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

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Review of economic evaluations of ADHD drug interventions in children and adolescents
adolescent psychiatry and family therapy
outpatient clinics was obtained from fund-holding
tariffs of four Trusts in the South West region.
Prices relate to the year 1997.
The incremental cost per QALY gained over
placebo with MPH per child was £9177 (range
£5965–14,233) assuming a 70% response rate.
A few multi-way sensitivity analyses, that is, varying
more than one parameter at a time, were
undertaken to test the robustness of findings to
plausible variations in QoL improvements, the
response rate and costs. Under the most optimistic
scenario, the cost–utility estimate was £5965 and
the most pessimistic scenario was £29,049.
In addition to the caveats mentioned in the review
of clinical effectiveness in Chapter 4 relating to
the outcomes measurement, there are a few
concerns about the economic evaluation data.
Little information was provided about the
process of obtaining resource use information
from the experts. NICE guidance states that the
reference case comparator should include
alternative therapies routinely used in the NHS
rather than a placebo alternative. However, it is
recognised that such head-to-head data may not
be available.
Lord and Paisley 4 conducted an economic
evaluation based on data from the MTA trial.
They compared combined treatment, based on IR-
MPH and BT, versus BT alone. The analysis was
conducted from the NHS perspective over 14
months, the length of the MTA trial, and only the
incremental costs of medication were considered
since the cost of BT was assumed to be common to
both interventions. A total of 94% of children
started with a 28-day dose titration, taking an
average of 10 mg of MPH per day, 70% took an
average of 30 mg per day over the 13-month
maintenance period, 12% took an average dose of
15 mg per day of DEX over the 13-month
TABLE 64 Cost-effectiveness estimates based on the MTA trial
maintenance period and 2% received an average
dose of 50 mg per day of imipramine. Half-hour
consultations with a pharmacotherapist were also
included. It was assumed that two visits were made
during the titration period and then monthly visits
throughout the maintenance period. Additionally,
it was assumed that 6% of children did not start
titration and that 7% of children who did not
make these visits remained persistently
unmedicated during the maintenance period.
There were 19 different outcome measures used in
the MTA trial and Lord and Paisley 4 chose the
teacher version of the SNAP-IV index of
hyperactivity/impulsivity since they argued that no
HRQoL measure was available and that SNAP-IV
was the most similar to the CTRS used in the
CCOHTA economic evaluation.
The best estimate of the incremental costeffectiveness
ratio (ICER) for combined therapy
versus BT was £1600 per one SD in the SNAP-IV
measure (UK 1999 £) as seen in Table 64. A few
one-way sensitivity analyses were conducted
including varying the incremental cost of
combination therapy (average of £750 per patient
over 14 months) over BT from £500 to £1000.
Sensitivity analysis conducted on the ICER
suggested that the ratio could be in the range
£700–4500.
The study of Lord and Paisley 4 was primarily
based on the MTA that was conducted in the USA,
where the diagnosis and treatment of ADHD
differs in a few respects from the UK, namely that
the diagnosis criteria are less stringent. The
behavioural treatment in the MTA trial was more
intensive than typical treatment in the UK. Little
information was reported about the two-way
sensitivity analyses conducted and a number of
assumptions included in the analysis do not
appear to have been tested in the sensitivity
analysis. As the authors mention, the MTA trial
Incremental effect (£) (standardised mean difference in SNAP-IV
teacher hyperactive/impulsive dimension at 14 months)
Incremental cost (£) Lower CL Mean Upper CL
0.22 0.47 0.72
500 2,273 1,064 694
750 3,409 1,596 1,042
1,000 4,545 2,128 1,389
CL, confidence limit.