs were not reported separately. The price year was Discounting was unnecessary since the follow-up period was one year. Statistical analysis of costs The costs were treated deterministically. Indirect Costs The indirect costs were not included in the analysis. Currency Canadian dollars (Can$). Sensitivity analysis Two one-way sensitivity analyses were performed. In one, the Ontario costs were substituted with those of two other Canadian provinces, New Brunswick and Alberta. In the other, the probability of total flap failure in the free TRAM flap technique was increased (3.5, 10 and 15%). The authors noted that these were plausible rates. Estimated benefits used in the economic analysis The QALYs for each health outcome were reported. However, the summary, expected QALYs for for all the modelled health outcomes for free TRAM and unipedicled TRAM flaps were not reported. The number of QALYs gained with the free TRM flap was 0.54 compared with the unipedicled TRAM flap. Cost results The mean costs in each health state were reported. However, the total costs for free TRAM and unipedicled TRAM flaps were not reported. The additional cost of the free TRAM flap was Can$2, compared with the unipedicled TRAM flap. Synthesis of costs and benefits The incremental cost of the free TRAM flap was Can$5, per QALY gained compared with the unipedicled TRAM flap. The incremental cost-effectiveness ratio (ICER) was Can$5, per QALY gained for the province of New Brunswick and Can$5, per QALY gained for the province of Alberta. By increasing the free flap failure to 10 or 15%, the ICER was Can$5, per QALY gained or Can$6, per QALY gained, respectively. Page: 3 / 5

4 Authors' conclusions The free TRAM (transverse rectus abdominis myocutaneous) flap is a cost-effective procedure for postmastectomy reconstruction in the Canadian healthcare system. CRD COMMENTARY - Selection of comparators The comparators used were justified on the grounds that they represented the most commonly used autogenous tissue techniques in breast reconstruction in the authors' setting. However, the recent technique, deep inferior epigastric pedicled perforator flap, could have been evaluated, even if its widespread acceptance has not yet been evaluated. There were also other relevant alternatives that may be of interest. You should consider whether these are widely used technologies in your own setting. Validity of estimate of measure of effectiveness The principal input parameters for the model were derived from published studies. The review seems to have been conducted systematically to identify relevant research and minimise biases. However, the authors did not report the methods used to judge the relevance of the data or to combine the primary studies. In addition, the probabilities of various complications were not investigated in a sensitivity analysis. Moreover, the probabilities reported in table 2 and in figure 3 were different. These facts limit the relevance of the data used. Validity of estimate of measure of benefit The estimation of benefits was modelled. The decision analysis model used to derive a measure of heath benefit was appropriate. The reader should decide whether the time horizon (1 year) for evaluating the complications was sufficient. The authors derived utility weights for calculating QALYs using experts' opinion. The authors acknowledged that utilities should, theoretically, be derived from mastectomy and reconstruction patients. However, they justified their approach noting that the surgical literature seems to favour using experts when evaluating novel techniques. The reader should decide whether this approach may limit the validity of the benefit estimates. Validity of estimate of costs The perspective of the Ministry of Health was adopted and only the direct costs were introduced in the study. The costs and the quantities were not reported separately, but details of cost items included in the cost analysis were given. The price year was unclear. These issues affect the generalisability of the results. The cost estimates were treated deterministically. The source of the cost data was reported. Sensitivity analyses were performed. Only the mean costs were reported. The authors noted that the lengths of hospitalisation may appear excessive, but they did not perform a sensitivity analysis. This may limit the relevance of the analysis. Other issues The generalisability of the results was not addressed. The findings were not compared with those of other studies, as no prior studies have evaluated both the effectiveness and costs of TRAM flaps. The authors did not report any further limitations of their study. They do not appear to have reported their results selectively. Implications of the study The authors recommended that a randomised controlled trial comparing free and unipedicled TRAM flaps be undertaken, with parallel cost collection. Bibliographic details Thoma A, Khuthaila D, Rockwell G, Veltri K. Cost-utility analysis comparing free and pedicled TRAM flap for breast reconstruction. Microsurgery 2003; 23(4): PubMedID Page: 4 / 5

5 Powered by TCPDF ( DOI /micr Other publications of related interest Serletti JM, Moran SL. Free versus the pedicled TRAM flap: a cost comparison and outcome analysis. Plastic and Reconstructive Surgery 1997;100: Indexing Status Subject indexing assigned by NLM MeSH Cost-Benefit Analysis; Costs and Cost Analysis; Decision Support Techniques; Female; Hospital Costs /statistics & numerical data; Humans; Mammaplasty /economics /methods; National Health Programs /economics; Ontario; Quality- Adjusted Life Years; Surgical Flaps /economics AccessionNumber Date bibliographic record published 31/07/2004 Date abstract record published 31/07/2004 Page: 5 / 5