Donepezil, rivastigmine, galantamine and memantine for ...

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Economic analysis
one another. We feel that the modeller should
define a mean value with a distribution around
that mean value to reflect uncertainty (where the
parameter input is uncertain it may be
appropriate to undertake different runs of the
model with separate input scenarios). Present
methods may mislead those interpreting results
from the model, as it indicates a distribution
around a mean has been used to capture
uncertainty (in fact, the modeller is uncertain on
which of four or six mean values to use).
Cost estimates used in the model for
institutionalised care are from data derived and
presented by Netten and colleagues, 130 and
although these may reflect resource use in the
sample studied by those authors, the rivastigmine
model does not take into account that not all costs
are met by the NHS and PSS, with many patients
in an institutional setting being privately funded
(or at least partially funded from private sources).
Furthermore, where publicly funded patients are
also in receipt of state pension payments, these
will be used as a transfer payment to offset
funding in an institutional setting [for further
discussion of this issue, see the section ‘Costing
considerations in the treatment of AD’ (p. 108)].
Furthermore, it would appear the different cost
items are in different base year prices
(institutionalisation at 2001£, drug and
monitoring costs at 2003£). Of note, we did find
that the estimates related to monitoring of
patients on rivastigmine were fairly resource
intensive, and therefore expensive, in relation to
information obtained from treating physicians.
The industry submission assumes all treated
patients will see a GP every month and have two
to four outpatient visits per year. We believe that
the additional monitoring resource use associated
with drug treatment is limited to two outpatient
visits per year, as recommended in previous NICE
guidance.
We have serious concerns over the methods used
to derive a QALY value, especially as it is related
to the MMSE which has been shown to have high
test–retest and inter-rater variation. It would
appear that the pathway from QoL data to QALY
value is a rather long one, with many areas subject
to uncertainty and measurement error. The
methodology remains unpublished (although the
submission states that the methodology was used
in the NICE submission in 2000), and the validity
of the approach remains uncertain.
See our adjustments to the industry model in the
section ‘SHTAC analysis of cost-effectiveness of
donepezil, rivastigmine and galantamine using the
industry models submitted to NICE’ (p. 131).
Economic evaluations of
galantamine
Characteristics of economic evaluations
Table 52 provides a summary of the study
characteristics for the five economic evaluations
reporting on the cost-effectiveness of
galantamine. 95–99 Studies represent countryspecific
analyses for Canada, Sweden, The
Netherlands, USA and the UK, with a broadly
similar methodology applied across all studies.
The ‘headline’ findings across studies are a
reduction in the time patients are expected to
need full-time care (FTC), together with cost
savings over time (four studies), or an almost costneutral
profile over time. Further detail on study
characteristics and methods is provided in
Appendix 13, with detail on study findings
provided in Appendix 14.
Systematic reviews on the costeffectiveness
of galantamine
One product-specific systematic review was
identified, by Lyseng-Williamson and Plosker, 107
to inform on the cost-effectiveness of galantamine;
it included three published economic studies 95–97
and four published abstracts (the full publication
relating to at least two of these abstracts is now
available). All the included published studies are
discussed in the current review. Lyseng-Williamson
and Plosker 107 summarise these studies and
conclude that treatment with galantamine may
result in cost savings from a healthcare payer
perspective as a consequence of delaying the need
for FTC. From a societal perspective caregiver
burden may be decreased and the length of time
that patients have without severe disease may be
extended. However the authors pointed out that
the model had several limitations, including the
use of short-term data to predict long-term
outcomes, the use of a single and small study as
the basis for the predictive equations used in the
model and that there were only two living health
states (pre-FTC and FTC) in the model which may
have masked any early benefits.
Estimation of outcomes within
economic evaluations (galantamine)
All published economic evaluations on
galantamine use the same methodology for
modelling disease progression in their estimation
of the cost-effectiveness of galantamine: the
Assessment of Health Economics in Alzheimer’s