Patient and public preferences for health states associated with AMD.

PURPOSE: Health utility values suitable for calculating quality-adjusted life-years are increasingly used to assess the cost-effectiveness of treatments for age-related macular degeneration (AMD). In the United States, health utilities are usually derived from the patients' own valuation or modeled using visual acuity as a surrogate outcome. In the United Kingdom and throughout Europe, health utilities are derived from public valuations. Our aim was to test if utility values for health states associated with AMD elicited directly from patients were different from those calculated from public tariffs for health-related quality of life (HRQoL) questionnaires. METHODS: Generic preference-based HRQoL questionnaires (EQ-5D and SF-6D) and the time trade-off (TTO) and visual analog scale (VAS) valuation techniques were administered to a sample of UK patients with AMD (N = 60). Health utilities were calculated using standard general population tariffs for the patient EQ-5D and SF-6D health states and directly from patient TTO and VAS scores. RESULTS: Mean utilities derived from the public tariffs were significantly higher than from patients' valuation (mean [±SD], 0.613 (±0.275) for the EQ-5D and 0.628 (±0.114) for the SF-6D compared with 0.481 [±0.411] for the TTO and 56.7 [±21.8] for the VAS score; p < 0.001). The EQ-5D was not significantly different from the SF-6D (p > 0.6). Visual acuity in the better seeing eye was not associated with any utility measure (all r < 0.08; p > 0.2). CONCLUSIONS: Patient and public preferences for health states associated with AMD are different, with patients valuing their health state more severely than the public tariffs of commonly used HRQoL questionnaires. Visual acuity did not predict health utility using any measure, and therefore, care should be taken when using visual acuity as a surrogate measure for utility in health economic analyses.

Exploring what lies behind public preferences for avoiding health losses caused by lapses in healthcare safety and patient lifestyle choices.

BACKGROUND: Although many studies have identified public preferences for prioritising health care interventions based on characteristics of recipient or care, very few of them have examined the reasons for the stated preferences. We conducted an on-line person trade-off (PTO) study (N=1030) to investigate whether the public attach a premium to the avoidance of ill health associated with alternative types of responsibilities: lapses in healthcare safety, those caused by individual action or lifestyle choice; or genetic conditions. We found that the public gave higher priority to prevention of harm in a hospital setting such as preventing hospital associated infections than genetic disorder but drug administration errors were valued similar to genetic disorders. Prevention of staff injuries, lifestyle diseases and sports injuries, were given lower priority. In this paper we aim to understand the reasoning behind the responses by analysing comments provided by respondents to the PTO questions. METHOD: A majority of the respondents who participated in the survey provided brief comments explaining preferences in free text responses following PTO questions. This qualitative data was transformed into explicit codes conveying similar meanings. An overall coding framework was developed and a reliability test was carried out. Recurrent patterns were identified in each preference group. Comments which challenged the assumptions of hypothetical scenarios were also investigated. RESULTS: NHS causation of illness and a duty of care were the most cited reasons to prioritise lapses in healthcare safety. Personal responsibility dominated responses for lifestyle related contexts, and many respondents mentioned that health loss was the result of the individual's choice to engage in risky behaviour. A small proportion of responses questioned the assumptions underlying the PTO questions. However excluding these from the main analysis did not affect the conclusions. CONCLUSION: Although some responses indicated misunderstanding or rejection of assumptions we put forward, the results were still robust. The reasons put forward for responses differed between comparisons but responsibility was the most frequently cited. Most preference elicitation studies only focus on eliciting numerical valuations but allowing for qualitative data can augment understanding of preferences as well as verifying results.

Does responsibility affect the public's valuation of health care interventions? A relative valuation approach to health care safety.

OBJECTIVE: Health services often spend more on safety interventions than seems cost-effective. This study investigates whether the public value safety-related health care improvements more highly than the same improvements in contexts where the health care system is not responsible. METHOD: An online survey was conducted to elicit the relative importance placed on preventing harms caused by 1) health care (hospital-acquired infections, drug administration errors, injuries to health care staff), 2) individuals (personal lifestyle choices, sports-related injuries), and 3) nature (genetic disorders). Direct valuations were obtained from members of the public by using a person trade-off or "matching" method. Participants were asked to choose between two preventative interventions of equal cost and equal health benefit per person for the same number of people, but differing in causation. If participants indicated a preference, their strength of preference was measured by using person trade-off. RESULTS: Responses were obtained from 1030 people, reflecting the sociodemographic mix of the UK population. Participants valued interventions preventing hospital-acquired infections (1.31) more highly than genetic disorders (1.0), although drug errors were valued similarly to genetic disorders (1.07), and interventions to prevent injury to health care staff were given less weight than genetic disorders (0.71). Less weight was also given to interventions related to lifestyle (0.65) and sports injuries (0.41). CONCLUSION: Our results suggest that people do not attach a simple fixed premium to "safety-related" interventions but that preferences depend more subtly on context. The use of the results of such public preference surveys to directly inform policy would therefore be premature.

Evaluating interventions in health: a reconciliatory approach.

Health-related Quality of Life measures have recently been attacked from two directions, both of which criticize the preference-based method of evaluating health states they typically incorporate. One attack, based on work by Daniel Kahneman and others, argues that 'experience' is a better basis for evaluation. The other, inspired by Amartya Sen, argues that 'capability' should be the guiding concept. In addition, opinion differs as to whether health evaluation measures are best derived from consultations with the general public, with patients, or with health professionals. And there is disagreement about whether these opinions should be solicited individually and aggregated, or derived instead from a process of collective deliberation. These distinctions yield a wide variety of possible approaches, with potentially differing policy implications. We consider some areas of disagreement between some of these approaches. We show that many of the perspectives seem to capture something important, such that it may be a mistake to reject any of them. Instead we suggest that some of the existing 'instruments' designed to measure HR QoLs may in fact successfully already combine these attributes, and with further refinement such instruments may be able to provide a reasonable reconciliation between the perspectives.

Simulation contact lenses for AMD health state utility values in NICE appraisals: a different reality.

BACKGROUND/AIMS: The National Institute for Health and Care Excellence (NICE) has recommended the use of ranibizumab for neovascular age-related macular degeneration (AMD) and for diabetic macular oedema (DMO) as part of its health technology appraisal process. In the economic evaluations of both interventions, utility values were derived from members of the general public wearing contact lenses with a central opacity that was meant to simulate the blind spot experienced by many patients with advanced retinal disease. This paper tests the validity of the contact lens simulation, and finding it to be invalid, explores the impact on prior economic evaluations. METHODS: Visual acuity, contrast sensitivity and visual fields were assessed with and without simulation lenses in five healthy subjects with normal vision. RESULTS: We identified important differences between the contact lens simulation and vision loss experienced by patients with AMD. The contact lens simulator did not cause the central scotoma which is characteristic of late-stage AMD and which leads to severe difficulty with everyday activities such as reading or recognising faces and objects. The contact lens instead caused a reduction in retinal illumination experienced by the subjects as a general dimming across the retina. CONCLUSIONS: A contact lens with a central opacity does not simulate a central scotoma. The clinical differences between simulated and actual AMD suggest there has been an underestimation of the severity of AMD health states. This brings into question the validity of the economic evaluations of treatments for AMD and DMO used by NICE.