A systematic review and economic model of the effectiveness and ...

122
Economic model
Probability cost-effective
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0 10,000 20,000 30,000 40,000 50,000
Willingness to pay per QALY (£)
The CEACs from the synthesis of all response
rates are very similar whether they are based on
CGI-I or ADHD-RS. Figure 27 shows the CEACs
when the response rates are synthesised against an
ADHD-RS baseline.
If society were willing to pay £30,000 per
additional QALY, strategy 13 has a 93%
probability of being most cost-effective (among
strategies including three active treatments). This
gain in certainty compared with the base case
reflects the incorporation of more trial data.
For both of these analyses, if DEX is not suitable
as first-line therapy, the optimal treatment strategy
is number 7 (first-line IR-MPH, second-line DEX,
third-line ATX). In the analysis with all response
rates synthesised against the parent-rated ADHD-
RS baseline, if society were willing to pay £30,000
per additional QALY, strategy 7 has a 100%
probability of being the optimal treatment
strategy. Again, the uncertainty is decreased by the
incorporation of more trial data. Also, the
uncertainty is reduced compared to the case where
DEX is considered suitable as first-line therapy
because there are six fewer strategies being
compared. Strategy 9 is not ruled out by
dominance or extended dominance, but the cost
per QALY gained compared with strategy 7 is
outside the range normally considered costeffective
(>£250,000 per QALY).
[Following this appraisal in 2004, the price of
dexamfetamine rose, in 2005, from £1.92 to £3.00
per 28 5-mg tablets. Despite this price increase, it
remained the cheapest of the alternative drug
treatments, and the results of the economic
analysis were robust to this price increase.]
Discussion
Strategy 13
Strategy 15
FIGURE 27 CEACs for 19 strategies compared: synthesising all response rates against an ADHD-RS baseline
60,000
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
This study sought to answer the question of which
treatment or treatment strategy is most costeffective
once one has assessed there to be a need
for medical management in children and
adolescents with ADHD. A very simple economic
model was constructed to assess the costeffectiveness
of alternative treatment options. The
model was necessarily simple owing to a lack of
data relating to, in particular, clinically meaningful
response rates, long-term effects of treatment and
response to treatment conditional on factors such
as previous treatment, ADHD subtype, gender and
age. Some of these data deficiencies were explored
in scenario analyses by specifying modelling
assumptions.
In the base case analysis, response rates were
calculated by using only few additional
assumptions above those found in a typical metaanalysis.
However, this severely reduced the
number of trials informing the model to only six