The development of a model and mapping of future dementia prevalence and service implications
Author:Norman Vetter and Nathan Lester
Date:17th March 2008 / Version:3
Status:Approved
Intended Audience:
Welsh Assembly Government
Purpose and Summary of Document:
This document has been commissioned by Welsh Assembly Government to support the implementation of the NHS Wales National service framework for older people in Wales. It describes a model and mapping of future dementia prevalence in Wales, based on available data and research evidence
Publication/Distribution:
For distribution to Welsh Assembly Government and publication on the NPHS vulnerable adults team document database
Contents Page
1 / Introduction / 32 / Purpose of document / 3
3 / Policy context / 3
4 / Definitions of dementia and client group/s / 4
5 / International criteria / 6
6 / Results of data collection and modelling / 6
6.1 / Incidence and prevalence / 6
6.2 / Incidence rates / 6
6.3 / Estimated prevalence Wales / 8
6.4 / Social background / 10
6.5 / Severity / 11
6.6 / Changes in incidence and prevalence – extrapolating for the future / 11
6.7 / Distribution – present and future / 13
7 / Evidence based good practice standards/ service options / 13
7.1 / Prevention / 13
7.2 / Assessment of needs / 14
7.3 / Timely diagnosis of dementia / 15
7.4 / Memory services (NICE guideline) / 16
7.5 / Community mental health teams / 16
7.6 / Structural imaging for diagnosis / 17
7.7 / Chronic disease management / 17
7.8 / Mental healthcare for older people in general hospitals / 18
7.9 / Day hospital services / 19
7.10 / Long term care / 19
7.11 / Treatment / 20
7.12 / Carers / 21
7.13 / Housing / 22
7.14 / Safety / 23
7.15 / Assistive technology / 23
7.16 / The economic cost of dementia / 23
8 / Possible interventions and their impact / 25
8.1 / Dementia registers / 25
8.2 / Problems identified / 25
9 / Glossary / 26
10 / References / 27
© 2008 National Public Health Service for Wales
1. Introduction
Mental health problems in older people including dementia are major threats to the lives of individuals and their families. They result in very significant requirements for health and social care. Based on UK figures, the annual direct cost to the NHS in Wales of caring for people with Alzheimer’s disease can be estimated to be at least £80-120 million.1 Taking into account the costs of informal caring and the costs to all statutory agencies, the total cost of caring is in the region of £700 million.1 There is considerable variation around the country in mental health services in both health and social care for older people. Recent data suggest that three quarters of people in non-specialist care homes have some degree of dementia. If all types of home are included the figure may well exceed 90%. It is by far the commonest reason for requiring institutional care and is therefore a major factor in social and health care.
2. Purpose of document
This planning guide for dementia will describe a model and mapping of future dementia prevalence in Wales, based on available data and research evidence. It will describe this in terms of the different forms of dementia. The guide will also describe the likely service implications of changes in future prevalence. It will discuss whether healthier lifestyles and compression of morbidity, as well as other factors may help to reduce dementia despite the ageing of the population. It is not the task of this paper to identify present use of services by people with dementia.
3. Policy context
The National Institute for Clinical Excellence(NICE) and the Social Care Institute for Excellence commissioned a practice guideline from the National Collaborating Centre for Mental Health in late 2006 on Supporting people with dementia and their carers in health and social care.1 This important document will form the basis for much of the following paper and has much more detail than is possible here. It is recommended for further reading, especially in the context of day-to-day care within the health or social services.
The Adult mental health strategy for Wales2, the Adult mental health national service framework for Wales3, updated in 2005 and the National service framework for older people in Wales4 provide the strategic framework and standards for mental health services for older people in the 21st century. The aims of mental health services for older people are to promote:
- Good mental health, social inclusion and tackle stigma;
- Service user and carer empowerment;
- Opportunities for a normal pattern of daily life;
- Equitable and accessible services;
- Commissioning and delivery of effective, comprehensive and responsive services;
- Effective client assessment and care pathways;
- Well staffed, skilled and supported workforce.
In addition, Designed for life,5a Welsh Assembly initiative, calls for each Local Health Board to develop the capacity of the voluntary sector to help support older people with mental health problems and their carers, by March 2008.
