The remission rates among responders and non-responders
by treatment options are listed in Table 2. The clinical
parameters for 'usual care' (strategy A) were estimated
using those observed in the placebo arm of the ACT studies
where some concurrent treatment with conventional drugs was allowed [10]. However, resource utilization and
costs for the 'usual care' were based on the inputs from
local clinicians to reflect the disease management process
in Canada. A proportion of non-responders to medical
treatment underwent surgery. The rate of surgery, within
one year after the initial therapy, was 0.291 [8], while the
rate of late surgery [i.e., beyond one year] was 0.087[22].
According to a large study by Fazio et al[23], the complication
rate, within 30 days after the surgery, was 0.274
and the later complication rate (> 30 days) was 0.507. The
overall success rate for the treatment of complications was
0.84[24]. These rates were not varied across treatment
strategies. Table 3 shows time-dependent clinical parameters
used in the model, including remission rate for each
of the treatment options, the rates of maintaining remission
over time and the proportion of non-responders in
those with active UC. All these parameters were directly
derived from the ACT studies[10]. To date only two small
studies reported that adalimumab offered clinical benefits
to a subgroup of patients (40% to 60%) that had a loss of
response or were intolerant to infliximab[16,17]. Based
on these findings, a conservative assumption was made
that remission and response rates of maintenance therapy
using adalimumab were equivalent to that of 5 mg/kg infliximab.
The remission rate induced by adalimumab