Alzheimer’s disease (AD) is the sixth leading cause of death, with an average survival estimated between 5 and 10 years after diagnosis. Despite recent advances in diagnostic criteria of AD, few studies have used biomarker-based diagnostics to determine the prognostic factors of AD. We investigate predictors of death and institutionalization in a population of AD patients with high probability of AD physiopathology process assessed by positivity of three CSF biomarkers. Three hundred twenty-one AD patients with abnormal values for CSF beta-amyloid peptide (Aβ42), tau, and phosphorylated tau levels were recruited from a memory clinic-based registry between 2008 and 2017 (Lariboisiere hospital, Paris, France) and followed during a median period of 3.9 years. We used multivariable Cox models to estimate the hazard ratio (HR) of death and institutionalization for baseline clinical data, genotype of the apolipoprotein E (APOE), and levels of CSF biomarkers. A total of 71 (22%) patients were institutionalized and 57 (18%) died during the follow-up. Greater age, male sex, lower MMSE score, and lower CSF Aβ42 level were associated with an increased risk of mortality. One standard deviation lower CSF Aβ42 (135 pg/mL) was associated with a 89% increased risk of death (95% CI = 1.25–2.86; p = 0.002). This association was not modified by age, sex, education, APOE e4, and disease severity. There was no evidence of an association of tau CSF biomarkers with mortality. None of the CSF biomarkers were associated with institutionalization. Lower CSF Aβ42 is a strong prognostic marker of mortality in AD patients, independently of age or severity of the disease. Whether drugs targeting beta-amyloid peptide could have an effect on mortality of AD patients should be investigated in future clinical trials.

/pdf/csf-level-of-b-amyloid-peptide-predicts-mortality-in-10i209x9ml.pdf

CSF level of β-amyloid peptide predicts mortality in Alzheimer’s disease

Objective 
To investigate the relationship between cerebrospinal fluid (CSF) β-amyloid peptide (Aβ42) and CSF Tau in a large population of patients referred to memory clinics for investigation of cognitive dysfunction.


Methods 
We analyzed Alzheimer’s disease (AD) biomarkers in CSF taken from 3565 patients referred to 18 French memory clinics. Patients were classified into four profiles according to levels of CSF biomarkers (A: amyloidosis, N: neurodegeneration). The association between CSF Tau and CSF Aβ42 were analyzed using general linear regression models, in the overall population and stratified by biomarkers profiles. We compared linear and quadratic models using Akaike information criterion. We also assessed change in biomarker profiles in a subset of patients who had 2 assessments of biomarkers.


Results 
CSF Tau was negatively associated with CSF Aβ42 in the overall population, following a non-linear quadratic model. However, the nature of this association was different in the 4 profiles: positive association in A-N- profile, negative association in A-N+ and A+N+ profiles, lack of association in A+N- patients. When considering patients with longitudinal data on profiles, 36% of those initially classified as A-N+ evolved to an A+N+ profile.


Conclusions 
The nature of the association between CSF Aβ42 and CFS Tau depends on the A/N profiles of patients. These results suggest an increase in CSF Aβ42 early in the disease before its decline while tau pathology progresses, this pattern is particularly observed in non-APOE4 subjects. This phenomenon may explain why some patients with neurodegeneration only markers convert to an AD profile (A+N+) over time.

/pdf/biomarker-profiles-of-alzheimer-s-disease-and-dynamic-of-the-utp76azdr9.pdf

Biomarker profiles of Alzheimer's disease and dynamic of the association between cerebrospinal fluid levels of β-amyloid peptide and tau.

Alzheimer's disease (AD) is the 5th leading cause of death in people 65 years and older. The ATN classification reflects a biological definition of AD pathology with markers of Aβ deposition (A), pathologic tau (T), and neurodegeneration (N). Little is known about the relationship between ATN status and the risk of mortality, leading us to examine this association in a relatively large population of patients seen at a memory clinic for cognitive disorders.Data were drawn from the BioCogBank Study, including patients seen for cognitive disorders in Lariboisiere Hospital (Paris, France), followed up to 15 years. All participants underwent a lumbar puncture for an assessment of the levels of CSF tau (tau), phosphorylated tau (p-tau181), and β-amyloid 42 peptide (Aβ42). Vital status on July 1, 2020, was recorded for each participant using the national mortality register. Individuals were categorized according to their ATN profiles based on CSF Aβ42 or Aβ42/40 ratio, p-tau181, and tau. Kaplan-Meier and multivariate Cox analyses were performed with A-T-N - participants as the reference using a short (5 years) and long follow-up (15 years).Of the 1353 patients in the study (mean age: 68 years old, 53% of women, mean MMSE score: 22.6), 262 died during the follow-up. At 5 years of follow-up, A-T-N + individuals had the highest risk of mortality in Kaplan-Meier and adjusted Cox analyses [HR (95% CI) = 2.93 (1.31-6.56)]. At 15 years of follow-up, patients in the AD spectrum had a higher mortality risk with a gradient effect for biomarker positivity: A-T + [HR = 1.63 (1.04-2.55)], A + T - [HR = 2.17 (1.44-3.26)], and A + T + individuals [HR = 2.38 (1.66-3.39)], compared to A-T-N - patients. Adjustments on potential confounders had little impact on these associations.This study shows ATN profiles to be associated with mortality in a relatively large patient cohort based on a memory clinic. Patients with isolated evidence of neurodegeneration had a higher mortality rate in the short follow-up, and patients with the AD profile had the highest mortality rate in the long follow-up. 

