Survival of Alzheimer's disease patients in Korea

Predictors for survival in patients with Alzheimer's disease: a large comprehensive meta-analysis

The prevalence of Alzheimer's disease (AD) is increasing as the population ages, and patients with AD have a poor prognosis. However, knowledge on factors for predicting the survival of AD remains sparse. Here, we aimed to systematically explore predictors of AD survival. We searched the PubMed, Embase and Cochrane databases for relevant literature from inception to December 2022. Cohort and case-control studies were selected, and multivariable adjusted relative risks (RRs) were pooled by random-effects models. A total of 40,784 reports were identified, among which 64 studies involving 297,279 AD patients were included in the meta-analysis after filtering based on predetermined criteria. Four aspects, including demographic features (n = 7), clinical features or comorbidities (n = 13), rating scales (n = 3) and biomarkers (n = 3), were explored and 26 probable prognostic factors were finally investigated for AD survival. We observed that AD patients who had hyperlipidaemia (RR: 0.69) were at a lower risk of death. In contrast, male sex (RR: 1.53), movement disorders (including extrapyramidal signs) (RR: 1.60) and cancer (RR: 2.07) were detrimental to AD patient survival. However, our results did not support the involvement of education, hypertension, APOE genotype, Aβ42 and t-tau in AD survival. Our study comprehensively summarized risk factors affecting survival in patients with AD, provided a better understanding on the role of different factors in the survival of AD from four dimensions, and paved the way for further research.

Clinical profile and survival analysis of Alzheimer's disease patients in a Brazilian cohort

OBJECTIVE

To investigate the clinical and epidemiological characteristics of a large sample of patients with dementia due to Alzheimer's disease (AD) who were followed up at a cognitive neurology outpatient clinic.

METHODS

Retrospective, longitudinal, and descriptive design. We collected data from patients with dementia due to AD who visited the outpatient clinic of the SARAH Network of Rehabilitation Hospitals in Rio de Janeiro, Brazil, between May 2009 and June 2019. The evaluated characteristics included age of onset, sex, education, family history, comorbidities, time until diagnosis, and survival rates.

RESULTS

Overall, 1434 patients were evaluated, 74% of whom were women, with a mean age at symptom onset of 72.7 years and 75.8 at diagnosis. A positive family history was reported in 602 patients, with a first-degree relative in 86.3% of them. Hypertension was the most prevalent comorbidity, affecting 61.2% of the sample, and 16.2% were classified as having early-onset AD. The mean survival rate for the sample population was 112.8 months (9.4 years). The sample population was positively affected by dyslipidaemia.

CONCLUSIONS

This study presents a clinical and epidemiological analysis of a large and diverse group of patients with AD. The study confirms previous observations such as a higher prevalence of AD in women, low education among sufferers, and the presence of a family history. The study also found that comorbidities significantly affected patient survival and provides new data on the survival rates of patients with early and late AD in the Brazilian population.

Disease severity and mortality in Alzheimer's disease: an analysis using the U.S. National Alzheimer's Coordinating Center Uniform Data Set

BACKGROUND

Evidence on the relative risk of death across all stages of Alzheimer's disease (AD) is lacking but greatly needed for the evaluation of new interventions. We used data from the Uniform Data Set (UDS) of the National Alzheimer's Coordinating Center (NACC) to assess the expected survival of a person progressing to a particular stage of AD and the relative risk of death for a person in a particular stage of AD compared with cognitively normal (CN) people.

METHODS

This was a retrospective observational cohort study of mortality and its determinants in participants with incident mild cognitive impairment (MCI) due to AD or AD dementia compared with CN participants. Overall survival and hazard ratios of all-cause mortality in participants ≥ 50 years of age with clinically assessed or diagnosed MCI due to AD, or mild, moderate, or severe AD dementia, confirmed by Clinical Dementia Rating scores, versus CN participants were estimated, using NACC UDS data. Participants were followed until death, censoring, or until information to determine disease stage was missing.

RESULTS

Aged between 50 and 104 years, 12,414 participants met the eligibility criteria for the study. Participants progressing to MCI due to AD or AD dementia survived a median of 3-12 years, with higher mortality observed in more severe stages. Risk of death increased with the severity of AD dementia, with the increase significantly higher at younger ages. Participants with MCI due to AD and CN participants had a similar risk of death after controlling for confounding factors.

