Fidaxomicin to prevent recurrent Clostridioides difficile : what will it cost in the USA and Canada?

Abstract

Importance
Recent changes in guidelines for managing Clostridioides difficile infections (CDI) have placed fidaxomicin as a first-line treatment.

Objective
To estimate the net cost of first-line fidaxomicin compared to vancomycin in the American and Canadian healthcare systems and to estimate the price points at which fidaxomicin would become cost saving for the prevention of recurrence.

Data sources and study selection
We identified randomized, placebo-controlled trials directly comparing fidaxomicin with vancomycin that reported on recurrence. Medication costs were obtained from the Veterans Affairs Federal Supply Schedule (US) and the Quebec drug formulary (Canada). The average cost of a CDI recurrence was established through a systematic review for each country.

Data extraction, synthesis and outcome measures
For efficacy, data on CDI recurrence at day 40 were pooled using a restricted maximal likelihood random effects model. For the cost review, the mean cost across identified studies was adjusted to reflect May 2022 dollars. These were used to estimate the net cost per recurrence prevented with fidaxomicin and the price point below which fidaxomicin would be cost saving.

Results
The estimated mean system costs of a CDI recurrence were $15 147USD and $8806CAD, respectively. Preventing one recurrence by using first-line fidaxomicin over vancomycin would cost $38 222USD (95%CI $30 577–$57 332) and $13 760CAD (95%CI $11 008–$20 640), respectively. The probability that fidaxomicin was cost saving exceeded 95% if priced below $1140USD or $860CAD, respectively.

Conclusions and Relevance
An increased drug expenditure on fidaxomicin may not be offset through recurrence prevention unless the fidaxomicin price is negotiated.

Full text

JAC Antimicrob Resist
https://doi.org/10.1093/jacamr/dlac138
JAC-
Antimicrobial
Resistance
Fidaxomicin to prevent recurrent Clostridioides difficile: what will
it cost in the USA and Canada?
Devangi Patel
1
, Julien Senecal
1
, Brad Spellberg
2
, Andrew M. Morris
3
, Lynora Saxinger
4
, Brent W. Footer
5
,
Emily G. McDonald
6,7
and Todd C. Lee
6,7,8
*
1
Faculty of Medicine and Health Sciences, McGill University, Montréal, Canada;
2
Los Angeles County and University of Southern California
Medical Center, Los Angeles, CA, USA;
3
Division of Infectious Diseases, Department of Medicine, Sinai Health, University Health Network,
and University of Toronto, Toronto, Canada;
4
Division of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton,
Canada;
5
Providence Portland Medical Center, Portland, USA;
6
Division of General Internal Medicine, Department of Medicine, McGill
University Health Centre, Montréal, Canada;
7
Clinical Practice Assessment Unit, Department of Medicine, McGill University Health Centre,
Montréal, Canada;
8
Division of Infectious Diseases, Department of Medicine, McGill University Health Centre, Montréal, Canada
*Corresponding author. E-mail: todd.lee@mcgill.ca
@DrToddLee, @ASPphysician, @DrEmilyMcD, @BrentFooter, @AntibioticDoc, @BradSpellberg
Received 18 August 2022; accepted 13 December 2022
Importance: Recent changes in guidelines for managing Clostridioides difficile infections (CDI) have placed fidax-
omicin as a first-line treatment.
Objective: To estimate the net cost of first-line fidaxomicin compared to vancomycin in the American and
Canadian healthcare systems and to estimate the price points at which fidaxomicin would become cost saving
for the prevention of recurrence.
Data sources and study selection: We identified randomized, placebo-controlled trials directly comparing fi-
daxomicin with vancomycin that reported on recurrence. Medication costs were obtained from the Veterans
Affairs Federal Supply Schedule (US) and the Quebec drug formulary (Canada). The average cost of a CDI recur-
rence was established through a systematic review for each country.
Data extraction, synthesis and outcome measures: For efficacy, data on CDI recurrence at day 40 were pooled
using a restricted maximal likelihood random effects model. For the cost review, the mean cost across identified
studies was adjusted to reflect May 2022 dollars. These were used to estimate the net cost per recurrence pre-
vented with fidaxomicin and the price point below which fidaxomicin would be cost saving.
Results: The estimated mean system costs of a CDI recurrence were $15 147USD and $8806CAD, respectively.
Preventing one recurrence by using first-line fidaxomicin over vancomycin would cost $38 222USD (95%CI
$30 577–$57 332) and $13 760CAD (95%CI $11 008–$20 640), respectively. The probability that fidaxomicin
was cost saving exceeded 95% if priced below $1140USD or $860CAD, respectively.