4. Definitions of dementia and client group/s
Dementia as a clinical syndrome is characterised by global cognitive impairment, which represents a decline from previous level of functioning, and is associated with impairment in functional abilities and, in many cases, behavioural and psychiatric disturbances. Several formal definitions exist, such as that of the International Classification of Diseases (ICD) 10: ‘a syndrome due to disease of the brain, usually of a chronic or progressive nature, in which there is disturbance of multiple higher cortical functions, including memory, thinking, orientation, comprehension, calculation, learning capability, language, and judgement. Consciousness is not impaired. Impairments of cognitive function are commonly accompanied, occasionally preceded, by deterioration in emotional control, social behaviour, or motivation. The syndrome occurs in Alzheimer’s disease, in cerebrovascular disease, and in other conditions primarily or secondarily affecting the brain’.
By convention, young-onset dementia refers to those who develop dementia before the age of 65 (previously called ‘pre-senile’ dementia); late-onset dementia refers to those who develop the illness after the age of 65 (previously ‘senile’ dementia). The distinction between young- and late-onset illness still has clinical utility because aetiology and characteristics of people with dementia differ between young- and late-onset cases, and people with dementia are thought to require and benefit from a different approach, leading to the widespread, but not yet universal, establishment of local specialist young-onset dementia services.6
There are a number of conditions that cause the symptoms of dementia. Alzheimer’s disease (AD) accounts for around 60% of all cases; other common causes in older people include cerebrovascular disease (vascular dementia [VaD]) and dementia with Lewy bodies (DLB) (accounting for 15–20% of cases each). In cases of young-onset, frontotemporal dementia (FTD) is also a common cause, second only to AD.
Numerous other causes exist, including other degenerative diseases (for example, Huntington’s disease), prion diseases (Creutzfeldt-Jakob Disease [CJD]), HIV dementia and several toxic and metabolic disorders (for example, alcohol-related dementia). Dementia also develops in between 30–70% of people with Parkinson’s disease, depending on duration and age 7. The distinction between Parkinson’s disease dementia (PDD) and DLB lies in the relationship between motor and cognitive impairment. If dementia precedes, or occurs within 12 months of, motor disorder, DLB is diagnosed.
Some conditions have been described that can cause a ‘reversible’ dementia, in other words, a global cognitive decline for which there is some potentially reversible cause. These include psychiatric disorders (particularly the ‘pseudodementia’ of depression), space-occupying lesions, toxic states and metabolic and endocrine abnormalities (for example, vitamin B12, folate deficiency and hypothyroidism). The differentiation between depression and dementia can be challenging and has important implications for treatment. The other conditions listed are not common causes of dementia (less than 5%) in the UK, since such physical problems would often be detected at an earlier stage, before giving rise to cognitive impairment. However, their importance lies in the fact that, when such conditions are detected, appropriate interventions offer a real chance of stabilisation, improvement or even (in rare cases) recovery.
Increasingly it is recognised that mixed cases of dementia (for example, AD and VaD, and AD and LBD) are commonly encountered, especially in older people. It has been shown that different pathologies can each contribute to the clinical expression of dementia.8 A large UK-based neuropathological study showed that mixed pathology was the most common finding at autopsy in the brains of older people.8
Dementia can be distinguished from the mild and variable cognitive decline associated with normal ageing by the severity and global nature of cognitive impairment and the accompanying functional disability that results. More challenging is its distinction from more subtle patterns of cognitive impairment which fall short of the standard definitions of dementia but which may represent a ‘pre-clinical’ dementia state. For example, the syndrome of ‘mild cognitive impairment’ (MCI) has been defined as an isolated cognitive impairment (or impairments) identified as abnormal by a statistical rule (usually 1 ½ standard deviations below that expected on the basis of age and education) and representing a decline from previous level of function. 9 Verification of cognitive difficulties by an informant and/or the individual concerned is required and the cognitive impairment should not be so severe as to affect social or occupational functioning (at which point the diagnosis of dementia would be more appropriate).
Often an individual may have been given a clinical diagnosis of a particular type of dementia but, on post mortem examination, there can be a mixture of the pathological characteristics of AD, LBD and VaD. The relationship of these different pathological processes to each other and their roles in causing the cognitive decline experienced by people with dementia remains to be fully explained.
5. International criteria
Table 1 International criteria for different types of diagnostic criteria in dementia
(see glossary)
Alzheimer’s disease. Preferred criteria / NINCDS /ADRDA. Alternatives include ICD-10 and DSM-IVVascular dementia. Preferred criteria / NINDS -AIREN. Alternatives include ICD-10 and DSM-IV
Dementia with lewy bodies / International Consensus criteria for dementia with lewy bodies
Frontotemporal dementia / Lund-Manchester criteria, NINDS criteria for frontotemporal dementia
6. Results of data collection and modelling
6.1 Incidence and prevalence
Dementia is a common condition but there is substantial variation in estimates of incidence and prevalence, because of difficulties of establishing caseness in marginal and mild cases. It is estimated that about 700,000 people in the UK have dementia, with the incidence and prevalence increasing with age. This represents 5% of the total population aged 65 and over, and 20% of the population aged 80 and over.
