http://repub.eur.nl/res/aut/14369/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/11451/ 1995-01-01T00:00:00Z This article explores various methodological issues of patient utility measurement in two randomized controlled clinical trials involving 85 patients with fibromyalgia and 144 with ankylosing spondylitis. In both trials one baseline and two follow-up measurements of the patients' preferences for their own health state and several hypothetical states were performed using the rating scale and the standard gamble methods. It was confirmed that standard gamble scores are consistently higher than rating scale scores for both the experienced and the hypothetical states. The 3-month test-retest reliability for hypothetical states measured by intraclass correlation coefficients ranged from 0.24 to 0.33 for the rating scale and from 0.43 to 0.70 for the standard gamble. Although the reproducibility is not high, the group mean scores are fairly stable over time. Mean standard gamble scores tend to differ depending on the way the measurements are undertaken. Utilities elicited with chained gambles were significantly higher than utilities elicited with basic reference gambles. At the individual level some inconsistent responses occurred. However, more than 70% of these fell within the bounds of the measurement error, which ranged from 0.11 to 0.13 on the standard gamble (0-1 scale) and from 8 to 10 on the rating scale (0-100 scale). The large number of negative utilities for the severe hypothetical state, which was used as an anchor point in the chained gambles, and the magnitude of these negative utilities (down to -19) calls for intensified research efforts to handle these responses in utility calculations http://repub.eur.nl/res/pub/11456/ 1993-01-01T00:00:00Z Utility measures of health-related quality of life are preference values that patients attach to their overall health status. In clinical trials, utility measures summarize both positive and negative effects of an intervention into one single value between 0 (equal to death) and 1 (equal to perfect health). These measures allow for comparison of patient outcomes of different diseases and allow for comparison between various health care interventions. There are two different approaches to utility measurement. The first is to classify patients into categories based on their responses to a number of questions about their functional status, as for instance the Quality of Well-Being questionnaire. The second approach is to ask patients to assign a single rating to their overall health by means of rating scale, standard gamble, time trade-off, or willingness to pay. The Quality Adjusted Life Year (QALY) as outcome measure includes both effects in terms of quality and quantity of life. Utilities are used as weights to adjust life years for the quality of life in order to calculate QALYs. Both QALYs and utilities are useful in decision-making regarding appropriate procedures for groups of patients.