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Cost effectiveness of bemiparin sodium versus unfractionated heparin and oral anticoagulants in the acute and long-term treatment of deep vein thrombosis |
Gomez-Outes A, Rocha E, Martinez-Gonzalez J, Kakkar V V |
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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 study compared three alternatives for the treatment of acute and long-term deep vein thrombosis (DVT).
Treatment A was unfractionated heparin (UFH) for 7 (+/- 2) days plus oral anticoagulant therapy (OAC).
Treatment B was subcutaneous bemiparin, 115 IU per kg for 7 (+/- 2) days plus OAC.
Treatment C was subcutaneous bemiparin, 115 IU per kg for 10 days followed by bemiparin 3,500 IU daily until day 90.
Study population The study population comprised adult patients with acute DVT of the lower limb.
Setting The setting was secondary care. The economic study was carried out in Spain.
Dates to which data relate The effectiveness and resource use data were taken from a study published in 2003. The price year was 2002.
Source of effectiveness data The effectiveness data were derived from a single study.
Link between effectiveness and cost data The resource use data were taken from the same patient sample that provided the effectiveness data.
Study sample A total of 378 patients were included in the study. These patients were allocated in equal groups to the three treatment options. The authors did not compare the patient sample with the wider patient population. No sample size or power calculations were reported. The authors referred to a publication detailing this study (Kakkar et al. 2003, see 'Other Publications of Related Interest' below for bibliographic details).
Study design The study was a multi-centred randomised controlled trial. Details of the randomisation process and any blinding to treatment group were not reported in the paper. The patients were followed up for 90 days, but it was unclear whether any patients were lost to follow-up. The reader should refer to the clinical paper (Kakkar et al. 2003) for full details.
Analysis of effectiveness It was unclear whether the data were analysed on an intention to treat or treatment completer only basis. The primary health outcome assessed in the clinical study was thrombus regression, as measured by Doppler sonograph on days 14 and 84. Mortality, bleeding rates and symptomatic venous thromboembolic events on day 84 were also used to assess effectiveness.
Effectiveness results Bemiparin resulted in greater thrombus regression compared with UFH on day 14 (72% versus 52%; p<0.001).
At day 84, symptomatic recurrent venous thromboembolic events, mortality and bleeding rates were similar in the three treatment groups.
Clinical conclusions The authors concluded that the treatment of DVT with bemiparin and OAC was the most effective of the three treatment options.
Modelling A decision analysis model was used to extrapolate the clinical results of the trial over the lifetime of the patients and combine them with the costs and utilities.
Measure of benefits used in the economic analysis The measures of health benefit used were life expectancy and quality-adjusted life-years (QALYs). The values of health states were taken from a published study, but the authors did not describe the methods used to identify these valuations.
Direct costs The direct costs of the health service were identified. These included the drug costs, costs of inpatient care, physician costs, and ancillary costs such as international normalised ratio tests. The unit costs for inpatient hospital care and physician costs were taken from Spanish administrative sources. The costs of drugs were taken from reported wholesale prices, while ancillary costs were taken from unpublished data relating to the clinical study (Kakkar et al. 2003). A breakdown of the unit costs and resource use was provided in the paper. The price year was 2002.
Statistical analysis of costs The cost data were treated deterministically.
Indirect Costs Inline with the perspective adopted, no indirect costs were included in this study.
Sensitivity analysis Univariate sensitivity analyses were undertaken to assess the impact of uncertainty and variability in the data. The ranges used were either the 95% confidence intervals taken from the literature or +/- 25% of the baseline data. Best- and worst-case scenarios were also calculated.
Estimated benefits used in the economic analysis The following estimates of life expectancy and QALYs were used in the economic analysis:
for treatment A (UFH+OAC), 17.56 years and 16.87 QALYs;
for treatment B (bemiparin plus OAC), 19.24 years and 18.59 QALYs; and
for treatment C (bemiparin), 18.31 years and 17.61 QALYs.
