A reevaluation of the duration of survival after the onset of dementia

A retrospective and prospective study of biostatistics in Canada

Biostatistics is foundational to public health research and Canada has a history of high impact contributions both in seminal methodological advances and in the rigorous application of methods for the design or analysis of public health studies. In this article, we provide a brief and personal review of selected contributions from Canadian biostatisticians to fields such as survival and life history analysis, sampling, clinical trial methodology, environmental risk assessment, infectious disease epidemiology, and early work on prediction. We also provide a brief look forward at the upcoming needs and future directions of biostatistical research.

Olfactory identification, cognition, depressive symptoms, and 5-year mortality in patients with subjective cognitive decline, mild cognitive impairment, and Alzheimer's disease

OBJECTIVE

An association between odor and cognitive impairment has been shown in many studies. The objective of the present hospital-based, single-center retrospective study was to assess the impact of odor impairment on the mortality of patients with Alzheimer's disease (AD), subjective cognitive decline (SCD), and mild cognitive impairment (MCI).

METHODS

Odor function was measured by Sniffin Sticks (Burghart Messtechnik, Holm, Germany) and the assessment of self-reported olfactory functioning and olfaction-related quality of life (ASOF) test. Cognitive performance was assessed by an extensive neuropsychological test battery, symptoms of depression were diagnosed with the Geriatric Depressive Scale (GDS). The influence of demographic factors such as gender, age, and education were examined.

RESULTS

Although the univariate analyses and pairwise post hoc comparison showed significant differences for some of the olfactory performance tests/subtests, the multivariate models showed no association between olfactory test performance and mortality among patients with cognitive impairment. "Attention," a domain of the Neuropsychological Test Battery Vienna (NTBV), as well as depressive symptoms, gender, and age, showed a significant influence on the mortality of the patient group.

CONCLUSION

Lower olfactory performance showed no impact on mortality. However, decreased cognitive function of "Attention" can be considered as an influential predictor for mortality.

Feasibility of Oral Function Evaluation According to Dementia Severity in Older Adults with Alzheimer's Disease

Oral function evaluation in older adults with dementia is important for determining appropriate and practical dietary support plans; however, it can be challenging due to their difficulties in comprehending instructions and cooperating during assessments. The feasibility of oral function evaluation has not been well studied. This cross-sectional study aimed to determine the feasibility of oral function evaluation in older adults with Alzheimer's disease (AD) according to Functional Assessment Staging of Alzheimer's Disease (FAST) stages. In total, 428 older adults with AD (45 men and 383 women; mean age: 87.2 ± 6.2 years) were included. Multilevel logistic regression models were used to examine the prevalence of participants who were unable to perform oral function evaluations, including oral diadochokinesis (ODK), repeated saliva swallow test (RSST), and modified water swallow test (MWST). In comparison to the reference category (combined FAST stage 1-3), FAST stage 7 was associated with the infeasibility of ODK (adjusted odds ratio, 95% confidence interval = 26.7, 4.2-168.6), RSST (5.9, 2.2-16.1), and MWST (8.7, 1.6-48.5, respectively). Oral function evaluation is difficult in older adults with severe AD. Simpler and more practical swallowing function assessments and indicators that can be routinely observed are required.

Xanthine oxidase inhibitors treatment or discontinuation effects on mortality: evidence of xanthine oxidase inhibitors withdrawal syndrome

Objectives: This study investigates the impact of xanthine oxidase inhibitors (XOI) on mortality in patients with cardiovascular diseases. XOI withdrawal has been reported to increased mortality risk due to rapid adenosine triphosphate (ATP) deficiency. This study aims to determine whether XOI treatment reduces mortality and whether XOI withdrawal increases mortality. Methods: This is a real-world database study using the Japanese Registry of All Cardiac and Vascular Diseases (J-ROAD). We analyzed 1,648,891 hospitalized patients aged 20-90 with acute coronary syndrome or heart failure. In the first study, mortality rates were compared between patients without urate-lowering agents (n = 1,292,486) and those with XOI agents (n = 315,388, excluding 41,017 on other urate-lowering agents). In the second study, mortality rates were compared between the XOI continuous medication group (n = 226,261) and the XOI withdrawal group (n = 89,127). Results: After multiple adjustments, XOI treatment group showed significantly lower mortality compared with that without any urate-lowering agent (odds ratio (OR), 0.576, 95% confidence interval (CI), 0.567-0.587, p < .001). In the sub-analysis, the group with allopurinol (OR, 0.578; 95% CI, 0.557-0.600), febuxostat (OR, 0.610; 95% CI, 0.599-0.622), and topiroxostat (HR, 0.545; 95% CI, 0.473-0.628) showed lower OR of mortality compared with that without any urate-lowering agent. XOI withdrawal group led to significantly higher death rates compared to XOI continuous group (19.8% vs. 0.03%; p < .001). Conclusion: XOI treatment for patients with cardiovascular diseases is associated with reduced mortality. Conversely, XOI withdrawal is linked to elevated mortality risk. This emphasizes the importance of both prescribing and discontinuing XOI carefully to optimize patient outcomes.

Time Path of Weight Status Before and After Incident Dementia

Objectives: Identifying whether obesity is a risk factor for dementia is complicated by the possibility of weight change as dementia evolves. This article investigates an extended time path of body mass index (BMI) before and after incident dementia in a nationally representative sample. Methods: Using the Health and Retirement Study (2000-2016), we examine (1) the longitudinal relationship between BMI and incident dementia and (2) heterogeneity in the BMI trajectory by initial BMI level. Results: Weight loss begins at least one decade before incident dementia, then accelerates in the years immediately preceding dementia onset and continues after incident dementia. Those with higher levels of BMI at baseline experienced a much greater decline relative to those with a normal weight. Discussion: Our results help explain the contradicting findings in the literature regarding the relationship between obesity and dementia and highlight the need for using extended longitudinal data to understand dementia risk.

Comparing survival and mortality in patients with late-onset and young-onset vascular dementia

OBJECTIVES

Vascular dementia (VD) is one of the more common types of dementia. Much is known about VD in older adults in terms of survival and associated risk factors, but comparatively less is known about VD in a younger population. This study aimed to investigate survival in people with young-onset VD (YO-VD) compared to those with late-onset VD (LO-VD) and to investigate predictors of mortality.

DESIGN

Retrospective file review from 1992 to 2014.

SETTING

The inpatient unit of a tertiary neuropsychiatry service in Victoria, Australia.

PARTICIPANTS

Inpatients with a diagnosis of VD.

MEASUREMENTS AND METHODS

Mortality information was obtained from the Australian Institute of Health and Welfare. Clinical variables included age of onset, sex, vascular risk factors, structural neuroimaging, and Hachinksi scores. Statistical analyses used were Kaplan-Meier curves for median survival and Cox regression for predictors of mortality.

RESULTS

Eighty-four participants were included with few clinical differences between the LO-VD and YO-VD groups. Sixty-eight (81%) had died. Median survival was 9.9 years (95% confidence interval 7.9, 11.7), with those with LO-VD having significantly shorter survival compared to those with YO-VD (6.1 years and 12.8 years, respectively) and proportionally more with LO-VD had died (94.6%) compared to those with YO-VD (67.5%), χ2(1) = 9.16, p = 0.002. The only significant predictor of mortality was increasing age (p = 0.001).

CONCLUSION

While there were few clinical differences, and older age was the only factor associated with survival, further research into the effects of managing cardiovascular risk factors and their impact on survival are recommended.

Prediction of 3-Year Survival in Patients with Cognitive Impairment Based on Demographics, Neuropsychological Data, and Comorbidities: A Prospective Cohort Study

OBJECTIVES

Based on readily available demographic data, neuropsychological assessment results, and comorbidity data, we aimed to develop and validate a 3-year survival prediction model for patients with cognitive impairment.

