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

Global cognitive trajectory patterns in Alzheimer's disease

OBJECTIVES

The literature on Alzheimer's disease (AD) provides little data about long-term cognitive course trajectories. We identify global cognitive outcome trajectories and associated predictor variables that may inform clinical research and care.

DESIGN

Data derived from the National Alzheimer's Coordinating Center (NACC) Uniform Data Set were used to examine the cognitive course of persons with possible or probable AD, a Mini-Mental State Examination (MMSE) of ≥10, and complete annual assessments for 5 years.

SETTING

Thirty-six Alzheimer's Disease Research Centers.

PARTICIPANTS

Four hundred and fourteen persons.

MEASUREMENTS

We used a hybrid approach comprising qualitative analysis of MMSE trajectory graphs that were operationalized empirically and binary logistic regression analyses to assess 19 variables' associations with each trajectory. MMSE scores of ±3 points or greater were considered clinically meaningful.

RESULTS

Five distinct cognitive trajectories were identified: fast decliners (32.6%), slow decliners (30.7%), zigzag stable (15.9%), stable (15.9%), and improvers (4.8%). The decliner groups had three subtypes: curvilinear, zigzag, and late decline. The fast decliners were associated with female gender, lower baseline MMSE scores, a shorter illness duration, or receiving a cognitive enhancer. An early MMSE decline of ≥3 points predicted a worse outcome. A higher rate of traumatic brain injury, the absence of an ApoE ϵ4 allele, and male gender were the strongest predictors of favorable outcomes.

CONCLUSIONS

Our hybrid approach revealed five distinct cognitive trajectories and a variegated pattern within the decliners and stable/improvers that was more consistent with real-world clinical experience than prior statistically modeled studies. Future investigations need to determine the consistency of the distribution of these categories across settings.

Proteomic clusters underlie heterogeneity in preclinical Alzheimer's disease progression

Heterogeneity in progression to Alzheimer's disease (AD) poses challenges for both clinical prognosis and clinical trial implementation. Multiple AD-related subtypes have previously been identified, suggesting differences in receptivity to drug interventions. We identified early differences in preclinical AD biomarkers, assessed patterns for developing preclinical AD across the amyloid-tau-(neurodegeneration) [AT(N)] framework, and considered potential sources of difference by analysing the CSF proteome. Participants (n = 10) enrolled in longitudinal studies at the Knight Alzheimer Disease Research Center completed four or more lumbar punctures. These individuals were cognitively normal at baseline. Cerebrospinal fluid measures of amyloid-β (Aβ)42, phosphorylated tau (pTau181), and neurofilament light chain (NfL) as well as proteomics values were evaluated. Imaging biomarkers, including PET amyloid and tau, and structural MRI, were repeatedly obtained when available. Individuals were staged according to the amyloid-tau-(neurodegeneration) framework. Growth mixture modelling, an unsupervised clustering technique, identified three patterns of biomarker progression as measured by CSF pTau181 and Aβ42. Two groups (AD Biomarker Positive and Intermediate AD Biomarker) showed distinct progression from normal biomarker status to having biomarkers consistent with preclinical AD. A third group (AD Biomarker Negative) did not develop abnormal AD biomarkers over time. Participants grouped by CSF trajectories were re-classified using only proteomic profiles (AUCAD Biomarker Positive versus AD Biomarker Negative = 0.857, AUCAD Biomarker Positive versus Intermediate AD Biomarkers = 0.525, AUCIntermediate AD Biomarkers versus AD Biomarker Negative = 0.952). We highlight heterogeneity in the development of AD biomarkers in cognitively normal individuals. We identified some individuals who became amyloid positive before the age of 50 years. A second group, Intermediate AD Biomarkers, developed elevated CSF ptau181 significantly before becoming amyloid positive. A third group were AD Biomarker Negative over repeated testing. Our results could influence the selection of participants for specific treatments (e.g. amyloid-reducing versus other agents) in clinical trials. CSF proteome analysis highlighted additional non-AT(N) biomarkers for potential therapies, including blood-brain barrier-, vascular-, immune-, and neuroinflammatory-related targets.

