Is function in instrumental activities of daily living a useful feature in predicting Alzheimer's disease dementia in subjective cognitive decline?

OBJECTIVE

Subjective cognitive decline (SCD), the earliest symptom in preclinical Alzheimer's disease (AD), is insufficient to identify individuals at risk for AD dementia. Therefore, we aimed to investigate whether function in instrumental activities of daily living (IADL) contributes to identification.

METHODS

We analysed data of cognitively unimpaired participants of the prospective German Study on Ageing, Cognition, and Dementia in Primary Care Patients (AgeCoDe) and its extension, the Study on Needs, Health Service Use, Costs and Health-related Quality of Life in a Large Sample of Oldest-old Primary Care Patients (AgeQualiDe), collected over 10.5 years. Development of AD dementia was quantified as incidence rates (IRs) per 1000 person-years. Cox regression was used to assess the association of SCD and IADL function in regard to incident AD dementia.

RESULTS

Of 1467 included individuals, 792 (54.0%) reported SCD at baseline. Impaired IADL were present in 50 (3.4%) individuals. IR for AD dementia was highest in individuals with SCD and impaired IADL (49.7; 95% CI, 24.8-99.3). Unadjusted and adjusted Cox analyses revealed an increased AD dementia risk for individuals with SCD and impaired IADL (uHR = 6.1; 95% CI, 2.9-13.0; P < 0.001; aHR = 2.5; 95% CI, 1.1-5.7; P < 0.05).

CONCLUSIONS

Consistent with the SCD concept, IADL function was largely well preserved in the majority of individuals with SCD. However, if difficulties in IADL were present, risk for AD dementia was increased. Therefore, screening for IADL impairment could serve as an economically viable indicator to assess AD dementia risk above and beyond SCD.

Cognitive performance before and after the onset of subjective cognitive decline in old age

Background

Our objectives were (1) to test the association between the report of subjective cognitive decline (SCD) and prospective objective cognitive performance in high age individuals and (2) to study the course of longitudinal cognitive performance before and after the first report of SCD.

Methods

Cognitively normal elderly participants of the German Study on Ageing, Cognition, and Dementia study (N = 2330) with SCD (subjective decline in memory with and without associated concerns) and without SCD at baseline were assessed over 8 years with regard to immediate and delayed verbal recall, verbal fluency, working memory, and global cognition. Baseline performance and cognitive trajectories were compared between groups. In addition, cognitive trajectories before and after the initial report of SCD (incident SCD) were modelled in those without SCD at baseline.

Results

Baseline performance in the SCD group was lower and declined more steeply in immediate and delayed verbal recall than in the control group (no SCD at baseline). This effect was more pronounced in the SCD group with concerns. Incident SCD was preceded by decline in immediate and delayed memory and word fluency.

Conclusions

SCD predicts future memory decline. Incident SCD is related to previous cognitive decline. The latter finding supports the concept of SCD indicating first subtle decline in cognitive performance that characterizes preclinical Alzheimer's disease.

The CERAD neuropsychological assessment battery total score detects and predicts Alzheimer disease dementia with high diagnostic accuracy

OBJECTIVES

To establish the diagnostic accuracy of the Total Score of the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological assessment battery (CERAD-NP) both for cross-sectional discrimination of Alzheimer disease (AD) dementia and short-term prediction of incident AD dementia.

DESIGN

Longitudinal cohort study with two assessments at a 1.5-year interval.

SETTING

Primary care sample randomly recruited via medical record registries.

PARTICIPANTS

As part of the German Study on Ageing, Cognition, and Dementia (AgeCoDe), a sample of elderly individuals (N = 1,606; mean age: 84 years) was assessed.

MEASUREMENTS

Subjects were assessed with the CERAD-NP and followed up for 18 months (97.6% follow-up rate). Logistic regression and receiver-operating-characteristic (ROC) curve analysis were used to compare the diagnostic accuracy of the CERAD-NP Total Score (CTS) with that of single CERAD-NP scores and the Mini-Mental-State-Examination (MMSE) score.