CONCLUSIONS

Relative all-cause mortality risk increases with AD severity, more so at younger ages. Mortality does not seem to be higher for those remaining in MCI due to AD. Findings might imply potential benefit of lower mortality if preventing or delaying the progression of AD is successful, and importantly, this potential benefit might be greater in relatively younger people. Future research should replicate our study in other samples more representative of the general US population as well as other populations around the world.

Combination of Antidepressants and Antipsychotics as A Novel Treatment Option for Psychosis in Alzheimer's Disease

Background

Psychotic symptoms are reported as one of the most common complications of Alzheimer's disease (AD), affecting approximately half of AD patients, in whom they are associated with more rapid deterioration and increased mortality. Empiric treatments, namely first and second-generation antipsychotics, confer modest efficacy in AD patients with psychosis (AD+P) and themselves increase mortality. A recent genome-wide meta-analysis and early clinical trials suggest the use and beneficial effects of antidepressants among AD+P patients. This motivates our rationale for exploring their potential as a novel combination therapy option amongst these patients.

Methods

We included University of Pittsburgh Medical Center (UPMC) electronic medical records (EMRs) of 10,260 AD patients from January 2004 and October 2019 in our study. Survival analysis was performed to assess the effects of the combination of antipsychotics and antidepressants on the mortality of these patients. To provide more valuable insights on the hidden mechanisms of the combinatorial therapy, a protein-protein interaction (PPI) network representing AD+P was built, and network analysis methods were used to quantify the efficacy of these drugs on AD+P. An indicator score combining the measurements on the separation between drugs and the proximity between the drugs and AD+P was used to measure the effect of an antipsychotic-antidepressant drug pair against AD+P.

Results

Our survival analyses replicated that antipsychotic usage is strongly associated with increased mortality in AD patients while the co-administration of antidepressants with antipsychotics showed a significant beneficial effect in reducing mortality. Our network analysis showed that the targets of antipsychotics and antidepressants are well-separated, and antipsychotics and antidepressants have similar proximity scores to AD+P. Eight drug pairs, including some popular recommendations like Aripiprazole/Sertraline and other pairs not reported previously like Iloperidone/Maprotiline showed higher than average indicator scores which suggest their potential in treating AD+P via strong synergetic effects as seen in our study.

Conclusion

Our proposed combinations of antipsychotics and antidepressants therapy showed a strong superiority over current antipsychotics treatment for AD+P. The observed beneficial effects can be further strengthened by optimizing drug-pair selection based on our systems pharmacology analysis.

Mortality in dementia is predicted by older age of onset and cognitive presentation

OBJECTIVES

Survival information in dementia is important for future planning and service provision. There have been limited Australian data investigating survival duration and risk factors associated with mortality in younger-onset dementia.

METHODS

This was a cross-sectional retrospective study investigating survival in inpatients with a diagnosis of dementia admitted to a tertiary neuropsychiatry service from 1991 to 2014. The Australian Institute of Health and Welfare National Death Index was used to obtain mortality information.

RESULTS

A total of 468 inpatients were identified, of which 75% had symptom onset at ⩽65 years of age (defined as younger-onset dementia). Dementia was categorised into four subtypes, Alzheimer's dementia, frontotemporal dementia, vascular dementia and other dementias; 72% of the patients had died. Overall median survival duration was 10.6 years with no significant differences in duration within the dementia subtypes (p = 0.174). Survival in older-onset dementia (symptom onset at >65 years of age) was about half of that in younger-onset dementia (median survival 6.3 years compared to 12.7 years, respectively). Independent predictors of mortality were having older-onset dementia (hazard ratio: 3.2) and having initial presenting symptoms being cognitive in nature (hazard ratio: 1.5). Females with an older-onset dementia had longer survival compared to males with an older-onset dementia, and this was reversed for younger-onset dementia. Older-onset dementia and younger-onset dementia conferred 3 and 6 times, respectively, increased risk of death compared to the general population.

CONCLUSION

This is the largest Australian study to date investigating survival and risk factors to mortality in dementia. We report important clinical information to patients with dementia and their families about prognosis which will assist with future planning. Our findings suggest that for both older-onset dementia and younger-onset dementia, 'new onset' psychiatric symptoms precede the cognitive symptoms of a neurodegenerative process. This, and sex differences in survival depending on the age of onset of the dementia warrant further investigation.