METHODS

In this prospective cohort study, 616 patients with cognitive impairment were included. Demographic information, data on comorbidities, and scores of the Mini-Mental State Examination (MMSE), Instrumental Activities of Daily Living (IADL) scale, and Neuropsychiatric Inventory Questionnaire were collected. Survival status was determined via telephone interviews and further verified in the official death register in the third year. A 7:3 ratio was used to divide patients into the training and validation sets. Variables with statistical significance (p < 0.05) in the single-factor analysis were incorporated into the binary logistic regression model. A nomogram was constructed according to multivariate analysis and validated.

RESULTS

The final cohort included 587 patients, of whom 525 (89.44%) survived and 62 (10.56%) died. Younger age, higher MMSE score, lower IADL score, absence of disinhibition, and Charlson comorbidity index score ≤ 1 were all associated with 3-year survival. These predictors yielded good discrimination with C-indices of 0.80 (0.73-0.87) and 0.85 (0.77-0.94) in the training and validation cohorts, respectively. According to the Hosmer-Lemeshow test results, neither cohort displayed any statistical significance, and calibration curves displayed a good match between predictions and results.

CONCLUSIONS

Our study provided further insight into the factors contributing to the survival of patients with cognitive impairment.

CLINICAL IMPLICATIONS

Our model showed good accuracy and discrimination ability, and it can be used at community hospitals or primary care facilities that lack sophisticated equipment.

Criminal Behaviour After Diagnosis of a Neurocognitive Disorder: A Nationwide Finnish Register Study

OBJECTIVE

To explore criminal behavior of individuals with Alzheimer's disease (AD), frontotemporal dementia (FTD), or Lewy body dementias (LBD) after the diagnosis.

DESIGN

Nationwide register study.

SETTING

Information on diagnoses and criminality was received from Finnish registers. Crime types and incidences were compared between disorders and the general population.

PARTICIPANTS

All Finnish individuals diagnosed with AD, LBD, or FTD (n = 92 189) during 1998-2015.

MEASUREMENTS

Types of crimes and incidences, the standardized criminality ratio (SCR, number of actual crimes per number of expected crimes), numbers of observed cases, and person-years at risk counted in 5-year age groups and for both sexes and yearly.

RESULTS

Among men, at least one crime was committed by 2.8% of AD, 7.2% of FTD, and 4.8% of LBD patients. Among women, the corresponding figures were 0.4%, 2.0%, and 2.1%. The most frequent type of crime was traffic offence, followed by property crime. After age adjustment, the relative number of crimes between groups did not differ, except that men with FTD and LBD committed more crimes than those with AD. The SCR (95% CI) among men were 0.40 (0.38-0.42) in AD, 0.45 (0.33-0.60) in FTD, and 0.52 (0.48-0.56) in LBD. Among women, these were 0.34 (0.30-0.38), 0.68 (0.39-1.09), and 0.59 (0.51-0.68).

CONCLUSIONS

The diagnosis of a neurocognitive disorder does not increase criminal behavior, but rather reduces it by up to 50%. Differences in crime activity are present between different neurocognitive disorders and between the sexes.

Public Health and Palliative Care

Meeting the needs of people at the end of life (EOL) is a public health (PH) concern, yet a PH approach has not been widely applied to EOL care. The design of hospice in the United States, with its focus on cost containment, has resulted in disparities in EOL care use and quality. Individuals with non-cancer diagnoses, minoritized individuals, individuals of lower socioeconomic status, and those who do not yet qualify for hospice are particularly disadvantaged by the existing hospice policy. New models of palliative care (both hospice and non-hospice) are needed to equitably address the burden of suffering from a serious illness.

Dementia and electronic health record phenotypes: a scoping review of available phenotypes and opportunities for future research

OBJECTIVE

We performed a scoping review of algorithms using electronic health record (EHR) data to identify patients with Alzheimer's disease and related dementias (ADRD), to advance their use in research and clinical care.

MATERIALS AND METHODS

Starting with a previous scoping review of EHR phenotypes, we performed a cumulative update (April 2020 through March 1, 2023) using Pubmed, PheKB, and expert review with exclusive focus on ADRD identification. We included algorithms using EHR data alone or in combination with non-EHR data and characterized whether they identified patients at high risk of or with a current diagnosis of ADRD.

RESULTS

For our cumulative focused update, we reviewed 271 titles meeting our search criteria, 49 abstracts, and 26 full text papers. We identified 8 articles from the original systematic review, 8 from our new search, and 4 recommended by an expert. We identified 20 papers describing 19 unique EHR phenotypes for ADRD: 7 algorithms identifying patients with diagnosed dementia and 12 algorithms identifying patients at high risk of dementia that prioritize sensitivity over specificity. Reference standards range from only using other EHR data to in-person cognitive screening.

CONCLUSION

A variety of EHR-based phenotypes are available for use in identifying populations with or at high-risk of developing ADRD. This review provides comparative detail to aid in choosing the best algorithm for research, clinical care, and population health projects based on the use case and available data. Future research may further improve the design and use of algorithms by considering EHR data provenance.

Danshensu inhibits Aβ aggregation and neurotoxicity as one of the main prominent features of Alzheimer's disease

It has been found that the main cause of neurodegenerative proteinopathies, especially Alzheimer's disease (AD) is the formation of Aβ amyloid plaques, which can be regulated by application of potential small molecules. In the present study, we aimed to investigate the inhibitory effect of danshensu on Aβ(1-42) aggregation and relevant apoptotic pathway in neurons. A broad range of spectroscopic, theoretical, and cellular assays were done to investigate the anti-amyloidogenic characteristics of danshensu. It was found that danshensu triggers its inhibitory effect against Aβ(1-42) aggregation through modulation of hydrophobic patches as well as structural and morphological changes through a stacking interaction. Furthermore, it was observed that incubation of Aβ(1-42) samples with danshensu during aggregation process recovered the cell viability and mitigated the expression of caspase-3 mRNA and protein as well caspase-3 activity deregulated by Aβ(1-42) amyloid fibrils alone. In general, obtained data showed that danshensu potentially inhibits Aβ(1-42) aggregation and associated proteinopathies through regulation of apoptotic pathway in a concentration-dependent manner. Therefore, danshensu may be used as a promising biomolecule against the Aβ aggregation and associated proteinopathies, which can be further analyzed in the future studies for the treatment of AD.

Survival Modelling For Data From Combined Cohorts: Opening the Door to Meta Survival Analyses and Survival Analysis using Electronic Health Records

Non-parametric estimation of the survival function using observed failure time data depends on the underlying data generating mechanism, including the ways in which the data may be censored and/or truncated. For data arising from a single source or collected from a single cohort, a wide range of estimators have been proposed and compared in the literature. Often, however, it may be possible, and indeed advantageous, to combine and then analyze survival data that have been collected under different study designs. We review non-parametric survival analysis for data obtained by combining the most common types of cohort. We have two main goals: (i) To clarify the differences in the model assumptions, and (ii) to provide a single lens through which some of the proposed estimators may be viewed. Our discussion is relevant to the meta analysis of survival data obtained from different types of study, and to the modern era of electronic health records.

Effect of Comorbidities on Ten-Year Survival in Patients with Dementia

BACKGROUND

There is a verified association between comorbidity and survival in patients with dementia.

OBJECTIVE

To describe the ten-year survival probability of patients with dementia and to identify the impact of comorbidity.

METHODS

The prognostic retrospective cohort study was conducted using data from adults with dementia who had visited the outpatient departments at Maharaj Nakorn Chiang Mai hospital between 2006 and 2012. Dementia was verified in accordance with standard practice guidelines. Secondary data detailing about patient age, gender, date of dementia diagnosis and death, types of dementia, and comorbidities at the time of dementia diagnosis was obtained from electronic medical records. The association between comorbidity, patients' underlying disease at dementia diagnosis, and overall survival were analyzed using a multivariable Cox proportional hazard model adjusted for age, gender, types of dementia, and other comorbidities.

