Donepezil, rivastigmine, galantamine and memantine for ...

136
Economic analysis
indicating that although intuitively attractive the
model contains data that cast serious doubt on the
validity of the results presented. Illustrative
findings are presented below from the use of the
industry model with some alternative parameter
inputs (below) to determine alternative estimates
of cost-effectiveness for memantine versus usual
care (no drug therapy). It is suggested that similar
issues are relevant to the consideration of the costeffectiveness
of memantine where it is compared
with usual care including donepezil treatment.
Memantine – SHTAC adjustments to
industry model
Where SHTAC have used the industry model with
alternative assumptions, for cost inputs, QALY
TABLE 76 SHTAC adjustments to the industry model for cost-effectiveness of memantine
Costs
Community
dependent
Community
independent
Institution
dependent
Institution
independent
QALYs
Independent
Dependent
values and discount rates, as in Table 76, the
model estimates a cost per QALY between £37,000
and £53,000 (depending on assumption on
percentage of institutional costs met by the NHS
and PSS) for memantine versus no
pharmacological therapy (all other functions in
the model remain the same as in the
manufacturer’s analysis; no re-wiring of the model
has been undertaken). Where we have commented
above on the optimistic or uncertain nature of
transit probabilities used, and the weak evidence
underlying these data, we have not been able to
use alternative assumptions in the model,
therefore the above SHTAC estimate is also based
on these data, and any further adjustments to
model effectiveness data (to offer a more
Industry (per SHTAC alternative Rationale for SHTAC adjustment
6-month cycle) (per 6-month cycle)
£5,670
£2,234
£32,919
£21,102
0.65
0.32
£2,589
£1,969
£11,672
£10,220
(£8,901 and £7,450
respectively, where
70% of patients are
publicly funded)
0.455
0.395
SHTAC cost estimate for full-time-care (FTC) in the
community (see Table 71)
SHTAC cost estimate for pre-FTC costs [see the section
‘SHTAC cost-effectiveness for mild to moderately severe
AD’ (p. 133)]
Industry estimates high and evidence base uncertain
We see institutional costs as the main cost driver for
institutionalised patients regardless of level of dependency.
Therefore, we see little difference between the cost for
institutionalised patients by dependency. For both
dependency levels we use an annual cost for institutional
care of £18,471 from Netten et al. 130 For dependent
patients we add to this the estimate of additional NHS
resource use for severe AD patients, £4874 per year, from
Kavanagh and Knapp 185 and Ward et al. 99 (see Table 71, and
related text). For independent patients we use annual
institutional costs, plus 50% of the estimated cost for
community independent AD patients (£1969 per year/£985
per cycle). We recognise that these cost estimates are
crude, but see them as more realistic than the industry cost
estimates
The industry utility estimates are from a sample that
comprises predominantly mild and independent AD patients,
whereas the model is based on moderately severe to severe
patients. We use data from Neumann et al., 187 who report
values for moderate AD and severe AD by community and
institutional setting (see Table 66). We use an average (across
moderate and severe AD) of community values as an
estimate for ‘independent’, and an average of institutional
values as an estimate for ‘dependent’, for use in the
memantine patient group
Discount rates
Costs 3.5% 6% NICE guidance for current wave of appraisals
Outcomes 3.5% 1.5%