|Cost-effectiveness of coarctation repair strategies: endovascular stenting versus surgery
|George J C, Shim D, Bucuvalas J C, Immerman E, Manning P B, Pearl J M, Beekman R H
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.
The use of endovascular stenting and primary surgical repair in children with coarctation of the aorta (CoA).
Economic study type
The study population comprised patients with a discrete, thoracic CoA without complex arch hypoplasia. Patients were excluded if they were younger than 5 years of age, or had coexisting cardiac pathology that required concurrent SUR.
The setting was secondary care. The economic study was carried out at the Cincinnati Children's Hospital Medical Centre, USA.
Dates to which data relate
The study reviewed patients treated with endovascular stent implantation or SUR between July 1997 and June 2001. The price year was not reported.
Source of effectiveness data
The effectiveness data were derived from a single study.
Link between effectiveness and cost data
The costing was undertaken retrospectively on the same patient sample as that used in the effectiveness study.
Power calculations were not performed retrospectively and a study sample was not planned. During the study period, 118 patients underwent repair of a native CoA. Only 22 of these were included in the study, as the majority of patients were either younger than 5 years or had associated cardiac defects requiring surgery. These 22 patients were divided into two treatment groups. Ten (6 males) underwent stent implantation (ST) and 12 (9 males) underwent primary SUR. The average age of the patients was 12.2 (+/- 3.9) years in the ST group and 9.5 (+/- 3.5) years in the SUR group.
The study was based on a retrospective cohort study that was carried out at Cincinnati Children's Hospital Medical Centre. The duration of follow-up was unclear, but the groups appear to have been followed until discharge from hospital. Owing to the retrospective nature of the study design, there was no loss to follow-up.
Analysis of effectiveness
All of the patients included in the study were accounted for in the analysis. The health outcomes used were post-procedural peak systolic blood pressure, complications and length of stay in the hospital. These were obtained from a review of hospital records. The two groups were comparable in terms of age and gender.
There was no residual systolic pressure gradient in either treatment group, acutely and at 1-year follow-up.
No complications were encountered in either group.
The length of hospital stay was significantly different between the two treatment groups, (p<0.001). The average length of stay was 0.8 (+/- 1.2) days (range: 0 - 4) in the ST group and 3.6 (+/- 0.5) days (range: 3 - 4) in the SUR group.
The study results showed that endovascular stenting resulted in a shorter length of hospital stay than primary SUR of a CoA.
Measure of benefits used in the economic analysis
No summary measure of benefit was derived. The study was, in effect, a cost-consequences analysis.
Resource use and costs were not reported separately. The direct costs included were those of the hospital. These comprised the costs of hospital room and board, pharmacy, laboratory, blood bank, radiology, respiratory care and home health. For the endovascular stent group, the cost of the device (Palmaz, Johnson and Johnson) was also included. The reported costs did not include consultant fees or the follow-up costs. The hospital costs were determined for each patient using cost accounting software developed by HBOC, and were adjusted for inflation. The authors did not state the sources from which the unit costs were derived. The authors also investigated the costs of a stent-first strategy, which was defined as an initial attempted repair of CoA using an endovascular stent, followed by surgery if the stent placement was unsuccessful. Discounting was not relevant, as the costs were incurred during a short time, and hence was not performed. The price year was not reported.
Statistical analysis of costs
The costs were treated stochastically. Group comparisons were performed using unpaired Student's t-tests. A p-value of less than 0.05 was required to indicate a significant difference.
The indirect costs were not included in the analysis.
A sensitivity analysis was performed to assess the impact of varying certain parameters on the costs of the stent-first strategy.
Estimated benefits used in the economic analysis
See the 'Effectiveness Results' section.
The average inflation-adjusted hospital cost was $7,148 (+/- 2,984) for the ST group and $11,769 (+/- 3,702) for the SUR group, (p=0.002). Thus, the hospital cost for the ST group was 39% less than that for the SUR group.
The hospital cost per patient was $8,325 (+/- 3,354) for the stent-first strategy, given a 10% failure rate. This represented a significantly lower cost than the cost of an SUR only (p<0.04).
Synthesis of costs and benefits
The costs and benefits were not combined. The sensitivity analysis suggested that the break-even point, where the hospital cost of a first strategy was no longer lower than that of the strategy of surgery only, occurred at a stent failure rate of 39%.
The repair of coarctation of the aorta (CoA) using an endovascular stent strategy was cost-effective in comparison with conventional surgical repair (SUR).
CRD COMMENTARY - Selection of comparators
SUR was justified as the comparator on the grounds that it represented current practice in the authors' setting. You should decide if this is a widely used health technology in your own setting.
Validity of estimate of measure of effectiveness
The basis of the analysis was a retrospective cohort study. This type of study design has the potential of inclusion bias, which might have affected the results of the study. Ideally, the authors would have based their analysis on a prospective cohort study or randomised controlled trial, as the potential for inclusion bias is minimised in these study designs. The study sample appears to have been representative of the study population. Appropriate statistical techniques were used to test for differences in hospital length of stay. Despite the small sample size, the authors managed to find these differences to be statistically significant.
Validity of estimate of measure of benefit
The authors did not derive a measure of health benefit. The analysis was therefore categorised as a cost-consequences analysis.
Validity of estimate of costs
All the categories of cost relevant to the hospital perspective adopted were included in the analysis. However, some relevant costs (e.g. consultant fees and follow-up costs) were excluded from the analysis. It is unclear how these omissions would have affected the authors' results. Resource use and costs were not reported separately, which will limit the generalisability of the authors' results. Although not explicitly reported, it would appear that the unit costs were derived from the authors' setting. An appropriate statistical analysis of the costs was conducted. The costs were appropriately adjusted for inflation, although the price year was not reported.
The authors did not make appropriate comparisons of their findings with those from other studies. The authors reported that the cost-effectiveness of stent implantation for the repair of CoA was not documented in the medical literature. The issue of generalisability to other settings was also not addressed. The authors do not appear to have presented their results selectively and their conclusions reflected the scope of the analysis.
The authors reported a number of further limitations to their study. First, the study participants were slightly older than was typical for patients treated for a native CoA. Second, the study involved a small sample size. Third, the study was based on a non-randomised retrospective study in which the patients were assigned to treatment groups according to the preference of the referring cardiologist. Finally, this study did not include long-term data.
Implications of the study
The authors recommended the need for further studies to evaluate the long-term outcomes and costs related to stent treatment of CoA.
George J C, Shim D, Bucuvalas J C, Immerman E, Manning P B, Pearl J M, Beekman R H. Cost-effectiveness of coarctation repair strategies: endovascular stenting versus surgery. Pediatric Cardiology 2003; 24(6): 544-547
Other publications of related interest
Redington AN, Hayes AM, Ho SY. Transcatheter stent implantation to treat aortic coarctation in infancy. British Heart Journal 1993;69:80-2.
Suarez de Lezo J, Pan M, Romero M, et al. Balloon-expandable stent repair of severe coarctation of the aorta. American Heart Journal 1995;129:1002-8.
Subject indexing assigned by NLM
Adolescent; Aortic Coarctation /economics /surgery; Child; Child, Preschool; Cost-Benefit Analysis; Female; Hospital Costs; Humans; Length of Stay /statistics & Male; Retrospective Studies; Stents /economics; Vascular Surgical Procedures /economics; numerical data
Date bibliographic record published
Date abstract record published