RESULTS

Of the 702 patients, 56.9% were female. Alzheimer's disease (39.6%) was the most prevalent type of dementia. Median overall survival was 6.0 years (95% CI 5.5- 6.7). The comorbidities associated with a high risk of mortality included liver disease (aHR 2.70, 95% CI 1.46- 5.00), atrial fibrillation (aHR 2.15, 95% CI 1.29- 3.58), myocardial infarction (aHR 1.55, 95% CI 1.07- 2.26), and type 2 diabetes mellitus (aHR 1.40, 95% CI 1.13- 1.74).

CONCLUSION

Overall survival rate of patients with dementia in Thailand was comparable to previous studies. Several comorbidities were associated with a ten-year survival. The prognosis of patients with dementia may be improved by appropriate care of comorbidities.

Validation of a Multivariate Prediction Model of the Clinical Progression of Alzheimer's Disease in a Community-Dwelling Multiethnic Cohort

BACKGROUND

The major aims of the three Predictors Studies have been to further our understanding of Alzheimer's disease (AD) progression sufficiently to predict the length of time from disease onset to major disease outcomes in individual patients with AD.

OBJECTIVES

To validate a longitudinal Grade of Membership (L-GoM) prediction algorithm developed using clinic-based, mainly white patients from the Predictors 2 Study in a statistically representative community-based sample of Hispanic (N = 211) and non-Hispanic (N = 62) older adults (with 60 males and 213 females) from the Predictors 3 Study and extend the algorithm to mild cognitive impairment (MCI).

METHODS

The L-GoM model was applied to data collected at the initial Predictors 3 visit for 150 subjects with AD and 123 with MCI. Participants were followed annually for up to seven years. Observed rates of survival and need for full-time care (FTC) were compared to those predicted by the algorithm.

RESULTS

Initial MCI/AD severity in Predictors 3 was substantially higher than among clinic-based AD patients enrolled at the specialized Alzheimer's centers in Predictors 2. The observed survival and need for FTC followed the L-GoM model trajectories in individuals with MCI or AD, except for N = 32 subjects who were initially diagnosed with AD but reverted to a non-AD diagnosis on follow-up.

CONCLUSION

These findings indicate that the L-GoM model is applicable to community-dwelling, multiethnic older adults with AD. They extend the use of the model to the prediction of outcomes for MCI. They also justify release of our L-GoM calculator at this time.

A nonparametric test for equality of survival medians using right-censored prevalent cohort survival data

The median is a robust summary commonly used for comparison between populations. The existing literature falls short in testing for equality of survival medians when the collected data do not form representative samples from their respective target populations and are subject to right censoring. Such data commonly occur in prevalent cohort studies with follow-up. We consider a particular case where the disease under study is stable, that is, the incidence rate of the disease is stable. It is known that survival data collected on diseased cases, when the disease under study is stable, form a length-biased sample from the target population. We fill the gap for the particular case of length-biased right-censored survival data by proposing a large-sample test using the nonparametric maximum likelihood estimator of the survivor function in the target population. The small sample performance of the proposed test statistic is studied via simulation. We apply the proposed method to test for differences in survival medians of Alzheimer's disease and dementia groups using the survival data collected as part of the Canadian Study of Health and Aging.

Regression modeling of restricted mean survival time for left-truncated right-censored data

The restricted mean survival time (RMST) is a clinically meaningful summary measure in studies with survival outcomes. Statistical methods have been developed for regression analysis of RMST to investigate impacts of covariates on RMST, which is a useful alternative to the Cox regression analysis. However, existing methods for regression modeling of RMST are not applicable to left-truncated right-censored data that arise frequently in prevalent cohort studies, for which the sampling bias due to left truncation and informative censoring induced by the prevalent sampling scheme must be properly addressed. The pseudo-observation (PO) approach has been used in regression modeling of RMST for right-censored data and competing-risks data. For left-truncated right-censored data, we propose to directly model RMST as a function of baseline covariates based on POs under general censoring mechanisms. We adjust for the potential covariate-dependent censoring or dependent censoring by the inverse probability of censoring weighting method. We establish large sample properties of the proposed estimators and assess their finite sample performances by simulation studies under various scenarios. We apply the proposed methods to a prevalent cohort of women diagnosed with stage IV breast cancer identified from surveillance, epidemiology, and end results-medicare linked database.

Life expectancy for community-dwelling persons with dementia and severe disability

BACKGROUND

Understanding life expectancy can help persons with dementia, their care partners, and policymakers plan for what lies ahead. We sought to determine life expectancy and predictors of mortality for community-dwelling persons with dementia and severe disability.

METHODS

Using the National Health and Aging Trends Study (NHATS) linked to Medicare claims, we identified community-dwelling respondents age 65+ who entered NHATS in 2011 with dementia and severe disability (defined as three impairments in activities of daily living), or who subsequently met criteria for dementia and then severe disability. We estimated time to death based on the timing of meeting severe disability criteria. We conducted parametric survival analyses using a Gompertz distribution to calculate risk of death and predicted median time to death. Predictors included demographic, functional, clinical characteristics, and behavioral symptoms (assessed among NHATS respondents with proxy interviews).

RESULTS

Among 842 community-dwelling persons with dementia and severe disability, 80.5% died during the study period. After adjusting for age and gender, overall predicted median time to death was 1.7 years (25th percentile 0.6, 75th percentile 3.8 years). Six notable characteristics were associated with shorter life expectancy: 1) older age (90+), with a predicted median time to death of 1.0 year (0.4, 2.1); 2) being bedbound, 1.1 years (0.4, 2.3); 3) being homebound, 1.2 years (0.5, 2.6); 4) having comorbid cancer, 1.2 years (0.5, 2.6); 5) unintended weight loss, 1.4 years (0.5, 3.1); and 6) comorbid depression, 1.5 years (0.6, 3.3).

CONCLUSIONS

Community-dwelling persons with dementia and severe disability lived a median of 1.7 years. Clinicians can use the study findings to provide anticipatory guidance to patients and care partners, and policymakers to inform design of longitudinal supportive services.

Causes of Mortality in Korean Patients with Neurodegenerative Dementia

The prevalence of neurodegenerative dementia is increasing owing to the rapid growth of the older population. We investigated risks and causes of mortality in Korean patients with neurodegenerative dementia using data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort with the aim to improve their care. From a pool of 1,125,691 patients, 11,215 patients aged ≥60 years who were diagnosed with dementia between 2002 and 2013 were examined along with 44,860 matched controls. A Cox proportional hazard model was used to calculate crude and adjusted hazard ratios (HRs). During the follow-up period, 34.5% and 18.8% of individuals in the neurodegenerative dementia and control groups, respectively, died (P < 0.001). The adjusted HR for mortality in the neurodegenerative dementia group was 2.11 (2.41 and 1.96 in men and women, respectively). Moreover, the adjusted HRs in patients with neurodegenerative dementia were 3.25, 2.77, and 1.84 for those diagnosed at ages 60–69, 70–79, and ≥80 years, respectively. The highest odds ratio for mortality was noted among patients with neurologic disease (15.93) followed by those with mental disease (4.89). These data show that the risk of mortality increased regardless of age and sex in Korean patients with neurodegenerative dementia.

