Cognitive and functional progression in Alzheimer disease: A prediction model of latent classes

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Objectives Previous studies have identified several subgroups (ie, latent trajectories) with distinct disease progression among people with dementia. However, the methods and results were not always consistent. This study aims to perform a coordinated analysis of latent trajectories of cognitive and functional progression in dementia across two datasets. Methods Included and analyzed using the same statistical approach were 1628 participants with dementia from the US National Alzheimer's Coordinating Center (NACC) and 331 participants with dementia from the Dutch Clinical Course of Cognition and Comorbidity study (4C‐Study). Trajectories of cognition and instrumental activities of daily living (IADL) were modeled jointly in a parallel‐process growth mixture model. Results Cognition and IADL tended to decline in unison across the two samples. Slow decline in both domains was observed in 26% of the US sample and 74% of the Dutch sample. Rapid decline in cognition and IADL was observed in 7% of the US sample and 26% of the Dutch sample. The majority (67%) of the US sample showed moderate cognitive decline and rapid IADL decline. Conclusions Trajectories of slow and rapid dementia progression were identified in both samples. Despite using the same statistical methods, the number of latent trajectories was not replicated and the relative class sizes differed considerably across datasets. These results call for careful consideration when comparing progression estimates in the literature. In addition, the observed discrepancy between cognitive and functional decline stresses the need to monitor dementia progression across multiple domains.

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 88%

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confidence: 99%

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Cognitive and functional progression of dementia in two longitudinal studies

Wang

Haaksma

Ramakers

et al. 2019

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“…Fifth, the K-MMSE we used in the present study is a relatively crude assessment of cognitive function. 43 Thus, subtle changes in cognitive function may be undetectable with this tool. Lastly, although we adjusted for chronic health conditions in our analyses, certain chronic diseases may be closely related to cognitive function among older adults.…”

Section: Growth Curve Model Resultsmentioning

confidence: 99%

“…Fourth and relatedly, the KLoSA datasets do not contain information regarding whether the spousal death was expected or unexpected, which may influence the impact of widowhood. Fifth, the K‐MMSE we used in the present study is a relatively crude assessment of cognitive function . Thus, subtle changes in cognitive function may be undetectable with this tool.…”

Section: Discussionmentioning

confidence: 97%

Trajectories of cognitive decline by widowhood status among Korean older adults

Lyu

Min

Kim

2019

Objectives Given the limited evidence regarding the longitudinal impact of widowhood on cognitive function in later life, the present study aimed to investigate the longitudinal effect of widowhood status on cognitive change among Korean older adults. Methods The study sample was drawn from a nationally representative data set, the Korean Longitudinal Study of Ageing (KLoSA); it consisted of 3,660 Korean adults aged 60 and over who were married at baseline. Our dependent variable, cognitive function, was measured by the Korean version of the Mini‐Mental State Examination (K‐MMSE). Widowhood status was measured with the combination of widowhood status and duration. Growth curve models were constructed using five waves of the KLoSA (2006‐2014) to examine the longitudinal trajectories of cognitive changes. Results In the unadjusted model, widowed older adults had significantly lower cognitive function than their nonwidowed counterparts regardless of widowhood duration. Adjusting for covariates, results from the growth curve models showed that widowed older adults with widowhood duration 4 to 6 years had a significantly steeper decline in cognitive function than nonwidowed older adults (P < 0.05). Conclusions These findings suggest that widowhood is detrimental for late‐life cognitive function. Further research is required to understand the mechanisms underlying this relationship. Policy and practice implications are discussed according to the cultural context.

Cognitive and functional progression in Alzheimer disease: A prediction model of latent classes

Haaksma

Calderón‐Larrañaga

Rikkert

et al. 2018

Objective We sought to replicate a previously published prediction model for progression, developed in the Cache County Dementia Progression Study (CCDPS), using a clinical cohort from the National Alzheimer’s Coordinating Center. Methods We included 1120 incident AD cases with at least one assessment after diagnosis, originating from 31 Alzheimer Disease centers from the United States. Trajectories of the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating sum of boxes (CDR-sb) were modeled jointly over time using parallel-process growth mixture models in order to identify latent classes of trajectories. Bias-corrected multinomial logistic regression was used to identify baseline predictors of class membership and compare these with the predictors found in the CCDPS. Results The best fitting model contained three classes; class 1 was the largest (63%) and showed the slowest progression on both MMSE and CDR-sb. Classes 2 (22%) and 3 (15%) showed moderate and rapid worsening, respectively. Significant predictors of membership in classes 2 and 3, relative to class 1, were worse baseline MMSE and CDR-sb, higher education and lack of hypertension. Combining all previously mentioned predictors yielded areas under the ROC curve of 0.70 and 0.75 for classes 2 and 3, relative to class 1. Conclusions Our replication study confirmed that it is possible to predict trajectories of progression in AD with relatively good accuracy. The class distribution was comparable with the original study, with most individuals being members of a class with stable or slow progression. This is important for informing newly diagnosed AD patients and their caregivers.