Age and Ageing Advance Access originally published online on July 5, 2006
Age and Ageing 2006 35(6):625-626; doi:10.1093/ageing/afl054
© The Author 2006. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org
Can procalcitonin testing reduce antibiotic prescribing for respiratory infections?
SIR—Christ-Crain and colleagues have recently reported
that procalcitonin (PCT) testing can reduce significantly antibiotic
prescribing (from 83% in the control group down to 44% with
PCT-guided treatment) in patients admitted with a lower respiratory
tract infection (LRTI) [
1]. Clearly, achieving such a large
reduction in antibiotic prescribing, and with no deleterious
effect on clinical outcomes as in this study, would be extremely
desirable in all health care settings. In the UK, both methicillin-resistant
Staphylococcus aureus (MRSA) and
Clostridium difficile are important
nosocomial infections, which recently have attracted much attention
by both the media and the Department of Health. Antibiotic usage
in hospitals has been shown to be a risk factor for both
C. difficile [
2] and MRSA [
3,
4], as well as for antibiotic resistance
in other bacterial species. Because of the common risk factors,
the same preventative strategies, including control of antibiotic
usage, can reduce both MRSA and
C. difficile [
5]. Recently,
there have been reports of both increasing numbers of
C. difficile and an increasing case-fatality ratio [
6,
7].
Inflammatory markers may help to identify patients who require antibiotics, and PCT may be preferable to C-reactive protein (CRP) testing. The main advantage of PCT is its faster response to inflammatory insults such as bacterial sepsis: as a result, PCT is both more sensitive and more specific than CRP in the diagnosis of bacterial infection [8]. We decided to conduct an assessment of whether the excellent results by Christ-Crain could be obtained in routine use, that is, outside the randomised trial settings typically associated with high level of enthusiasm and commitment. As our assessment was not a randomised trial, we primarily aimed at auditing the proportion of patients receiving antibiotics despite a low PCT test result, using as standard the low antibiotic usage (10.4%) achieved by Christ-Crain et al. [1] for this category of patients in their randomised trial.
 |
Methods
|
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The Microbiology Department took a Kryptor analyser on a temporary
loan for over a period of 2 months (February and March 2005)
and conducted 188 tests for care of the elderly patients (aged
70 years and above) and 31 for chest medicine patients. Before
the testing started, a protocol had been distributed and meetings
had been arranged with the physicians in these two units. All
physicians in these two units were encouraged to utilise the
PCT result, as well as the clinical and radiology findings,
as the basis for their antibiotic decision. All PCT test results
had comments added by the medical microbiologists to encourage
an appropriate response in line with the findings in the report
by Christ-Crain and colleagues [
1]: thus, antibiotic use was
discouraged, but not completely banned, if the PCT test result
was <0.25 µg/l. During the study conducted by Christ-Crain,
PCT testing was always done soon after admission, presumably
involving the out-of-hours service in Clinical Chemistry, whereas
we accepted we did not have the resources to offer anything
more than one daily run of PCT tests, which guaranteed a result
within 24 h of the specimen collection. We thought that this
delay in testing would not necessarily be a major disadvantage,
because the admitting staff may have more confidence in a low
PCT result excluding bacterial infection after chest X-rays
and other tests had also been done. Unlike Christ-Crain
et al.
[
1], we included patients with both community-acquired and hospital-acquired
LRTIs but excluded LRTIs in the intensive care unit.
|
Results
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|---|
The key findings of our assessment are summarised in Table
1.
View this table:
[in this window]
[in a new window]
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Table 1.. The key findings in our assessment of procalcitonin (PCT) testing in patients presenting or developing a lower respiratory tract infection
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The directly verifiable savings, from patients whose antibiotics
were stopped, were estimated to be about £1,306: this
was much less than the overall cost for the PCT tests (£6,570).
|
Conclusions
|
|---|
PCT testing did allow a reduction in antibiotic usage but not
to the same extent as in the previously published randomised
trial: 34.7% of our evaluable patients whose PCT was <0.25
µg/l were continued on antibiotics, as opposed to only
10.4% in the study by Christ-Crain. Our failure to match the
standard set by Christ-Crain in their study could be because
of differences in the settings or, perhaps, of the greater difficulty
in enlisting support and collaboration in routine use as opposed
to during a clinical trial.
The overall measurable savings as a result of antibiotic discontinuation did not match what would have been the overall cost of the PCT tests: one of the reasons for this was that the antibiotics discontinued in our hospital after the PCT test result were mainly inexpensive oral antibiotics (such as doxycycline and amoxicillin). Another explanation for the limited directly verifiable drug budget savings is that 37% of our patients with a low PCT were not on antibiotics at the time of the test: the low PCT result is likely to have influenced the decision of not starting antibiotics afterwards, but these savings cannot be measured or verified in a non-trial situation without a comparison group.
