Assessment of patient preferences: Integrating treatments and outcomes

Objectives. The purpose of this study was to develop a patient-centered measure of treatment preference applicable across a range of diseases and treatment decisions. Methods. Instrument development was based on previous research supplemented by open-ended interviews and focus groups. Psychometric properties of the instrument were determined by administration to 125 persons aged 60 or older with a limited life expectancy secondary to congestive heart failure, chronic obstructive pulmonary disease, or cancer. Test-retest and inter-rater reliability were established using intraclass correlation coefficients. Construct validity was established by examining associations of the measure with a single-item question regarding treatment goals and with age, ethnicity, and functional impairment, characteristics known to be associated with preferences. The Willingness to Accept Life-Sustaining Treatment instrument (WALT) consists of 6 scenarios in which respondents weigh treatment burden against treatment outcomes expressed in terms of the likelihood of different health states and length of life following treatment. Results. Inter-rater reliability ranged from .73 to .95 and test-retest reliability from .49 to .93. WALT scores were significantly associated with a simpler measure of preference and with age, ethnicity, and functional impairment. Conclusions. The WALT measures patients' treatment preferences, assessed in the context of treatment burden and multiple aspects of treatment outcome with sound psychometric properties.