6.2 Incidence rates
A recent French review of the literature on the incidence and prevalence of dementia in the very old has suggested a particular problem for trying to extrapolate the future need for services.10 They selected 95 articles on the prevalence of dementia and 56 articles on its incidence. They find that the data on prevalence and incidence of dementia show a marked heterogeneity as far as the population of subjects over the age of 85 years is concerned. This heterogeneity may be due to small numbers, the diagnostic criteria used and the methods and analyses employed. Generally studies divide into two camps; those that show a continued rise in incidence and prevalence with age into the oldest age groups and those where there is a fall off in both the oldest groups.
The oldest age groups are those which are changing proportionately most rapidly, as life expectancy increases, and are also the group least likely to have informal carers. As a result it is difficult to give an accurate estimate of numbers needing care in the oldest old. The importance of this is underlined by figure 1 from the European Studies of Dementia pooled analyses for dementia, and figure 2 for AD.11 This shows incidence rates, and emphasises that the confidence intervals widen with age. As the over 85’s show the highest incidence and prevalence the figures need to be treated with considerable flexibility.
A recent study prepared by the Personal Social Services Research Unit at the London School of Economics and the Institute of Psychiatry at King’s College, London for the Alzheimer’s Society examined the prevalence of dementia in the UK, with appendices for the Celtic countries.12 This was a Delphi study using a group of experts in the field to agree, from existing sources, the prevalence of dementia of different types and to attempt to estimate future changes.
This included some estimates of the prevalence in Wales and the Welsh local authorities. The publication is an impressive piece of work but after some discussion it has been decided that the data on overall prevalence are similar to those produced here, but that, when it comes to small area data and the subgroups of dementia the document over-stretches the existing data. To illustrate this we have included the 95% confidence intervals around the dementia figures for those over and under 65 years.
6.3 Estimated prevalence Wales
Table 2Estimated number of people with dementia in Wales aged over 65; mild to severe disease based on published England and Wales rates 1
Age group / Prevalence ofdementia (rate/100
people)13 / Population in
Wales (1000;s)
(2003)14 / Estimated number
of people in Wales
with dementia (95% CI)
Age / Males / Females / Males / Females / Males / Females
65-69 / 1.4 / 1.5 / 69.1 / 73.5 / 967
(907-1,028) / 1,103
(1,038 – 1,168)
70-74 / 3.1 / 2.2 / 57.9 / 67.6 / 1,795
(1,713-1,877) / 1,487
(1,412 – 1,562)
75-79 / 5.6 / 7.1 / 45.2 / 61.1 / 2,531
(2,435 – 2,627) / 4,338
(4,214 – 4,462)
80-84 / 10.2 / 14.1 / 30.4 / 50.6 / 3,101
(2,998 – 3,204) / 7,135
(6,982 – 7,288)
≥85 / 19.6 / 27.5 / 16.4 / 42.2 / 3,214
(3,114 – 3,314) / 11,605
(11,425 – 11,785)
Total / 11,609 / 25,667
(≥65) All: 8,579,400 All: 633,870
It can be seen from table 2 that even with the most robust data the confidence intervals show a possible difference of 132 people between highest and lowest estimate for males aged 65-69 and 190 for the highest prevalence (in women over 85 years). Data for the sub-groups of dementia will be much less robust. (Tables 3 and 4).
Table 3 Estimated number of people with AD in England and Wales
aged over 65)
Agegroup / Prevalence of AD
(rate/100 people)15 / Population in
Wales (1000;s)
(2003)14 / Estimated number
of people in Wales
with AD
Males / Females / Males / Females / Males / Females
65-69 / 0.6 / 0.7 / 69.1 / 73.5 / 415 / 515
70-74 / 1.5 / 2.3 / 57.9 / 67.6 / 869 / 1555
75-79 / 1.8 / 4.3 / 45.2 / 61.1 / 814 / 2527
80-84 / 6.3 / 8.4 / 30.4 / 50.6 / 1915 / 4250
85-89 / 8.8 / 14.2 / Data / not / available / –
≥90 / 17.6 / 23.6 / Data / not / available / –
Table 4 Estimated Number of people with vascular dementia in England and Wales
aged over 65
Agegroup / Prevalence of VaD
(rate/100 people)16 / Population in
Wales (1000;s)
(2003) / Estimated number
of people in Wales
with VaD
X / Males / Females / Males / Females / Males / Females
65-69 / 0.5 / 0.1 / 69.1 / 73.5 / 346 / 74
70-74 / 0.8 / 0.6 / 57.9 / 67.6 / 463 / 406
75-79 / 1.9 / 0.9 / 45.2 / 61.1 / 859 / 550
80-84 / 2.4 / 2.3 / 30.4 / 50.6 / 730 / 1,164
85-89 / 2.4 / 3.5 / Data / not / available / –
≥90 / 3.6 / 5.8 / Data / not / available / –
Table 5 shows data for the numbers of people with young onset dementia. The authors of the original study provide 95% confidence intervals, which are translated to the population of Wales. It can be seen that, with low prevalence rates and small numbers in the original study the figures are very imprecise.