Association of marital status with cognitive function in Chinese hypertensive patients: a cross-sectional study

PURPOSE

The aim of this study was to evaluate the association of marital status with cognitive function and to examine the potential effect modifiers in Chinese hypertensive populations.

METHODS

A total of 9,525 adult Chinese hypertensive patients were enrolled in this cross-sectional study. Cognitive function, as the dependent variable in our study, was assessed by the Chinese version of the Mini-Mental State Examination (MMSE). We adjusted for potential confounding factors in multiple linear regression models to examine the relationship of marital status with cognitive function. In addition, we divided the population according to sex to explore whether there were sex-specific differences.

RESULTS

Among the 9,525 study participants, the mean (SD) age for men was 63.5 (10.3) years, and the mean MMSE score was 24.9 ± 5.0, whereas for women, the mean (SD) age was 63.8 (9.3) years, and the mean MMSE score was 19.4 ± 6.4. Unmarried persons had lower scores on the MMSE and lower subscores in each of the cognitive domains. A stronger correlation between marital status and a lower MMSE score was statistically significant in men (unmarried men: β = -1.55; 95% CI: -1.89, -1.21) but not women (unmarried women: β = -0.22; 95% CI: -0.56, 0.12; p interaction = 0.006). Compared to men who were widowed or divorced, never married men were more likely to have lower MMSE scores (β = -2.30, 95% CI -3.10,-1.50; p < 0.001).

CONCLUSIONS

Our study demonstrated that being unmarried is an extremely important but neglected social risk factor for cognitive function. Sex was a strong effect modifier: being unmarried was correlated with a higher risk of cognitive decline than being married in Chinese hypertensive men, especially among older men, but this correlation was not observed among women. Moreover, never married men showed poorer cognitive function than those who were divorced or widowed.

Model-based stratification of progression along the Alzheimer disease continuum highlights the centrality of biomarker synergies

BACKGROUND

The progression rates of Alzheimer's disease (AD) are variable and dynamic, yet the mechanisms that contribute to heterogeneity in progression rates remain ill-understood. Particularly, the role of synergies in pathological processes reflected by biomarkers for amyloid-beta ('A'), tau ('T'), and neurodegeneration ('N') in progression along the AD continuum is not fully understood.

METHODS

Here, we used a combination of model and data-driven approaches to address this question. Working with a large dataset (N = 321 across the training and testing cohorts), we first applied unsupervised clustering on longitudinal cognitive assessments to divide individuals on the AD continuum into those showing fast vs. moderate decline. Next, we developed a deep learning model that differentiated fast vs. moderate decline using baseline AT(N) biomarkers.

RESULTS

Training the model with AT(N) biomarker combination revealed more prognostic utility than any individual biomarkers alone. We additionally found little overlap between the model-driven progression phenotypes and established atrophy-based AD subtypes. Our model showed that the combination of all AT(N) biomarkers had the most prognostic utility in predicting progression along the AD continuum. A comprehensive AT(N) model showed better predictive performance than biomarker pairs (A(N) and T(N)) and individual biomarkers (A, T, or N).

CONCLUSIONS

This study combined data and model-driven methods to uncover the role of AT(N) biomarker synergies in the progression of cognitive decline along the AD continuum. The results suggest a synergistic relationship between AT(N) biomarkers in determining this progression, extending previous evidence of A-T synergistic mechanisms.

Incident Care Trajectories for Older Adults with and without Dementia

OBJECTIVE

Despite cross-sectional evidence that persons living with dementia receive disproportionate hours of care, studies of how care intensity progresses over time and differs for those living with and without dementia have been lacking.

METHODS

We used the 2011-2018 National Health and Aging Trends Study to estimate growth mixture models to identify incident care hour trajectories ("classes") among older adults (N=1,780).

