3A.8 Results of the base-case economic evaluation
Page last updated: September 2016
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- Calculate the proposed medication cost per patient (Subsection 3A.8.1)
- Provide a stepped presentation of the cost-effectiveness results, and present the base-case incremental cost-effectiveness ratio (Subsection 3A.8.2)
- Present disaggregated and aggregated costs and outcomes for the proposed medicine and its main comparator (Subsection 3A.8.3)
- Summarise the base-case estimate of the incremental cost-effectiveness ratio (Subsection 3A.8.4)
3A.8.1 Intervention costs per patient
Present the expected costs of the proposed medicine and comparator (individually) per patient per course for an acute or self-limited therapy, or the cost per patient per year for a chronic or continuing therapy. This estimate should be consistent with estimates of per-patient use in Section 4.
3A.8.2 Stepped presentation of results
If the model translates clinical data, present the results of the key steps involved in transforming the comparative data (from Section 2) into the modelled base-case estimate of incremental cost-effectiveness.
Begin with an analysis of costs and outcomes that are directly associated with the comparative data presented in Section 2. Where the following procedures are undertaken to estimate the base case, sequentially present re-estimated costs and outcomes (and interim results) for each step:
- transformation(s) for applicability
- transformation of surrogate outcomes to clinical outcomes
- extrapolation of data over longer time periods
- additional data or assumptions
- transformation of clinical outcomes to final health outcomes (QALYs).
Identify the steps or assumptions of the model that have important impacts on the ICER.
Table 3A.8.1 shows an example of how to present this analysis.
|
Steps (only included if undertaken) |
Proposed medicine costs |
Comparator costs |
Incremental costs |
Proposed medicine health outcomes |
Comparator health outcomes |
Incremental health outcomes |
Incremental cost-effectiveness ratio |
|---|---|---|---|---|---|---|---|
|
Comparative study data (as presented in Section 2); Setting: (trial setting); Time horizon: (trial follow-up) |
[A]a |
[B]a |
[A – B] |
[C] (surrogate outcome)b |
[D] (surrogate outcome)b |
[C – D] (surrogate outcome) |
$[A – B]/[C – D] per [surrogate outcome] |
|
Study evidence transformed from surrogate to clinical outcome (C→E, D→F)c |
[A] |
[B] |
[A – B] |
[E] (clinical outcome) |
[F] (clinical outcome) |
[E – F] (clinical outcome) |
$[A – B]/[E – F] per [clinical outcome] |
|
Study evidence transformed to clinical outcome and translated to the Australian population and/or Australian setting (may need multiple steps) |
[modified A]d |
[modified B]d |
[modified A – modified B] |
[modified E]e |
[modified F]e |
[modified E – modified F] |
$[modified A – modified B]/[modified E – modified F] per [clinical outcome] |
|
Study evidence transformed to clinical outcome, translated to the Australian population/setting, and extrapolated to the appropriate time horizon |
[modified & extrapolated A] = [G] |
[modified & extrapolated B] = [H] |
[G – H] |
[modified & extrapolated E] = [I] |
[modified & extrapolated F] = [J] |
[I – J] |
$[G – H]/[I – J] per [clinical outcome] |
|
Study evidence transformed to clinical outcome, translated to the Australian population/setting, extrapolated and with additional assumptions or modelled information |
(G + w) = [K]f |
(H + x) = [L]f |
[K – L] |
(I + y) = [M]g |
(J + z) = [N]g |
[M – N] |
$[K – L]/[M – N] per [clinical outcome] |
|
Study evidence translated to clinical outcomes, the Australian population/setting, extrapolated, with additional modelling and transformed into a relevant health outcome (eg QALYs)(M→O, N→P) |
K |
L |
[K – L] |
[O] |
[P] |
[O – P] |
$[K – L]/[O – P] per QALY |
QALY = quality-adjusted life year
a Key outcome(s) from comparative data (presented in Section 2) used to generate
‘treatment effect’ in the economic evaluation, without any modification.
b If resource data are not provided, estimate resource use and apply costs (Australian
$)
within the study period.
c Evidence to justify the transformation of the surrogate outcome to the clinical outcome
and the method employed should be fully documented in Subsection 3A.5.
d Include here any transformations to estimated outcomes to increase applicability
to the
Australian population or setting.
e Include here any modelled changes in the provision of resources that would occur
in
the Australian health care setting.
f Re-estimate of outcomes after including additional data or assumptions that were
not
captured in the key comparative clinical data (eg adverse events or second-line
treatments).
g Re-estimate of costs after including additional data or assumptions that were not
captured in the key comparative clinical data (eg adverse events or second-line
treatments).
The order of the steps for the translation of the trial-based economic evaluation may vary. Firstly, incorporate the patient-relevant health outcome if the study outcome is a surrogate. Secondly, translate the effect as necessary to match the Australian population.
The final row of Table 3A.8.1 incorporates all translation studies and additional modelling to complete the impacts of translation of the trial-based economic evaluation into a modelled economic evaluation. Ensure that this corresponds to the base-case ICER.