Conclusions and Relevance: An increased drug expenditure on fidaxomicin may not be offset through recur-
rence prevention unless the fidaxomicin price is negotiated.
© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.
This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (https://
creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided
the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
Introduction
Clostridioides difficile infection (CDI) is a major cause of
healthcare-associated diarrhoea in North America. It is esti-
mated that in 2017 there were nearly 462 000 cases in the USA
and in 2012
1
there were approximately 37 900 cases in
Canada.
2
Of these, approximately 20%–25% represent recurrent
infections.
2,3
The prevention of incident and recurrent episodes of
CDI is therefore an important public health goal. Several pharma-
cologic and nonpharmacologic interventions have been investi-
gated as initial treatment, and more specifically, to reduce risk
of recurrence. For much of the twenty-first century, the recom-
mended initial treatment of CDI has been oral metronidazole or
vancomycin. In 2011, fidaxomicin was first demonstrated to be
non-inferior to oral vancomycin for clinical cure.
4
This has ultim-
ately been shown in two out of three double-blind, randomized,
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Patel et al.
placebo-controlled trials,
4,5
with all three providing evidence of a
reduced risk of recurrence at day 40.
4–6
However, recommenda-
tions for fidaxomicin as first-line therapy have lagged in guide-
lines and formulary uptake has been slow, presumably due to
fidaxomicin’s higher cost. Issues surrounding affordability were
highlighted in the 2017 Infectious Diseases and Healthcare
Epidemiology Societies of America (IDSA-SHEA) guidelines
7
and
in the 2018 Association of Medical Microbiology and Infectious
Diseases of Canada (AMMI) guidelines.
8
Now more than a decade
since the initial trial was published, the 2021 update to the
IDSA-SHEA C. difficile guidelines recommended fidaxomicin as
first-line therapy for all patients.
9
At the current pricing, treating
all American
10
and Canadian
11
patients with fidaxomicin would
cost an estimated $2.06 billion US dollars (USD) and $60 million
Canadian dollars (CAD) per year, respectively.
Due to higher drug costs, other groups have attempted to
evaluate the costs associated with first-line fidaxomicin in the
USA and Canada, with mixed results. In one of the earliest evalua-
tions, Bartsch et al. estimated that fidaxomicin would be domi-
nated by other available options.
12
Reveles et al. suggested
fidaxomicin had similar overall costs to compounded vancomycin
and that it might be cost saving in some high-risk populations.
13
By contrast, Rajasingham et al. estimated that fidaxomicin would
be cost-effective below a willingness-to-pay threshold of $100 000
per quality-adjusted life year (QALY).
14
In Canada, Wagner et al. es-
timated fidaxomicin use would be associated with an overall aver-
age cost increase of $13 202 per recurrence prevented, assuming a
drug cost of $2200.
15
Consequently, we believe that whether reductions of recurrent
CDI will offset the higher up-front costs of fidaxomicin has not yet
been determined. We therefore sought to estimate: (i) the net
(added) cost of first-line use of fidaxomicin required to prevent
a recurrence as compared to oral vancomycin and compare
this with (ii) the estimated cost of a CDI recurrence so that we
could determine (iii) the price point where a treatment course
with fidaxomicin becomes unequivocally cost saving in the
American and Canadian contexts.
Methods
To estimate the comparative efficacy of fidaxomicin versus vancomycin
we conducted a meta-analysis of the three double-blind, placebo-
controlled, randomized controlled trials identified by IDSA-SHEA
9
wherein
fidaxomicin was compared head-to-head with vancomycin.
4–6
We ex-
cluded a fourth open-label trial that compared a longer total duration
of fidaxomicin (30 versus 10 days in all other included studies).
16
This trial
was excluded because the open-label nature of the study could create
bias in favour of the treatment group both in terms of patient reported
symptoms and subsequent physician testing and treating behaviour.
We examined the primary outcome of the first CDI recurrence by day
40, which was the longest common duration reported, and
meta-analysed the risk ratio with 95% confidence intervals using a re-
stricted maximum likelihood random effects model in STATA v.17
(StataCorp LP). Using the overall control event rate as the expected base-
line rate of recurrence, we then estimated the absolute risk difference,
number needed to treat, and associated 95% confidence intervals.
