Donepezil, rivastigmine, galantamine and memantine for ...

TABLE 1 Estimated prevalence of AD by age in England and Wales
Age group (years) Population of England and Wales
Estimated prevalence for England and
Wales
Table 1 uses the prevalence rates for AD from the
pooled estimates in the study by Lobo and
colleagues 9 to provide an estimate of the prevalence
of AD for the population of England and Wales
(based on mid-2002 population estimates). 20 This
shows that there are approximately 290,000
people in England and Wales with AD. Assuming
that 50–64% of people with AD have the mild to
moderate form of the disease we would expect to
find between 145,000 and 185,600 cases of mild to
moderate disease.
Estimated prevalence for primary care
trust
Table 2 uses the same prevalence rates for AD as
above to provide an estimate of the prevalence of
AD for an average population of a primary care
trust (PCT). A PCT with a population of 200,000
might expect to have approximately 30,000 people
over the age of 65 years and approximately 1100
cases of AD. It can also be seen in Table 2 that,
assuming that 50–64% of people with AD have the
Health Technology Assessment 2006; Vol. 10: No. 1
Males Females Prevalence of AD Estimated prevalence
(rate/100 people) of AD
© Queen’s Printer and Controller of HMSO 2006. All rights reserved.
Male Female Males Females
65–69 1,116,000 1,199,000 0.6 0.7 6,696 8,393
70–74 950,000 1,126,000 1.5 2.3 14,250 25,898
75–79 731,000 999,000 1.8 4.3 13,158 42,957
80–84 470,000 786,000 6.3 8.4 29,610 66,024
85–89 204,000 458,000 8.8 14.2 17,952 65,036
Total 65+ 81,666 208,308
Based on population data from mid-2002 estimates.
TABLE 2 Estimated prevalence of AD by age for a standard PCT
Age group (years) Standard PCT (200,000 people)
Population Prevalence of AD Estimated Estimated prevalence
(rate/100 people) prevalence of AD of mild to moderate AD
Male Female
65–69 8822 0.6 0.7 58 29–37
70–74 7911 1.5 2.3 153 76–98
75–79 6593 1.8 4.3 213 106–136
80–84 4786 6.3 8.4 364 182–233
85–89 1823 8.8 14.2 316 158–202
Total 65+ 1104 551–706
mild to moderate form of the disease, a PCT
might expect to have between 551 and 706 cases
of mild to moderate disease.
Incidence
The 1-year incidence of all-cause dementia
increases from 0.01 per 1000 population at
65 years to 80 per 1000 at age 85 years. 3 The
incidence of AD appears to have been stable over
the past two decades, although demographic
changes (e.g. ageing population) may result in an
increase in prevalence in the future. 16 Incidence
rates for AD in those aged over 65 years from
recent studies range from 4.9 per 1000 personyears
21 in a UK study; 6.55 [95% confidence
interval (CI) 4.92 to 8.17] per 1000 person-years
in an Italian study; 22 and 14.26 (95% CI: 12.2 to
16.7) 23 in a US study.
Age-related incidence
A recent pooled estimate from eight European
population-based studies of persons aged
≥ 65 years demonstrated rising incidence rates
with increasing age. 24 The age-specific incidence
5