Dementia, depression and delirium in the very old prevalences and associated factors

Abstract: Emotional suffering in old age is largely caused by a variety of psychiatric disorders which are often, however, undertreated and underrecognized. This leads to reduced quality of life and functional status and increased morbidity and mortality. Dementia, delirium and depression are common disorders in the very old, and are similar in several ways. All have multiple causes and are diagnosed by means of symptomatic criteria, are challenging to diagnose and difficult to differentiate from each other in the very old. They often coexist in the same individual, and may have common risk factors.The overall aim of this thesis was to add to our knowledge about threats to successful aging, by investigating the prevalences of dementia, depression and delirium, and factors associated with these three disorders. Further aims were to measure change over time in the prevalence of dementia and depression, respectively, and to investigate the risk factors for incident depression. This thesis uses the population-based Umeå85+/GErontological Regional DAtabase (GERDA) material.In 2000-2002, every other 85-year-old, all 90-year-olds and all people ?95 years living in six municipalities in Västerbotten, Sweden were invited to participate, and in 2005-2007 the process was repeated, with the additional inclusion of the corresponding populations of two municipalities in Österbotten, Finland. A third data collection was carried out in 2010-2012. Trained assessors carried out assessments in the form of structured interviews during one or more home visits, recorded current medication and reviewed medical records obtained from general practitioners and hospitals. In 2000-2002 the prevalence of dementia was 17% among 85-year-olds, 24% among 90-year-olds and 46% among those aged ?95 years. In 2005-2007 dementia prevalence reached 28% among 85-year-olds, 40% among 90-yearolds and 45% among those aged ?95 years. The prevalence of dementia in the total sample was 27% in 2000-2002 and 37% in 2005-2007 (p=0.001). In 2000-2002 the prevalence of depressive disorders was 24% among 85-yearolds, 34% among 90-year-olds and 31% among those aged ?95 years. In 2005-2007 the prevalence of depressive disorders was 33% among 85-year-olds, 39% among 90-year-olds and 38% among those aged ?95 years. The prevalence of depressive disorders in the total sample was 29% in 2000-2002 and 37% in 2005-2007 (p=0.025). Among participants not depressed at baseline, 26% had developed depression after five years. Factors independently associated with new cases of depression at follow-up were hypertension, a history of stroke and a higher score on the 15-item Geriatric Depression Scale at baseline. The thirtyday prevalence of delirium in 2005-2007 was 17% among 85-year-olds, 21% among 90-year-olds and 39% among participants aged ?95 years. Delirium prevalence among individuals with dementia was higher than among those without dementia (52% vs. 5%, p<.001). Factors independently associated with delirium superimposed on dementia in a multivariate logistic regression model were depression, heart failure, living in an institution and prescribed antipsychotics.There was a high prevalence of dementia, depression and delirium in the papers comprising this thesis, and 55% had at least one of the three disorders. The prevalence of dementia and depression also increased between 2000-2002 and 2005-2007, after controlling for age and sex. Dementia and depression were important associated factors for delirium and half of those with dementia were depressed. The increasing age-specific prevalence of depression seems to be associated with the increasing age-specific prevalence of dementia. The papers presented are among the first to report a significantly increasing age-specific prevalence of dementia and depression among very old people. More knowledge about associated factors and risk factors concerning these disorders may be helpful for carers and decision-makers, as well as providing reference values for studies in other regions. Further efforts are needed in both care and research to better prevent, screen for, diagnose and treat dementia, depression and delirium, especially considering the growing number of very old people.