The report is available in English with a French summary - KCE

KCE Reports 120 Plasma 93
Based on these methods and the assumptions described under table 40, we have
estimated that 576 kg (method A) and 483 kg (method B) of IG would be annually
needed to treat these 11 diseases, thus not including CLL. This would represent
respectively 70% (A) and 59% (B) of the IG amount reimbursed in 2006 based on
INAMI/RIZIV data (Table 41).
Though we have not used statistical tests given the high intrinsic uncertainty around
some estimates and assumptions, the proportion of total IG use that would be required
to treat these 11 diseases is lower than calculated in the 4 studies, for both methods A
and B: these 11 diseases consumed 75%, 68%, 88% and 72% of the total IG amount in
New Zealand, Toronto (Canada), Massachusset (US) and the Canadian Atlantic
provinces, with a weighted average of 74%. If we compare our estimates to the annual
IG amount reported by Belgian hospitals in 2008 (919.6 kg, KCE survey), this
proportion would be even lower, representing 63% (A) and 53% (B) of total amount.
Our estimation suggests that a higher proportion of IG is used for other indications
than those included here, compared to other countries. In other studies, 12% to 32% of
total IG amounts was consumed by the remaining indications, while this would
represent as much as 37% (A) and 41% (B) in Belgium. This is not surprising when we
observed that, in Belgium, already 16% of IG has been prescribed by lung specialists in
2008.
However conclusions on the yearly amount of IG required in Belgium cannot be based
on this exercise, as this estimation has many methodological limitations.
3.3.3.4 Limitations
The main limitations to this estimation that we have identified are:
• This method has probably underestimated the number of cases under IG
treatment for several diseases: First, our calculations were based on data
from scientific studies, where all cases were verified for adherence with
defined case definition and criteria; in a real life setting, many more cases
are likely to be treated. For instance, we estimated that 150 cases of
Guilllain Barré occur every year in Belgium, based on incidence from
neighbouring countries, while RCM/MKG data for code ICD9CM 357-0 in
2000-2007 show annual numbers ranging 609-717 cases. Second, many
studies were based on old data from the nineties and probably
underestimated disease rate as the prevalence of several diseases is
known to increase with time, due to population ageing and improved
diagnostic.
• This estimation could not include cases of CLL.
• We have found several other inconsistencies when comparing our
estimates to other Belgian data, which may be due to the assumptions
used or the lack of representativeness of practices in the centres
surveyed. This was mainly observed for bone marrow transplant (BMT)
where we likely underestimated the number of cases under treatment:
the proportion of transplant cases treated with IG is based on data from
two university hospitals and may be higher in other hospitals. Indeed, 56
transplant cases under treatment were reported in the survey from 4
paediatric wards and an adult ward, while our overall estimate of BMT
treated with IG in the whole Belgium is 105. This was also suggested by
the lower proportion of total IG amount used in BMT in Belgium
compared to other studies (3-4% vs. 11%). The number of ITP cases
under IG treatment extrapolated from incidence rates from other studies
did not correspond to the number reported by Belgian centres (52 cases
under treatment are reported from 5 university hospitals vs. 49 for all
Belgium based on other studies).
• Data on IG use are compared to four studies from three non-European
countries (US, Canada, New Zealand), where IG use was reported to be
high.