Impact of social functioning and vitality on preference for life in patients with Parkinson's disease.

The determinants of preference for life in patients with Parkinson's disease are not well known. We assessed the effect of functional status on the preference for life as measured by the time trade-off method with a 10-year life span. Our survey was based on a random sample of 1,200 patients from the Japanese Association of Patients with Parkinson's Disease. Patients' demographics, clinical information, and functional status as measured by the MOS Short Form 36 were considered independent variables. The response rate was 63.5%. Linear regression showed that men had a significantly stronger preference for current health than women (by 10.4 months on a scale of 10 years). Patients with higher physical functioning, social functioning, and vitality had significantly higher preferences for life (each 10-point improvement in physical or social functioning led to a 1.5-month increment in preference for current health; a 10-point improvement in vitality led to a 3-month increment). Longer duration of disease and advanced Hoehn and Yahr stage were significantly associated with a lower preference for current health (by 0.5 months/year of disease and by 2.6 months/stage). Interventions that target social functioning and vitality may be beneficial to preference for life.