Willingness-to-pay stated preferences for 8 health-related quality-of-life domains in psoriasis: a pilot study

Abstract

Background: Psoriasis is a chronic skin condition that has a major impact on health-related quality of life (QOL). We evaluated health-related QOL via willingness to pay and a ranking task for 8 domains of health relevant to psoriasis: intimacy, physical comfort, self-care, ability to work or volunteer, ability to concentrate, emotional health, social comfort, and ability to sleep.

Objective: The goals of the study were to pilot test a new method to measure QOL impact in psoriasis and identify the areas of life most affected by psoriasis.

Methods: Forty participants with a history of psoriasis were interviewed in a face-to-face format. First, participants were asked to rank the 8 domains of health we were investigating. Second, patients were asked how much money they would be willing to pay for a hypothetical cure for each domain of health. Responses in US dollars were interpreted as strength of preference rather than absolute monetary values.

Results: About half of the patients in the sample (48%) were female, 60% had a college degree or further education, and 38% had an income level over $45,000/y. Physical comfort, social comfort, and emotional health were highly ranked by more than 75% of respondents. Ability to concentrate was least likely to be affected by psoriasis with just a quarter (25.7%) of respondents ranking this domain as important. The median amount patients were willing to pay for a hypothetical cure of psoriasis specific to a particular domain was highest for physical comfort ($2000, 25th quartile = $500, 75th quartile = $5500) and emotional health ($2000, 25th quartile = $250, 75th quartile = $5000), and lowest for ability to sleep ($625, 25th quartile = $50, 75th quartile = $5000).

Limitations: The sample size is modest for this pilot study. Willingness to pay as a method of eliciting stated preferences for qualitative aspects of health may be influenced by individual perception of money.

Conclusions: This study successfully pilot tested a willingness-to-pay method and a ranking task to measure the relative severity of 8 domains of health-related QOL and found that physical comfort, social comfort, and emotional health were the domains of health most affected by psoriasis.