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Cost-effectiveness of anterotemporal lobectomy in medically intractable complex partial epilepsy |
Langfitt J T |
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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 Anterotemporal lobectomy (ATL) for medically intractable complex partial temporal lobe epilepsy.
Study population Hypothetical population with medically intractable complex partial epilepsy.
Setting Hospital. The study was carried out at the Strong Memorial Hospital (University of Rochester Medical Centre), Rochester, New York, USA.
Dates to which data relate Effectiveness data were collected from studies previously published between 1982 and 1995. Cost data were based on charges incurred by patients between 1991 and 1993 and on 1995 accounting costs. The price year was 1995.
Source of effectiveness data Effectiveness data were derived from a review of previously published studies and expert opinion.
Modelling A decision analytic model was constructed to estimate the cost-utility of ATL as compared with MEDMAN. The model adopted a lifetime perspective.
Outcomes assessed in the review The review assessed the following outcomes: probabilities of experiencing a clinical event, mortality and morbidity rates, and quality adjustments.
Study designs and other criteria for inclusion in the review Sources searched to identify primary studies It appears that a search of English language journals in the past 10 years via MEDLINE was undertaken along with a review of major textbooks on epilepsy surgery.
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 Approximately 22 studies were included.
Methods of combining primary studies Investigation of differences between primary studies Results of the review The probability of a treatment strategy consisting of evaluation for ATL after long-term video-EEG monitoring (LTM) was 0.71. The probability of ATL after LTM and after invasive cranial monitoring was 0.55 and 0.65, respectively. ATL morbidity and mortality were 0.05 and 0.004, respectively. With ATL, the probability of CPS-free and persisting CPS was 0.50 in both cases. The percentage of CPS-free with AURAS and CPS-free without AURAS was 0.50 and 0.36, respectively. Without ATL, the probability of CPS-free was 0.05 and of persisting CPS was 0.5. The percentage of CPS-free with AURAS was 0.95. Quality adjustments for CPS-free, CPS-free with AURAS, persisting CPS after ATL, persisting CPS after MEDMAN were 0.89, 0.8, 0.72, and 0.62, respectively. These data formed the principal inputs (effectiveness) for the decision tree.
Methods used to derive estimates of effectiveness Estimates of effectiveness were also arrived at from expert opinion.
Estimates of effectiveness and key assumptions For ATL patients it was assumed that undergoing LTM or invasive cranial monitoring does not affect seizure control. Quality adjustments for CPS-free no AURAS and AURAS-only patients who did not undergo ATL were assumed to be equal to those of the ATL patients with similar outcomes. Differences in seizure control and medication status were assumed to capture treatment effects on costs and outcomes adequately, either directly or indirectly.
Measure of benefits used in the economic analysis Quality adjusted life years (QALYs) were used as the measure of benefit. Quality adjustments reflected patient perception of quality of life in each outcome state. Quality adjustments for post-ATL patients were total scores of the Epilepsy Surgery Inventory-55 calculated from published results for 147 patients assessed an average of 5.6 years after ATL. Different quality adjustments were assigned to CPS-free no AURAS, AURAS only, and persisting CPS patients. QALYs were discounted at a rate of 5% per year.
Direct costs Direct costs were discounted at a rate of 5% per year. Quantities and costs were not reported separately. Costs included both medical costs directly related to evaluation and ATL incurred between the time of the first CEP outpatient visit and 2 months after ATL, and lifetime follow-up costs of utilisation of epilepsy related health care services. The quantity/cost boundary adopted was that of the health service. The estimation of quantities and costs was based on actual data. Accounting costs for all medical services were derived from the Strong Memorial Hospital. Accounting costs for services not billed through the hospital were obtained from local providers. ATL costs were based on charges incurred by 25 consecutive ATL patients through the Comprehensive Epilepsy Program at the University of Rochester. Follow-up costs were based on expert opinion. The price year was 1995.
Statistical analysis of costs Sensitivity analysis One-way sensitivity analyses were conducted on the probabilities, costs and quality adjustments. Best case and worst case scenarios for ATL treatment were obtained by multi-way sensitivity analysis.
Estimated benefits used in the economic analysis The treatment strategy of evaluation for ATL yielded average discounted QALYs of 12.12 as compared with 10.51 QALYs for MEDMAN.
Cost results Costs for a treatment strategy of evaluation for ATL and MEDMAN were $109,362 and $84,276, respectively.
Synthesis of costs and benefits The marginal cost-utility of the treatment strategy of evaluation for ATL over MEDMAN was $15,581/QALY. This result was sensitive to changes in the efficiency of patient selection, the probability of being free of seizures after ATL, evaluation and follow-up costs, quality adjustments, and the discount rate.
Authors' conclusions Under all but the most pessimistic assumptions, the cost-utility of ATL compares favourably with that of other health technologies.
CRD COMMENTARY - Selection of comparators rationale for the choice of the comparator was clear. You, as a user of this database, should verify whether these health technologies are relevant to your setting and country.
Validity of estimate of measure of benefit effectiveness results should be viewed with caution because the data and the assumptions in the model may be open to question and do not generalise well across settings. Quality adjustments were based on a rating-scale measure of quality of life. Rating scales do not take into account attitudes towards risk, time preference, and individual preferences for particular health stat
Validity of estimate of costs y direct medical costs were included. Indirect costs, direct non-medical costs, and patients' out-of-pocket medical expenses were excluded. Evaluation costs were sampled from a small number of patients at a single centre. Follow-up costs were estimated from a model derived from expert opinion. Hence, costs are unlikely to be generalisable to other settings or countries. Hospital-based accounting costs were used, which do not reflect true production costs.
Implications of the study Prospective multicentre studies of regional cost and practice variations, long-term probabilities of year-to-year transitions between seizure outcome states and their effects on quality of life, and the effect of non-surgical treatments on seizure control and quality of life are needed to provide the critical data to confirm these estimates.
Bibliographic details Langfitt J T. Cost-effectiveness of anterotemporal lobectomy in medically intractable complex partial epilepsy. Epilepsia 1997; 38(2): 154-163 Other publications of related interest 1. King J T, Sperling M R, Justice A C, O'Connor M J. A cost-effectiveness analysis of anterior temporal lobectomy for intractable temporal lobe epilepsy. Journal of Neurosurgery 1997;87(1):20-28.
2. Kriedel T. Cost-benefit of epilepsy clinics. Social Science and Medicine 1980;14:35-39.
3. Wiebe S, Gafni A, Blume W T, Girvin J P. An economic evaluation of surgery for temporal lobe epilepsy. Journal of Epilepsy 1995;8:227-235.
Indexing Status Subject indexing assigned by NLM MeSH Anticonvulsants /therapeutic use; Cost-Benefit Analysis; Direct Service Costs; Drug Costs; Epilepsy, Complex Partial /drug therapy /economics /surgery; Health Care Costs; Humans; Probability; Quality-Adjusted Life Years; Temporal Lobe /surgery; Treatment Outcome AccessionNumber 21997006501 Date bibliographic record published 31/01/2000 Date abstract record published 31/01/2000 |
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