Alzheimer’s disease (AD) is experienced by > 600,000 Canadians. Disease-modifying therapies (DMTs) for earlier stages of disease are in development. Existing health system capacity constraints and the need for biomarker-driven diagnostics to confirm DMT eligibility are concerning. This study aimed to characterize the capacity gap related to early AD (eAD) treatment with DMTs in Canada.

A capacity model was developed to simulate the flow of a patient from screening to treatment for eAD to quantify the gap between available and required healthcare resources and qualify the bottlenecks restricting the patient journey at a provincial and national level. The model inputs (epidemiological, human resource, and clinical) were evidence-based, healthcare professional-, and patient advocate-informed.

The model estimated that nationally < 2% of patients would have access to the required healthcare resources for treatment with a DMT. Eligibility assessment represented the step with the largest capacity gap across all provinces, with a wait list of about 382,000 Canadians one year following DMT introduction. The top three resource gaps included AD specialist time and positron emission tomography and magnetic resonance imaging exam slots. Sensitivity analysis showed that full reliance on cerebrospinal fluid for eligibility testing increased capacity for assessment by about 47,000 patients.

This model highlights that the Canadian health system is critically under-resourced to diagnose, assess, and treat patients with eAD with DMT. It underscores an urgent need for national policy and provincial resource allocation to close the gap.

Alzheimer’s disease (AD) cerebrospinal fluid (CSF) biomarkers are promising tools to help identify the underlying pathology of neurocognitive disorders. In this manuscript, we report our experience with AD CSF biomarkers in 262 consecutive patients in a tertiary care memory clinic.

We retrospectively reviewed 262 consecutive patients who underwent lumbar puncture (LP) and CSF measurement of AD biomarkers (Aβ1–42, total tau or t-tau, and p-tau181). We studied the safety of the procedure and its impact on patient’s diagnosis and management.

The LP allowed to identify underlying AD pathology in 72 of the 121 patients (59%) with early onset amnestic mild cognitive impairment (aMCI) with a high probability of progression to AD; to distinguish the behavioral/dysexecutive variant of AD from the behavioral variant of frontotemporal dementia (bvFTD) in 25 of the 45 patients (55%) with an atypical neurobehavioral profile; to identify AD as the underlying pathology in 15 of the 27 patients (55%) with atypical or unclassifiable primary progressive aphasia (PPA); and to distinguish AD from other disorders in 9 of the 29 patients (31%) with psychiatric differential diagnoses and 19 of the 40 patients (47%) with lesional differential diagnoses (normal pressure hydrocephalus, encephalitis, prion disease, etc.). No major complications occurred following the LP.

Our results suggest that CSF analysis is a safe and effective diagnostic tool in select patients with neurocognitive disorders. We advocate for a wider use of this biomarker in tertiary care memory clinics in Canada.

The Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) cohort study of the Canadian Consortium on Neurodegeneration in Aging (CCNA) is a national initiative to catalyze research on dementia, set up to support the research agendas of CCNA teams. This cross-country longitudinal cohort of 2310 deeply phenotyped subjects with various forms of dementia and mild memory loss or concerns, along with cognitively intact elderly subjects, will test hypotheses generated by these teams.

The COMPASS-ND protocol, initial grant proposal for funding, fifth semi-annual CCNA Progress Report submitted to the Canadian Institutes of Health Research December 2017, and other documents supplemented by modifications made and lessons learned after implementation were used by the authors to create the description of the study provided here.

The CCNA COMPASS-ND cohort includes participants from across Canada with various cognitive conditions associated with or at risk of neurodegenerative diseases. They will undergo a wide range of experimental, clinical, imaging, and genetic investigation to specifically address the causes, diagnosis, treatment, and prevention of these conditions in the aging population. Data derived from clinical and cognitive assessments, biospecimens, brain imaging, genetics, and brain donations will be used to test hypotheses generated by CCNA research teams and other Canadian researchers. The study is the most comprehensive and ambitious Canadian study of dementia. Initial data posting occurred in 2018, with the full cohort to be accrued by 2020.

Availability of data from the COMPASS-ND study will provide a major stimulus for dementia research in Canada in the coming years.