Predicting Cognitive and Functional Trajectories in People With Late-Onset Dementia: 2 Population-Based Studies

Abstract

Objectives: Previous studies have shown large heterogeneity in the progression of dementia, both within and between patients. This heterogeneity offers an opportunity to limit the global and individual burden of dementia through the identification of factors associated with slow disease progression in dementia. We explored the heterogeneity in dementia progression to detect disease, patient, and social context factors related to slow progression. Design: Two longitudinal population-based cohort studies with follow-up across 12 years. Setting and Participants: 512 people with incident dementia from Stockholm (Sweden) contributed to the Kungsholmen Project and the Swedish National Study of Aging and Care in Kungsholmen. Methods: We measured cognition using the Mini-Mental State Examination and daily functioning using the Katz Activities of Daily Living Scale. Latent classes of trajectories were identified using a bivariate growth mixture model. We then used bias-corrected logistic regression to identify predictors of slower progression. Results: Two distinct groups of progression were identified; 76% (n ¼ 394) of the people with dementia exhibited relatively slow progression on both cognition and daily functioning, whereas 24% (n ¼ 118) demonstrated more rapid worsening on both outcomes. Predictors of slower disease progression were Alzheimer's disease (AD) dementia type [odds ratio (OR) 2.07, 95% confidence interval (CI) 1.15-3.71], lower age (OR 0.88, 95% CI 0.83-0.94), fewer comorbidities (OR 0.77, 95% CI 0.66-0.90), and a stronger social network (OR 1.72, 95% CI 1.01-2.93). Conclusions/Implications: Lower age, AD dementia type, fewer comorbidities, and a good social network appear to be associated with slow cognitive and functional decline. These factors may help to improve the counseling of patients and caregivers and to optimize the planning of care in dementia.

Cognitive and functional progression of dementia in two longitudinal studies

“…In contrast, we used IADL items, which solely measure daily functioning in instrumental activities. The finding that non‐AD dementia types are most common in the rapidly progressing class of the NACC sample is consistent with other studies reporting that non‐AD dementia types tend to progress more rapidly . Another potential explanation for differences in rates of cognitive decline across classes may lie in the theory of “cognitive reserve,” stating that more education is associated with faster cognitive decline.…”

“…This replication study yielded three latent trajectories . A recent study based on a sample of incident dementia cases derived from two Swedish population‐based cohorts identified two distinct trajectories of MMSE and activities of daily functioning . These observed disparities in trajectories across cohorts may have resulted from differences in study design of the cohorts.…”

“…The finding that non-AD dementia types are most common in the rapidly progressing class of the NACC sample is consistent with other studies reporting that non-AD dementia types tend to progress more rapidly. 8,36 Another potential explanation for differences in rates of cognitive decline across classes may lie in the theory of "cognitive reserve," 37 stating that more education is associated with faster cognitive decline. Higher-educated people might be better able to cope with the initial signs of the disease and maintain their daily functioning, up until a certain threshold, after which they exhibit a sudden and steep decline.…”

“…7 Some studies adopted a promising way to find patterns of decline using growth mixture modeling (GMM). [8][9][10][11] This method is particularly suitable for identifying homogeneous subgroups (ie, classes) within a larger heterogeneous population to increase our understanding of . This replication study yielded three latent trajectories.…”

“…12 A recent study based on a sample of incident dementia cases derived from two Swedish population-based cohorts identified two distinct trajectories of MMSE and activities of daily functioning. 8 These observed disparities in trajectories across cohorts may have resulted from differences in study design of the cohorts. The NACC database consists of a referral-based/volunteer case series, 13 while the CCDPS is a population-based cohort.…”