Pharmacoeconomics 2008; 26 (4): 269-280

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 1. Valuation Methods for Informal Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 1.1 Proxy Good Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 1.2 Opportunity Cost Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 1.3 Contingent Valuation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 1.4 Conjoint Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 1.5 Valuation of Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 1.6 Valuation of Well-Being . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276 1.7 Objective and Subjective Burden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277 1.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277 2. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278 3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279 This paper compares several applied valuation methods for including informal Abstract care in economic evaluations of healthcare programmes: the proxy good method; the opportunity cost method; the contingent valuation method (CVM); conjoint measurement (CM); and valuation of health effects in terms of health-related quality of life (HR-QOL) and well-being. The comparison focuses on three questions: what outcome measures are available for including informal care in economic evaluations of healthcare programmes; whether these measures are compatible with the common types of economic evaluation; and, when applying these measures, whether all relevant aspects of informal care are incorporated. All types of economic evaluation can incorporate a monetary value of informal care (using the opportunity cost method, the proxy good method, CVM and CM) on the cost side of an analysis, but only when the relevant aspects of time costs have been valued. On the effect side of a cost-effectiveness or cost-utility analysis, the health effects (for the patient and/or caregiver) measured in natural units or 270 Koopmanschap et al. QALYs can be combined with cost estimates based on the opportunity cost method or the proxy good method. One should be careful when incorporating CVM and CM in cost-minimization, cost-effectiveness and cost-utility analyses, as the health effects of patients receiving informal care and the carers themselves may also have been valued separately. One should determine whether the caregiver valuation exercise allows combination with other valuation techniques. In cost-benefit analyses, CVM and CM appear to be the best tools for the valuation of informal care. When researchers decide to use the well-being method, we recommend applying it in a cost-benefit analysis framework. This method values overall QOL (happiness); hence it is broader than just HR-QOL, which complicates inclusion in traditional health economic evaluations that normally define outcomes more narrowly. Using broader, non-monetary valuation techniques, such as the CarerQol instrument, requires a broader evaluation framework than cost-effectiveness/cost-utility analysis, such as cost-consequence or multicriteria analysis. Informal care constitutes a substantial part of anticipated demographic trends; as a result of the total healthcare provided, especially, although not ageing of the population, the demand for both forexclusively, in the context of chronic diseases. mal and informal care is likely to increase, while, at Many people provide care tasks for someone in need the same time, the availability of professional workof care in their social environment, mostly as a noners in the formal care sector is likely to decrease. professional and unpaid. In general, the odds of Rationing of care will become increasingly necesbeing involved in the provision of informal care are sary.[4-9] considerable. In the Netherlands, for instance, about Whenever informal care plays a substantial role 10% of the population of 16 million inhabitants in the treatment of patients, we argue that it needs to provide informal care.[1] Inherently, informal care is be considered in economic evaluations of healthcare not formally organized and is normally not paid out programmes. The normally advocated societal perof healthcare budgets. As such, it is often an unnospective indeed dictates that all costs and effects ticed part of total healthcare. As a consequence, need to be included in an analysis.[10] This holds for attention on informal care has been limited, both in patient-centered interventions in which informal general and in the context of economic evaluations. care is an important input, as well as for interventions that are targeted at informal caregivers, such as However, in recent years, both at a policy level support programmes and respite care. and in the area of economic evaluations, attention on informal carers has begun to increase. Several studThe fact that costs and outcomes of informal care ies have demonstrated the impact of informal care are often ignored in economic evaluations someon carers, sometimes leading to high personal and times relates to the fact that the societal perspective societal costs, adverse health effects and even inis not adhered to, with a healthcare budget perspeccreased mortality risks.[2,3] Nonetheless, as long as tive being taken instead. Although one may criticize such costs and effects are not systematically considsuch a narrow perspective for not considering all ered in healthcare decisions and analyses, informal relevant societal costs,[11] it needs to be noted that care will continue to be considered a ‘zero cost’ even from such a restricted perspective, the position substitute for formal care, leading to potentially of carers should not be ignored, because possible undesirable outcomes from a societal perspective. adverse health effects in this group are also relevant Therefore, more attention on informal care is warfrom a healthcare budget perspective.