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.

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.

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.

Survival Analysis of Patients with Alzheimer's Disease: A Study Based on Data from the Korean National Health Insurance Services' Senior Cohort Database

BACKGROUND

Korea's rapidly aging population has experienced a sharp rise in the prevalence of dementia. Patients with Alzheimer's disease (AD), which is estimated to be about three-quarters of all patients with dementia, tend to have higher mortality rates compared with patients without Alzheimer's disease. In this study, a survival analysis of patients with AD was conducted in order to provide knowledge to those who provide medical care to these patients.

METHODS

Data on individuals over 65 years old in 2004 were extracted from the Korean National Health Insurance Services' Senior Cohort database (2002-2013). The subjects were 209,254 patients, including 2,695 who were first diagnosed with AD (the AD group) and 206,559 that had not been diagnosed with the disease (non-AD group). To investigate the independent effect of AD on survival, the Cox proportional-hazards model, hazard ratios (confidence interval of 95%), and the Kaplan-Meier method were used.

RESULTS

Mean survival time in the AD group was 5.3±3.3 years, which was about 2.5 years shorter than that in the non-AD group (7.8±2.4 years). The mortality rate in the AD group (66.3%) was higher than that in the non-AD group (26.3%). The adjusted hazard ratio in the AD group was 2.5 and, therefore, it was found that the AD group had a 2.5-fold higher risk of death than the non-AD group.

CONCLUSION

Overall, AD has a large, independent impact on survival. Survival time was shorter, and the mortality rate and risk were generally higher in the AD group, compared with the non-AD group.

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.

Mortality of Alzheimer's Disease Patients: A 10-Year Follow-up Pilot Study in Shanghai

BACKGROUND

Identifying risk factors and mortality of individuals with Alzheimer's disease (AD) could have important implications for the clinical management of AD.

OBJECTIVE

This pilot study aimed to examine the overall mortality of AD patients over a 10-year surveillance period in Shanghai, China. This study is an extension of our previous investigation on mortality of neurodegenerative diseases.

METHODS

One hundred and thirty-two AD patients recruited from the memory clinics of two hospitals in Shanghai in 2007 were followed up until December 31, 2017 or death, representing a follow-up period of up to 10 years. Overall standardized mortality ratios (SMRs) were calculated, and predictors for survival at recruitment were estimated.

RESULTS

Sixty-seven patients had died by December 31, 2017, and the SMR at 10 years of follow-up was 1.225 (95% confidence interval 0.944-1.563). Employing Cox's proportional hazard modeling, lower Mini-Mental State Examination score, and comorbid diabetes predicted poor survival in this cohort.

CONCLUSION

This pilot study suggests a similar survival trend of patients with AD compared to the general population in Shanghai urban region. Poor cognitive status and comorbid diabetes had a negative impact on the survival of AD patients.

Estimating Life Expectancy and Lifetime Healthcare Costs for Alzheimer's Disease in Taiwan: Does the Age of Disease Onset Matter?

BACKGROUND

People with early onset Alzheimer's disease (EOAD) seem to suffer greater impact. But there is a lack of population-based studies on loss of life expectancy (LE) and lifetime healthcare costs.

OBJECTIVES

We conducted this study to estimate LE, expected years of life lost (EYLL), and lifetime healthcare costs for Alzheimer's disease (AD) in Taiwan stratified by onset age and gender, using a method which integrates the product of the survival function and the mean cost function over a lifetime horizon.

METHODS

We linked the National Health Insurance datasets with the National Mortality Registry and extrapolated the survival to lifetime to estimate the mean cumulative costs since the date of the first AD diagnosis using medical claims between 2001 and 2012.

RESULTS

A total of 21,615 mild to moderate AD patients (including 20,358 late-onset (LOAD) and 1,257 EOAD) were recruited. The average onset age for EOAD was 61 years old, while that of LOAD was 78. Although the LE of EOAD was 4.8 years longer than that of LOAD due to younger age, the EYLL for the former was 8.7 years versus 1.7 years for the latter. EOAD also had higher lifetime healthcare costs than the LOAD group (USD$37,957±2,403 versus 33,809±786).

