Valeurs seuils pour le rapport coût-efficacité en soins de santé - KCE

KCE reports 100 ICER Thresholds 19
Figure 4: Cost-effectiveness acceptability curve
Probability intervention being cost
effective
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Value of the threshold ratio (cost per QALY gained)
However, not only the ICER of interventions is uncertain, also the ICER threshold value
-being the ICER of the last intervention financed from the budget- is subject to
uncertainty. Therefore, the ICER threshold value will not be a single value but rather
again a variable with a distribution. 47 For practical use, the ICER threshold value could
be defined as a range with limits defined by the upper- and lower limits of the 95%
confidence or credibility interval around the ICER of the marginally funded health
programme. h The cost-effectiveness acceptability curve, however, does not account for
the uncertainty around the ICER threshold value. 47
Given the uncertainty about the precise value of the ICER threshold and its definition in
terms of an interval, the kind of conclusions drawn from these curves can no longer be
that “there is a probability of Y% that the ICER is below the threshold value” but rather
that “the probability that the ICER falls below the ICER threshold value is between X%
and Z%.” The range for the probabilities is defined by the applied range for the ICER
threshold value.
In conclusion, the uncertainty around the ICER threshold value adds to the uncertainty
around the ICER estimate, thereby increasing the uncertainty about an intervention’s
cost-effectiveness.
2.6.2 Comparison with an appropriate comparator
The theoretical ICER threshold value can only be defined if for each intervention in the
league table the ICER is calculated relative to a cost-effective comparator or relative to
doing nothing. 3 If the comparator is an alternative intervention (and hence not ‘doing
nothing’) it should be an intervention that is currently financed because it is considered
worthwhile given the fixed budget constraint and the health maximisation objective. i In
other words, the league table approach assumes that all health interventions currently
financed from the healthcare budget fit within the health maximisation rationale and are
financed only because they are cost-effective. Hence, if a new intervention emerges as
an alternative to an existing and already funded intervention, the existing intervention is
an appropriate comparator.
h In case of economic modelling, the term “credibility interval” is used rather than “confidence interval” to
make the distinction between variability in directly observed values versus variability in values resulting
from an economic model.
i Comparison with an appropriate alternative treatment is recommended in most guidelines for economic
evaluation. The WHO’s “Guidelines on generalized cost-effectiveness analysis”, however, recommend the
evaluation of an intervention’s cost-effectiveness relative to “doing nothing” (i.e. relative to the natural
history of disease) as a standard approach.52 The WHO has a very specific mandate and has therefore
specific reasons for electing this approach. For a full discussion on the generalized cost-effectiveness
analysis, see WHO (2003).53