We obtained the US drug costs from the Veterans Affairs Federal
Supply Schedule (FSS)
10
by choosing the lowest FSS price. We obtained
the Canadian drug costs from the Quebec formulary
11
(the province
with the highest rate of CDI). A 10-day course of fidaxomicin was
estimated to cost $3845.44USD and $1584 CAD, and that of vancomycin
at $23.28USD (capsules) and $208 CAD (capsules). While some jurisdic-
tions use the IV formulation as a PO treatment with consequent lower
costs, our comparison is based on commercial products. The difference
in estimated costs and the NNT were used to calculate the additional
cost per recurrence prevented.
We estimated the cost of a CDI recurrence in USD and CAD through a
systematic review of the literature. Is the USA, we assumed cost would
apply to an insurer and/or patient, and in Canada, to the public payer.
We searched PubMed on 10 July 2022, with the search terms described
in Appendix 1. We included studies that were primary research articles,
contained a cost-analysis of CDI, included cases of recurrent CDI, and
were calculated with cost parameters based on the American or
Canadian healthcare systems. Studies were excluded if the population ex-
clusively contained hospitalized patients, as the purpose of this analysis
was to evaluate fidaxomicin use in all cases of CDI from mild outpatient
to more severe inpatient cases and analyses based only on hospitalized
patients might inflate costs and not be representative. Studies of paedi-
atric populations were also excluded. References for all included studies
were examined for additional applicable studies. Screening and data ex-
traction was performed in duplicate (D.P., J.S. and T.C.L.) with disagree-
ment resolved by consensus. All costs were converted to the May 2022
dollar rate using the Consumer Price Index Inflation Calculator
17
(USD)
and Bank of Canada Inflation Calculator
18
(CAD), respectively. Across in-
cluded studies, the average 2022 dollar cost was calculated and used
for the analysis. We also extracted the cost perspective that was exam-
ined in each of the included studies (e.g. public payer, traditional insurers,
patient, societal, Medicare, Medicaid or third-party payer).
Finally, we calculated the probability of various effect sizes from the
baseline recurrence rate and 95% confidence interval associated with
the relative risk. We then identified how probable it was, at a specified
price for fidaxomicin (rounded down to nearest $10), that the total cost
of treating all patients with fidaxomicin relative to vancomycin would
be offset by the cost savings from preventing recurrences (probability of
cost equivalence). We created scatter plots of the probability of cost
equivalence as a function of fidaxomicin price. For visualization purposes,
a smooth line of best fit was generated with curvefit
19
for STATA using a
rational estimator. A graphical summary of this analysis is shown in
Figure S1 (available as Supplementary data at JAC-AMR online).
Results
Fidaxomicin effectiveness
The overall relative risk for recurrence with 10 days of fidaxomicin
versus 10 days of vancomycin was 0.58 (95% CI 0.46–0.74;
Figure 1). This corresponds to an absolute risk reduction of
10.8% (95% CI 6.7%–14%) or a NNT of 10 (95% CI 8–15) using
the pooled control event rate of 25.9%. At the current fidaxomi-
cin and vancomycin prices, the estimated additional cost to pre-
vent one recurrence in the USA was estimated as $38 222USD
(95%CI $30 577–$57 332) and in Canada this was estimated at
$13 760CAD (95%CI $11,008-$20 640).
Cost of recurrence
The results of the systematic literature review for the cost of a CDI
recurrence in the American and Canadian healthcare systems are
presented in Table 1. Additional descriptions of each included
study are contained in Tables S1 and S2. For the USA, the initial
search for the cost of a CDI recurrence yielded 786 results. Of
these results, 110 articles were selected for further review. Of
the 110 articles, 13 were reviews or meta-analyses, 36 included
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Cost of fidaxomicin to prevent recurrence of C. difficile
only hospitalized patients, 50 did not calculate the cost of a recur-
rent CDI episode, three included only a paediatric population, and
one was not based in the USA. The seven remaining articles were
retained for the final analysis.
20–26
One article was subsequently
excluded because it calculated the 12-month all-cause medical
costs (as opposed to the attributable cost) of patients with recur-
rent CDI episodes.
26
Additionally, Luo et al. calculated the cost of
recurrent CDI based on differing treatment strategies; the cost of
the treatment with fidaxomicin was excluded from the overall
average.
20
The search for the cost of a recurrence in Canada yielded 123 re-
sults, of which 18 articles were reviewed based on the title and
abstract. Of these 18 studies, 14 studies were excluded: five studies
did not include cases of recurrent CDI, four studies did not measure
the cost of CDI, four studies were literature reviews, and one study
measured the cost of readmission to hospital due to CDI without
specifying whether it was for first episode or recurrence. Four re-
maining studies included cases of recurrent or relapsed CDI and
their cost.