RESULTS

We identified four incident care hour classes: "Low, stable," "High, increasing," "24/7 then high, stable," and "Low then resolved." The high-intensity classes had the highest proportions of care recipients with dementia and accounted for nearly half of that group. Older adults with dementia were 3-4 times as likely as other older adults to experience one of the two high-intensity trajectories. A substantial proportion of the 4 in 10 older adults with dementia who were predicted to be in the "Low, stable" class lived in residential care settings.

DISCUSSION

Information on how family caregiving is likely to evolve over time in terms of care hours may help older adults with and without dementia, the family members, friends, and paid individuals who care for them, as well as their health care providers assess and plan for future care needs.

Is Amyloid Burden Measured by 18F-Flutemetamol PET Associated with Progression in Clinical Alzheimer's Disease?

Background:

Patients with Alzheimer’s disease (AD) show heterogeneity in clinical progression rate, and we have limited tools to predict prognosis. Amyloid burden from ¹⁸F-Flutemetamol positron emission tomography (PET), as measured by standardized uptake value ratios (SUVR), might provide prognostic information.

Objective:

We investigate whether ¹⁸F-Flutemetamol PET composite or regional SUVRs are associated with trajectories of clinical progression.

Methods:

This observational longitudinal study included 94 patients with clinical AD. PET images were semi-quantified with normalization to pons. Group-based trajectory modeling was applied to identify trajectory groups according to change in the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) over time. Multinomial logistic regression models assessed the association of SUVRs with trajectory group membership.

Results:

Three trajectory groups were identified. In the regression models, neither composite nor regional SUVRs were associated with trajectory group membership.

Conclusion:

There were no associations between CDR progression and ¹⁸F-Flutemetamol PET-derived composite SUVRs or regional SUVRs in clinical AD.

Classification, Prediction, and Concordance of Cognitive and Functional Progression in Patients with Mild Cognitive Impairment in the United States: A Latent Class Analysis

Background:

Progression trajectories of patients with mild cognitive impairment (MCI) are currently not well understood.

Objective:

To classify patients with incident MCI into different latent classes of progression and identify predictors of progression class.

Methods:

Participants with incident MCI were identified from the US National Alzheimer’s Coordinating Center Uniform Data Set (09/2005-02/2019). Clinical Dementia Rating (CDR^®) Dementia Staging Instrument-Sum of Boxes (CDR-SB), Functional Activities Questionnaire (FAQ), and Mini-Mental State Examination (MMSE) score longitudinal trajectories from MCI diagnosis were fitted using growth mixture models. Predictors of progression class were identified using multivariate multinomial logistic regression models; odds ratios (ORs) and 95% confidence intervals (CIs) were reported.

Results:

In total, 21%, 22%, and 57% of participants (N = 830) experienced fast, slow, and no progression on CDR-SB, respectively; for FAQ, these figures were 14%, 23%, and 64%, respectively. CDR-SB and FAQ class membership was concordant for most participants (77%). Older age (≥86 versus≤70 years, OR [95% CI] = 5.26 [1.78–15.54]), one copy of APOE ɛ4 (1.94 [1.08–3.47]), higher baseline CDR-SB (2.46 [1.56–3.88]), lower baseline MMSE (0.85 [0.75–0.97]), and higher baseline FAQ (1.13 [1.02–1.26]) scores were significant predictors of fast progression versus no progression based on CDR-SB (all p < 0.05). Predictors of FAQ class membership were largely similar.

Conclusion:

Approximately a third of participants experienced progression based on CDR-SB or FAQ during the  4-year follow-up period. CDR-SB and FAQ class assignment were concordant for the vast majority of participants. Identified predictors may help the selection of patients at higher risk of progression in future trials.

Trajectories and risk factors of dementia progression: a memory clinic cohort followed up to 3 years from diagnosis

OBJECTIVES

Patients with dementia follow different trajectories of progression. We aimed to investigate which factors at the time of diagnosis could predict trajectory group membership.