No effect of thyroid hormones on 5-year mortality in patients with subjective cognitive decline, mild cognitive disorder, and Alzheimer's disease

The present study aimed to investigate differences in circulating thyroid hormone levels, gender, education, depressive symptoms, and cognitive performance among patients with cognitive impairment, and also to examine their associations, as well as that of cognitive decline, with 5-year mortality. Between 1998 and 2017, a hospital-based, single-centre (Neurology Department of the General Hospital in Vienna, Austria), retrospective follow-up study enrolled 2102 patients with mild to severe cognitive impairment (grouped into subjective cognitive decline, mild cognitive impairment, and Alzheimer's disease). Cox proportional hazards models were used to calculate hazard ratios (HRs), with 95% confidence intervals (CIs), as well as to calculate stepwise adjustments for demographic variables (age, gender, and education), depressive symptoms (Geriatric Depression Scale, GDS-15), and neuropsychological abilities (four domains of a neuropsychological test battery of Vienna, NTVB). In univariate analyses, total triiodothyronine (TT3) levels differed significantly between Alzheimer's disease and mild cognitive impairment patients (p_diff  = .001). No other differences in cognitive impairment subgroups with any of the measured thyroid hormones were observed. Furthermore, in multivariate models, circulating TT3 was not associated with mortality (multivariable-adjusted HR per unit increase in TT3 = 0.56; 95% CI = 0.29-1.07). In multivariate models, we observed significantly lower 5-year mortality among women (HR = 0.56; 95% CI = 0.43-0.73) and those who scored higher on any of the four domains of the NBTV (e.g., attention and perceptual speed, HR = 0.63; 95% CI = 0.54-0.72); we also observed significantly higher 5-year mortality among patients with depressive symptoms (HR per one point score increase in GDS-15 = 1.06; 95% CI = 1.02-1.10), regardless of cognitive impairment subgroup. Among patients with various degrees of cognitive impairment, we found no associations of thyroid hormone levels with 5-year mortality. Gender, neuropsychological abilities, and depressive symptoms were each significant predictors of 5-year mortality. These results suggest that a neurocognitive test performance could serve as an important predictor of 5-year mortality among patients with cognitive impairment, although further studies with a more complete adjustment for comorbidities are needed to confirm these findings.

The Possible Application of Ketamine in the Treatment of Depression in Alzheimer's Disease

Depression is a leading cause of disability globally, with a prevalence of 3.8% among the whole population, 5% of the adult population, and 5.7% of the elderly population over 60 years of age. There is evidence that depression is linked to certain neurodegenerative diseases, one being Alzheimer's disease (AD). The efficacy of conventional antidepressants to treat depression in AD is conflicting, especially regarding selective serotonin reuptake inhibitors (SSRIs). A recent systemic review and meta-analysis of 25 randomized controlled trials including fourteen antidepressant medications showed no high efficacy in treating AD patients' symptoms. However, ketamine, a nonselective N-methyl-D-aspartate (NMDA) receptor antagonist, can mediate a wide range of pharmacological effects, including neuroprotection, anti-inflammatory and anticancer properties, multimodal analgesia, and treatment of depression, suicidal attempts, and status epilepticus. Esketamine, which is ketamine formulated as a nasal spray, was approved by the Federal Drug Administration (FDA) in March 2019 as an adjuvant drug to treat treatment-resistant depression. NMDA receptor antagonists treat AD through offsetting AD-related pathological stimulation of subtypes of glutamate receptors in the central nervous system. Recent clinical findings suggest that ketamine may provide neuroprotection and reduce neuropsychiatric symptoms associated with AD. In the present investigation, we evaluate the potential role of ketamine and its postulated mechanism in AD management.

Stacked survival models for residual lifetime data

When modelling the survival distribution of a disease for which the symptomatic progression of the associated condition is insidious, it is not always clear how to measure the failure/censoring times from some true date of disease onset. In a prevalent cohort study with follow-up, one approach for removing any potential influence from the uncertainty in the measurement of the true onset dates is through the utilization of only the residual lifetimes. As the residual lifetimes are measured from a well-defined screening date (prevalence day) to failure/censoring, these observed time durations are essentially error free. Using residual lifetime data, the nonparametric maximum likelihood estimator (NPMLE) may be used to estimate the underlying survival function. However, the resulting estimator can yield exceptionally wide confidence intervals. Alternatively, while parametric maximum likelihood estimation can yield narrower confidence intervals, it may not be robust to model misspecification. Using only right-censored residual lifetime data, we propose a stacking procedure to overcome the non-robustness of model misspecification; our proposed estimator comprises a linear combination of individual nonparametric/parametric survival function estimators, with optimal stacking weights obtained by minimizing a Brier Score loss function.

Amelioration of Alzheimer's disease pathology by mitophagy inducers identified via machine learning and a cross-species workflow

A reduced removal of dysfunctional mitochondria is common to aging and age-related neurodegenerative pathologies such as Alzheimer’s disease (AD). Strategies for treating such impaired mitophagy would benefit from the identification of mitophagy modulators. Here we report the combined use of unsupervised machine learning (involving vector representations of molecular structures, pharmacophore fingerprinting and conformer fingerprinting) and a cross-species approach for the screening and experimental validation of new mitophagy-inducing compounds. From a library of naturally occurring compounds, the workflow allowed us to identify 18 small molecules, and among them two potent mitophagy inducers (Kaempferol and Rhapontigenin). In nematode and rodent models of AD, we show that both mitophagy inducers increased the survival and functionality of glutamatergic and cholinergic neurons, abrogated amyloid-β and tau pathologies, and improved the animals’ memory. Our findings suggest the existence of a conserved mechanism of memory loss across the AD models, this mechanism being mediated by defective mitophagy. The computational–experimental screening and validation workflow might help uncover potent mitophagy modulators that stimulate neuronal health and brain homeostasis.

Two potent mitophagy inducers, identified and characterized via unsupervised machine learning and a cross-species screening approach, ameliorated the pathology of Alzheimer’s disease in worms and mice.

Predictors of Life Expectancy in Autopsy-Confirmed Alzheimer's Disease

BACKGROUND

Life expectancy (LE) following Alzheimer's disease (AD) is highly variable. The literature to date is limited by smaller sample sizes and clinical diagnoses.

OBJECTIVE

No study to date has evaluated predictors of AD LE in a retrospective large autopsy-confirmed sample, which was the primary objective of this study.

METHODS

Participants (≥50 years old) clinically and neuropathologically diagnosed with AD were evaluated using National Alzheimer's Coordinating Center (N = 1,401) data. Analyses focused on 21 demographic, medical, neuropsychiatric, neurological, functional, and global cognitive predictors of LE at AD dementia diagnosis. These 21 predictors were evaluated in univariate analyses. Variables found to be significant were then entered into a forward multiple regression. LE was defined as months between AD diagnosis and death.

RESULTS

Fourteen predictors were significant in univariate analyses and entered into the regression. Seven predictors explained 27% of LE variance in 764 total participants. Mini-Mental State Examination (MMSE) score was the strongest predictor of LE, followed by sex, age, race/ethnicity, neuropsychiatric symptoms, abnormal neurological exam results, and functional impairment ratings. Post-hoc analyses revealed correlations of LE were strongest with MMSE ≤12.

CONCLUSION

Global cognitive functioning was the strongest predictor of LE following diagnosis, and AD patients with severe impairment had the shortest LE. AD patients who are older, male, white, and have more motor symptoms, functional impairment, and neuropsychiatric symptoms were also more likely have shorter LE. While this model cannot provide individual prognoses, additional studies may focus on these variables to enhance predictions of LE in patients with AD.

Estimating the Risk of Chemotherapy Toxicity in Indian Geriatric Patient Population and Utility of Chemotherapy Risk Assessment Scale for High Age Patients (CRASH) Score

Background Aging is a heterogeneous process, and elderly population is diverse in health status and functional reserve. The present study was undertaken to predict severe chemotherapy toxicity using the Chemotherapy Risk Assessment Scale for High-Age Patients’ (CRASH) score.

