PMS82 - Assessing Willigness to Pay Among Psoriasis and Psoriatic Arthritis Patients

Abstract

It is estimated that 30% of psoriasis (PSO) patients also develops psoriatic arthritis (PSA). This potential disease evolution brings along new symptoms such as swollen and painful joints and mobility problems. Since both diseases are potentially degenerative, the aim of this study was to measure which group of patients (PSO or PSA) is willing to pay most out of pocket to avoid their health related quality of life (HRQoL) to worsen. 395 US patients diagnosed with either psoriasis (n=151) or psoriatic arthritis (n=247) completed a questionnaire as part of a broader survey of treatment of PSO/PSA. The questionnaire included the EQ-5D-5L instrument and accompanying VAS. Patients were additionally asked to indicate by reference to the EQ-5D VAS scale the amount of money per month they would be willing to pay for treatments that would prevent a decline in HRQoL by 10 points. Price sensitivity curves were created by means of linear regression analysis that predict the proportion of patients willing to pay a certain amount of $ out of pocket per month. For both PSO (R² = 0,82) and PSA (R² = 0,86) monthly cost out of pocket (x-variable) was a good predictor of the proportion of patients that is willing to pay a certain amount out of pocket per month (y-variable). Regression models look as follows. For PSO: y =0,77e-0,005x for PSA: y = 0,86e-0,007x. To give a specific example 42% of the PSA patients is willing to pay $100 per month out of pocket whereas this is 47% among PSO patients. PSO patients are prepared to pay more out of pocket on a monthly basis to avoid their HRQoL to worsen than PSA patients. Further research is required to understand what drives this difference.