Gender-dependence of substituted judgment on quality of life in patients with dementia

212 patients with dementia and their proxies were interviewed in their homes. Dementia syndrome was characterized with cognitive, non-cognitive and functional scales. Quality of life (QoL) was assessed with the QoL-AD.Substituted judgment of the patient's QoL was unrelated to dementia severity but also correlated with the proxie's own QoL (r = 0.356; p < 0.001). Gender-specific analysis reveals that for male proxies the most important variable is severity of patient's depression (r = -0.895; p = 0.001) while for female proxies it is the proxie's own QoL (r = 0.371; p < 0.001). Subjective burden correlates with the proxie's QoL in females (r = -0.282; p = 0.001) but not in males (r = -0.163, p = 0.161).Substituted judgment of the patient's QoL does not correlate with dementia severity. Substituted judgment is subject to proxy-related variables in a gender-dependent fashion and therefore not suited to serve as an appropriate surrogate of the patients' quality of life.Alzheimer's disease (AD) is a neurodegenerative disease with increasing prevalence in the aging societies of the Western hemisphere. Similarly, the prevalence of other age-related diseases increases. For all these diseases and conditions therapeutic interventions are being developed and improved. Common outcome variables are requested by today's health care systems to allow a comparison of the impact of diseases and the efficacy of treatments. One widely considered option to analyze the impact of disease on patients' life is to evaluate "Quality of life" (QoL).The World Health Organisation defines QoL as "the individual's perceptions of their position in life in the context of the culture and value systems in which they live, and in relationship to their goals, expectations, and standards" (WHO-QoL, 1995). By this definition QoL is a subjective construct, being evaluated by the affected person by means of self reports. A widely used model assumes four domains which contribute to the individual's QoL: beha