The stepped presentation informs the face validity of the results, and identifies assumptions and approaches to be examined in more detail in sensitivity analyses. For example, if the main impact is achieved by extrapolating the final outcome over time, then undertake comprehensive sensitivity analyses around the extrapolation methods.
Present the base-case incremental cost, incremental effectiveness and ICER (calculated as the incremental costs divided by the incremental health outcomes).
3A.8.3 Disaggregated and aggregated base-case results
If a decision-tree model is used, present a detailed disaggregation of costs incurred at each branch by resource type for the intervention and comparator groups. For state transition models, present disaggregated discounted costs by resource type for each health state for the intervention and comparator groups. In all models, report the proportions of patients predicted to experience alternative target clinical outcomes in the intervention and comparator groups.
Alternative examples of tables showing disaggregated costs are provided in Tables 3A.8.2 and 3A.8.3.
|
Type of resource item |
Subtype of resource item |
Costsa for proposed medicine |
Costsa for main comparator |
Incremental costa |
% of total incremental costa |
|---|---|---|---|---|---|
|
Medicines |
PBS medicine |
$x1 $x2 $xk |
$y1 $y2 $yk |
$x1 – $y1 $x2 – $y2 $xk – $yk |
z1% z2% zk% |
|
Health state 1 |
∑$x |
∑$y |
∑$x – ∑$y |
∑z% |
|
|
Health state 2 |
[add] |
[add] |
[add] |
[add] |
|
|
[etc] |
[add] |
[add] |
[add] |
[add] |
|
|
Total |
[add] |
[add] |
[add] |
[add] |
|
|
Non-PBS medicine |
[add] |
[add] |
[add] |
[add] |
|
|
Health state 1 |
[add] |
[add] |
[add] |
[add] |
|
|
Health state 2 |
[add] |
[add] |
[add] |
[add] |
|
|
[etc] |
[add] |
[add] |
[add] |
[add] |
|
|
Total |
[add] |
[add] |
[add] |
[add] |
|
|
Medical services |
Type of medical practitioner attendance |
As above |
As above |
As above |
As above |
|
Health state 1 |
[add] |
[add] |
[add] |
[add] |
|
|
[etc] |
[add] |
[add] |
[add] |
[add] |
|
|
Total |
[add] |
[add] |
[add] |
[add] |
|
|
Hospital services |
Hospital admission |
[add] |
[add] |
[add] |
[add] |
|
Health state 1 |
[add] |
[add] |
[add] |
[add] |
|
|
[etc] |
[add] |
[add] |
[add] |
[add] |
|
|
Total |
[add] |
[add] |
[add] |
[add] |
|
|
Residential care |
ACFI category |
A$x |
A$y |
$x – $y |
z% |
|
Total |
A$x |
A$y |
$x – $y |
100% |
ACFI = Aged Care Funding Instrument; PBS = Pharmaceutical Benefits Scheme
a Indicate clearly whether cost values are discounted costs (use of discounted costs is appropriate).
|
Health state in model |
Resource use by health state (modelled) |
Proposed medicine costs |
Main comparator costs |
Incremental cost |
Total incremental cost (%) |
|---|---|---|---|---|---|
|
Health state 1 |
Resource type 1 |
$x1 |
$y1 |
$x1 – $y1 |
z1 |
|
Resource type 2 |
$x2 |
$y2 |
$x2 – $y2 |
z2 |
|
|
[etc] |
$x etc |
$y etc |
$x etc – $y etc |
z etc |
|
|
Total for health state 1 |
∑$x |
∑$y |
∑$x – ∑$y |
∑z |
|
|
Health state 2 |
Resource type 1 |
$xx1 |
$yy1 |
$xx1 – $yy1 |
zz1 |
|
Resource type k |
$xxk |
$yyk |
$xxk – $yyk |
zzk |
|
|
Total for health state 2 |
∑$xx |
∑$yy |
∑$xx – ∑$yy |
∑zz |
|
|
[etc] |
[etc] |
[etc] |
[etc] |
[etc] |
[etc] |
|
Total |
– |
∑$x + ∑$xx etc |
∑$y + ∑$yy etc |
(∑$x + ∑$xx etc) – (∑$y + ∑$yy etc) |
100 |
– = not required
Similarly, an example of a table showing outcomes disaggregated by health state is given in Table 3A.8.4.
|
Health state in model |
Outcome for proposed medicine |
Outcome for main comparator |
Incremental outcome |
Total incremental outcome (%) |
|---|---|---|---|---|
|
Health state 1 |
x1 |
y1 |
x1 – y1 |
z1 |
|
Health state 2 |
x2 |
y2 |
x2 – y2 |
z2 |
|
[etc] |
[x etc] |
[y etc] |
[x etc – y etc] |
[z etc] |
|
Total |
x |
y |
x – y |
100 |
Identify which health states and resources contribute to the greatest incremental differences between the proposed medicine and the comparator.
3A.8.4 Summary of base-case results
Summarise the base-case estimate of the incremental outcome(s), incremental cost and the cost-effectiveness ratio(s) obtained in the economic evaluation(s), including both CUA and CEA where relevant.
If the ICER is based on an outcome other than life-years or QALYs gained, compare the presented results with any previous PBAC decisions based on the same measure of outcome.