Survival in Huntington's disease and other young‐onset dementias.

Objectives: To compare survival and risk factors associated with mortality in common young‐onset dementias (YOD) including Huntington's disease. Methods: This retrospective cohort study included inpatients from an Australian specialist neuropsychiatry service, over 20 years. Dementia diagnoses were based on consensus criteria and Huntington's disease (HD) was confirmed genetically. Mortality and cause of death were determined using linkage to the Australian Institute of Health and Welfare National Death Index. Results: There were 386 individuals with YOD included. The dementia types included frontotemporal dementia (FTD) (24.5%), HD (21.2%) and Alzheimer's disease (AD) (20.5%). 63% (n = 243) individuals had died. The longest median survival was for those who had HD, 18.8 years from symptom onset and with a reduced mortality risk compared to AD and FTD (hazard ratio 0.5). Overall, people with YOD had significantly increased mortality, of 5–8 times, compared to the general population. Females with a YOD had higher standardised mortality ratio compared to males (9.3 vs. 4.9) overall. The most frequent cause of death in those with HD was reported as HD, with other causes of death in the other YOD‐subtypes related to dementia and mental/behavioural disorders. Discussion: This is the first Australian study to investigate survival and risk factors of mortality in people with YOD. YOD has a significant risk of death compared to the general population. Our findings provide useful clinical information for people affected by YOD as well as future planning and service provision. Key points: Dementia is a leading cause of death in Australia and the leading cause of death in females. There is limited mortality information pertaining to younger people with dementia.We investigated mortality and risk factors in young‐onset dementia, including Huntington's disease. Huntington's disease had the longest survival ‐ 18.8 years, with Alzheimer's disease, frontotemporal and vascular dementias having 11 and 13 years median survival. Young‐onset dementia conferred between 5 and 8 times increased risk of death compared to the general population.Young‐onset dementia is a fatal disease with shortened lifespan. Early identification and timely age‐appropriate services are necessary for these individuals. [ABSTRACT FROM AUTHOR]