To compare limitations in health between Dutch patients with gout and the general population and to determine factors influencing societal and patient values for health as assessed with different utility approaches.
A cross-sectional study was done among 110 patients with gout under the care of a rheumatologist, with patients completing the EuroQol 5-domain instrument (EQ-5D), the EQ-5D visual analog scale (EQ-5D VAS), and the Short Form 6-dimensions health survey (SF-6D). Scores on EQ-5D domains were compared with age- and sex-matched general population data. Agreement between utility measures was assessed using the intraclass correlation coefficient (ICC). Mixture modeling was used to assess factors associated with the different approaches to assess utility.
Compared to the general population, gout patients reported more limitations in mobility (66% versus 12%), self-care (24% versus 8%), daily activities (49% versus 24%), and pain (76% versus 45%), but equal anxiety/depressive symptoms (18% versus 19%). For patients with gout, utilities were reduced: the mean, median, and interquartile range, respectively, were 0.74, 0.81, and 0.69-0.84 for EQ-5D, 0.69, 0.67, and 0.59-0.81 for SF-6D, and 66, 70, and 57-77 for EQ-5D VAS. ICC agreement between each pair of utilities was only moderate (0.52-0.59). Only minor differences were seen in the type of variables associated with each utility approach, with worse Health Assessment Questionnaire scores, cardiovascular disease (CVD), gout concern, and gout pain consistently associated with lower utility. The strength of contribution of these variables, however, differed among the 3 approaches.
Patients with gout experience substantially impaired health compared to the general population. Although absolute values of utility varied between instruments and perspectives, functional disability, CVD, and higher gout impact contributed to utility independently of which instrument was used.