Materials and Methods Elderly patients (age ≥65 years) with malignancy, who were planned to be treated with a new course of cytotoxic chemotherapy, were enrolled. The CRASH score was calculated, and patients were stratified into four categories, that is, low (0–3), intermediate (Int)-low (4–6), Int-high (7–9), and high (<9). Patients developing grade 3/4/5 nonhematologic (NH) or grade 4/5 hematologic (H) toxicity were taken as the development of severe toxicity.

Results Of 100 enrolled patients, 64 (64%) were able to complete their prescribed treatment. Forty-four percent of patients (44 patients) of our study cohort experienced grade-4 H or grade 3/4 NH toxicity. The highest score in each category (heme/nonheme/CRASH) predicts nearly 100% toxicity risk. At a critical value of CRASH ≥ 6.5, the sensitivity is calculated as 100%, while specificity is 89.09%. The accuracy of prediction is 93.88%. The median time taken to develop toxicity was 39.5 days.

Conclusion CRASH score utilizes clinical assessment and basic laboratory values. Yet, it accurately predicts severe chemotherapy toxicity above a critical value of 6.5. Based on the above study, the first 30 days are crucial as 45% of patients experienced toxicity in this time frame. With the help of these clinical predictive markers, the care of elderly will be optimized.

Mortality rates in Alzheimer's disease and non-Alzheimer's dementias: a systematic review and meta-analysis

BACKGROUND

People with dementia die prematurely. Identifying differences in mortality rates between different types of dementia might aid in the development of preventive interventions for the most vulnerable populations. The aim of this study was to compare the difference in mortality rates between individuals without dementia and individuals with various types of dementia.

METHODS

For this systematic review and meta-analysis, we did a systematic search of MEDLINE, PubMed, Embase, and Cochrane Library from inception to July 11, 2020, for cross-sectional or cohort studies that assessed mortality and survival-related outcomes among people with different types of dementia compared with people without dementia. Single-arm studies without comparison groups and autopsy studies or family studies that used a selected sample were excluded. The Newcastle-Ottawa Scale was used by two authors (D-JL and C-SC) independently to measure the methodological quality of included studies, and two authors (F-CY and P-TT) independently extracted data. We assessed differences in all-cause mortality rate and survival time from dementia diagnosis between individuals without dementia, individuals with Alzheimer's disease, and individuals with non-Alzheimer's disease dementias. The secondary outcomes were age at death and survival time from disease onset. Random-effects meta-analyses were done. Effect sizes included hazard ratios (HRs) and mean differences (MDs) with 95% CIs. Potential moderators, including age-associated moderators, were identified through meta-regression and subgroup analyses. This study is registered with PROSPERO, CRD42020198786.

FINDINGS

Our database search identified 11 973 records, and we included 78 eligible studies in our analyses, encompassing 63 125 individuals with dementia and 152 353 controls. Individuals with any type of dementia had a higher mortality rate than individuals without dementia (HR 5·90, 95% CI 3·53 to 9·86), and the HR for all-cause mortality was highest for Lewy body dementia (17·88, 5·87 to 54·46). After diagnosis, the mean survival time for people with Alzheimer's disease was 5·8 years (SD 2·0). Compared with people with Alzheimer's disease, a diagnosis of any non-Alzheimer's disease dementia was associated with a higher risk of all-cause mortality (HR 1·33, 1·21 to 1·46), a shorter survival time from diagnosis (MD -1·12 years, 95% CI -1·52 to -0·72), and a younger age at death (-1·76 years, -2·66 to -0·85). Survival time from disease onset was also shorter in people with non-Alzheimer's dementia, across types, compared with people with Alzheimer's disease, but the subgroup analysis revealed that this difference was only significant for vascular dementia (MD -1·27 years, -1·90 to -0·65) and dementia with Lewy bodies (MD -1·06 years, -1·68 to -0·44). The interactions between age and several survival-related outcomes were significant. 39 (50%) of the 78 included studies were rated as good quality, and large heterogeneity (I2>75%) was observed for most of the study outcomes.

INTERPRETATION

Alzheimer's disease is the most common type of dementia and one of the major causes of mortality worldwide. However, the findings from the current study suggest that non-Alzheimer's disease dementias were associated with higher morality rates and shorter life expectancy than Alzheimer's disease. Developing tailored treatment and rehabilitation programmes for different types of dementia is important for mental health providers, patients, and their families.

FUNDING

None.

Trends of Dementia among Community-Dwelling Adults in Ontario, Canada, 2010-2015

BACKGROUND

There are increasing numbers of people living with dementia (PLWD) and most reside in community settings. Characterizing the number of individuals affected with dementia and their transitions are important to understand in order to plan for their healthcare needs. Using administrative health data in Ontario, Canada, we examined recent trends in the prevalence and incidence of dementia among the community-dwelling population, described their characteristics, and investigated admissions to long-term care (LTC) and overall survival.

METHODS

Using a validated case ascertainment algorithm, we performed a population-based retrospective cohort study of community-dwelling PLWD aged 40-105 years old between 2010 and 2015. We assessed crude and age- and sex-adjusted prevalence and incidence, cohort characteristics, and time to LTC admission and survival.

RESULTS

Between 2010 and 2015, the adjusted community prevalence increased by 9.5% (p < 0.001), while the incidence decreased by 15.8% (p < 0.001). Demographic and socioeconomic characteristics remained similar over time, while the prevalence of comorbidities increased significantly from 2010 to 2015. There was no difference in the time to LTC admission for individuals diagnosed in 2014 when compared to 2010 (p = 0.06). A lower risk of 2-year mortality was observed for individuals diagnosed in 2015 compared to 2010 (HR 0.93, 95% CI 0.90-0.97, p < 0.001).

CONCLUSION

There was an increase in the prevalence of dementia despite decreasing incidence among community-dwelling PLWD. Lower rates of mortality indicate that PLWD are surviving longer following diagnosis. Adequate resources and planning are required to support this growing population, considering the changing population size and characteristics.

Ending One's Life in Advance

If you developed Alzheimer disease, would you want to go all the way to the end of what might be a decade-long course? Some would; some wouldn't. Options open to those who choose to die sooner are often inadequate. Do-not-resuscitate orders and advance directives depend on others' cooperation. Preemptive suicide may mean giving up years of life one would count as good. Do-it-yourself methods can fail. What we now ask of family and clinicians caring for persons with dementia, and of patients given no better option than to go on with lives they may not want, is unacceptable. To explore how one might better control one's own dying and avoid burdening others with overwhelming care and morally painful choices, we propose a thought experiment: an advance directive implant that would enable persons with early dementia, while competent, to arrange their own deaths without the subsequent intervention of anyone else.

Factors Associated with Mortality Including Nursing Home Transitions: A Retrospective Analysis of 25,418 People Prescribed Anti-Dementia Drugs in Northern Ireland

BACKGROUND

Understanding factors associated with mortality after a dementia diagnosis can provide essential information to the person with dementia, their family, and caregivers. To date very little is known about the factors associated with mortality after a dementia diagnosis in Northern Ireland.

OBJECTIVE

To determine how demographic and other factors such as deprivation and comorbidity medications influence mortality rates after a dementia diagnosis in Northern Ireland and whether these factors are influenced through nursing home transitions.

METHODS

25,418 people prescribed anti-dementia medication were identified through the enhanced prescribing database between 2010 and 2016. The impact of covariates including age, gender, marital status, deprivation measure, urban/rural classification, and comorbidity medications were examined using cox proportional hazard models with hazard ratios (HR) and 95% confidence intervals.

RESULTS

Between 2010 and 2016, 12,129 deaths occurred, with 114 deaths/1,000 person years. Males had significantly higher mortality rates in comparison to females (HR = 1.28; 95% CI = 1.23-1.33); this was true regardless of whether the person with dementia transitioned to a nursing home. People prescribed anti-dementia drugs living with lower levels of deprivation had significantly lower mortality rates in comparison to people living with the highest levels of deprivation (HR = 0.93; 95% CI = 0.89-0.97). Diabetic (HR = 1.18; 95% CI = 1.07-1.29) and anti-arrhythmic (HR = 2.44; 95% CI = 1.01-5.91) medication in particular significantly influenced mortality.

