|
Cost-effectiveness of pharmacological and psychosocial interventions for schizophrenia |
Phanthunane P, Vos T, Whiteford H, Bertram M |
|
|
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 the cost-effectiveness of interventions to treat schizophrenia, including typical antipsychotics, generic risperidone, olanzapine, clozapine, and family intervention. The authors concluded that atypical antipsychotics, such as risperidone, at generic prices, were cost-effective compared with typical antipsychotics, and family intervention was a cost-effective addition. Clozapine could be cost-effective for the most severe patients who did not respond to risperidone. The methods were valid and the details were extensively reported. The authors’ conclusions appear to be robust. Type of economic evaluation Study objective This study assessed the cost-effectiveness of interventions to treat schizophrenia, including typical antipsychotics, generic risperidone, olanzapine, clozapine, and family interventions. Interventions The analysis considered four drug interventions (typical antipsychotics, risperidone, olanzapine, and clozapine) with or without family intervention. These were compared with no intervention. Location/setting Thailand/primary and secondary care. Methods
Analytical approach:The analysis was based on a Markov model, with a lifetime horizon. The authors stated that the analysis was carried out from the perspective of the government.
Effectiveness data:National databases and surveys supplied some of the epidemiological inputs, such as prevalence and mortality. The efficacy of the interventions, which was a key input for the model, was mainly from published systematic reviews. Most of the studies included in these reviews were conducted in Western countries. The authors conducted meta-analyses to pool data from multiple sources.
Monetary benefit and utility valuations:Disability weights were estimated using the effect sizes from published trials that used the Brief Psychiatric Rating Scale (BPRS) and the Positive and Negative Syndrome Scale (PANSS). A meta-analysis was used to pool the evidence from multiple sources. Some data were from a cross-sectional descriptive survey of 307 people with schizophrenia in Thailand that was conducted by two of the authors.
Measure of benefit:Disability-adjusted life-years (DALYs) were the summary benefit measure and they were discounted at an annual rate of 3%.
Cost data:The economic analysis included the costs of the interventions, medical treatment, medical prevention of side-effects, hospitalisation, and time and travel for patients and families. The unit costs and resource quantities were presented in an online appendix. The patterns of resource consumption were from published literature. The unit costs were mainly from Thai reference prices and Thai studies. The cost of risperidone was based on authors’ assumptions as it was not available in Thailand. All costs were in Thai baht (THB) and were discounted at a rate of 3% per annum. The price year was 2005.
Analysis of uncertainty:One-way sensitivity analyses were performed, by varying the intervention costs, including or excluding time and travel costs for patients and families, and varying the cost of risperidone. A probabilistic analysis was carried out, using Monte Carlo simulation, and probabilistic distributions were assigned to all the inputs. Confidence intervals were generated for all model outcomes. Results The total DALYs averted in 2005, for the Thai eligible population, were 440,000 with typical antipsychotics, 530,000 with risperidone, 570,000 with olanzapine, 630,000 with clozapine, and 910,000 with family intervention plus risperidone. The total costs were THB 13,000 with typical antipsychotics, THB 11,000 with risperidone, THB 88,000 with olanzapine, THB 21,000 with clozapine, and THB 15,000 with family intervention plus risperidone.
The threshold for a highly cost-effective intervention was the gross domestic product (GDP) per capita in Thailand, which was THB 110,000. All treatments, except olanzapine and clozapine, were dominant over no intervention, as they were more effective and less expensive. The incremental cost per DALY averted was THB 1,000,000 for olanzapine and THB 12,000 for clozapine.
When only treatment costs were included, the cost-utility ratios were higher (less cost-effective), but all treatments, except olanzapine, remained cost-effective.
The incremental cost per DALY averted of adding family intervention to risperidone was THB 1,900. Compared with this, the incremental cost per DALY averted of providing clozapine instead of risperidone to one-third of patients, with the most severe disorder, was THB 320,000 per DALY averted (95% CI 26,000 to dominated); this was cost-effective, at three times the GDP per capita (THB 330,000), in 51% of simulations.
If the price of generic risperidone was less than THB 10 per 2mg tablet, it was dominant over the typical antipsychotics, and it was highly cost-effective (less than THB 110,000) up to a price of THB 19. Authors' conclusions The authors concluded that atypical antipsychotics, such as risperidone, at generic prices, were cost-effective compared with typical antipsychotics. Family intervention was a cost-effective addition. Clozapine could be cost-effective for the most severe patients who did not respond to risperidone. CRD commentary
Interventions:The authors stated that the interventions were chosen on the basis of published evidence, and the feasibility of their introduction in Thailand. A brief description of the family intervention was provided.
Effectiveness/benefits:The clinical data were generally from appropriate sources; local databases provided the epidemiological data and systematic reviews provided the treatment effect. The authors conducted meta-analyses to synthesise the data from multiple sources and to account for potential differences in outcome measures between studies. Uncertain parameters were extensively tested in the sensitivity analyses. The authors noted that a potential limitation of their analysis was the use of clinical data from Western countries, and these might not be directly applicable to Thailand. DALYs were an appropriate benefit measure, given the impact of the disease on both survival and health-related quality of life. The derivation of the disability weights was extensively described. The methods used to calculate the DALYs appear to have been appropriate.
Costs:The economic analysis was appropriately carried out and transparently presented. The cost categories were consistent with the stated government perspective and patient costs were considered, for a broader perspective. The unit costs, resource quantities, data sources, price year, and discounting were clearly presented. The impact of variations in the key costs was tested in the sensitivity analyses.
Analysis and results:The results were extensively presented. Incremental cost-utility ratios were calculated to synthesise the costs and benefits of the alternative strategies. Valid approaches were used to deal with uncertainty and the findings were clearly reported. The authors stated that a limitation of their analysis was the assumption that patients remained continuously on the same treatment without switching, but it is unlikely that this had a dramatic impact on the findings. The authors compared their results with those of other published economic evaluations, and these were generally consistent with their analysis. The results cannot be transferred to other settings and should be considered to be specific to Thailand.
Concluding remarks:The methods were valid and the details were extensively reported. The authors’ conclusions appear to be robust. Funding Funding received from the Wellcome Trust, UK, and the National Health and Medical Research Council of Australia. Bibliographic details Phanthunane P, Vos T, Whiteford H, Bertram M. Cost-effectiveness of pharmacological and psychosocial interventions for schizophrenia. Cost Effectiveness and Resource Allocation 2011; 9:6 Indexing Status Subject indexing assigned by CRD MeSH Antipsychotic Agents; Benzodiazepines; Clozapine; Cost-Benefit Analysis; Family Therapy; Humans; Markov Chains; Risperidone; Schizophrenia; Thailand AccessionNumber 22011001153 Date bibliographic record published 16/11/2011 Date abstract record published 26/01/2012 |
|
|
|