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Online ISSN: 1099-176X    Print ISSN: 1091-4358
The Journal of Mental Health Policy and Economics
Volume 10, Issue 2, 2007. Pages: 101-108
Published Online: 18 Jun 2007

Copyright © 2007 ICMPE.


 

Cost-effectiveness Analysis in Severe Mental Illness: Outcome Measures Selection

A. Dennis Stant,1* Erik Buskens,2 Jack A. Jenner,3 Durk Wiersma,4 Elisabeth M. TenVergert5

1Ph.D., Office for Medical Technology Assessment, UniversityMedicalCenterGroningen, University of Groningen, the Netherlands
2Ph.D., Department of Epidemiology, UniversityMedicalCenterGroningen, University of Groningen, the Netherlands
3Ph.D., Department of Psychiatry, University Medical Center Groningen, University of Groningen, Mental Health Care Foundation Groningen, the Netherlands
4Ph.D., Department of Psychiatry, UniversityMedicalCenterGroningen, University of Groningen, the Netherlands
5Ph.D., Office for Medical Technology Assessment, UniversityMedicalCenterGroningen, University of Groningen, the Netherlands

* Correspondence to: A.D. Stant, Office for Medical Technology Assessment, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, the Netherlands.
Tel.: +31 50 361 2152
Fax: +31 50 361 1738
E-mail: a.d.stant@mta.umcg.nl

Source of Funding: Dutch National Health Insurance Board (OG-98-040) and UniversityMedicalCenterGroningen.

Abstract

The QALY is widely recommended as outcome measure for economic evaluations. However, most cost-effectiveness studies in mental healthcare have applied outcomes aimed at a (disease) specific aspect of health. This approach may lead to complications. The current study used data of a previously conducted economic evaluation in patients with schizophrenia for illustrative purposes. Economic analyses based on the selected primary health outcome were compared with results of other outcomes, including QALYs. No relevant differences between groups were found on the primary health outcome. However, economic analyses based on three additionally assessed health outcomes strongly favoured the examined intervention. QALY results did not show differences between groups. Decision-makers in mental healthcare should carefully interpret cost-effectiveness studies using single outcome measures aimed at a specific aspect of health. QoL instruments may have advantages over these specific instruments. Furthermore, QALY results should be examined in the context of additionally assessed health outcomes.

 

Background: Most economic evaluations conducted in mental healthcare did not include widely recommended preference-based health outcomes like the QALY (Quality-Adjusted Life Years). Instead, studies have mainly been designed as cost-effectiveness analyses that include single outcome measures aimed at a (disease) specific aspect of health.

Aims of the Study: To raise awareness about the potential problems related to the selection of outcome measures for economic studies in patient populations with severe mental illness. Furthermore, to make suggestions that may prevent these problems in future economic evaluations.

Methods: Data of a previously conducted economic evaluation assessing the cost-effectiveness of the HIT (Hallucination focused Integrative Treatment) intervention in patients with schizophrenia were used for the analyses presented in the current paper. Economic analyses based on the results of the selected primary health outcome (Positive and Negative Syndrome Scale: PANSS) were compared with results based on various other health outcomes assessed during the study, including QALYs.

Results: No relevant differences between groups were found on the single primary health outcome initially included in the cost-effectiveness analysis. In contrast, relevant and significant differences were identified on three of the four additionally assessed health outcomes. Conclusions based on the results of multiple cost-effectiveness analyses and acceptability curves were strongly in favour of the experimental intervention when including these three additional instruments. QALY results did not show differences between groups.

Discussion: Selecting between outcome measures for cost-effectiveness analysis in the field of mental healthcare appears to be a complicated process, which may have considerable consequences for the results of economic studies and subsequent policy decisions. It was argued that inconsistent results across the selected primary health outcome and additionally assessed health outcomes should explicitly be presented to decision-makers. Until there is consensus on a preference-based instrument suited for severe mental illness, QoL instruments could be applied instead of instruments aimed at specific aspects of health.

Implications for Health Policies: Decision-makers in the field of mental healthcare should be careful when interpreting results of economic studies that included outcome measures aimed at a specific aspect of health. Such instruments may provide too narrow a view on relevant changes in health and findings may be difficult to generalise. Due to current reservations on the use of QALYs in mental healthcare, QALY outcomes should be considered in the context of the results of additionally assessed health outcomes.


Received 7 March 2006; accepted 12 April 2007

Copyright 2007 ICMPE