CONCLUSIONS

Since EOAD patients had both higher EYLL and lifetime healthcare costs than LOAD, future studies should pay more attention to the needs of EOAD patients.

Trends in Hospital Morbidity From Alzheimer's Disease in the European Union, 2000 to 2014

BACKGROUND

Alzheimer's disease (AD) has become a concerning public health issue. We aimed to analyze the trends of hospital morbidity from AD in the European Union (EU) in the period 2000 to 2014.

METHODS

Data from hospital discharges of men and women over 50 years old hospitalized due to AD in the EU were extracted from Eurostat database. We tested for secular trends computing anual percent change, and identified significant changes in the linear slope of the trend.

RESULTS

Hospital morbidity from AD showed a 0.8% (95% confidence intervals -2.2 to 0.6) slight declining trend in the EU. In men and women, we recorded a -0.5% and -1.0% decrease in hospital morbidity rates, respectively. Several countries showed changing trends during the study period.

CONCLUSION

Alzheimer's disease hospital morbidity has slightly declined in the entire EU in the past years. Eastern European countries showed steadily increasing trends, whereas in western and Mediterranean countries the rates decreased or leveled off.

Mortality Risk after Diagnosis of Early-Onset Alzheimer's Disease versus Late-Onset Alzheimer's Disease: A Propensity Score Matching Analysis

BACKGROUND/OBJECTIVE

We aimed to compare the risk of mortality in patients with early-onset Alzheimer's disease (EOAD) versus those with late-onset AD (LOAD) using a large number of study subjects. We applied propensity score matching (PSM) to minimize confounding biases in the comparison between EOAD and LOAD.

METHODS

We obtained data from elderly Korean subjects with AD (n = 3,611) at baseline from the CREDOS cohort study, which was conducted from November 2005 to July 2013. We conducted PSM to reduce the bias due to confounding variables related to survival in patients with AD. The risks of mortality associated with EOAD and LOAD were evaluated by Cox proportional hazard analyses, controlling for relevant covariates.

RESULTS

After propensity score matching, 312 subjects with EOAD and 624 subjects with LOAD were selected for further analysis. The Cox proportional hazard analysis showed that patients with EOAD are at a greater risk for mortality compared to those with LOAD (Hazard Ratio: 2.01, 95% CI: 1.01-4.00, p-value: 0.04) when controlling for the direct effect of aging on mortality. The results did not change after adjusting for age at diagnosis, general cognitive function, nutritional factor related to body mass index, and physical disability using activities of daily living. The results support the assumption that EOAD takes a more malignant course than LOAD.

CONCLUSIONS

Our results provide support for the idea that EOAD takes a clinical course that is distinct from that of LOAD, especially as pertains to the risk of mortality.

[Psychometric properties of the Alzheimer's Disease Knowledge Scale--Korean Version]

PURPOSE

The purpose of this study was to evaluate the psychometric properties of the Korean version of the Alzheimer's Disease Knowledge Scale (ADKS-K) to determine its applicability to Korean adults.

METHODS

Cross-cultural validity was performed according to Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN). The Kuder-Richardson Formula 20 for internal consistency and Intraclass Correlation Coefficient (ICC) for test-retest reliability were conducted. Content validity, criterion related validity and construct validity were evaluated. The Classical Test Theory (CTT) model and the Item Response Theory (IRT) model were applied in performing the item analysis.

RESULTS

The KR 20 was .71, and the ICC was .90, indicating that the ADKS-K has internal consistency and stability reliability. Thirty items of the ADKS-K had significant Content Validity Ratio (CVR) values, i.e., mean of 0.82 and range of 0.60~1.00. Mean item difficulty and discrimination indices calculated by TestAn program were 0.63 and 0.23, respectively. Mean item difficulty and discrimination indices calculated by BayesiAn program were -0.60 and 0.77, respectively. These tests indicate that ADKS-K has an acceptable level of difficulty and discriminating efficiency.

CONCLUSION

Results suggest that ADKS-K has the potential to be a proper instrument for assessing AD knowledge in Korean adults.

