Estimating the Prevalence of Dementia in New Zealand Using Capture-Recapture Analysis on Routinely Collected Health Data.

OBJECTIVES: Community based dementia prevalence studies are expensive and resource intensive. Aotearoa New Zealand (NZ) has never had a community based dementia prevalence study representing all major ethnic groups. In recent years, dementia prevalence estimates have been derived from routinely collected health data but issues of underdiagnosis and undercoding limit their utility. Capture-recapture techniques can estimate the number of dementia cases missing from health datasets by modelling the ascertained overlaps between linked data sources. METHODS: Three routinely collected national health data sets-interRAI, Public hospital discharges, and Pharmaceuticals-were linked and all prevalent cases of dementia in NZ for the year 1 January 2021-31 December 2021 were identified. Capture-recapture analysis fitted eight loglinear models to the data, with the best fitting model used to estimate the number of prevalent cases missing from all three datasets. RESULTS: We estimated that almost half (47.8%) of dementia cases are not present in any of the three datasets. Dementia prevalence increased from 3.7% to 7.1% (95% CI 6.9%-7.4%) in the NZ 60+ population and from 4.9% to 9.2% (95% CI 8.9%-9.6%) in the NZ 65+ population when missing cases were included. Estimates of missing cases were significantly higher (p < 0.001) in Maori (49.2%), Pacific peoples (50.6%) and Asian (59.6%) compared to Europeans (46.4%). CONCLUSIONS: This study provides updated estimates of dementia prevalence in NZ and the proportion of undiagnosed dementia in NZ, highlighting the need for better access to dementia assessment and diagnosis.

Are Population-Level Approaches to Dementia Risk Reduction Under-Researched? A Rapid Review of the Dementia Prevention Literature.

Dementia is forecast to become increasingly prevalent, particularly in low- and middle-income countries, and is associated with high human and economic costs. Primary prevention of dementia -preventing risk factors leading to disease development - is an emerging global public health priority. Primary prevention can be achieved in two ways: individual-level or population-level. In this rapid review, we quantify the proportion of contributing interventional evidence to the dementia primary prevention literature that is concerned with either approach. We searched Medline, the National Institute for Health and Care Excellence, Cochrane, the World Health Organization, and Google to identify systematic reviews that described primary prevention interventions for dementia. We used search terms related to dementia risk reduction, intervention/policy, and review. We analysed reference lists of included dementia prevention reviews to identify contributing primary prevention evidence, and categorised these as either individual-level or population-level. Additionally, we examined search strategies to investigate the likelihood of reviews identifying available population-level interventions. We included twelve of the 527 articles retrieved. Population-level evidence was summarised by only two reviews. In these two reviews, <2.5% of the interventions described where population-level interventions. Most search strategies were weighted towards identifying individual-level evidence. Existing systematic reviews of dementia primary prevention interventions include almost no population-level evidence. Correction of this imbalance is needed to ensure that dementia prevention policies can achieve meaningful reductions in the prevalence of, and inequalities in, dementia.

What is a population-level approach to prevention, and how could we apply it to dementia risk reduction?

The World Health Organisation's 2022 'blueprint for dementia research' highlights the need for more research into population-level risk reduction. However, definitions of population-level prevention vary, and application to dementia is challenging because of its multi-factorial aetiology and a maturing prevention evidence base. This paper compares and contrasts key concepts of 'population-level prevention' from the literature, explores related theoretical models and policy frameworks, and applies this to dementia risk reduction. We reach a proposed definition of population-level risk reduction of dementia, which focusses on the need to change societal conditions such that the population is less likely to develop modifiable risk factors known to be associated with dementia, without the need for high-agency behaviour change by individuals. This definition, alongside identified policy frameworks, can inform synthesis of existing evidence and help to co-ordinate the generation of new evidence.

Psychiatric liaison service referral patterns during the UK COVID-19 pandemic: An observational study.

BACKGROUND AND OBJECTIVES: COVID-19 has had a profound effect on mental health. Liaison psychiatry teams assess and treat people in mental health crises in emergency departments (EDs) and on hospital wards. During the first pandemic wave, new Mental Health Crisis Assessment Services (MHCAS) were created to divert people away from EDs. Our objective was to describe patterns in referrals to psychiatric liaison services across the North Central London care sector (NCL) and explore the impact of a new MHCAS. METHODS: Retrospective study using routinely collected data (ED and ward referrals) from five liaison psychiatry services across NCL (total population 1.5 million people). We described referrals (per week and month) by individual liaison services and cross-sector, and patterns of activity (January 1st 2020 -September 31st 2020, weeks 1-39) compared with the same period in 2019. We calculated changes in the proportion of ED attendees (all-cause) referred to liaison psychiatry. RESULTS: From 2019-2020, total referrals decreased by 16.5% (12,265 to 10,247), a 16.4% decrease in ED referrals (9528 to 7965) and 16.6% decrease in ward referrals (2737 to 2282). There was a marked decrease in referrals during the first pandemic wave (March/April 2020), which increased after lockdown ended. The proportion of ED attendees referred to liaison psychiatry services increased compared to 2019. CONCLUSIONS: People in mental health crisis continued to seek help via ED/MHCAS and a higher proportion of people attending ED were referred to liaison psychiatry services just after the first pandemic wave. MHCAS absorbed some sector ED activity during the pandemic.

The Lancet Commission on Dementia Prevention, Intervention, and Care: a call for action.

The purpose of this Editorial is to summarise the key recommendations of the Lancet Commission on Dementia Prevention, Intervention, and Care, reporting on the best available evidence to date on what we can do to prevent and intervene for dementia. We briefly describe the new life-course model of dementia prevention incorporating nine modifiable risk factors and their potential effect in reducing individuals' risk of dementia. We also summarise the recommendations of the report about which pharmacological, psychological, and social interventions are effective, and improve outcomes for people with dementia and their families. Recent developments highlight that there is good potential for the prevention of dementia. Progress in evidence-based approaches indicate the potential for dementia care to be of high-quality and widely accessible. Acting upon this knowledge now will reduce the global burden of dementia and improve the lives of people living with dementia and their families.