Defining utility values for patients with tardive dyskinesia

Objective To measure health state preferences and estimate utility values for tardive dyskinesia (TD) from the perspective of the US general population, accounting for factors affecting quality of life (QOL). Methods Participants from the general population were recruited and asked to watch and assess videos of professional actors simulating nine health states, including psychiatric disorders with/without TD and moderate-to-severe TD without any underlying disease. Time tradeoff (TTO) methods were used to elicit utility values, which ranged from -1 (worse than death) to +1 (perfect health) and represented individual preferences for avoiding specific health states associated with TD. Lower TTO utility values indicated individuals' willingness to give up more years of life to avoid living in each health state. Results Based on TTO responses (n = 157), mean +/- standard deviation utility for TD alone was 0.59 +/- 0.38. Mean utilities for schizophrenia with negative symptoms (without TD: 0.43; with TD: 0.29) and positive symptoms (without TD: 0.44; with TD: 0.30) were generally lower than those for bipolar disorder (without TD: 0.59; with TD: 0.46) and major depressive disorder (without TD: 0.60; with TD: 0.44). According to utility decrements associated with TD (0.13-0.16), respondents were willing to give up 1.3 to 1.6 years during a 10-year lifespan to avoid living with TD. Conclusions Utility decrements for TD in this study were slightly larger than previously reported values, potentially due to incorporation of QOL and social consequences in TD health state descriptions. An important limitation of this analysis is that participants' willingness to trade future years of healthy life may not indicate actual willingness to accept the life decrement. These findings can be leveraged to improve cost-effectiveness analyses used to assess the value of treatments for TD.