2,15,27,28
One study that included cases of recurrent CDI
was subsequently excluded as it presented the cost in median
($1812CAD) instead of mean.
28
This left three studies that were in-
cluded in the Canadian analysis for the cost of recurrence.
The estimated mean 2022 systemic costs for a recurrence of
CDI in the American and Canadian healthcare systems,
Overall, REML (I2= 6.2%, p = 0.345)
Mikamo et Al. J. Infect Chemotherapy 2018
Cornely et Al. Lancet Inf Dis. 2012
Louie et Al. NEJM 2011
Study
0.58 (0.46, 0.74)
0.77 (0.45, 1.34)
0.47 (0.31, 0.71)
0.61 (0.43, 0.87)
(95% CI)
Risk Ratio
100.00
19.24
34.80
45.96
Weight
%
.25 1 4
NOTE: Weights are from random-effects model
Figure 1. Forest plot of fidaxomicin randomized controlled trials risk of recurrent CDI.
Table 1. Summary of CDI recurrence cost by study
Study Recurrence cost May 2022 dollars Cost perspectives
USA
McFarland et al.
25
$1914.00 $3405.08 Healthcare perspective; costs obtained from medical billing records
and laboratory charges
Desai et al.
22
$9501.74 $11 722.81 Healthcare perspective; study used societal perspective however
indirect costs (productivity loss) were excluded from present
analysis
Rodrigues et al.
21
$34 104.00 $41 049.68 Payer perspective; most cost values obtained from Centers for
Medicare and Medicaid Services, with hospitalization cost from
Healthcare Cost Utilization Project Nationwide Inpatient Sample
(all-payer hospitalization database)
Zilberberg et al.
24
, 2017 $12 043.00 $14 495.70 Payer perspective; costs measured as Medicare payments
Zhang et al.
23
$10 580.00 $12 476.42 Healthcare perspective; total healthcare costs were calculated as
amount paid by primary and secondary insurers and by patients
(i.e. copayment and deductibles) across all claims
Luo et al.
20
$6826.00 $7734.25 Modified third-party payer’s perspective (included costs of
medications, hospitalizations and any procedures)
Average USA cost $15 147.32
Canada
Wagner et al.
15
$8250.05 $9961.71 Public payer perspective
Levy et al.
2
$8157.89 $9765.04 Public payer perspective; study used a societal perspective however
indirect costs were excluded from present analysis
Lapointe-Shaw et al.
27
Metronidazole: $5386.00
Vancomycin: $5929.00
Metronidazole:$6351.97
Vancomycin:$6692.35
Public payer perspective, only vancomycin pathway cost considered
Average Canada cost $8806.37
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Patel et al.
respectively, were $15 147USD and $8806CAD. In the USA, cost
perspectives included payer and healthcare system perspectives,
calculated using Medicare, third-party payers, and traditional in-
surers. In Canada, all studies reported costs based on a public
payer perspective.
Cost equivalence
With respect to the USA, at the quoted price for 10 days of fidax-
omicin and for 10 days of vancomycin capsules, there is a 0%
chance that fidaxomicin will be cost equivalent by preventing
the first CDI recurrence (Figure 2). At a price of approximately
$1650 ($1630 more than the current cost of 10-day course of
vancomycin) the probability of cost equivalence rises to 50%
and at approximately $1140 ($1120 more than vancomycin)
the probability rises to 95%. Therefore, fidaxomicin is very likely
to be cost saving if priced below $1140 in the USA.
For Canada, at the current 10-day price of $1580 CAD for fi-
daxomicin and $208 CAD for vancomycin, there is less than a
0.25% chance that fidaxomicin will be cost equivalent by pre-
venting the next CDI recurrence (Figure 3). At a fidaxomicin price
of approximately $1150 CAD ($950 more than the current cost of
a 10-day course of vancomycin) the probability of cost equiva-
lence rises to 50% and at approximately $860 CAD ($660 more
than vancomycin) the probability rises to 95%. In Canada, at
any price below $860 CAD, fidaxomicin is likely to be cost saving.
