HEALTH ECONOMICS LETTER SHOULD COST-EFFECTIVENESS ANALYSIS INCLUDE THE COST OF CONSUMPTION ACTIVITIES? AN EMPIRICAL INVESTIGATION CHARLES CHRISTIAN ADARKWAH 1,2 , AMIRHOSSEIN SADOGHI 3 and AFSCHIN GANDJOUR 3, * 1 Department of General Practice/Family Medicine, University of Marburg, Marburg, Germany 2 Department of Health Services Research, Maastricht University, Maastricht, The Netherlands 3 Management Department, Frankfurt School of Finance & Management, Frankfurt, Germany ABSTRACT There has been a debate on whether cost-effectiveness analysis should consider the cost of consumption and leisure time activities when using the quality-adjusted life year as a measure of health outcome under a societal perspective. The purpose of this study was to investigate whether the effects of ill health on consumptive activities are spontaneously considered in a health state valuation exercise and how much this matters. The survey enrolled patients with inflammatory bowel disease in Germany (n = 104). Patients were randomized to ex- plicit and no explicit instruction for the consideration of consumption and leisure effects in a time trade-off (TTO) exercise. Explicit instruction to consider non-health-related utility in TTO exercises did not influence TTO scores. However, spontaneous consideration of non-health-related utility in patients without explicit instruction (60% of respondents) led to significantly lower TTO scores. Results suggest an inclusion of consumption costs in the numerator of the cost-effectiveness ratio, at least for those re- spondents who spontaneously consider non-health-related utility from treatment. Results also suggest that exercises eliciting health valuations from the general public may include a description of the impact of disease on consumptive activities. Copyright © 2015 John Wiley & Sons, Ltd. Received 18 April 2014; Revised 17 December 2014; Accepted 18 January 2015 KEY WORDS: consumption; Crohn’s disease; leisure time; quality-adjusted life year; time trade-off; ulcerative colitis; validation study 1. INTRODUCTION There has been a debate on whether cost-effectiveness analysis should include health-related costs in added life years that are unrelated to the disease or intervention in question. Several authors have argued in favor of this inclusion (Feenstra et al., 2008; Gandjour 2006; Meltzer 1997; Nyman 2004; Rappange et al., 2008). A perhaps even more controversial debate has been around the question whether cost-effectiveness analysis should con- sider the cost of consumption and leisure time activities when using the quality-adjusted life year (QALY) as a measure of health outcome under a societal perspective. For example, Meltzer (1997) argues that consump- tion costs and earnings during added years of life should be included in cost–utility analyses. Nevertheless, Nyman (2004) suggests otherwise based on the argument that none of the existing direct or indirect utility mea- sures explicitly recognizes variations in consumption or foregone leisure. The underlying principle is that costs should be excluded from cost–utility analyses if they represent resources that produce utility that is not being measured in the denominator of the cost–utility ratio. For life-extending treatments, however, handling of the cost of consumption and leisure time activities seems less controversial. As satisfying primary needs such as food, shelter, and clothing contributes to the ad- ditional survival time and the associated utility, the costs associated with these resources should also be *Correspondence to: Management Department, Frankfurt School of Finance & Management, Frankfurt, Germany. E-mail: a.gandjour@fs.de Copyright © 2015 John Wiley & Sons, Ltd. HEALTH ECONOMICS Health Econ. (2015) Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/hec.3162