CONCLUSION

Male gender, higher comorbidity medications, and living in areas of higher deprivation significantly increased mortality rates for people prescribed anti-dementia drugs in our study population. When comorbidity medications were classified, only anti-arrhythmia and diabetic medications significantly increased mortality. Future research should continue to investigate factors which influence mortality after a dementia diagnosis.

APOE2: protective mechanism and therapeutic implications for Alzheimer's disease

Investigations of apolipoprotein E (APOE) gene, the major genetic risk modifier for Alzheimer's disease (AD), have yielded significant insights into the pathogenic mechanism. Among the three common coding variants, APOE*ε4 increases, whereas APOE*ε2 decreases the risk of late-onset AD compared with APOE*ε3. Despite increased understanding of the detrimental effect of APOE*ε4, it remains unclear how APOE*ε2 confers protection against AD. Accumulating evidence suggests that APOE*ε2 protects against AD through both amyloid-β (Aβ)-dependent and independent mechanisms. In addition, APOE*ε2 has been identified as a longevity gene, suggesting a systemic effect of APOE*ε2 on the aging process. However, APOE*ε2 is not entirely benign; APOE*ε2 carriers exhibit increased risk of certain cerebrovascular diseases and neurological disorders. Here, we review evidence from both human and animal studies demonstrating the protective effect of APOE*ε2 against AD and propose a working model depicting potential underlying mechanisms. Finally, we discuss potential therapeutic strategies designed to leverage the protective effect of APOE2 to treat AD.

Advance care planning information intervention for persons with mild dementia and their family caregivers: Impact on end-of-life care decision conflicts

Persons with dementia are at high risk for loss of decision-making ability due to increased cognitive decline as the disease progresses. Participation in advance care planning (ACP) discussions in the early stages of dementia is crucial for end-of-life (EoL) decision-making to ensure quality of EoL care. A lack of discussions about ACP and EoL care between persons with dementia and family caregivers (FCGs), can lead to decisional conflicts when persons with dementia are in the later stages of the disease. This study explored the effects of a family-centered ACP information intervention among persons with dementia and FCGs. The study was conducted in outpatient clinics in Taiwan. Participants were dyads (n = 40) consisting of persons diagnosed with mild cognitive impairment or mild dementia and their FCGs. A one-group, pretest–posttest, pre-experimental design was employed. The intervention was provided by an ACP-trained senior registered nurse and was guided by ACP manuals and family-centered strategies. Outcome data were collected with four structured questionnaires regarding knowledge of end-stage dementia treatment, knowledge of ACP, attitude towards ACP, and EoL decisional conflict about acceptance or refusal of cardiopulmonary resuscitation, ventilators, and tracheostomy. Paired t tests compared differences between pre-intervention data and 4-weeks’ post-intervention data. The intervention resulted in significant improvements among persons with dementia and FCGs for knowledge of end-stage dementia treatment (p = .008 and p < .001, respectively), knowledge of ACP (both p < .001), and significant reductions in decisional conflicts (both p < .001). Scores for positive and negative attitude toward ACP did not change for persons with dementia; however, there was a reduction in negative attitude for FCGs (p = .001). Clinical care for persons with dementia should incorporate ACP interventions that provide knowledge about EoL dementia care using family-centered care strategies that facilitate regular and continuous communication between FCGs, persons with dementia, and medical personnel to reduce decisional conflicts for EoL care.

Parametric models for combined failure time data from an incident cohort study and a prevalent cohort study with follow-up

A classical problem in survival analysis is to estimate the failure time distribution from right-censored observations obtained from an incident cohort study. Frequently, however, failure time data comprise two independent samples, one from an incident cohort study and the other from a prevalent cohort study with follow-up, which is known to produce length-biased observed failure times. There are drawbacks to each of these two types of study when viewed separately. We address two main questions here: (i) Can our statistical inference be enhanced by combining data from an incident cohort study with data from a prevalent cohort study with follow-up? (ii) What statistical methods are appropriate for these combined data? The theory we develop to address these questions is based on a parametrically defined failure time distribution and is supported by simulations. We apply our methods to estimate the duration of hospital stays.

A second X chromosome contributes to resilience in a mouse model of Alzheimer's disease

A major sex difference in Alzheimer's disease (AD) is that men with the disease die earlier than do women. In aging and preclinical AD, men also show more cognitive deficits. Here, we show that the X chromosome affects AD-related vulnerability in mice expressing the human amyloid precursor protein (hAPP), a model of AD. XY-hAPP mice genetically modified to develop testicles or ovaries showed worse mortality and deficits than did XX-hAPP mice with either gonad, indicating a sex chromosome effect. To dissect whether the absence of a second X chromosome or the presence of a Y chromosome conferred a disadvantage on male mice, we varied sex chromosome dosage. With or without a Y chromosome, hAPP mice with one X chromosome showed worse mortality and deficits than did those with two X chromosomes. Thus, adding a second X chromosome conferred resilience to XY males and XO females. In addition, the Y chromosome, its sex-determining region Y gene (Sry), or testicular development modified mortality in hAPP mice with one X chromosome such that XY males with testicles survived longer than did XY or XO females with ovaries. Furthermore, a second X chromosome conferred resilience potentially through the candidate gene Kdm6a, which does not undergo X-linked inactivation. In humans, genetic variation in KDM6A was linked to higher brain expression and associated with less cognitive decline in aging and preclinical AD, suggesting its relevance to human brain health. Our study suggests a potential role for sex chromosomes in modulating disease vulnerability related to AD.

Perspectives of Australian family carers of people with dementia on the 'cottage' model of respite: Compared to traditional models of residential respite provided in aged care facilities

The majority of people living with dementia reside in the community and are often reliant on the support of informal carers to do so. Family carers face many challenges in supporting the person with dementia to remain at home, and short-term respite care is a valued service that offers a temporary break from the role. Respite cottages provide short-term care in a residential home-like setting with a limited number of clients and is a more flexible approach to accessing the service. Disproportionate use of cottage respite in Australia suggests this model is preferred over traditional respite within residential aged care facility (RACF) settings, yet limited research exists to compare these models. This study sought to understand the perceptions of carers who had used cottage respite in comparison to other models, and explore the contribution of cottage respite for supporting carers to continue in their role and maintain their care recipient (CR) living at home. Semi-structured interviews were conducted with 126 family carers who had used one of two New South Wales-based respite cottages within a 2-year period; 67 of whom had also used RACF respite. Thematic analysis revealed four main themes around the benefits of cottage respite: (a) an effective essential service, (b) flexibility, (c) familiarity and (d) appropriateness, especially for early stage or younger onset dementia. Carers indicated that the more homely, familiar and intimate cottage model of respite care was preferential to that of the larger, institutional-style RACF respite setting. Carers credited the cottage model of respite service with delaying their need for permanent residential placement by over 12 months. The cottage respite model provides an important avenue to supporting the individual needs of dementia dyads, with potential to delay permanent placement, and should be offered more broadly to provide people with more choice about their care.

A prediction model for one- and three-year mortality in dementia: results from a nationwide hospital-based cohort of 50,993 patients in the Netherlands

Objective

to develop a model to predict one- and three-year mortality in patients with dementia attending a hospital, through hospital admission or day/memory clinic.

Design

we constructed a cohort of dementia patients through data linkage of three Dutch national registers: the hospital discharge register (HDR), the population register and the national cause of death register.

Subjects

patients with dementia in the HDR aged between 60 and 100 years registered between 1 January 2000 and 31 December 2010.

Methods

logistic regression analysis techniques were used to predict one- and three-year mortality after a first hospitalisation with dementia. The performance was assessed using the c-statistic and the Hosmer–Lemeshow test. Internal validation was performed using bootstrap resampling.