DESIGN

Longitudinal observational study.

SETTING

Specialized memory clinic, Oslo University Hospital in Norway.

PARTICIPANTS

Patients assessed at the memory clinic, between 12 January 2009 and 31 July 2016, who were registered in the Norwegian Registry of persons assessed for cognitive symptoms (NorCog) and diagnosed with dementia after the baseline examination period (n = 442). The patients were followed up to 3 years, with an average of 3.5 examinations.

MEASUREMENTS

Clinical Dementia Rating Scale Sum of Boxes (CDR-SB), Mini-Mental State Examination (MMSE), the Consortium to Establish a Registry of Alzheimer's disease (CERAD) 10-item word list delayed recall, the Clock Drawing Test, (CDT) Trail Making Test A (TMT-A), and Neuropsychiatric Inventory Questionnaire (NPI-Q). Based on changes in scores on the CDR-SB, we used group-based trajectory modeling (GBTM) to explore the presence of trajectory groups. Multinomial logistic regression was used to explore whether a set of baseline variables could predict trajectory group membership.

RESULTS

Three trajectory groups were identified, one with a slow progression rate and two with more-rapid progression. Rapid progression was associated with older age, lower cognitive function (MMSE and TMT-A), and more-pronounced neuropsychiatric symptoms (NPI-Q) at the time of diagnosis.

CONCLUSIONS

Our findings demonstrate the heterogeneity of dementia progression and describe risk factors for rapid progression, emphasizing the need for individual follow-up regimes. For future intervention studies, our results may guide the selection of patients.

Neuropsychiatric symptoms and comorbidity: Associations with dementia progression rate in a memory clinic cohort

OBJECTIVES

Neuropsychiatric symptoms (NPS) are associated with dementia severity and progression rate. NPS clusters have different neurobiological underpinnings; therefore, their effect on dementia progression may differ. Furthermore, little is known about whether individual comorbidities affect progression rate. We investigated the effect of NPS clusters and individual comorbidities on dementia progression.

METHODS

A memory clinic cohort with all-cause dementia (N = 442) was followed for up to 3 years from diagnosis. Previously, we found trajectory groups of dementia progression in this cohort: one with slow progression and two with rapid progression. In the present study, using principal component analysis, three symptom clusters of NPS were identified on the Neuropsychiatric Inventory Questionnaire (NPI-Q): agitation, affective and psychosis symptom clusters. Data regarding comorbidity were collected by linkage to the Norwegian Patient Registry. Multinomial logistic regression was applied to explore the association between NPS clusters and comorbidity with trajectory-group membership.

RESULTS

Adjusted for demographics, dementia aetiology, comorbidity and cognition, we found that, at the time of dementia diagnosis, for every point within the psychosis symptom cluster of the NPI-Q, the risk of rapid progression increased by 53%; for every point within the affective symptom cluster, the risk of rapid progression increased by 29%. A previous diagnosis of mental and behavioural disorders (excluding dementia) decreased the risk of rapid dementia progression by 65%.

CONCLUSIONS

Psychosis and affective symptom clusters at the time of diagnosis were associated with rapid progression of dementia. Previous diagnoses of mental and behavioural disorders (excluding dementia) were associated with slow progression.

Long-term Effects of Cholinesterase Inhibitors on Cognitive Decline and Mortality

Objective

To investigate whether cholinesterase inhibitors (ChEIs) are associated with slower cognitive decline in Alzheimer dementia and decreased risk of severe dementia or death.

Methods

Patients with Alzheimer dementia from the Swedish Dementia Registry starting on ChEIs within 3 months of the dementia diagnosis were included and compared to nontreated patients with Alzheimer dementia. In a propensity score–matched cohort, the association between ChEI use and cognitive trajectories assessed by Mini-Mental State Examination (MMSE) scores was examined with a mixed model, and severe dementia (MMSE score <10) or death as an outcome was assessed with Cox proportional hazards models.

