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Cost-effectiveness of clozapine treatment in therapy-refractory schizophrenia |
Jonsson D, Walinder J |
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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 Clozapine vs traditional antipsychotic treatment for therapy-refractory schizophrenia.
Economic study type Cost-effectiveness analysis.
Study population All patients were diagnosed according to DSM-III-R criteria. The patients were therapy-refractory in the sense that satisfactory treatment response was not achieved, in spite of adequate neuroleptics for at least 12 months. Ofthe 20 patients completing the study, 7 were women and 13 men. The average age at start was 33 years, and the patients had been mentally ill for an average period of 10 years.
Setting The setting was the Department of Psychiatry, University Hospital (Linkoping) Sweden.
Dates to which data relate Effectiveness and resource data were taken from case records over the period 1989 - 1991. All costs were calculated according to prices for 1990 ($1=SEK 7.9).
Source of effectiveness data Effectiveness data was taken from a single study.
Link between effectiveness and cost data Costing was undertaken retrospectively on the same patient sample as that used in the effectiveness study.
Study sample The sample consisted of 21 consecutive patients and was appropriate in that patients were diagnosed according to DSM-III-R criteria. The sample size was not determined by a power calculation.
Study design A single centre, before and after study in which the patients were studied for 18 months prior to (i.e. conventional treatment) and after the initiation of the clozapine treatment. The length of the study was 3 years but no further follow-up was stated. One patient dropped out from the study after a period of 12 months because of too strong sedation as a side effect as well as an insufficient clinical effect.
Analysis of effectiveness Analysis was based on treatment completers only. The primary health outcomes used in the study were based on rating scales for symptoms and social functioning. The effects on mental health have been operationalized as changes in the Clinical Global Impression Scale (CGI) (9) and Social Functional Scale (10). The number of improved patients was also considered.
Effectiveness results The symptom rating scale for patients treated with clozapine increased by 20 from 34 to 54 over the study period. Similarly, the social functioning rating scale increased by 18, from 40 to 58. In general, those patients initially displaying more serious symptoms or poor social functioningability showed the greatest improvement. Clozapine treatment improved the mental health status for 16 patients with regard to symptoms or social functioning. Four patients showed no improvement, whilst no patients deteriorated.
Clinical conclusions The results of this study confirmed previous findings that clozapine treatment for mentally ill patients has a beneficial clinical effect.
Measure of benefits used in the economic analysis Symptom and social functioning rating scales were used in the study based on the Clinical Global Impression Scale (CGI) (9) and Social Functional Scale (10). The values used to assess the health states were based on 21 consecutive patients. The number of improved patients was also considered.
Direct costs Costs and quantities were not reported separately. Costs were based on actual data and have been taken from the hospital department's operational balance sheet for 1990. The prices of drugs were received from the University hospital pharmacy. Data were given for inpatient, outpatient, and other costs, which included drugs and laboratory tests. No discounting of costs was stated.1990 prices were used.
Currency Swedish Kroner (SEK)/US Dollars ($). $1 = SEK 7.9.
Sensitivity analysis No sensitivity analysis was performed.
Estimated benefits used in the economic analysis The symptom rating scale for patients treated with clozapine increased by 20 from 34 to 54 over the study period. Similarly, the social functioning rating scale increased by 18, from 40 to 58. In general, those patients initially displaying more serious symptoms or poor social functioningability showed the greatest improvement. Clozapine treatment improved the mental health status for 16 patients with regard to symptoms or social functioning. Four patients showed no improvement, whilst no patients deteriorated.
Cost results The inpatient, outpatient and other costs (drugs and laboratory tests) of traditional neuroleptics in 1000 SEK($) were 6,748(854), 396(50), and 108(14), respectively. The total cost and cost per patient were 7,252(918) and 363(46), respectively. The inpatient, outpatient and other costs (drugs and laboratory tests) of clozapine in 1000 SEK($) were 6,176(782), 1,402(177), and 377(48), respectively. The total cost and cost per patient were 7,955(1,007) and 398(50), respectively. Therefore, whilst inpatient costs fell by 8% (SEK 572K, $72K), the cost of outpatient care increased by 254% (SEK 1,006K, $127K) and other costs increased by 250% (SEK 269K, $34K).
Synthesis of costs and benefits Both total costs and the cost per patient increased by 10%, by SEK 703K($89K) and SEK 35K($5K), respectively. The average additional cost per improved patient was SEK 43,934 ($ 5,600). The additional cost in proportion to improvement in symptoms was SEK 35,147 ($4,400) and in social functioning SEK 39,052 ($4,900).
Authors' conclusions The results of this study confirmed previous findings that clozapine treatment for mentally ill patients had a beneficial clinical effect. However, the total cost of a clozapine regimen was approximately 10% higher than traditional neuroleptic treatment and although inpatient care costs decreased, the cost for outpatient care and other costs (drugs and laboratory tests) increased. Thus, clozapine treatment required active rehabilitation efforts in outpatient care. Clozapine treatment would be cost-saving if initial monitoring of clozapine treatment could take place in an outpatient setting. More studies are required however, in order to identify which patients would benefit most from clozapine treatment and when such treatment would be the most cost-effective.
CRD Commentary No justification was provided for the choice of a before and after study. The sample size, as the authors acknowledged, was rather small and most of the population characteristics are unknown. Costs were derived from a single hospital and average costs were used, which may not account for variations in inpatient care costs. A randomised controlled trial would have been a more appropriate study design with which to evaluate the effectiveness of clozapine and with which to eliminate bias. Statistical analysis was not present with respect to effectiveness data and data were not subjected to sensitivity analysis. The above factors have implications for both the internal and external validity of the study and therefore the results provided in this article cannot easily be generalised to other settings or to other countries.
Implications of the study The study suggests that resource allocation decisions need to be addressed with respect to the treatment of the mentally ill. However, without a more stringent economic evaluation of clozapine and traditional neuroleptics, there is little evidence that policy will be affected.
Bibliographic details Jonsson D, Walinder J. Cost-effectiveness of clozapine treatment in therapy-refractory schizophrenia. Acta Psychiatrica Scandinavica 1995; 92(3): 199-201 Indexing Status Subject indexing assigned by NLM MeSH Adult; Ambulatory Care /economics; Clozapine /adverse effects /economics /therapeutic use; Cost-Benefit Analysis; Female; Humans; Length of Stay /economics; Male; Recurrence; Retrospective Studies; Schizophrenia /drug therapy /economics; Schizophrenic Psychology; Social Adjustment; Sweden AccessionNumber 21995001037 Date bibliographic record published 31/07/1998 Date abstract record published 31/07/1998 |
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