RESULTS

ROC curve analysis resulted in excellent (area under the curve [AUC]: 0.97) cross-sectional discrimination between non-AD and AD dementia subjects. Prediction of incident AD dementia with the CTS was also very good (AUC: 0.89), and was significantly better than prediction based on the MMSE.

CONCLUSIONS

The cross-sectional results confirm that the CTS is a highly accurate diagnostic tool for detecting AD dementia in elderly primary care patients. In addition, we provide evidence that the CTS is also accurate for the prediction of incident AD dementia. These findings further support the validity of the CTS as an index of overall cognitive functioning for detection and prediction of AD dementia.

Apolipoprotein E epsilon 4 genotype and a physically active lifestyle in late life: analysis of gene-environment interaction for the risk of dementia and Alzheimer's disease dementia

BACKGROUND

As physical activity may modify the effect of the apolipoprotein E (APOE) ε4 allele on the risk of dementia and Alzheimer's disease (AD) dementia, we tested for such a gene-environment interaction in a sample of general practice patients aged ⩾75 years.

METHOD

Data were derived from follow-up waves I-IV of the longitudinal German study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe). The Kaplan-Meier survival method was used to estimate dementia- and AD-free survival times. Multivariable Cox regression was used to assess individual associations of APOE ε4 and physical activity with risk for dementia and AD, controlling for covariates. We tested for gene-environment interaction by calculating three indices of additive interaction.

RESULTS

Among the randomly selected sample of 6619 patients, 3327 (50.3%) individuals participated in the study at baseline and 2810 (42.5%) at follow-up I. Of the 2492 patients without dementia included at follow-up I, 278 developed dementia (184 AD) over the subsequent follow-up interval of 4.5 years. The presence of the APOE ε4 allele significantly increased and higher physical activity significantly decreased risk for dementia and AD. The co-presence of APOE ε4 with low physical activity was associated with higher risk for dementia and AD and shorter dementia- and AD-free survival time than the presence of APOE ε4 or low physical activity alone. Indices of interaction indicated no significant interaction between low physical activity and the APOE ε4 allele for general dementia risk, but a possible additive interaction for AD risk.

CONCLUSIONS

Physical activity even in late life may be effective in reducing conversion to dementia and AD or in delaying the onset of clinical manifestations. APOE ε4 carriers may particularly benefit from increasing physical activity with regard to their risk for AD.

A hierarchy of predictors for dementia-free survival in old-age: results of the AgeCoDe study

OBJECTIVE

Progression from cognitive impairment (CI) to dementia is predicted by several factors, but their relative importance and interaction are unclear.

METHOD

We investigated numerous such factors in the AgeCoDe study, a longitudinal study of general practice patients aged 75+. We used recursive partitioning analysis (RPA) to identify hierarchical patterns of baseline covariates that predicted dementia-free survival.

RESULTS

Among 784 non-demented patients with CI, 157 (20.0%) developed dementia over a follow-up interval of 4.5 years. RPA showed that more severe cognitive compromise, revealed by a Mini-Mental State Examination (MMSE) score < 27.47, was the strongest predictor of imminent dementia. Dementia-free survival time was shortest (mean 2.4 years) in such low-scoring patients who also had impaired instrumental activities of daily living (iADL) and subjective memory impairment with related worry (SMI-w). Patients with identical characteristics but without SMI-w had an estimated mean dementia-free survival time of 3.8 years, which was still shorter than in patients who had subthreshold MMSE scores but intact iADL (4.2-5.2 years).

CONCLUSION

Hierarchical patterns of readily available covariates can predict dementia-free survival in older general practice patients with CI. Although less widely appreciated than other variables, iADL impairment appears to be an especially noteworthy predictor of progression to dementia.

Predictors of institutionalisation in incident dementia--results of the German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe study)

BACKGROUND/AIMS

In the past few decades, a number of studies investigated risk factors of nursing home placement (NHP) in dementia patients. The aim of the study was to investigate risk factors of NHP in incident dementia cases, considering characteristics at the time of the dementia diagnosis.