Results

The matched cohort included 11,652 ChEI users and 5,826 nonusers. During an average of 5 years of follow-up, 255 cases developed severe dementia, and 6,055 (35%) died. ChEI use was associated with higher MMSE score at each visit (0.13 MMSE points per year; 95% confidence interval [CI] 0.06–0.20). ChEI users had a 27% lower risk of death (0.73, 95% CI 0.69–0.77) compared with nonusers. Galantamine was associated with lower risk of death (0.71, 95% CI 0.65–0.76) and lower risk of severe dementia (0.69, 95% CI 0.47–1.00) and had the strongest effect on cognitive decline of all the ChEIs (0.18 MMSE points per year, 95% CI 0.07–0.28).

Conclusions

ChEIs are associated with cognitive benefits that are modest but persist over time and with reduced mortality risk, which could be explained partly by their cognitive effects. Galantamine was the only ChEI demonstrating a significant reduction in the risk of developing severe dementia.

Classification of Evidence

This study provides Class III evidence that for patients with Alzheimer dementia ChEIs decrease long-term cognitive decline and risk of death and that galantamine decreases the risk of severe dementia.

Modifiable, Non-Modifiable, and Clinical Factors Associated with Progression of Alzheimer's Disease

There is an extensive literature relating to factors associated with the development of Alzheimer's disease (AD), but less is known about factors which may contribute to its progression. This review examined the literature with regard to 15 factors which were suggested by PubMed search to be positively associated with the cognitive and/or neuropathological progression of AD. The factors were grouped as potentially modifiable (vascular risk factors, comorbidities, malnutrition, educational level, inflammation, and oxidative stress), non-modifiable (age at clinical onset, family history of dementia, gender, Apolipoprotein E ɛ4, genetic variants, and altered gene regulation), and clinical (baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs). Although conflicting results were found for the majority of factors, a positive association was found in nearly all studies which investigated the relationship of six factors to AD progression: malnutrition, genetic variants, altered gene regulation, baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs. Whether these or other factors which have been suggested to be associated with AD progression actually influence the rate of decline of AD patients is unclear. Therapeutic approaches which include addressing of modifiable factors associated with AD progression should be considered.

Cognitive Decline in Alzheimer's Disease Is Not Associated with APOE

BACKGROUND

The rate of cognitive decline in Alzheimer's disease (AD) has been found to vary widely between individuals, with numerous factors driving this heterogeneity.

OBJECTIVE

This study aimed to compute a measure of cognitive decline in patients with AD based on clinical information and to utilize this measure to explore the genetic architecture of cognitive decline in AD.

METHODS

An in-house cohort of 616 individuals, hereby termed the Cardiff Genetic Resource for AD, as well as a subset of 577 individuals from the publicly available ADNI dataset, that have been assessed at multiple timepoints, were used in this study. Measures of cognitive decline were computed using various mixed effect linear models of Mini-Mental State Examination (MMSE). After an optimal model was selected, a metric of cognitive decline for each individual was estimated as the random slope derived from this model. This metric was subsequently used for testing the association of cognitive decline with apolipoprotein E (APOE) genotype.

RESULTS

No association was found between the number of APOEɛ2 or ɛ4 alleles and the rate of cognitive decline in either of the datasets examined.

CONCLUSION

Further exploration is required to uncover possible genetic variants that affect the rate of decline in patients with AD.

A longitudinal study using latent curve models of groups with mild cognitive impairment and Alzheimer's disease

BACKGROUND

This study explores how mild cognitive impairment (MCI) and Alzheimer's disease (AD) develop over time. NEW METHOD: this study involves a new application of latent curve models (LCM) to examine the development trajectory of a healthy, MCI, and AD groups on a series of clinical and neural measures. Multiple-group latent curve models were used to compare the parameters of the trajectories across groups.