Table 5 Estimated number of people with young onset dementia (aged under 65) in
England and Wales
Agegroup / Prevalence of
young onset
dementia17 (rate/100
people) / Population in
Wales (1000;s)
(2003)14 / Estimated number
of people in Wales with
young onset
dementia (± 95% CI)
X / Males / Females / Males / Females / Males / Females
30-34 / 0.013 / 0.013 / 92.9 / 99.4 / 12
(2-24) / 13
(3-37)
35-39 / 0.005 / 0.011 / 103.2 / 109.0 / 5
(0-31) / 11
(1-41)
40-44 / 0.005 / 0.026 / 100.9 / 105.2 / 5
(0-30) / 27
(9-62)
45-49 / 0.036 / 0.030 / 92.5 / 96.2 / 34
(12-73) / 29
(9-67)
50-54 / 0.066 / 0.059 / 95.6 / 98.3 / 63
(30-116) / 58
(27-110)
55-59 / 0.200 / 0.103 / 99.3 / 101.4 / 199
(132-287) / 104
(57-174)
60-64 / 0.205 / 0.129 / 79.0 / 81.9 / 162
(106-237) / 106
(62-170)
Total / 415
(326-520) / 315
(237-409)
(30-64) All: 24,935,800 All: 14,449
From the age of 35 onwards,the prevalence of dementia approximately doubles with each 10year increase in age.
6.4 Social background
Dementia is associated with complex needs and, especially in the later stages, high levels of dependency and morbidity. These care needs are often beyond the skills and capacity of carers and services. Of the people with dementia, it is estimated that about 7,400 live alone. Those living with carers present serious challenges to their carers and wider social networks. About 14,000 patients live in care homes, with about a third receiving antipsychotic medication. Recent evidence suggests that some types of antipsychotic may also increase the risk of stroke amongst people with some types of dementia. The annual direct costs in England of caring for people with AD alone were estimated by the latest NICE guideline(p 298)18 at 2001 costs at £7–15 million. Indirect costs are likely to be very much higher than this; indeed some estimates suggest that overall costs, including social costs run into £billions (see pp 23-4 of this report).
As the condition progresses and in the later stages, people with dementia can present carers and social care staff with complex and challenging management and support problems including aggressive behaviour, restlessness and wandering. eating problems, incontinence, delusions and hallucinations, and mobility difficulties which can lead to falls and fractures. The impact of dementia upon a person may be compounded by personal circumstances such as changes in accommodation or bereavement.
People from minority ethnic groups have special considerations. Increased incidence of hypertension and diabetes among African, Caribbean and Asian people increase the risk of developing VaD in older age. Also, impairment of memory can exacerbate communication problems if English is not the person’s first language.
6.5 Severity
Several different methods are used to assess the severity of AD. These include: the Clinician's Interview-based Impression of Change (CIBIC) and CIBIC-plus for global outcomes; the Progressive Deterioration Scale (PDS) for functional/quality-of-life scales; and the Alzheimer’s Disease Assessment Scale − cognitive subscale (ADAS-cog − 70 points) or the Mini Mental State Examination (MMSE − 30 points) for cognitive outcomes. MMSE score, for example, denotes the severity of cognitive impairment as follows:
- Mild AD: MMSE 21 to 26
- Moderate AD: MMSE 10 to 20
- Moderately severe AD: MMSE 10 to 14
- Severe AD: MMSE less than 10.
In people with AD, 50−64% are estimated to have mild to moderately severe disease, and approximately 50% have moderately severe to severe AD. People with mild dementia are sometimes able to cope without assistance, but as the disease progresses, all eventually require the aid of carers, and about half need residential care. The total cost of care for people with dementia is estimated by the Audit Commission to be £6 billion per year in England, with half of this amount attributed to health and social services.19