METHODS

254 incident dementia cases from a German general practice sample aged 75 years and older which were assessed every 1.5 years over 4 waves were included. A Cox proportional hazard regression model was used to determine predictors of NHP. Kaplan-Meier survival curves were used to evaluate the time until NHP.

RESULTS

Of the 254 incident dementia cases, 77 (30%) were institutionalised over the study course. The mean time until NHP was 4.1 years. Significant characteristics of NHP at the time of the dementia diagnosis were marital status (being single or widowed), higher severity of cognitive impairment and mobility impairment.

CONCLUSION

Marital status seems to play a decisive role in NHP. Early initiation of support of sufferers may ensure remaining in the familiar surroundings as long as possible.

Prediction of incident dementia: impact of impairment in instrumental activities of daily living and mild cognitive impairment-results from the German study on ageing, cognition, and dementia in primary care patients

OBJECTIVES

There is an increasing call for a stronger consideration of impairment in instrumental activities of daily living (IADL) in the diagnostic criteria of Mild Cognitive Impairment (MCI) to improve the prediction of dementia. Thus, the aim of the study was to determine the predictive capability of MCI and IADL impairment for incident dementia.

DESIGN

Longitudinal cohort study with four assessments at 1.5-year intervals over a period of 4.5 years.

SETTING

: Primary care medical record registry sample.

PARTICIPANTS

As part of the German Study on Ageing, Cognition, and Dementia in Primary Care Patients, a sample of 3,327 patients from general practitioners, aged 75 years and older, was assessed.

MEASUREMENTS

The predictive capability of MCI and IADL impairment for incident dementia was analysed using receiver operating characteristics, Kaplan-Meier survival analyses, and Cox proportional hazards models.

RESULTS

MCI and IADL impairment were found to be significantly associated with higher conversion to, shorter time to, and better predictive power for future dementia. Regarding IADL, a significant impact was particularly found for impairment in responsibility for one's own medication, shopping, and housekeeping, and in the ability to use public transport.

CONCLUSIONS

Combining MCI with IADL impairment significantly improves the prediction of future dementia. Even though information on a set of risk factors is required to achieve a predictive accuracy for dementia in subjects with MCI being clinically useful, IADL impairment should be a very important element of such a risk factor set.

Prevalence and risk factors of depressive symptoms in latest life--results of the Leipzig Longitudinal Study of the Aged (LEILA 75+)

INTRODUCTION

Because the oldest old will be the fastest-growing age group in the future and information about epidemiology of depressive symptoms in latest life is scarce, the present study aims at determining the age-specific and gender-specific prevalence rates and risk factors of depressive symptoms in latest life.

METHODS

As part of the Leipzig Longitudinal Study of the Aged (LEILA 75+), a population-based sample of 1,006 individuals aged 75 years and older were interviewed on socio-demographic, clinical and psychometric variables. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (cut-off score ≥16); mild cognitive impairment (MCI) was diagnosed according to criteria of the International Working Group on MCI. Factors associated with depressive symptoms were determined with multiple logistic regression models.

RESULTS

Of the overall sample, 38.2% (95% confidence interval, CI 35.2-41.2) were classified as depressed. In the full multivariate model, the following variables were significantly associated with depressive symptoms: divorced or widowed marital status, low educational level, poor self-rated health status, functional impairment, multi-domain MCI, stressful life events and poor social network. All variables but MCI remained significant correlates of depressive symptoms in the parsimonious model.

DISCUSSION

Because depressive symptoms are common in oldest age and associated with broad categories of risk factors, latest-life depression represents an important public health issue. Employment of comprehensive geriatric assessment to ascertain depressive symptoms and its concomitants could help to improve treatment success.

The assessment of changes in cognitive functioning: age-, education-, and gender-specific reliable change indices for older adults tested on the CERAD-NP battery: results of the German Study on Ageing, Cognition, and Dementia in Primary Care Patients (AgeCoDe)

OBJECTIVES

The Consortium to Establish a Registry for Alzheimer's Disease-Neuropsychological (CERAD-NP) battery represents a commonly used neuropsychological instrument to measure cognitive functioning in the elderly. This study provides normative data for changes in cognitive function that normally occur in cognitively healthy individuals to interpret changes in CERAD-NP test scores over longer time periods.