Discussion
From our detailed review of the literature and associated cal-
culations, we found that for both the USA and Canada, the
use of fidaxomicin as first-line treatment for CDI will cost sub-
stantially more to both the public payer in Canada and to US
payers compared with potential cost savings realized through
recurrence reduction. We identified price points of approxi-
mately $1140 USD and $860 CAD at or below which the use
of fidaxomicin is highly probable to be cost equivalent or cost
saving. Despite double-blind, randomized, placebo-controlled
trial evidence that 10 days of fidaxomicin is superior to 10
days of vancomycin for the secondary outcome of prevention
of first recurrence at day 40, this efficacy has not translated
into a meaningful uptake of fidaxomicin that we hypothesize
is due to this very high financial impact. In Canada, individual
provinces have their own drug plans, and negotiation with the
manufacturer to obtain a more cost-equivalent price point is
possible, which could facilitate a financially viable practice
change. In the USA, such negotiations are generally
not currently permitted by Medicare by law; however, negoti-
ation of pricing could save the USA billions per year for all
drugs, including fidaxomicin.
29
Individual US insurance com-
panies, particularly ones with large formulary budgets may
have negotiating power to reduce costs.
Previous economic analyses in the North American context
have yielded conflicting results regarding the cost-benefit of fi-
daxomicin. Bartsch et al. used a decision-analytic model to com-
pare fidaxomicin versus no fidaxomicin and estimated that
vancomycin would be dominated unless the cost was reduced
to below $150 without strain typing (and $400 with strain typ-
ing).
12
A decision-analytic model comparing fidaxomicin to
vancomycin by Reveles et al. for hospitalized patients yielded
similar overall treatment costs per patient ($14 442 for fidaxomi-
cin versus $14 179 for vancomycin), using fidaxomicin cost of
$2350.
13
By contrast, Rajasingham used a Markov model ap-
proach and found fidaxomicin to be cost-effective with a cost
of $31 751/QALY assuming a fidaxomicin cost of $1767.20.
14
In
Canada, Wagner et al. estimated fidaxomicin use would be
Figure 2. Probability of fidaxomicin cost equivalence—USA.
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Cost of fidaxomicin to prevent recurrence of C. difficile
associated with an overall average cost increase of $13 202 per
recurrence prevented assuming a drug cost of $2200 and ac-
counting for CDI-related admissions to hospital.
15
In terms of observational studies with paired economic
analyses, McDaniel et al.
30
conducted a retrospective single-
centre study using electronic medical record data. Comparing
pre- versus post-implementation of a treatment pathway fa-
vouring fidaxomicin for first and second episodes of C. difficile,
they found 30-day C. difficile recurrence rates fell from 18.0%
to 6.3% with lower total costs post-intervention for index admis-
sions ($2588.63) and 30-day readmissions ($4738.62). However,
metronidazole was used in 48% of cases pre-implementation
falling to 1.6% post, suggesting the results may reflect compar-
isons with metronidazole as much as they do vancomycin.
Further, while fidaxomicin was independently associated with
a sustained response in a multivariable model (odds ratio
1.96; 95% CI 1.03–3.72), this did not represent a direct compari-
son between vancomycin and fidaxomicin. Another retrospect-
ive analysis by Gallagher et al.
31
evaluated a protocol which
encouraged fidaxomicin for high-risk patients and compared
those who received fidaxomicin and vancomycin. They found
that 90-day readmission for C. difficile recurrence occurred in
20.4% and 41.3%, respectively, and that at a fidaxomicin cost
of $1840, fidaxomicin use saved the hospital $3047 per patient
based on lower readmission costs.
These observational studies have several key challenges.
Principally, subsequent testing and treating behaviour could be
biased by knowledge of fidaxomicin treatment in an open-label
context. Second, confounding by indication can be challenging
to eliminate, particularly in small studies. Finally, before–after
designs may not adequately control for other temporal trends
(e.g. changes in dominant strains) and time-series methods are
generally preferred in terms of the hierarchy of evidence. Given
large and granular enough data sets, a target trial emulation
study with adjustment for temporal trends could be an important
addition to the literature.
Our analysis has several limitations. At the current price of fi-
daxomicin, any strategy that increases the efficacy of vancomy-
cin, for example, the use of an up-front decreasing dose taper to
prevent recurrence (NCT04138706), would affect our results and
would require recalculation. We have presented a best-case
scenario for fidaxomicin by comparing it to a 10-day course of
vancomycin. Furthermore, the efficacy of fidaxomicin to prevent
recurrence at day 56 (the IDSA-SHEA definition of recurrence), or
day 90, was not studied in the included randomized trials. Up to
31% of recurrences may occur after day 42
32
and there are no
RCT data to allow comparisons including delayed recurrences.
