Original Title: Valor monetario de un ańo de vida ajustado por calidad: revisión y valoración crítica de la literatura

Authors' objectives: This report aims at identifying and critically appraise the methodologies and estimates of the MVQALY available in the literature. Therefore, the aim is two-fold: 1) to identify the different methodologies and estimates of the MVQALY and, 2) to validate the current results and to consider needs for further research.

Authors' results and conclusions: RESULTS: SYSTEMATIC REVIEW: 43 articles were selected and classified in two groups: articles estimating the MVQALY from the demand perspective, i.e., articles estimating the value that society places on a QALY (29 articles); and articles estimating the MVQALY from the supply perspective, i.e., estimating the incremental cost per QALY gained that institutions can afford given their budget constraints (9 articles). The rest of studies undertook a review of economic evaluations in the literature (5 articles). STUDIES FROM THE DEMAND PERSPECTIVE: With respect to this type of articles, most of them (26 out of 29 studies) have estimated the willingness to pay (WTP) for one QALY using surveys on population samples. This methodology consists of asking individuals how much they would be willing to pay for a certain good under a hypothetic scenario. In the case of the MVQALY, these surveys focus on estimating the WTP for a small health gain and then aggregate the WTP needed to gain a QALY. The techniques used for this methodology are, in the most articles, those already established in economic evaluation analyses for valuing health states, which are combined with other techniques used to measure the WTP that are widely applied in other areas of the public sector in several countries. The results of the 26 studies show a large variability in the estimates of the MVQALY depending on the country, population surveyed, illness considered, the methods of valuing health status, the question format and the aggregation method. Some studies also observe that the estimated values are not sensitive to the variables WTP is expected to respond to, such as the illness severity, duration and risk. Among the published studies so far, the EuroVAQ project carried out online surveys in 9 countries, including Spain. The value of the WTP of the Spanish society was approximately between 20,000 € and 40,000 € per QALY. Two previous studies exclusively focusing on the Spanish case showed a much higher variability in their estimates, reporting two ranges, one from 10,000 € to 40,000 € and another from 5.000 € to 125,000 € per QALY. The most recent study conducted in Spain and published in 2014 estimated values between 12,000 € and 33,000 € (all values are reported as euros of 2014). The rest of studies that focused on the demand side have used the information about the Value of a Statistical Life (VSL) estimated in some countries, mainly in the context of the traffic safety. The information on the VSL is then related to the quality-adjusted life expectancy, and both pieces of information are combined to infer a QALY value. Again, a large variability under this methodology is found, mainly due to the variability of the VSL. Among the 4 studies applying this methodology, two of them have information on the Spanish case. One of them is the EuroVAQ project, previously mentioned, that estimates values between 96,000 € and 185,000 € (assuming 2.5 € million as VSL), and the other study, specifically to the Spanish case, estimates 54,000 € per QALY (using 1.3 € million as the VSL). STUDIES FROM THE SUPPLY PERSPECTIVE: The studies under the supply perspective aim at estimating the affordable threshold of the incremental cost per QALY for institutions. The identified studies can also be categorized into two different methodologies. On the one hand, we identify studies that aim at estimating the implicit affordable threshold of the incremental cost per QALY by observing recommendations and decisions on health technology investments and disinvestments made by institutions. Their objective is to identify the cost per QALY under which favourable decisions are made. This methodology may be most suitable to infer the institutions’ WTP per QALY, however, this methodology requires complete information on funding decisions and the explicit role of the cost-effectiveness criteria. We identified 4 studies in Australia, USA and England. None of them showed a clear conclusion about the MVQALY threshold. The second methodology from the supply perspective aims at empirically estimating the relationship between health expenditure and health outcomes using regression analysis. The aim of these studies is to estimate the marginal expenditure needed to obtain an additional health outcome unit. This methodology has been applied in 5 empirical articles. One of them was carried out in the Spanish context, estimating the Life Year Gained (LYG) cost, i.e., not adjusting for quality of life, and estimating a marginal cost per LYG from 11,000 € and 16,000 €. OTHER STUDIES: A series of articles (5 articles) have conducted systematic reviews of published economic evaluations that provided recommendations on adopting or not a health technology. The authors then compare the cost per LYG/QALY gained reported with the recommendation provided by the authors. It is important to note that this methodology is not strictly considered an empirical estimation of the MVQALY, but it is a review of the assessments reported by authors publishing economic evaluations. 