/pdf/association-between-atn-profiles-and-mortality-in-a-clinical-39zk4hvp.pdf

Association between ATN profiles and mortality in a clinical cohort of patients with cognitive disorders

BACKGROUND The prevalence of cognitive impairment is high among alcohol-dependent patients. Although the clinical presentation of alcohol-related cognitive disorder (ARCD) may resemble that of Alzheimer's disease (AD), the prognosis and treatment of the 2 diseases are different. Cerebrospinal fluid (CSF) biomarkers (tau, phosphorylated tau, and amyloid β) have high diagnostic accuracy in AD and are currently being used to discriminate between psychiatric disorders and AD, but are not used to diagnose ARCD. The aim of this study was to characterize CSF biomarkers in a homogeneous, cognitively impaired alcohol-dependent population. METHODS This single-center study was conducted in an addiction medicine department of a Parisian Hospital. We selected patients with documented persistent cognitive impairment whose MoCA (Montreal Cognitive Assessment) score was below 24/30 after at least 1 month of documented inpatient abstinence from alcohol. We measured the CSF biomarkers (tau, phosphorylated tau, and amyloid β 1-42 and 1-40) in 73 highly impaired alcohol-dependent patients (Alcohol Use Disorders Identification Test score over 11 for women and 12 for men) with. RESULTS Patients' average age was 60 ± 9.1 years and 45 (61.6%) had a normal CSF profile, 8 (11.0%) had a typical CSF AD profile, and 20 (27.4%) had an intermediate CSF profile. CONCLUSIONS This study revealed a high prevalence of AD in alcohol-dependent patients with persistent cognitive deficits and several anomalies in their CSF profiles. Thus, it is important to consider AD in the differential diagnosis of persistent cognitive deficits in patients with alcohol dependence and to use CSF biomarkers in addition to imaging and neuropsychological testing to evaluate alcohol-related cognitive impairment.

Cerebrospinal Fluid Biomarkers in Patients With Alcohol Use Disorder and Persistent Cognitive Impairment.

BACKGROUND
The ATN scheme was proposed as an unbiased biological characterization of the Alzheimer's disease (AD) spectrum, grouping biomarkers into three categories: brain Amyloidosis-A, Tauopathy-T, Neurodegeneration-N. Although this scheme was mainly recommended for research, it is relevant for diagnosis.


OBJECTIVE
To evaluate the ATN scheme performance in real-life cohorts reflecting the inflow of patients with cognitive complaints and different underlying disorders in general neurological centers.


METHODS
We included patients (n = 1,128) from six centers with their core cerebrospinal fluid-AD biomarkers analyzed centrally. A was assessed through Aβ 42/Aβ 40, T through pTau-181, and N through tTau. Association between demographic features, clinical diagnosis at baseline/follow-up and ATN profiles was assessed.


RESULTS
The prevalence of ATN categories was: A-T-N-: 28.3% ; AD continuum (A + T-/+N-/+): 47.8% ; non-AD (A- plus T or/and N+): 23.9% . ATN profiles prevalence was strongly influenced by age, showing differences according to gender, APOE genotype, and cognitive status. At baseline, 74.6% of patients classified as AD fell in the AD continuum, decreasing to 47.4% in mild cognitive impairment and 42.3% in other neurodegenerative conditions. At follow-up, 41% of patients changed diagnosis, and 92% of patients that changed to AD were classified within the AD continuum. A + was the best individual marker for predicting a final AD diagnosis, and the combinations A + T+(irrespective of N) and A + T+N+had the highest overall accuracy (83%).


CONCLUSION
The ATN scheme is useful to guide AD diagnosis real-life neurological centers settings. However, it shows a lack of accuracy for patients with other types of dementia. In such cases, the inclusion of other markers specific for non-AD proteinopathies could be an important aid to the differential diagnosis.

Alzheimer's Disease Diagnosis Based on the Amyloid, Tau, and Neurodegeneration Scheme (ATN) in a Real-Life Multicenter Cohort of General Neurological Centers.

Background CSF Alzheimer's disease (AD) biomarkers allow classifying individuals based on their levels of amyloid and neurodegeneration pathologies. Objective To investigate the distribution of AD biomarker profiles from patients suffering from cognitive disorders. Methods We analyzed 3001 patients with cognitive disorders and referred by 18 French memory clinics located in and around Paris. Patients were classified as normal, amyloidosis (A+/N-), amyloidosis and neurodegeneration (A+/N+) or suspected non-AD pathophysiology (SNAP), according to their CSF levels of biomarkers. Analysis were performed for the overall population and stratified by gender, age quintiles, and Mini-Mental State Examination (MMSE) score quintiles. Results were compared to previous findings in cohorts of healthy elderly adults. Results 37% of the sample were classified as A+/N+, 22% were classified A+/N-, and 15% as SNAP. The A+/N+ profile was associated with female gender, advanced age, and lower MMSE score, while the A+/N-profile was observed more frequently in men and the distribution was stable across age and MMSE. The SNAP profile showed no association with gender or age, was less frequent in patients with lower MMSE, and had a lower repartition than the one previously reported in asymptomatic populations. Conclusions While A+/N+ patients had the clinical characteristics typically observed in AD, A+/N-patients had a different epidemiological pattern (higher frequency in men, no association with advanced age or lower MMSE). The SNAP profile was less frequent than previously reported in the general elderly population, suggesting that this profile is not a frequent cause of memory impairment in this population.

Distribution of Cerebrospinal Fluid Biomarker Profiles in Patients Explored for Cognitive Disorders.

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Distribution of Cerebrospinal Fluid Biomarker Profiles in Patients Explored for Cognitive Disorders.