RESULTS

LCM results showed that a linear functional form of growth was adequate for all the clinical and neural measures. Positive and significant differences in initial levels were seen across groups on all of the clinical and neural measures. In all groups, the following measures increased slightly, or considerably, over time: Clinical Dementia Rating, Alzheimer's disease Cognitive Assessment, and Montreal Assessment Test for Dementia. In contrast, a slight or a greatly decreasing trajectory was observed on the following measures: Fluorodeoxyglucose, Mini-Mental State Exam, Rey Auditory Verbal Learning Test as well as Hippocampus, Fusiform and Entorhinal Cortex volume measures. However, a constant mean trajectory was seen on Cognition Self Report Memory and languages scores. COMPARISION WITH EXISTING METHODS: there are no prior studies that applied LCM on large AD datasets.

CONCLUSIONS

cognitive decline occurs in the cognitively normal (CN), MCI, and AD groups but at different rates. Further, some important cognitive, neural, and clinical variables that (a) best differentiate between CN, MCI, and AD as well as (b) differentially change over time in MCI and AD, which may explain disease progression.

Receiver Operating Characteristic Prediction for Classification: Performances in Cross-Validation by Example

The stability of receiver operating characteristic in context of random split used in development and validation sets, as compared to the full models for three inflammatory ratios (neutrophil-to-lymphocyte (NLR), derived neutrophil-to-lymphocyte (dNLR) and platelet-to-lymphocyte (PLR) ratio) evaluated as predictors for metastasis in patients with colorectal cancer, was investigated. Data belonging to patients admitted with the diagnosis of colorectal cancer from January 2014 until September 2019 in a single hospital were used. There were 1688 patients eligible for the study, 418 in the metastatic stage. All investigated inflammatory ratios proved to be significant classification models on both the full models and on cross-validations (AUCs > 0.05). High variability of the cut-off values was observed in the unrestricted and restricted split (full models: 4.255 for NLR, 2.745 for dNLR and 255.56 for PLR; random splits: cut-off from 3.215 to 5.905 for NLR, from 2.625 to 3.575 for dNLR and from 134.67 to 335.9 for PLR), but with no effect on the models characteristics or performances. The investigated biomarkes proved limited value as predictors for metastasis (AUCs < 0.8), with largely sensitivity and specificity (from 33.3% to 79.2% for the full model and 29.1% to 82.7% in the restricted splits). Our results showed that a simple random split of observations, weighting or not the patients with and whithout metastasis, in a ROC analysis assures the performances similar to the full model, if at least 70% of the available population is included in the study.

Shifting Tides Toward a Proactive Patient-Centered Approach in Dysphagia Management of Neurodegenerative Disease

Purpose Persons with neurodegenerative disease frequently develop comorbid dysphagia as part of their disease process. Current "reactive" approaches to dysphagia management address dysphagia once it manifests clinically and consist of compensatory approaches. The purpose of this article is to propose a paradigm shift in dysphagia management of patients with neurodegenerative disease from a "reactive to proactive" approach by highlighting amyotrophic lateral sclerosis (ALS) and dementia as case examples. Method The authors present several areas of special consideration for speech-language pathologists (SLPs) treating dysphagia in patients with neurodegenerative disease. The drawbacks of historical "reactive" approaches to dysphagia management are described. Concepts of functional reserve for swallowing and homeostenosis are discussed. A "proactive" patient-centered paradigm of care for these patients is proposed with evidence to support its importance. A rationale for use of this approach in patients with ALS and dementia is provided with strategies for implementation. Results When treating dysphagia in patients with neurodegenerative disease, SLPs must balance a variety of factors in their decision making, including disease severity and expected progression, cultural considerations, goals of care, patient empowerment, and caregiver support. Reactive approaches to dysphagia management in these populations are problematic in that they disempower patients by focusing on use of compensatory techniques (e.g., diet modification, postural changes, feeding tube placement). Proactive approaches that employ rehabilitative interventions to increase functional reserve, such as resistance training, may result in improvement or maintenance of swallowing function longer into disease progression. An interdisciplinary team with early SLP involvement is necessary. Conclusions SLPs play a critical role in the management of dysphagia in patients with neurodegenerative disease and should be integrated early in the care of these patients. By focusing on a proactive patient-centered approach, patients with neurodegenerative conditions, such as ALS and dementia, will experience improved quality of life and health outcomes for a longer time.

