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Strategies for diagnosis and treatment of suspected leptospirosis: a cost-benefit analysis |
Suputtamongkol Y, Pongtavornpinyo W, Lubell Y, Suttinont C, Hoontrakul S, Phimda K, Losuwanaluk K, Suwancharoen D, Silpasakorn S, Chierakul W, Day N |
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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 This study assessed whether screening tests for leptospirosis were cost-effective in the management of patients with acute fever and suspected leptospirosis, and identified the most cost-effective diagnostic strategy. The authors concluded that treatment with antibiotics for all patients was the best option, but if the use of antibiotics had to be reduced, the latex test was the most cost-effective strategy. The study was not fully reported, especially for the costs, which makes it hard to assess the authors’ conclusions. Type of economic evaluation Study objective The objective was to determine whether screening tests for leptospirosis were cost-effective in the management of patients aged over 14 years, who had acute fever and suspected mild leptospirosis, and to identify the most cost-effective diagnostic strategy. Interventions Five strategies were compared. In the first strategy, there was no testing and no antibiotic treatment. In the second strategy, all patients were given a seven-day course of doxycycline, an antibiotic treatment. In the remaining three strategies patients were given a screening test for leptospirosis, followed by treatment with doxycycline for those who tested positive. The three screening tests were a lateral flow test, a microcapsule agglutination test (MCAT), and a latex test. Methods Analytical approach:: A state-transition model was used to synthesise the data from a concurrent clinical study, the published literature, and expert opinion. This model estimated the costs and effectiveness outcomes for a hypothetical cohort of 10,000 patients. The time horizon was seven days and the authors stated that the study took a societal perspective.
Effectiveness data:The effectiveness data came mainly from a single concurrent clinical study, which was supplemented with data from published literature and expert opinion. The sensitivity and specificity of each of the screening tests were compiled from a number of published studies. The main clinical effectiveness parameter was the duration of fever, following attendance at the hospital.
Monetary benefit and utility valuations:The monetary benefit was the productivity lost due to time off work with a fever.
Measure of benefit:The measure of benefit was the benefit-to-cost ratio.
Cost data:The cost categories included those of the antibiotics, screening tests, treatment for antibiotic side-effects and complications, and productivity lost due to fever. The costs of serious complications included hospital costs, intravenous antibiotics, and other necessary treatment. The cost data were from the concurrent clinical study and published literature. They were reported in US dollars ($) and the costs of the screening tests were provided at 2004 prices.
Analysis of uncertainty:The authors performed univariate sensitivity analyses to assess the impact of parameter uncertainty on the results. Results The mean duration of fever was longest with no treatment, at 5.35 days, and shortest with antibiotic treatment for all patients, at 2.24 days. The screening strategies resulted in mean duration of fever of 4.30 days with the latex test, 4.66 days with lateral flow, and 4.83 with the MCAT. The mean cost was $13.30 per patient with no treatment, $2.70 with antibiotic for all, and ranged from $15.30 to $17.20 for the screening strategies.
Treatment for all patients was dominant as it was least costly and most effective, when compared with the other strategies. When compared with no treatment, the three screening tests provided productivity gains, but higher costs. The latex test was the only screening and treatment strategy to have a benefit-to-cost ratio greater than one (2.68), meaning that it could be considered to be cost-effective.
In the sensitivity analysis, varying the leptospirosis prevalence, increasing the test sensitivity and specificity, and increasing the costs of the treatments did not significantly alter the results. Authors' conclusions The authors concluded that treatment of all patients with antibiotics was the most cost-effective option, but if the use of antibiotics had to be reduced, the latex test was the most cost-effective strategy. CRD commentary Interventions:The interventions were adequately described and the comparison included the usual care in the study setting. It is likely that these interventions were relevant to other settings.
Effectiveness/benefits:Most of the effectiveness data came from a clinical study concurrent to this economic evaluation. The clinical study was not described in detail which makes it difficult to assess its quality. It is unclear whether other relevant studies were available or whether a systematic literature review was conducted; therefore it is not clear if the best available evidence was used. The time horizon of seven days might not have fully captured the differences in health outcomes. The methods used to estimate the monetary benefit were only briefly mentioned, and it is difficult to assess their quality.
Costs:The authors stated that the perspective was societal and those costs relevant to this perspective were included. The authors did not describe how the resource use was measured and the costs were presented as category totals, which would be difficult to replicate. The reporting around the cost data was poor; the references for the sources were provided, but were incomplete. The authors stated the price year for the screening tests, but it was unclear if this was the price year for the other costs, making it difficult to ascertain if the costs were appropriately adjusted.
Analysis and results:: The analytic approach was satisfactorily reported; the model structure was described and a diagram was presented. The results were reported clearly. One-way sensitivity analyses were performed and reported. This type of sensitivity analysis goes some way towards addressing the parameter uncertainty, but a probabilistic sensitivity analysis could have more thoroughly assessed it. The reporting was satisfactory and the base-case estimates were given. The authors acknowledged and highlighted some limitations to their study.
Concluding remarks:: The study was not fully reported, especially for the costs, which makes it hard to assess the authors’ conclusions. Funding Funded by the Thailand Research Fund, and the Ministry of Public Health of Thailand. Bibliographic details Suputtamongkol Y, Pongtavornpinyo W, Lubell Y, Suttinont C, Hoontrakul S, Phimda K, Losuwanaluk K, Suwancharoen D, Silpasakorn S, Chierakul W, Day N. Strategies for diagnosis and treatment of suspected leptospirosis: a cost-benefit analysis. PLOS Neglected Tropical Diseases 2010; 4(2):e610 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents /therapeutic use; Case Management /economics; Doxycycline /therapeutic use; Female; Humans; Leptospirosis /diagnosis /drug therapy /economics; Male; Middle Aged; Time Factors; Treatment Outcome; Young Adult AccessionNumber 22010000803 Date bibliographic record published 11/08/2010 Date abstract record published 16/02/2011 |
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