2 out of the 5 studies focused on the Spanish case, which found that recommendations on adopting new health technologies are generally under 30,000 € per LYG, that is extended to the range from 30,000 € to 45,000 € in an updated study (these estimates are not updated to 2014 values). CRITICAL ASSESSMENT: We critically assess the methodologies and techniques used in the identified studies. The expert consultation allows us to assess the existing information and to identify the areas where further research would be beneficial. In particular, the panel concluded that additional research was required on both the demand and supply perspective, and a series of suggestions were presented for the design of future studies with the aim of overcoming some of the methodological limitations highlighted in this review. CONCLUSIONS: This report describes the existing and growing scientific literature about the value of a QALY for its use in economic evaluations. This systematic review shows that studies have taken different perspectives and have applied different methodologies. The most popular method are related with WTP surveys, and thus focus on the demand side. However, some authors have stressed the needed of considering the opportunity cost of health care funding when making investment decisions within a fixed budget context. In these cases, it is not considered appropriate to use a threshold based on society valuations to inform on the allocation of a specific budget, but it might be used to guide decisions about the size of the health care budget. In other words, we might consider the threshold based on demand side values as an indication of whether a technology has positive net benefits, according to society’s view, but the threshold based on the opportunity cost should indicate whether incorporating such technology is considered appropriate given the current budget constraints. Studies that consider the Spanish case have mostly taken the demand perspective, while on the supply side, a single article has been identified. However, the approach of this work was limited to the cost per LYG and therefore, does not report a monetary value of a QALY. We made the following recommendations: • We recommend to set a threshold which indicates if a health technology is viewed as a cost-effective use of resources in Spain and which would inform decision making in health care funding. In order for the use of such threshold to be effective, the cost-effectiveness criterion should have the support and be promoted by the relevant authorities, and to share the understanding and acceptance of the society as a whole. • We should be informed about both the value that society places on a QALY (demand perspective), as well as the cost of generating QALYs in a health care system (supply perspective). While the first piece of information would allow us to estimate whether a technology has positive net benefits according to society valuations, the second piece of information would allow us to identify if the incorporation of such technology is acceptable given the current budget limitations. • We recommend to undertake additional research to overcome some of the methodological limitations identified in previous work conducted in Spain, and taking both perspectives into account. • In particular, with respect to the valuation that society places on health, the suggested design involves undertaking a survey to a sample of the population using discrete choice experiment techniques. • With regards to the estimation of the cost per QALY, we recommend to use administrative population data on health care expenditure and health outcomes on a number of health areas.

Authors' methods: We undertake a systematic review of empirical analyses on the MVQALY in the literature. A searching strategy was defined and conducted in different databases (Medline, EMBASE, EconLit). A further searching in the references of the retrieved articles was undertaken and experts were contacted. Selected articles were classified by the perspective of analysis and the methodology applied. Then, we described each study and extracted the estimates of MVQALY. We critically appraised the identified information based on a consultation to a panel of 14 experts in the field. The consultation process involved three steps: individual interviews, a multi-conference involving all experts and an online Delphi questionnaire.

Project Status: Completed

Year Published: 2014

URL for published report: https://sescs.es/valor-monetario-de-un-ano-de-vida-ajustado-por-calidad-revision-y-valoracion-critica-de-la-literatura/

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: Spain

Organisation Name: Canary Health Service

Contact Address: Dirección del Servicio. Servicio Canario de la Salud, Camino Candelaria 44, 1ª planta, 38109 El Rosario, Santa Cruz de Tenerife

Contact Name: sescs@sescs.es

Contact Email: sescs@sescs.es