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Effectiveness and cost-effectiveness of salicylic acid and cryotherapy for cutaneous warts: an economic decision model

Thomas, K.S.; Keogh-Brown, M.R.; Chalmers, J.R.; Fordham, R.J.; Holland, R.C.; Armstrong, S.J.; Bachmann, M.O.; Howe, A.H.; Rodgers, S.; Avery, Anthony; Harvey, I.; Williams, H.C.


K.S. Thomas

M.R. Keogh-Brown

J.R. Chalmers

R.J. Fordham

R.C. Holland

S.J. Armstrong

M.O. Bachmann

A.H. Howe

S. Rodgers

Anthony Avery

I. Harvey

H.C. Williams


Objectives: To estimate the costs of commonly used
treatments for cutaneous warts, as well as their health
benefits and risk. To create an economic decision model
to evaluate the cost-effectiveness of these treatments,
and, as a result, assess whether a randomised controlled
trial (RCT) would be feasible and cost-effective.
Data sources: Focus groups, structured interviews
and observation of practice. Postal survey sent to 723
patients. A recently updated Cochrane systematic
review and published cost and prescribing data.
Review methods: Primary and secondary data
collection methods were used to inform the
development of an economic decision model. Data from
the postal survey provided estimates of the
effectiveness of wart treatments in a primary care
setting. These estimates were compared with outcomes
reported in the Cochrane review of wart treatment,
which were largely obtained from RCTs conducted in
secondary care. A decision model was developed
including a variety of over-the-counter (OTC) and GPprescribed
treatments. The model simulated 10,000
patients and adopted a societal perspective.
Results: OTC treatments were used by a substantial
number of patients (57%) before attending the GP
surgery. By far the most commonly used OTC
preparation was salicylic acid (SA). The results of the
economic model suggested that of the treatments
prescribed by a GP, the most cost-effective treatment
was SA, with an incremental cost-effectiveness ratio
(ICER) of 2.20 £/% cured. The ICERs for cryotherapy
varied widely (from 1.95 to 7.06 £/% cured) depending
on the frequency of applications and the mode of
delivery. The most cost-effective mode of delivery was
through nurse-led cryotherapy clinics (ICER =
1.95 £/% cured) and this could be a cost-effective
alternative to GP-prescribed SA. Overall, the OTC
therapies were the most cost-effective treatment
options. ICERs ranged from 0.22 £/% cured for OTC
duct tape and 0.76 £/% cured for OTC cryotherapy to
1.12 £/% cured for OTC SA. However, evidence in
support of OTC duct tape and OTC cryotherapy is
very limited. Side-effects were commonly reported for
both SA and cryotherapy, particularly a burning
sensation, pain and blistering.
Conclusions: Cryotherapy delivered by a doctor is an
expensive option for the treatment of warts in primary
care. Alternative options such as GP-prescribed SA and
nurse-led cryotherapy clinics provide more costeffective
alternatives, but are still expensive compared
with self-treatment. Given the minor nature of most
cutaneous warts, coupled with the fact that the
majority spontaneously resolve in time, it may be
concluded that a shift towards self-treatment is
warranted. Although both duct tape and OTC
cryotherapy appear promising new self-treatment
options from both a cost and an effectiveness
perspective, more research is required to confirm the
efficacy of these two methods of wart treatment. If
these treatments are shown to be as cost-effective as
or more cost-effective than conventional treatments,
then a shift in service delivery away from primary care
towards more OTC treatment is likely. A public
awareness campaign would be useful to educate
patients about the self-limiting nature of warts and the
possible alternative OTC treatment options available.
Two future RCTs are recommended for consideration:
a trial of SA compared with nurse-led cryotherapy in
primary care, and a trial of home treatments. Greater
understanding of the efficacy of these home treatments
will give doctors a wider choice of treatment options,
and may help to reduce the overall demand for
cryotherapy in primary care.


Thomas, K., Keogh-Brown, M., Chalmers, J., Fordham, R., Holland, R., Armstrong, S., …Williams, H. (2006). Effectiveness and cost-effectiveness of salicylic acid and cryotherapy for cutaneous warts: an economic decision model. NHS R&D HTA Programme

Book Type Monograph
Publication Date Jan 1, 2006
Deposit Date Mar 20, 2008
Publicly Available Date Mar 20, 2008
Public URL
Additional Information NIHR Health Technology Assessment programme: Executive Summaries, Vol 10 no 25.