DESIGN

Longitudinal cohort study with three assessments at 1.5-year intervals over a period of 3 years.

SETTING

: Primary care medical record registry sample.

PARTICIPANTS

As part of the German Study on Ageing, Cognition, and Dementia in Primary Care Patients, a sample of 1,450 cognitively healthy general practitioner patients, age 75 years and older, was assessed.

MEASUREMENTS

Age-, education-, and gender-specific Reliable Change Indices (RCIs) were computed for a 90% confidence interval for selected subtests of the CERAD-NP battery.

RESULTS

Across different age, education, and gender subgroups, changes from at least six to nine points in Verbal Fluency, four to eight points in Word List Memory, two to four points in Word List Recall, and one to four points in Word List Recognition indicated significant (i.e. reliable) changes in CERAD-NP test scores at the 90% confidence level. Furthermore, the calculation of RCIs for individual patients is demonstrated.

CONCLUSIONS

Smaller changes in CERAD-NP test scores can be interpreted with only high uncertainty because of probable measurement error, practice effects, and normal age-related cognitive decline. This study, for the first time, provides age-, education-, and gender-specific CERAD-NP reference values on the basis of RCI methods for the interpretation of cognitive changes in older-age groups.

Clock drawing test - screening utility for mild cognitive impairment according to different scoring systems: results of the Leipzig Longitudinal Study of the Aged (LEILA 75+)

BACKGROUND

There is a strong demand for screening instruments for mild cognitive impairment (MCI), as a pre-stage of dementia. The clock drawing test (CDT) is widely used to screen for dementia, but the utility in screening for MCI remains uncertain. In particular, it is still questionable which scoring system is the best in order to screen for MCI. We therefore aimed to compare the utility of different CDT scoring systems for screening for MCI.

METHODS

In a sample of 428 subjects of the Leipzig Longitudinal Study of the Aged (LEILA 75+) study, CDT scores of different scoring systems were compared between subjects with and without MCI. Comparison of receiver operating characteristic (ROC; area under the curve, sensitivity, specificity) was performed and inter-rater reliability was calculated.

RESULTS

The CDT scores differed significantly between MCI and non-MCI subjects according to all scoring systems applied. However, ROC of the CDT scores was not adequate.

CONCLUSIONS

None of the present CDT scoring systems has sufficient utility to screen reliably for MCI. The clinical value of the CDT could be improved by using semi-quantitative scoring, having a wider score range and focusing on specific details of the clock (e.g. the hands and numbers).

Impact of impairment in instrumental activities of daily living and mild cognitive impairment on time to incident dementia: results of the Leipzig Longitudinal Study of the Aged

BACKGROUND

Early diagnosis of dementia requires knowledge about associated predictors. The aim of this study was to determine the impact of mild cognitive impairment (MCI) and impairment in instrumental activities of daily living (IADL) on the time to an incident dementia diagnosis.

METHOD

Data were derived from the Leipzig Longitudinal Study of the Aged (LEILA75+), a population-based study of individuals aged ≥75 years. Kaplan-Meier survival analysis was used to determine time to incident dementia. Cox proportional hazards models were applied to determine the impact of MCI and IADL impairment on the time to incident dementia.

RESULTS

In total, 180 (22.0%) of 819 initially dementia-free subjects developed dementia by the end of the study. Mean time to incident dementia was 6.7 years [95% confidence interval (CI) 6.5-6.9]. MCI combined with IADL impairment was associated with a higher conversion rate to dementia, a shorter time to clinically manifest diagnosis and a lower chance of reversibility to cognitive normal. The highest risk for a shorter time to incident dementia was found for amnestic MCI combined with IADL impairment. The mean time to incident dementia was 3.7 years (95% CI 2.9-4.4) and thus half as long as in subjects without MCI and IADL impairment.

CONCLUSIONS

Subjects with MCI and IADL impairment constitute a high-risk population for future dementia. The consideration of both--MCI and IADL impairment-- might help to improve the prediction of dementia.