Results

50,993 patients were included in the cohort. Two models were constructed, which included age, sex, setting of care (hospitalised versus day clinic) and the presence of comorbidity using the Charlson comorbidity index. One model predicted one-year mortality and the other three-year mortality. Model discrimination according to the c-statistic for the models was 0.71 (95% CI 0.71–0.72) and 0.72 (95% CI 0.72–0.73), respectively.

Conclusion

both models display acceptable ability to predict mortality. An important advantage is that they are easy to apply in daily practise and thus are helpful for individual decision-making regarding diagnostic/therapeutic interventions and advance care planning.

Predictors of Mortality in the Oldest Old Patients with Newly Diagnosed Alzheimer Disease in a Residential Aged Care Facility

BACKGROUND

In Taiwan, the causes of death and related factors in the oldest old people with Alzheimer disease (AD) are not well characterized. We investigated the factors associated with mortality in the oldest old patients with newly diagnosed AD admitted to a long-stay residential facility.

METHODS

We performed a prospective study of newly diagnosed AD patients at a veterans' home between 2012 and 2016. At admission, all eligible participants received a comprehensive geriatric assessment, including demographic variables, lifestyle habits, cognitive evaluations, medical conditions (comorbidities, Age-Adjusted Charlson Comorbidity Index score, and polypharmacy), nutritional status evaluated by the Mini Nutritional Assessment-Short Form and body mass index (BMI), and global functional status. A Cox proportional hazards model was used to evaluate the predictive values of clinical parameters for all-cause mortality.

RESULTS

The cohort comprised 84 newly diagnosed AD patients (mean age 86.6 ± 3.9 years) with a mean follow-up period of 2.1 ± 1.2 years. The overall median survival was 3.5 years from the time of AD diagnosis (95% confidence interval, 3.1-3.9 years). BMI was significantly lower in the deceased group than in the alive group (20.7 ± 2.9 vs. 22.6 ± 3.4, p = 0.023). Logistic regression demonstrated that the clinical parameters significantly associated with mortality were high global comorbidity, low nutritional status (malnutrition and underweight), and impaired physical function at the time of AD diagnosis.

CONCLUSION

Comorbidity burden, nutritional status, and physical functional status at the time of dementia diagnosis are important contributors to poor outcome in the oldest old. Efforts to control concurrent chronic disorders, nutritional interventions, and physical independency as a long-term care strategy for dementia may provide survival benefit.

Parametric modelling of prevalent cohort data with uncertainty in the measurement of the initial onset date

In prevalent cohort studies with follow-up, if disease duration is the focus, the date of onset must be obtained retrospectively. For some diseases, such as Alzheimer's disease, the very notion of a date of onset is unclear, and it can be assumed that the reported date of onset acts only as a proxy for the unknown true date of onset. When adjusting for onset dates reported with error, the features of left-truncation and potential right-censoring of the failure times must be modeled appropriately. Under the assumptions of a classical measurement error model for the onset times and an underlying parametric failure time model, we propose a maximum likelihood estimator for the failure time distribution parameters which requires only the observed backward recurrence times. Costly and time-consuming follow-up may therefore be avoided. We validate the maximum likelihood estimator on simulated datasets under varying parameter combinations and apply the proposed method to the Canadian Study of Health and Aging dataset.

End-of-Life Care of Persons With Alzheimer Disease: An Update for Clinicians

While end-of-life (EOL) care has been a relatively common option for patients with terminal cancer, the utilization of EOL care in Alzheimer disease and other dementias has become available more recently. By the time end-stage dementia is present, the clinicians and caregivers become faced with multiple clinical issues—their inability to provide subjective complaints of pain and discomfort, behavioral symptoms, delirium, food refusal, and so on. In addition to providing quality EOL care to the patients, clinicians need to work with their families in an open and empathic manner, assuring that their loved ones will receive supportive measures to keep them comfortable.

Mortality Rates and Mortality Risk Factors in Older Adults with Dementia from Low- and Middle-Income Countries: The 10/66 Dementia Research Group Population-Based Cohort Study

BACKGROUND

Dementia is the main cause of disability in older people living in low- and middle-income countries (LMIC). Monitoring mortality rates and mortality risk factors in people with dementia (PwD) may contribute to improving care provision.

OBJECTIVE

We aimed to estimate mortality rates and mortality predictors in PwD from eight LMICs.

METHODS

This 3-5-year prospective cohort study involved a sample of 1,488 older people with dementia from eight LMIC. Total, age- and gender-specific mortality rates per 1,000 person-years at risk, as well as the total, age- and gender-adjusted mortality rates were estimated for each country's sub-sample. Cox's regressions were used to establish the predictors of mortality.

RESULTS

At follow-up, vital status of 1,304 individuals (87.6%) was established, of which 593 (45.5%) were deceased. Mortality rate was higher in China (65.9%) and lower in Mexico (26.9%). Mortality risk was higher in males (HR = 1.57; 95% CI: 1.32,1.87) and increased with age (HR = 1.04; 95% CI: 1.03,1.06). Neuropsychiatric symptoms (HR = 1.03; 95% CI: 1.01,1.05), cognitive decline (HR 1.04; 95% CI: 1.03,1.05), undernutrition (HR = 1.55; 95% CI: 1.19, 2.02), physical impairments (HR = 1.15; 95% CI: 1.03,1.29), and disease severity (HR = 1.43; 95% CI: 1.22,1.63) predicted higher mortality risk.

CONCLUSION

Several factors predicted higher mortality risk in PwD in LMICs. Males, those with higher age, higher severity of neuropsychiatric symptoms, higher number of physical impairments, higher disease severity, lower cognitive performance, and undernutrition had higher mortality risk. Addressing these indicators of long-term adverse outcomes may potentially contribute to improved advanced care planning, reducing the burden of disease in low-resourced settings.

Sex difference in Alzheimer's disease: An updated, balanced and emerging perspective on differing vulnerabilities

Sex biology influences Alzheimer's disease (AD). Sex differences exist in the epidemiologic, imaging, biomarker, and pathology studies of this uniquely human condition. The mandate to understand sex differences in major diseases like AD is important for many reasons. First, AD is the most common neurodegenerative condition and a devastating disease-experienced as an insidious and progressive erosion of memory, cognition, and other brain functions. Second, since true sex differences in AD exist, their precise understanding could reveal what protects one sex or makes the other vulnerable-and this knowledge could inform development of new therapeutic approaches to benefit both sexes. Third, AD develops in the aging brain in a milieu of decreased circulating gonadal hormones. Thus, how sex-specific depletion affects the brain along with how replacement of androgens in men and estrogens and progestins in women alters vulnerability to AD are relevant questions, with clinical implications in a future of personalized medicine. This review will highlight advances in sex differences in AD in human populations with a focused perspective on epidemiology, biomarkers, and clinical trials. A thorough and concise overview of sex differences reviewed here indicates varying vulnerabilities in men and women. This review examines several lines of recent and strong evidence that collectively indicate the following: (1) men die faster with AD, (2) more women live with AD, (3) both sexes show similar risk of developing AD until advanced ages when women show increased risk, (4) both sexes show largely similar AD biomarker burden with notable exceptions for higher tau levels in subgroups of women with high amyloid, (5) women show brain reserve and resilience to tau pathology, (6) both sexes are vulnerable to the genetic risk of carrying APOE4, with women showing higher risk, and (7) neither sex has shown clear benefit of hormone replacement for AD or dementia risk in randomized clinical trials to date.

Amyloid β42 and Total Tau Levels in Cerebrospinal Fluid Associate with Survival in an 85-Year-Old Population-Based Cohort Followed until Death

BACKGROUND

Dementia of Alzheimer's type (AD) is related to decreased survival. It is not clear whether also biological markers of AD are related to mortality. Low levels of amyloid beta-42 (Aβ42) and high levels of total tau (T-tau) protein in cerebrospinal fluid (CSF) are established biomarkers for AD.