Prescribing medications of questionable benefit prior to death: a retrospective study on older nursing home residents with and without dementia in Germany

Purpose

We studied the prevalence of medications of questionable benefit in the last 6 months of life among older nursing home residents with and without dementia in Germany.

Methods

A retrospective cohort study was conducted on claims data from 67,328 deceased nursing home residents aged 65+ years who were admitted between 2010 and 2014. We analyzed prescription regimens of medications of questionable benefit in the 180–91-day period and the 90-day period prior to death for residents with dementia (n = 29,052) and without dementia (n = 38,276). Factors associated with new prescriptions of medications of questionable benefit prior to death were analyzed using logistic regression models among all nursing home residents and stratified by dementia.

Results

A higher proportion of nursing home residents with dementia were prescribed at least one medication of questionable benefit in the 180–91-day (29.6%) and 90-day (26.8%) periods prior to death, compared with residents without dementia (180–91 days, 22.8%; 90 days, 20.1%). Lipid-lowering agents were the most commonly prescribed medications. New prescriptions of medications of questionable benefit were more common among residents with dementia (9.8% vs. 8.7%). When excluding anti-dementia medication, new prescriptions of these medications were more common among residents without dementia (6.4% vs. 8.0%). The presence of dementia (odds ratio [OR] 1.40, 95% confidence interval [95%CI] 1.32–1.48) and excessive polypharmacy were associated with new prescriptions of medications of questionable benefit prior to death (OR 4.74, 95%CI 4.15–5.42).

Conclusion

Even when accounting for anti-dementia prescriptions, the prevalence of nursing home residents with dementia receiving medications of questionable benefit is considerable and may require further attention.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02859-3) contains supplementary material, which is available to authorized users.

Cognitive and functional progression of dementia in two longitudinal studies

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.

Trajectories of cognitive decline by widowhood status among Korean older adults

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.

Understanding and predicting the longitudinal course of dementia

PURPOSE OF REVIEW

To date, most research in dementia has focused either on the identification of dementia risk prediction or on understanding changes and predictors experienced by individuals before diagnosis. Despite little is known about how individuals change after dementia diagnosis, there is agreement that changes occur over different time scales and are multidomain. In this study, we present an overview of the literature regarding the longitudinal course of dementia.

RECENT FINDINGS

Our review suggests the evidence is scarce and findings reported are often inconsistent. We identified large heterogeneity in dementia trajectories, risk factors considered and modelling approaches employed. The heterogeneity of dementia trajectories also varies across outcomes and domains investigated.

SUMMARY

It became clear that dementia progresses very differently, both between and within individuals. This implies an average trajectory is not informative to individual persons and this needs to be taken into account when communicating prognosis in clinical care. As persons with dementia change in many more ways during their patient journey, heterogeneous disease progressions are the result of disease and patient characteristics. Prognostic models would benefit from including variables across a number of domains. International coordination of replication and standardization of the research approach is recommended.

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

OBJECTIVE

We sought to replicate a previously published prediction model for progression, developed in the Cache County Dementia Progression Study, using a clinical cohort from the National Alzheimer's Coordinating Center.

METHODS

We included 1120 incident Alzheimer disease (AD) cases with at least one assessment after diagnosis, originating from 31 AD centres from the United States. Trajectories of the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating sum of boxes (CDR-sb) were modelled 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 Cache County Dementia Progression Study.

RESULTS

The best-fitting model contained 3 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 receiver operating characteristic curve of 0.70 and 0.75 for classes 2 and 3, respectively, 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 that of 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.