At-risk alcohol drinking in primary care patients aged 75 years and older

BACKGROUND

Little is known about the prevalence and risk factors of alcohol problems among older people (especially those aged 75 years and more). The aims of this study were to report alcohol consumption patterns and to determine their association with socio-demographic variables and health characteristics.

METHOD

3224 non-demented subjects aged 75 and over and attending general practitioners (GPs) (n = 138) in an urban area of Germany were studied by structured clinical interviews including detailed assessment of alcohol consumption patterns distinguishing between abstainers, moderate drinkers and at-risk drinkers (>20 g of alcohol for women and >30 g of alcohol for men).

RESULTS

A high proportion (50.1%) of the sample were abstainers, 43.4% were moderate drinkers. The prevalence of at-risk alcohol consumption was 6.5% (95% CI 5.6-7.4). Rates were significantly higher for men (12.1%; 95% CI 10.2-14.0) compared to women (3.6%; 95% CI 2.8-4.4). After full adjustment for confounding variables we found that compared to moderate drinking abstaining from alcohol was significantly associated with female gender, lower education, and mobility impairment. Compared to moderate drinking at-risk drinking was significantly higher among men, individuals with a liver disease, and current smokers.

CONCLUSIONS

Multivariate analysis revealed that, apart from liver disease, at-risk drinking in a non-demented population aged 75 and over was associated with relatively good physical and mental health. Nevertheless, public prevention measures should focus on at-risk drinkers to make them aware of potential risks of high alcohol consumption in old age.

Prevalence and risk factors for depression in non-demented primary care attenders aged 75 years and older

BACKGROUND

Depression among the elderly is an important public health issue. The aims of this study were to report the prevalence of depression and to determine the impact of socio-demographic variables, functional impairment and medical diagnoses, lifestyle factors, and mild cognitive impairment on depression as part of the German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe Study).

METHODS

Included in the cross-sectional survey were 3327 non-demented subjects aged 75 and over attending general practitioners (GPs) (n=138) in an urban area of Germany. The GDS-15 Geriatric Depression Scale was used to measure depression with a threshold of <6/6+. Associations with social and clinical risk factors were assessed by means of multiple logistic regression models.

RESULTS

The prevalence of depression was 9.7% (95% confidence interval 8.7-10.7). In a univariate analysis, the following variables were significantly associated with depression: female gender, increasing age, living alone, divorce, lower educational status, functional impairment, comorbid somatic disorder, mild cognitive impairment, smoking, and abstinence from alcohol. After full adjustment for confounding variables, odds ratios for depression were significantly higher only for functional impairment, smoking, and multi-domain mild cognitive impairment.

LIMITATIONS

Recruitment procedures might have led to an underestimation of current prevalence. The cross-sectional data did not allow us to analyze the temporal relationship between risk factors and depression.

CONCLUSIONS

The prevalence of depression in the elderly is high and remains high into old age. In designing prevention programs, it is important to call more attention to the impact of functional and cognitive impairment on depression.

Direct costs associated with mild cognitive impairment in primary care

BACKGROUND/AIMS

Little is known about the direct costs of individuals with Mild Cognitive Impairment (MCI). This study investigates the direct costs associated with MCI according to recent diagnostic criteria from a societal perspective.

METHODS

Four hundred and fifty-two primary care patients aged 75+ from Leipzig, Germany, were investigated in face-to-face interviews regarding MCI according to the current diagnostic criteria of the International Working Group on MCI, resource utilisation and costs (questionnaire of service utilisation and costs), as well as chronic medical illness (Chronic Disease Score). Resource utilisation was monetarily valued using 2004/2005 prices.

RESULTS

Mean annual direct costs were 4,443 euro for patients with MCI (n=39) and 3,814 euro for patients without MCI (n=413) (p=0.34). Looking at the cost components, patients with and without MCI only significantly differed regarding pharmaceutical costs (1,210 euro vs 1,062 euro; p<0.05) not caused by antidementive drugs.

CONCLUSION

Direct costs of individuals having MCI are not significantly increased in comparison to direct costs of individuals without cognitive deficits.