[12,13] Another ranted. This is even more important in light of important reason for the lack of systematic inclusion © 2008 Adis Data Information BV. All rights reserved. Pharmacoeconomics 2008; 26 (4) Methods and Applications to Value Informal Care 271 of informal care in economic evaluations is that • measurement of health effects, in terms of healthstandardized methods to value informal care that are related quality of life (HR-QOL); compatible with the common types of economic • measurement of well-being, in terms of subjecevaluation in healthcare are not available. The availtive (monetized) well-being, care-related QOL ability, development and use of such methods are (CarerQol) and process utility. prerequisites for the systematic incorporation of inThese methods are presented consecutively in formal care in economic evaluations. sections 1.1–1.6, along with a discussion of their In this article, we compare valuation methods for compatibility with the common types of economic including informal care in economic evaluations of evaluation and whether they incorporate all caregivhealthcare programmes, focusing on three queser effects (see table I for an overview). Two other tions: important measures in the area of informal care • What outcome measures are available for includ(objective burden and subjective burden), although ing informal care in economic evaluations of not valuation techniques, are also briefly discussed healthcare programmes? (see section 1.7). • Are these measures compatible with the common types of economic evaluation? 1.1 Proxy Good Method • When applying these measures, are all relevant The proxy good (or market cost) method[10,15,16] is aspects of informal care incorporated? the most straightforward valuation method, and valThe discussion is restricted to methods that aim ues the time spent on informal caregiving at the to value the time invested by informal caregivers price of a close market substitute. The value of and the associated disutility. Measurement of the caregiver time can then differ for different tasks. For amount of informal care provided and other costs (in example, housework is valued at the market wage addition to time) of informal caregiving fall outside rate of a professional housekeeper, and personal the scope of this article and have been discussed care is valued at the market wage rate of a profesextensively by others.[14,15] sional nurse. The proxy good method thus requires a list of the care tasks performed, the time spent on 1. Valuation Methods for Informal Care these tasks and proxy values for each task. It is important to emphasize that different types One advantage of the proxy good method (as of economic evaluations require different informacompared with the methods in sections 1.2–1.6) is tion regarding informal care. This may affect the that the proxy value of each task can be estimated possible and preferred measures for valuing inforonce and then used for different caregiving situamal care in those different contexts. All types of tions. The method also has some disadvantages. economic evaluations require information regarding First, by using wage rates as the proxy value of time, costs of informal care, whereas the required inforone assumes that formal care and informal care are mation on effects or on benefits for informal careperfect substitutes and that, for instance, no differgivers may vary per method. The distinction beences in efficiency and quality exist. The method tween costs and effects of informal care is not alalso assumes that informal caregiving does not inways straightforward, for example, when valuing volve direct (dis)utility. This means that neither the leisure time lost. care recipient nor the informal caregiver has a prefVarious methods have been applied for the valuaerence for informal over formal care, or vice versa tion of informal care in economic evaluations: (e.g. it does not take into account that informal • the proxy good method; caregivers may experience fulfilment from provid• the opportunity cost method; ing care to a loved one). • the contingent valuation method (CVM); The costs of informal care estimated using the • the conjoint measurement method (CM); proxy good method can be incorporated on the cost © 2008 Adis Data Information BV. All rights reserved. Pharmacoeconomics 2008; 26 (4) 272 Koopmanschap et al. Table I. Preferred valuation methods for informal care according to type of economic evaluation Preferred valuation methods Cost-minimization analysis Proxy good method or opportunity cost method Cost-effectiveness analysis If health effects of carers are included on the effect side: a,b Proxy good method/opportunity cost method on the cost side combined with health effects for patients and carers on the effect side Contingent valuation method focusing on costs not health Conjoint measurement focusing on costs not health If health effects of carers are not included on effect side: c Contingent valuation method focusing on costs and health Conjoint measurement focusing on costs and health Cost-utility analysis If health effects of carers are included on effect side: a Proxy good method/opportunity cost method on the cost side combined with QALYs for patients and carers on the effect side Contingent valuation method focusing on costs not health Conjoint measurement focusing on costs not health If health effects of carers are not included on effect side: c Contingent valuation method focusing on costs and health Conjoint measurement focusing on costs and health Cost-benefit analysis If the aim is capturing only costs and health effects: Contingent valuation (including only costs and health effects) Conjoint analysis (including only costs and health effects) Proxy good method or opportunity cost method supplemented with additional monetary measures for health and other costs (avoiding