Clinical Recommendations for the Use of Donepezil 23 mg in Moderate-to-Severe Alzheimer's Disease in the Asia-Pacific Region

Background

The ‘Asia-Pacific Expert Panel (APEX) for donepezil 23 mg’ met in November 2015 to review evidence for the recently approved high dose of donepezil and to provide recommendations to help physicians in Asia make informed clinical decisions about using donepezil 23 mg in patients with moderate-to-severe Alzheimer's disease (AD).

Summary

In a global phase III study (study 326) in patients with moderate-to-severe AD, donepezil 23 mg/day demonstrated significantly greater cognitive benefits versus donepezil 10 mg/day, with a between-treatment difference in mean change in the Severe Impairment Battery score of 2.2 points (p < 0.001) in the overall population and 3.1 points (p < 0.001) in patients with advanced AD. A subanalysis of study 326 demonstrated that the benefits and risks associated with donepezil 23 mg/day versus donepezil 10 mg/day in Asian patients with moderate-to-severe AD were comparable to those in the global study population.

Key Message

Donepezil 23 mg is a valuable treatment for patients with AD, particularly those with advanced disease. The APEX emphasized the importance of patient selection (AD severity, tolerability of lower doses of donepezil, and absence of contraindications), a stepwise titration strategy for dose escalation, and appropriate monitoring and counseling of patients and caregivers in the management of patients with AD.

Blood cadmium levels and Alzheimer's disease mortality risk in older US adults

BACKGROUND

Cadmium, a ubiquitous environmental pollutant, exhibits potential neurotoxic risk. Although compelling evidence suggests cadmium accumulation has a role in the formation of amyloid-β plaques and neurofibrillary tangles, which are the hallmarks of Alzheimer's disease (AD) pathogenesis, the supporting evidence in humans is limited and conflicting. In this study, we investigated the association between blood cadmium levels and AD mortality among older adults by analyzing the prospective data from the 1999-2004 Third National Health and Nutrition Examination Survey (NHANES) and the Linked Mortality File.

METHODS

The data were obtained from the 1999-2004 NHANES and the NHANES (1999-2004) Linked Mortality File. A total of 4,064 participants aged ≥60 years old with available blood cadmium data and no other missing information on their questionnaires at baseline were included in this study. AD was denoted as G30 based on the ICD-10 underlying causes of death.

RESULTS

Of the 4,064 participants, 51 subjects died as a result of AD. Compared with participants with low blood cadmium levels (≤0.3 μg/L), those with high cadmium levels (>0.6 μg/L) exhibited a 3.83-fold (hazard ratio = 3.83; 95 % CI = 1.39-10.59) increased risk of AD mortality. In the Kaplan-Meier survival curves for cumulative AD mortality, higher levels of blood cadmium showed marginally significant association with increased mortality at baseline and in patients over 60 years of age (p = 0.0684).

CONCLUSIONS

We observed a significant association between blood cadmium levels and AD mortality among older adults in the US. Our findings suggest that environmental exposure to cadmium may be a risk factor for AD.

Survival in Subcortical Vascular Dementia: Predictors and Comparison to Probable Alzheimer's Disease in a Tertiary Memory Clinic Population

BACKGROUND

Subcortical vascular dementia (SVaD) is one of the most common dementias, after Alzheimer's disease (AD) dementia. Few survival analyses in SVaD patients have been reported.

METHODS

The dates and causes of death of 146 SVaD and 725 AD patients were included. We used the Cox proportional hazards model to compare survival between SVaD and AD patients and to explore possible factors related to survival of SVaD patients.

RESULTS

The median survival time after the onset of SVaD (109 months) was shorter than that recorded for AD (152 months). The most common cause of death in SVaD was stroke (47.1%). Factors associated with shorter survival in SVaD were late onset, male sex, worse baseline cognition, absence of hypertension and a family history of stroke.

CONCLUSIONS

Stroke prevention may be important in SVaD treatment because 47.1% of SVaD patients died of stroke. A family history of stroke and absence of hypertension were associated with a shorter survival in SVaD, suggesting the existence of genetic or unknown risk factors.

Effect of Vascular Risk Factors and Diseases on Mortality in Individuals with Dementia: A Systematic Review and Meta-Analysis

OBJECTIVES

To assess the effect of cardiovascular diseases and risk factors on mortality in individuals with dementia.

