Dimensions Used in Instruments for QALY Calculation: A Systematic Review

Abstract

Economic assessment is of utmost importance in the healthcare decision-making process. The quality-adjusted life-year (QALY) concept provides a rare opportunity to combine two crucial aspects of health, i.e., mortality and morbidity, into a single index to perform cost-utility comparison. Today, many tools are available to measure morbidity in terms of health-related quality of life (HRQoL) and a large literature describes how to use them. Knowing their characteristics and development process is a key point for elaborating, adapting, or selecting the most well-suited instrument for further needs. In this aim, we conducted a systematic review on instruments used for QALY calculation, and 46 studies were selected after searches in four databases: Medline EBSCO, Scopus, ScienceDirect, and PubMed. The search procedure was done to identify all relevant publications up to June 18, 2020. We mainly focused on the type of instrument developed (i.e., generic or specific), the number and the nature of dimensions and levels used, the elicitation method and the model selected to determine utility scores, and the instrument and algorithm validation methods. Results show that studies dealing with the development of specific instruments were mostly motivated by the inappropriateness of generic instruments in their field. For the dimensions’ and levels’ selection, item response theory, Rasch analysis, and literature review were mostly used. Dimensions and levels were validated by methods like the Loevinger H, the standardised response mean, or discussions with experts in the field. The time trade-off method was the most widely used elicitation method, followed by the visual analogue scale. Random effects regression models were frequently used in determining utility scores.

Instruments to assess quality of life in people with mental health problems: a systematic review and dimension analysis of generic, domain- and disease-specific instruments

“…The instruments with the best coverage of the dimensions of the evaluation framework lack a preference-based scoring algorithm, at present. In line with the study of Touré and colleagues [ 58 ], it was found that all identified preference-based instruments, which were all generic, cover the dimension “Physical health”, but generally lack coverage of mental health related (sub)dimensions. Of the five instruments that were found to have a preference-based scoring algorithm, the AQoL-8D had the most overlap with the framework of Connell and colleagues [ 12 , 13 ].…”

Cost-utility of a web-based intervention to promote maternal mental health among postpartum women presenting low risk for postpartum depression

“…Furthermore, measurements were based on self-reports and, in the case of cost data, this could have resulted in recall bias and led to over- or underestimation of total costs. Third, the use of a measure that is more sensitive to changes in healthy populations and that does not have a tendency for ceiling effects (such as the SF-6D or the CORE-6D; 49;51) could be beneficial to differentiate between high scores of the healthy utility range. Fourth, consistent with other studies of web-based interventions (52), dropout rates were relatively high, particularly at the last assessment point.…”

Development of a balanced instrument to measure global health-related quality of life: The 13-MD

“…In each round, using specific questions, points of view, suggestions, and misunderstandings of respondents were collected anonymously (all respondents did not know the individual opinions of other participants but were informed of the global distribution of responses). In each round, a revised version of the questionnaire, based on the respondents' observations and suggestions in the previous round, was created—except for the first round—where the dimensions proposed were derived from the study by Touré et al ( 7 ), which is a systematic review of the dimensions covered by HRQoL instruments and the different steps necessary for the creation of those instruments for QALY calculation. Further details on the selected studies and the dimensions can be found elsewhere ( 7 ).…”

“…Meanwhile, generic instruments are adapted for all types of health profiles to allow for the comparison between patients with different diseases ( 6 ). However, many differences may be perceived among the generic instruments available regarding their composition, where dimensions related to physical aspects of health are depicted more often than dimensions related to mental or social aspects ( 7 ). The general observation is that almost all generic instruments contain one or more dimensions related to physical aspects (e.g., disability, discomfort/pain) at the expense of other dimensions, such as mental/cognitive function, wellbeing/happiness, or sadness/depression ( 7 ).…”

“…The general observation is that almost all generic instruments contain one or more dimensions related to physical aspects (e.g., disability, discomfort/pain) at the expense of other dimensions, such as mental/cognitive function, wellbeing/happiness, or sadness/depression ( 7 ). Additionally, few instruments consider dimensions relative to the social domain ( 7 ). Thus, clear differences are noticed in generic instruments that aim to measure the patient's perceived global health-related quality of life (GHRQoL) most effectively.…”