QUALITY-OF-LIFE IN EPILEPSY - COMPARISON OF 4 PREFERENCE MEASURES

Several specific and general measures are available for the assessment of overall health related quality of life in epilepsy. Few of the com monly used measures provide utility weights for use in cost-utility an alyses. This study compares four methods for measuring utility weights : time trade-off (TTO), standard gamble (SG), 15D, end the EuroQol vis ual analog scale. All patients aged 18-67 years with a diagnosis of ep ilepsy, who had been admitted to or attended the outpatient clinic at a large county hospital 1987-1994, received a comprehensive questionna ire. From 397 respondents, 82 patients were randomly selected. Most of the 57 patients completing the study generally had well-controlled ep ilepsy, but were still on anti-epileptic medication. Mean age was 44 y ears. Fourty-one percent were male and 59% female. The resulting utili ty weights differed considerably between the measures, both with regar d to central tendency and dispersion. Median utility scores: EuroQol v isual analog scale 0.75, 15D 0.90, TTO 0.98, SG 0.99. There was a good association between the EuroQol rating scale and the 15D, and a moder ate association between SG and TTO. These preference instruments measu re different aspects of health-related quality of life and thus yield different results. Caution should be taken when interpreting cost-util ity studies, as results will depend on the choice of utility instrumen t. (C) 1998 Elsevier Science B.V. All rights reserved.