Cost results The total cost of treatment was EUR 4,128 for treatment A (UFH+OAC), EUR 3,359 for treatment B (bemiparin plus OAC) and EUR 3,220 for treatment C (bemiparin).
Synthesis of costs and benefits For treatment B (bemiparin plus OAC) versus treatment A (UFH+OAC), treatment B was dominant.
For treatment C (bemiparin) versus treatment A (UFH+OAC), treatment C was dominant.
For treatment C (bemiparin) versus treatment B (bemiparin plus OAC), treatment C was dominant.
The sensitivity analysis showed that the effectiveness of preventing future venous thromboembolic events was the most significant factor in determining cost-effectiveness. Both the bemiparin-based treatment regimens were cost-saving in comparison with UFH in the worst- and best-case scenarios.
Authors' conclusions Bemiparin with oral anticoagulation (OAC) and long-term bemiparin were dominant strategies in comparison with unfractionated heparin (UFH) plus OAC.
CRD COMMENTARY - Selection of comparators This study compared bemiparin plus OAC and long-term bemiparin with UFH+OAC. UFH was chosen as a comparator as it represented previous usual practice in the authors' setting. You should consider how these three treatment options compare with usual practice in your own setting.
Validity of estimate of measure of effectiveness The measure of clinical effectiveness was taken from a randomised controlled trial. This was an appropriate study design for the research question. The mean age and weight of the patients included in the sample were reported, but the authors did not compare their sample and the wider patient population. The full details of the clinical trial were not presented in this paper, thus it is not possible to make any inferences about the internal validity of the clinical study. The reader should refer to the original paper (Kakkar et al. 2003) for details of the clinical study.
Validity of estimate of measure of benefit The measure of health benefit was derived using the life expectancy from the clinical trial and extrapolating using Spanish life expectancy data. The utilities were obtained from the literature in order to obtain QALYS, although the methods used to obtain the health state valuations were not described in the paper.
Validity of estimate of costs A health care perspective was adopted in this study. As such, all the appropriate costs appear to have been included. A comprehensive breakdown of resource use and unit costs was provided. Several sensitivity analyses were undertaken to assess uncertainty in the data. These factors add to the generalisability of the study. It was unclear whether the future costs were appropriately discounted, and if discounting was undertaken no rate was reported. However, a clear price year was reported, which will aid future reflation exercises.
Other issues The authors do not appear to have presented their results selectively and their conclusion reflected their analysis. The authors compared the findings of this study with other relevant studies and noted similar findings. This study was designed to reflect the position in Spain, but the authors did not discuss how the study results may be applied to other settings.
Implications of the study The authors stated that further studies are needed to compare the cost-effectiveness of specific low molecular weight heparins and to assess the long-term impact of DVT and associated complications on quality of life.
Source of funding Financed by an unrestricted research grant from Laboratorios Farmaceuticos Rovi.
Bibliographic details Gomez-Outes A, Rocha E, Martinez-Gonzalez J, Kakkar V V. Cost effectiveness of bemiparin sodium versus unfractionated heparin and oral anticoagulants in the acute and long-term treatment of deep vein thrombosis. PharmacoEconomics 2006; 24(1): 81-92 Other publications of related interest Kakkar VV, Gebska M, Kadziola Z, et al. Low-molecular weight heparin in the acute and long-term treatment of deep vein thrombosis. Thromb Haemost 2003;89:674-80.
Indexing Status Subject indexing assigned by NLM MeSH Administration, Oral; Anticoagulants /administration & Cost-Benefit Analysis; Decision Trees; Economics, Pharmaceutical; Heparin /administration & Heparin, Low-Molecular-Weight /administration & Humans; Male; Middle Aged; Quality-Adjusted Life Years; Venous Thrombosis /drug therapy /economics; dosage /economics /therapeutic use; dosage /economics /therapeutic use; dosage /economics /therapeutic use AccessionNumber 22006008106 Date bibliographic record published 31/08/2006 Date abstract record published 31/08/2006 |
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