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

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Economic model
TABLE 88 Resource use and unit cost data used to populate the economic model
Item Average per year Lower CI limit Upper CI limit Unit cost (£)
Responders:
Consultations
Psychiatrist 3.5 2.3 4.7 109.5
Paediatrician 2.25 0.6 3.7 188
GP 3 1.3 4.7 24
Tests
Blood test 0.05 0 0.1 7
Non-responders:
Consultations
Psychiatrist 5.75 4.3 7.4 109.5
Paediatrician 2.5 0.9 3.7 188
GP 2.75 0.6 4.7 24
Tests
Blood test 0.35 0.06 0.76 7
ECG 0.33 0 0.79 29.48
EEG 0.43 0.06 0.85 111.93
Allergy test 0.5 0.09 0.91 67
assumptions would not be reasonable given the
lack of available data, which would render the
results of any sensitivity analysis around
compliance uninformative to decision-makers.
Resource utilisation and cost data
As identified in the review of existing economic
evaluations, there are few observed data on the
resource use associated with ADHD. In the
absence of readily available data, it was necessary
to base the resource use in the model on estimates
obtained from expert opinion. Hence the resource
use in the model is based on that used in the
submission by Janssen-Cilag, reviewed in
Chapter 5. The study from which these estimates
were obtained 129 has been reviewed in more detail
in Chapter 5. The estimates of resource use were
obtained from a Delphi panel, in which the
UK-based experts were asked to specify their drug
treatment programmes according to treatment
used, response status and presence of adverse
events. These data are updated with current, UKspecific
price data (NHS reference costs 2003). 153
The resource use includes visits to psychiatrists
and paediatricians to reflect a more comprehensive
treatment programme than drug therapy alone.
Current guidance 1 recommends IR-MPH as part
of a comprehensive treatment programme. The
details of such a programme are not defined, but
it does not need to include specific psychological
treatment, that is, what we refer to as BT.
The uncertainty around the estimated resource use
was characterised using a gamma distribution.
Table 88 shows the resource use and unit costs
employed in the economic model.
The impact of using alternative estimates of
resource use for children and adolescents with
ADHD was assessed in a sensitivity analysis. As
noted earlier in this chapter, the review found no
data on resource use associated with long-term use
of ADHD. In order to extrapolate the model
beyond 1 year, it was assumed that patients who
come off therapy due to remission of symptoms
would incur the same non-drug resource use as
responders. This acknowledges the fact that
patients in remission of symptoms are not ‘cured’
of ADHD, but likely overestimates the costs in the
long run.
The average dose for each active medication was
taken from the trials used in calculating response
rates. Although these doses may not reflect exactly
current UK practice, they are the doses at which
the effectiveness data were obtained. As we only
have clinical trial data for treatment effectiveness,
it is not possible to determine the effectiveness at
the current average UK dose. Hence the drug
costs are consistent with the effectiveness data
used in the model. The drug prices were obtained
from published UK pricing lists, 29 where available.
ER-MPH8 is not currently priced in the UK, so
the model employs the prices reported in the
manufacturer’s submission. 154 Table 89 displays the
dose and unit cost data employed in the economic
model. The unit cost data for IR-MPH are based
on the generic formulation (note that the cost of
10-mg Ritalin is the same as that for 10-mg
generic IR-MPH).
The data regarding average drug dose are entered
deterministically, which means that the model is