Fidaxomicin treatment outcomes have not been properly studied
in patients with multiple recurrences, but it is possible that pre-
venting the first recurrence could reduce the risk of subsequent
recurrences and therefore be more attractive. Such an evaluation
would ideally be conducted with randomized data, which is cur-
rently limited. Also, US drug prices are not fully transparent, and
the costs borne to different parts of the system (patient, insur-
ance company, hospitals/facilities) are often unclear. We used
publicly available data to estimate the costs, but these costs
may not reflect the costs to each party. Finally, further reducing
the cost of vancomycin through the compounding of generic IV
vancomycin into liquid form or reducing the cost of other formu-
lations would increase the break-even price of fidaxomicin, par-
ticularly in Canada.
The estimation of CDI recurrence cost through systematic re-
view for each country also has some limitations. The articles from
the USA had differing cost perspectives, with half the articles hav-
ing a payer perspective while the other half had a healthcare per-
spective. The time frame of both Canadian and US studies also
differed, ranging from within 6 weeks of a recurrence to up to
12 months from a recurrence, with some studies having an
Figure 3. Probability of fidaxomicin cost equivalence—Canada.
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Patel et al.
unspecified time frame. Another limitation stems from the cost of
recurrence calculations in the studies retained. All the Canadian
studies used decision models, with resource use and costs being
derived from Canadian surveillance programmes, Canadian hos-
pitals, and published literature. Out of the six US studies, four had
real-world data, either from observational studies
21,23,24
or a clin-
ical trial.
25
The remaining two studies used decision models.
20,22
Finally, the aim of our study was to evaluate only direct med-
ical costs from either a payer or healthcare perspective. This
study did not look at broader indirect costs, such as costs related
to patient time and lost productivity. Only two of the studies in-
cluded evaluated costs from a broader societal perspective.
2,22
Therefore, additional studies are needed to draw conclusions
based on broader societal perspective costs.
A strength of our study is the use of a meta-analytic as-
sessment of the effect size for fidaxomicin from all the placebo-
controlled trials, coupled with a systematic estimate of recurrence
costs to produce a practical and easily understood compari-
son. Comparing additional drug costs versus an estimate of
the cost of a recurrence is a different analytic perspective
than the cost per quality-adjusted life-year point of view.
Previous cost-effectiveness studies have been conducted,
most showing a fractional difference (e.g. 0.02
33
–0.03
14
) in
QALYs. More fundamentally, cost-effectiveness is not the
same as cost saving. Cost-effectiveness measures, including
cost per QALY and cost per incremental cost-effectiveness ra-
tio, assess added costs by a subjectively perceived threshold of
value. Often this is contextualized against the historical price
for a year of haemodialysis, which is lifesaving. However, hos-
pitals, patients and governments do not have unlimited bud-
gets and most treatments are not a crucially lifesaving as
haemodialysis. Even if an intervention is perceived as valuable,
if the cost is unsustainable, cost-effectiveness may be irrele-
vant whereas cost equivalence or cost saving compared to cur-
rent effective therapies is always relevant.
CDI causes a major burden to health systems worldwide and
reduction of recurrence has value. Yet, health system sustainabil-
ity requires thoughtful assessment of both current and future
costs and benefits. At current pricing, a switch to first-line fidax-
omicin will cost billions of excess healthcare dollars to US and
Canadian payers and, on the basis of this analysis, these costs
will not be recouped through the reduction of recurrent CDI.
Assuming vancomycin costs remain the same, and until addition-
al placebo-controlled trials of novel vancomycin or fidaxomicin
dosing strategies are available, a reduction of the cost of fidaxo-
micin to below $1140USD and $860CAD, respectively, would sup-
port a substantial change to fidaxomicin prescribing practices.
Funding
This study was carried out as part of routine work.
Transparency declarations
TCL and EGM receive research salary support from the Fonds de Recherche
du Québec—Santé, unrelated to this work. All other authors: non to
declare.
Conflicts of interest
EGM and TCL are principal investigators on a Canadian Institutes of Health
Research Funded clinical trial looking at alternative vancomycin dosing
strategies for the first episode of C. difficile.
CRediT author statement
Conceptualization—TCL, DP; methodology—TCL; validation—TCL, DP; for-
mal analysis—TCL, DP; investigation—TCL, DP, JS; resources—TCL; data
curation—TCL, DP, JS; writing—original draft—DP, EGM, TCL, JS; writing:
review and editing—all authors; visualization—DP, TCL; supervision—
TCL; project administration—TCL.
Supplementary data
Figure S1 and Tables S1 and 2 are available as Supplementary data at
JAC-AMR online.
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