OBJECTIVE

Our aim was to investigate whether levels of Aβ42 and T-tau are associated with survival among octogenarians independently of dementia status.

METHODS

Sixty-five 85-year-olds underwent lumbar puncture and were followed with repeated neuropsychiatric examinations until death.

RESULTS

Lower CSF Aβ42 (p = 0.010) and higher CSF T-tau (p = 0.005) at the age of 85 were associated with lower survival independently of dementia status at baseline and follow-up. Low CSF Aβ42 and high CSF T-tau were also related to baseline dementia at the age of 85 years, and lower CSF Aβ42 with increased dementia incidence during the first 3 years of follow-up.

CONCLUSIONS

Biological markers of AD are associated with mortality in octogenarians. The reason for this needs further study. Our findings highlight the importance to consider the competing risk of death when evaluating biological markers of AD in the very old.

Increased levels of Aβ42 decrease the lifespan of ob/ob mice with dysregulation of microglia and astrocytes

Clinical studies have indicated that obesity and diabetes are associated with Alzheimer's disease (AD) and neurodegeneration. Although the mechanisms underlying these associations remain elusive, the bidirectional interactions between obesity/diabetes and Alzheimer's disease (AD) may be involved in them. Both obesity/diabetes and AD significantly reduce life expectancy. We generated App^NL-F/wt knock-in; ob/ob mice by crossing App^NL-F/wt knock-in mice and ob/ob mice to investigate whether amyloid-β (Aβ) affects the lifespan of ob/ob mice. App^NL-F/wt knock-in; ob/ob mice displayed the shortest lifespan compared to wild-type mice, App^NL-F/wt knock-in mice, and ob/ob mice. Notably, the Aβ42 levels were increased at minimum levels before deposition in App^NL-F/wt knock-in mice and App^NL-F/wt knock-in; ob/ob mice at 18 months of age. No differences in the levels of several neuronal markers were observed between mice at this age. However, we observed increased levels of glial fibrillary acidic protein (GFAP), an astrocyte marker, in App^NL-F/wt knock-in; ob/ob mice, while the levels of several microglial markers, including CD11b, TREM2, and DAP12, were decreased in both ob/ob mice and App^NL-F/wt knock-in; ob/ob mice. The increase in GFAP levels was not observed in young App^NL-F/wt knock-in; ob/ob mice. Thus, the increased Aβ42 levels may decrease the lifespan of ob/ob mice, which is associated with the dysregulation of microglia and astrocytes in an age-dependent manner. Based on these findings, the imbalance in these neuroinflammatory cells may provide a clue to the mechanisms by which the interaction between obesity/diabetes and early AD reduces life expectancy.

A Review of Medical Conditions and Behavioral Problems in Dogs and Cats

Not all animals behave identically when faced with the same situation. These individual differences in the expression of their behavior could be due to many factors, including medical conditions. These medical problems can change behavior directly or indirectly. The aims of this review are to describe the state of the art of the relationship among some medical and behavioral problems, and to propose new lines of investigation. The revision is focused on the relation between behavioral problems and pain, endocrine diseases, neurological problems, vomeronasal organ alterations, and cardiac disorders. These problems represent a diagnostic challenge from a practical point of view. The most common sign of pain in animals is a change in behavior. Although the relation of pain to behavioral problems has been widely studied, it is not absolutely clear. As an example, the relation between sleep disorders and pain is poorly known in veterinary medicine. New studies in humans and laboratory animals show that a reciprocal relationship does, in fact, exist. More specifically, the literature suggests that the temporal effect of sleep deprivation on pain may be stronger than that of pain on sleep. Some behavioral problems could modify the sleep-awake cycle (e.g., cognitive dysfunction). The impact of these behavioral problems on pain perception is completely unknown in dogs and cats. Thyroid hormones play an important role, regarding behavioral control. Both hypothyroidism and hyperthyroidism have been related to behavioral changes. Concerning hypothyroidism, this relationship remains controversial. Nonetheless, new neuro-imaging studies provide objective evidence that brain structure and function are altered in hypothyroid patients, both in laboratory animals and in humans. There are many neurological problems that could potentially change behavior. This paper reviews those neurological problems that could lead to behavioral changes without modifying neurological examination. The most common problems are tumors that affect central nervous system silent zones, mild traumatic brain injury, ischemic attacks, and epilepsy. Most of these diseases and their relationship to behavior are poorly studied in dogs and cats. To better understand the pathophysiology of all of these problems, and their relation to behavioral problems, may change the diagnostic protocol of behavioral problems.

Diagnostic diversity among patients with cognitive complaints: A 3-year follow-up study in a memory clinic

OBJECTIVES

To describe the distribution and estimate the mortality risks of degenerative dementias and nondegenerative conditions in a memory clinic.

METHODS

We enrolled 727 consecutive patients with cognitive complaints who visited the memory clinic in Buddhist Tzu Chi General Hospital during 2013 to 2016. Three main diagnostic groups were defined: pure type dementia, in which only one type of dementia was diagnosed, such as Alzheimer disease (AD), vascular dementia (VaD), Parkinson disease with dementia (PDD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD); mixed type dementia; and nondegenerative conditions. We described the frequency of different diagnoses and employed Cox proportional hazards regression models to examine the mortality risks for each diagnostic group after adjusting for age, sex, education, and cognitive status. All patients alive on or after September 30, 2018, were censored in the analysis.

RESULTS

Two-thirds of patients (n = 496, 68.2%) were diagnosed with degenerative dementias. Pure type to mixed type dementia ratio was about 2: 1. AD remained the most common pure dementia subtype, followed by VaD and PDD. Among all nondegenerative conditions, depression/anxiety and subjective cognitive decline were the most common diagnoses. During a mean follow-up of 3.4 years, 150 deaths were documented, and the mortality risk was 61 deaths/1000 person-years. Mortality risks were associated with age, sex, education, and cognitive function at diagnosis but did not differ by diagnostic group.

CONCLUSIONS

Clinical diagnoses for patients with cognitive complaints are diverse, and nearly one-third are of nondegenerative conditions. Baseline cognitive function is a stronger predictor for survival than clinical diagnosis.

[Evaluation of the elderly patient with cancer]

PURPOSE

To explain the notion of frailty, then to explain how crucial is the detection of frailty detection in the elderly patient, and, in cases of suspected frailty, how crucial is the need for geriatric assessment. To describe (i) how this assessment of the elderly cancer patient is performed, (ii) how the results of this geriatric assessment must drive the decision making, and (iii) the role of the geriatrician in the care pathway.

METHOD

Bibliographic research from the Medline bibliographic database (NLM Pubmed tool) and Embase, as well as on the websites of scientific geriatric societies, from the National Cancer Institute using the following keywords: elderly, geriatrics, cancer, frailty, assessment, decision making.

RESULTS

The goal of frailty detection is to optimize care, to maintain the independence and the survival of the patient. The prevalence of frailty increases with the age and the diagnosis of cancer. Detection of frailty in the elderly patient with cancer is performed using the G8 questionnaire recommended by the INCa. In case of anomaly or clinical justification, the patient receives a geriatric assessment, which is a multidimensional and multidisciplinary procedure. The clinician can call on the UCOG of the region in which he practices. The relevance of medical decisions will be based on the results of this geriatric assessment. The geriatrician plays a crucial role and will be involved throughout the care.

CONCLUSION

The detection of frailty in the elderly patient with cancer is obligatory. Consecutive geriatric assessment can be performed by the UCOG of the region. The results of the geriatric assessment must serve as a basis for any therapeutic decision making and the preservation of the independence of the patient must remain the priority.