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Cost-effectiveness analysis of different embryo transfer strategies in England |
Dixon S, Faghih Nasiri F, Ledger W L, Lenton E A, Duenas A, Sutcliffe P, Chilcott J B |
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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. CRD summary The study assessed the cost-effectiveness of different embryo transfer strategies (single or double, fresh or frozen) for a single cycle, when two embryos are available, in women undergoing in vitro fertilisation. The cost-effectiveness of these options depended on maternal age, relevance of a single embryo transfer option, the value that society places on a live birth, and the impact of adverse outcomes. The study methodology appears to be good and the authors’ conclusions are likely to be valid. Type of economic evaluation Cost-effectiveness analysis Study objective The objective was to assess the cost-effectiveness of different embryo transfer strategies (single or double, fresh or frozen), for a single cycle, when two embryos are available, in three age groups (under 30 years, 30 to 35 years, and 36 to 39 years) of women undergoing in vitro fertilisation (IVF). Interventions The three strategies compared were single embryo transfer (SET), double embryo transfer (DET), and SET plus frozen SET (fzSET). A single cycle of IVF was considered. Location/setting UK/secondary care (fertility centre). Methods Analytical approach:A decision analytic model was developed to assess the clinical and economic impact of the different strategies. The time horizon of the analysis was five years and the authors stated that the perspective of the UK National Health Service (NHS) was adopted.
Effectiveness data:The clinical data appear to have been derived from a selection of known, relevant, mainly observational studies. Specifically, birth outcomes were derived from five fertility centres covering 5,508 fresh cycles and 1,295 frozen cycles. Given the low numbers available from these centres, birth rates for SET and SET plus fzSET were calculated by fitting a published model to the DET and frozen DET regional data. Rates of adverse events were taken from a published study, the details of which were not provided.
Monetary benefit and utility valuations:None.
Measure of benefit:The summary benefit measure was the rate of live birth following a transfer. This outcome was estimated using the decision model. The rate of adverse events was also considered, including the number of multiple births, premature births, cerebral palsy, and neonatal intensive care unit admissions.
Cost data:The health services were those associated with frozen and fresh transfer cycles, maternal and paediatric care (for singleton, twins, and triplets), and intensive care for mothers and babies. A breakdown of cost items was not given. The costs and quantities were mainly derived from six local providers and these figures were then adjusted using updated reference costs. The costs were expressed in UK pounds sterling (£) at 2003 to 2004 prices. A 3.5% annual discount rate was applied when appropriate.
Analysis of uncertainty:A probabilistic sensitivity analysis was undertaken by assigning probabilistic distributions to model inputs. Cost-effectiveness acceptability curves were generated. Results For women under 30 years, the live birth rate was 0.171 with SET, 0.243 with SET plus fzSET, and 0.308 with DET. The costs were £3,435 with SET, £4,771 with SET plus fzSET, and £5,435 with DET. The ranking of the alternatives did not change in the other age groups, although lower live birth rates were observed with increasing age.
For the under 30 year group, the incremental cost per additional live birth was £18, 463 with SET plus fzSET over SET, and £10,339 with DET over SET plus fzSET. For the 30 to 35 year group, the findings were very similar. For the 36 to 39 year group, however, DET dominated SET plus fzSET, and its incremental cost per live birth over SET was £11,959.
In general, DET provided better results than SET plus fzSET in terms of incremental cost per live birth, which was weekly dominated for all age groups. However, DET was associated with much higher adverse events compared with SET and SET plus fzSET. For example, in the under 30 year group, the cumulative premature births per 1,000 was 21 with SET, 31 with SET plus fzSET, and 66 with DET.
The probabilistic sensitivity analysis suggested that SET plus fzSET was not a cost-effective option at any threshold, while the cost-effectiveness of DET compared with SET depended on the value given to an additional live birth. Authors' conclusions The authors could not draw any definitive conclusion on the preferred embryo transfer strategy, since the cost-effectiveness of these options depended on several factors such as maternal age, relevance of a SET option, the value that society places on a live birth, and the impact of adverse outcomes. CRD commentary Interventions:The choice of the three strategies was appropriate as they were the relevant options in the authors’ setting.
Effectiveness/benefits:The approach used to identify primary studies was not described. However, the authors' justification for the selection of observational studies, rather than randomised clinical trials (RCTs), to derive clinical inputs for the model, was that they were more representative of the patient groups in the UK population. The use of these data should ehance the external validity of the analysis. In addition, observational data were used for DET (where there is little selection bias) and then these data were used to derive birth rates for SET, which appears to be an appropriate approach. The summary benefit measure reflects a typical end point of IVF programmes.
Costs:The categories of costs were relevant from the perspective of the study. However, costs were presented as macro-categories, which reduces the transparency of the economic analysis. The sources of costs were given and are likely to reflect the UK setting. The probabilistic sensitivity analysis addressed the issue of uncertainty around cost estimates and the price year and use of discounting were reported.
Analysis and results:The synthesis of costs and benefits was appropriately performed and presented. The subgroup analysis was appropriate given the different outcomes observed in various age cohorts. Adverse events were reported but were not incorporated in the cost-effectiveness ratios. The key characteristics of the decision model were reported. The issue of uncertainty was extensively addressed in the sensitivity analysis. The authors discussed the results of other studies and compared them with those from the current analysis. The authors noted some limitations of their analysis such as the simplicity of the decision model and the use of observational data, which are more generalisable but less robust than data from RCTs.
Concluding remarks:The study methodology appears to be good. The results of the analysis were clearly presented and the sensitivity analysis was appropriately carried out. Thus, the authors’ conclusions are likely to be valid. Funding Funded by the Evidence-Based Commissioning Collaboration. Bibliographic details Dixon S, Faghih Nasiri F, Ledger W L, Lenton E A, Duenas A, Sutcliffe P, Chilcott J B. Cost-effectiveness analysis of different embryo transfer strategies in England. BJOG. An International Journal of Obstetrics and Gynaecology 2008; 115(6): 758-766 Other publications of related interest Scotland GS, McNamee P, Bhattacharya S. Is elective single embryo transfer a cost-effective alternative to double embryo transfer? BJOG 2007;114:5–7
Wolner-Hanssen P, Rydhstroem H. Cost-effectiveness analysis of in-vitro fertilization: estimated costs per successful pregnancy after transfer of one or two embryos. Hum Reprod 1998;13:88–94.
Fiddelers AA, van Montfoort AP, Dirksen CD et al. Single versus double embryo transfer: cost-effectiveness analysis alongside a randomized clinical trial. Hum Reprod 2006;21:2090–7 Indexing Status Subject indexing assigned by NLM MeSH Adult; Age Distribution; Cost-Benefit Analysis; Critical Care /economics /statistics & Embryo Transfer /economics /methods; Female; Humans; Intensive Care Units, Neonatal /economics /statistics & Pregnancy; Pregnancy Outcome; Premature Birth /epidemiology; numerical data; numerical data AccessionNumber 22008100657 Date bibliographic record published 01/12/2008 Date abstract record published 03/02/2009 |
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