Apart from the savings in the drug budget, it is likely that other benefits may be derived from PCT testing, but, again, these cannot be measured outside clinical trial settings. These further likely benefits may include a reduction in the side-effects associated with antibiotics or the use of IV lines, a reduction in C. difficile and a reduction in MRSA. Wilcox in 1996 estimated that preventing one single case of C. difficile would save an excess of £4,000, with a reduction in the length of stay accounting for most of the extra cost [9].
Our conclusion is that the introduction of routine PCT testing in our hospital can help to reduce antibiotic prescribing in patients presenting with LRTIs, but not to the same extent as in the study by Christ-Crain et al. [1]. We have also highlighted how the directly verifiable savings, based on antibiotic discontinuations in patients with low PCT, may not match the cost of PCT testing and cannot be used as the sole justification for this rather expensive test. We hope that in future, increased competition between manufacturers may reduce the price of PCT testing. Ideally, PCT testing should be available on the same platform used for the common biochemistry tests done on admission, and not on a separate dedicated analyser, so that there would be negligible extra labour costs and the test could be more easily made available out-of-hours.
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Key points
|
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- We audited the introduction of PCT testing for patients presenting with lower respiratory tract infections: 34.7% of patients with a low PCT were continued on antibiotics as opposed to 10.7% in the recently published randomised trial.
- The overall cost of PCT testing (about £30 per test) did exceed the directly verifiable savings in the drug budget, but the full extent of the savings and the impact of the other potential benefits can only be measured in a clinical trial.
- A cheaper PCT test available on the same platform used for the common biochemistry tests conducted on admission, and not on a separate dedicated analyser, could be of significant interest.
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Conflicts of interest
|
|---|
None.
G. E. Bignardi1,*,
R. Dhar2,
R. Heycock3,
S. Bansal4 and
N. Majmudar4
1 Microbiology Department, Sunderland Royal Hospital, Kayll Road, Sunderland, SR4 7TP, UK
2 Respiratory and General Medicine, Freeman Hospital, Freeman Road, High Heaton, Newcastle Upon Tyne, NE7 7DN, UK
3 Hartlepool General Hospital, Holdforth Road, Hartlepool, TS24 9AH, UK
4 Department of Care of the Elderly, Microbiology Department, Sunderland Royal Hospital, Kayll Road, Sunderland, SR4 7TP, UK
* To whom correspondence should be addressed at: Tel: (+191) 565 6256x 41350, Fax: (191) 541 0501, Email: giuseppe.bignardi{at}chs.northy.nhs.uk
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Acknowledgements
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Our audit of PCT testing was possible, thanks to a temporary
free loan of a Kryptor analyser from Immunodiagnostic Systems
Ltd [Boldon, Tyne and Wear].
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References
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- Christ-Crain M, Jaccard-Stolz D, Bingisser R et al. Effect of procalcitonin-guided treatment on antibiotic use and outcome in lower respiratory tract infections: cluster-randomised, single-blinded intervention trial. Lancet 2004; 363: 600–7.[CrossRef][Web of Science][Medline]
- Bignardi GE. Risk factors for Clostridium difficile infection. J Hosp Infect 1998; 40: 1–15.[Web of Science][Medline]
- Coello R, Glynn JR, Gaspar C, Picazo JJ, Fereres J. Risk factors for developing clinical infection with methicillin resistant Staphylococcus aureus (MRSA) amongst hospital patients initially only colonised with MRSA. J Hosp Infect 1997; 37: 39–46.[CrossRef][Web of Science][Medline]
- Marshall C, Wolfe R, Kossmann T, Wesselingh S, Harrington G, Spelman D. Risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) by trauma patients in the intensive care unit. J Hosp Infect 2004; 57: 245–52.[CrossRef][Web of Science][Medline]
- Stone SP, Beric V, Quick A, Balestrini AA, Kibbler CC. The effect of an enhanced infection-control policy on the incidence of Clostridium difficile and methicillin-resistant Staphylococcus aureus colonization in acute elderly medical patients. Age Ageing 1998; 27: 561–8.[Abstract/Free Full Text]
- Pépin J, Valiquette L, Alary ME et al. Clostridium difficile-associated diarrhoea in a region of Quebec from 1991 to 2003: a changing pattern of disease severity. CMAJ 2004; 171: 466–72.[Abstract/Free Full Text]
- Health Protection Agency. Outbreak of Clostridium difficile infection in a hospital in south east England. CDR Weekly 2005; 15: 2–3.
- Simon L, Gauvin F, Amre DK, Saint-Louis P, Lacroix J. Serum procalcitonin and C-reactive protein levels as markers of bacterial infection: a systematic review and meta-analysis. Clin Infect Dis 2004; 39: 206–17.[CrossRef][Web of Science][Medline]
- Wilcox MH, Cunniffe JG, Trundle C, Redpath C. Financial burden of hospital-acquired Clostridium difficile infection. J Hosp Infect 1996; 34: 23–30.[CrossRef][Web of Science][Medline]
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