DESIGN

Systematic review and meta-analysis. English- and Dutch-language studies in PubMed, EMBASE, and PsycINFO databases were searched in April 2014 with hand-searching of in-text citations and no publication limitations. Inclusion criteria were original studies reporting on cardiovascular risk factors or diseases and their relationship with survival in individuals with dementia. The Quality In Prognosis Studies tool was used to appraise all included articles.

SETTING

Population-, hospital-, and nursing home-based.

PARTICIPANTS

Community-dwelling, hospitalized individuals and nursing home residents with dementia.

MEASUREMENTS

A random-effects meta-analysis was performed to investigate the effect of several cardiovascular diseases and risk factors on overall mortality.

RESULTS

Twelve studies with 235,865 participants were included. In pooled analyses, male sex (hazard ratio (HR)=1.67, 95% confidence interval (CI)=1.56-1.78), diabetes mellitus (DM) (HR=1.49, 95% CI=1.33-1.68), smoking (ever vs never) (HR=1.37, 95% CI=1.17-1.61), coronary heart disease (CHD) (HR=1.21, 95% CI=1.02-1.44) and congestive heart failure (CHF) (HR=1.37, 95% CI=1.18-1.59) were associated with mortality. Stroke, high blood pressure, being overweight, and hypercholesterolemia were not statistically significantly related to mortality.

CONCLUSION

Individuals with dementia and DM, smoking, CHD, and CHF have a greater risk of death than individuals with dementia without these risk factors or diseases.

The natural history of dementia

This review summarizes studies on the natural history of dementia with a focus on Alzheimer's disease and vascular dementia. Understanding the course of dementia is important not only for patients, caregivers, and health professionals, but also for health policy-makers, who have to plan for national resources needed in the management of an increasing number of dementia cases. From the available published data, the life expectancy of elderly people with dementia is shorter than that of non-demented elderly. Reports on survival after a diagnosis of dementia vary from 3 to 12 years. The wide variation is partly due to the diagnostic criteria used in the studies and the sites where they were conducted (i.e. hospitals, clinics, or homes). There is an apparent difference in survival between Alzheimer's disease patients with onset of illness before 75 years and those after 75 years: the younger patients have a longer life expectancy. However, there are conflicting data on survival (in years) comparing male and female patients and comparing patients of different ethnicities. For vascular dementia, published papers on life expectancy vary between 3 to 5 years. Vascular dementia appears to have a poorer prognosis than Alzheimer's disease. The stages of severity of dementia were compared in a follow-up of a sample of Alzheimer's disease patients in Singapore, and the mean duration of the mild phase (clinical dementia rating 1) was 5.6 years, the moderate phase (clinical dementia rating 2) was 3.5 years, and the severe phase (clinical dementia rating 3) was 3.2 years. At the various phases of the disease, the demand on health-care services and economic cost are different.

Mortality rates and predictors in community-dwelling elderly individuals with cognitive impairment: an eight-year follow-up after initial assessment

BACKGROUND

We assessed eight-year mortality rates and predictors in a rural cohort of elderly individuals with cognitive impairment.

METHODS

A total of 1,035 individuals, including 155 (15.0%) individuals with cognitive impairment, no dementia (CIND), and 69 (6.7%) individuals with clinically diagnosed dementia were followed for eight years from 1997. The initial assessment involved a two-step diagnostic procedure performed during a door-to-door survey, and mortality data were obtained from the Korean National Statistical Office (KNSO). The relationship between clinical diagnosis and risk of death was examined using the Cox proportional hazards model after adjusting for age, sex, and education.

RESULTS

During follow-up, 392 individuals died (37.9%). Compared to persons without cognitive impairment, mortality risk was nearly double among those with CIND (hazard ratio [95% confidence interval], 1.92 [1.46-2.54]), and this increased more than three-fold among those with dementia (3.20 [2.30-4.44]). Old age and high scores on the behavioral changes scale at diagnosis were two common predictors of mortality among those with CIND and dementia. Among the items on the behavioral changes scale, low sociability, less spontaneity, and poor hygiene were associated with increased mortality in individuals with CIND. Conversely, low sociability, excessive emotionality, and irritability were associated with increased mortality in patients with dementia.

CONCLUSIONS

Both dementia and CIND increased mortality risk compared with normal cognition in this community cohort. It is important to identify and manage early behavioral changes to reduce mortality in individuals with CIND and dementia.