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A cost-effectiveness analysis of directly observed therapy vs self-administered therapy for treatment of tuberculosis |
Burman W J, Dalton C B, Cohn D L, Butler J R G, Reves R R |
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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 Directly observed therapy in the treatment of active tuberculosis.
Economic study type Cost-effectiveness analysis.
Study population Patients with initial drug-susceptible tuberculosis.
Setting Hospital. The study was carried out in Denver, USA.
Dates to which data relate Effectiveness data were retrieved from the Tarrant County tuberculosis control program published in 1994. Resource use and cost data were derived from 1993 and 1994 sources. The price year was 1994.
Source of effectiveness data Effectiveness data were derived from a literature review.
Modelling A decision analytic model was used to determine the cost-effectiveness of the two administration modes.
Outcomes assessed in the review The review assessed clinical event rates for treatment of drug-susceptible tuberculosis using DOT or SAT.
Study designs and other criteria for inclusion in the review Sources searched to identify primary studies 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 Effectiveness estimates were derived from one study, which was a retrospective review of SAT (January 1980 - October 1986) and DOT (November 1986 - December 1992). The analysis of this study was based on intention to treat.
Methods of combining primary studies Investigation of differences between primary studies Results of the review Cure and failure rates following SAT were 0.79 and 0.21, respectively. 71% of patients for whom SAT failed had drug-susceptible tuberculosis and 29% had multi-drug resistant tuberculosis. Cure and failure rates following DOT were 0.945 and 0.055, respectively. 84% of patients for whom SAT failed had drug-susceptible tuberculosis and 16% had multi-drug resistant tuberculosis.
Measure of benefits used in the economic analysis The number of patients cured after initial therapy was used as the primary measure of benefits.
Direct costs Treatment and patient time costs incurred over several years were discounted at an annual discount rate of 5% and 8%. Quantities and resources were reported separately. Direct costs included costs of initial therapy, costs for treatment failure and patient time costs. The quantity/cost boundary adopted was either that of the hospital (outpatient costs only) or the health care system (with and without patient time costs). The estimation of quantities and costs was based on actual data. Drug and nursing time costs were derived from the Denver Metro Tuberculosis Clinic. The cost of physician time was based on salary data collected from the Denver Health and Hospitals system. Laboratory costs were derived from a commercial laboratory in Denver. Blue Cross/Blue Shield reimbursement rates were used to estimate the cost of follow-up chest radiographs. Hospitalisation costs were derived from Denver General Hospital and a study published in 1993. The price year was 1994.
Statistical analysis of costs Sensitivity analysis A one-way threshold analysis was performed on drug costs, nursing time, hospitalisation costs, failure rates of initial therapy, proportion of treatment failures acquiring multidrug resistance, and patient time costs.
Estimated benefits used in the economic analysis The number of patients cured after initial therapy was 94.5 for DOT and 79 for SAT.
Cost results Total outpatient costs amounted to $140,500 for DOT and $231,400 for SAT. Total costs of initial therapy and costs of treatment failures (excluding patient time costs) amounted to $278,500 for DOT and $1,052,900 for SAT. Total costs of initial therapy and costs of treatment failures (including patient time costs) amounted to $399,900 for DOT and $1,216,700 for SAT.
Synthesis of costs and benefits The net cost per additional patient cured with DOT was $-5,865 (outpatient costs only), $-49,961 (costs of initial therapy and costs of treatment failures excluding patient time costs), or $-52,697 (costs of initial therapy and costs of treatment failures including patient time costs). These results remained stable over a wide range of costs and event rates.
Authors' conclusions Despite its greater initial cost, DOT was a more cost-effective strategy than SAT because it achieved a higher cure rate after initial therapy, and thereby decreased treatment costs associated with failure of therapy and acquired drug resistance.
CRD COMMENTARY - Selection of comparators The 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.
Validity of estimate of measure of benefit A relevant measure of benefit was used. The clinical event rates were derived from only one study. The possible transmission of tuberculosis to other people was not considered. The authors acknowledged that there may be considerable local differences in terms of hospitalisation for the treatment of patients who fail to respond to the initial course of therapy.
Validity of estimate of costs Only costs associated with the first episode of treatment failure were considered. Costs of contact investigation, preventive therapy, or treatment of secondary cases of active disease due to transmission from patients who fail to respond to therapy were not included. In some instances, the authors had to rely on specific charge/cost or payment/charge ratios to estimate costs. Cost estimates for treatment of multidrug-resistant tuberculosis were retrieved from a tertiary referral centre and may not be generalisable to other settings. Costs of a fatal relapse of tuberculosis were not included.
Other issues The generalisability of the results to other settings or countries was discussed, but no comparisons with other relevant studies were made.
Implications of the study The effectiveness and cost-effectiveness of DOT should be studied in developing countries, where the burden of tuberculosis is greatest.
Bibliographic details Burman W J, Dalton C B, Cohn D L, Butler J R G, Reves R R. A cost-effectiveness analysis of directly observed therapy vs self-administered therapy for treatment of tuberculosis. Chest 1997; 112(1): 63-70 Other publications of related interest 1. Moore R D, Chaulk C P, Griffiths R, Cavalcante S, Chaisson R E. Cost-effectiveness of directly observed versus self-administered therapy for tuberculosis. American Journal of Respiratory & Critical Care Medicine 1996;154(4):1013-1019.
2. Chaulk C P, Kazandjian V A. Directly observed therapy for treatment completion of pulmonary tuberculosis: consensus statement of the public health tuberculosis guidelines panel. JAMA 1998;279(12):943-948.
3. Weis S E. Universal directly observed therapy: a treatment strategy for tuberculosis. Clinics in Chest Medicine 1997;18(1): 155-163
Indexing Status Subject indexing assigned by NLM MeSH Antitubercular Agents /administration & Communicable Disease Control /economics; Cost-Benefit Analysis; Costs and Cost Analysis; Decision Support Techniques; Drug Therapy, Combination; Hospital Costs; Humans; Patient Compliance; Self Administration; Treatment Failure; Tuberculosis /drug therapy /economics /epidemiology; Tuberculosis, Multidrug-Resistant /drug therapy /economics /epidemiology; United States /epidemiology; dosage /economics /therapeutic use AccessionNumber 21997001013 Date bibliographic record published 30/04/2000 Date abstract record published 30/04/2000 |
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