This article is more than 5 years old. Information may no longer be current.
Q&A: Promise of C-reactive protein testing in COPD
Click Here to Manage Email Alerts
Antibiotic prescribing in primary care practice for patients with COPD exacerbations is generally based on clinical features only, which are subjective and suboptimal for identifying patients who will benefit from antibiotic treatment.
However, a recent study published in The New England Journal of Medicine demonstrated that using a point-of-care C-reactive protein (CRP) test to guide treatment for COPD exacerbations in primary care lessened the use of antibiotics without worsening outcomes for patients.
Christopher C. Butler, FMedSci, professor of primary care at the University of Oxford, United Kingdom, professorial fellow at Trinity College, clinical director of the Primary Care Clinical Trials Unit, clinical director of the NIHR Oxford Community Medtech and In Vitro Diagnostics Cooperative, NIHR senior investigator and general practitioner for the Cwm Taf University Health Board, discussed the findings as well as some of the larger issues surrounding the use of antibiotics in patients with COPD.
Q: How often are people with COPD prescribed antibiotics for treatment of exacerbations?
A: As we reported in the background of the NEJM paper, about 2% of the adult population in the United Kingdom have a diagnosis of COPD in their primary care medical record. Each year, approximately half the patients living with COPD have one or more acute exacerbations of the disease and one-quarter have two or more acute exacerbations per year. More than 80% of these patients receive antibiotic prescriptions in the United States and in Europe. Indeed, nearly 80% used antibiotics in the control arm of our study during the 4 weeks of follow-up after consulting with an acute exacerbation.
Q: How often is antibiotic treatment warranted?
A: This is unknown, but most people, even those with milder forms of COPD, are prescribed antibiotics when they have an exacerbation, and trials have shown that those with a low CRP value are unlikely to benefit from antibiotic treatment. In our study, we found that 20% fewer antibiotics were prescribed for those who had a CRP test and that these patients who were tested and used fewer antibiotics recovered just as quickly as those who did not get a test and, thus, used more antibiotics.
Q: What are the most commonly cited reasons for prescribing antibiotics in COPD?
A: These include increases in breathlessness, cough or sputum quantity or color change.
Q: Is there concern about the overuse of antibiotics in these patients, especially given the rise in multidrug-resistant infections?
A: There is indeed concern because there is clear evidence that recent antibiotic use is associated with increased carriage of antibiotic-resistant organisms in the damaged lungs of people who live with COPD.
Q: The study published in NEJM indicates that CRP testing may help reduce the use of antibiotics for COPD exacerbations. Why is this important and how can clinicians use CRP testing to guide treatment?
A: People living with COPD are often concerned about the consequences of overusing antibiotics. Of course, they wish to take antibiotics when there is a good chance of benefit, but they are also often concerned about the possible impact of frequent antibiotics on the flora and fauna in their lungs. A public contributor who was part of the trial management group of our study, Jonathan Bidmead, commented: “We need to highlight not only how many people are saved by antibiotics but also that many are harmed through unnecessary antibiotic use. As a COPD sufferer, I know that antibiotics are routinely used at the first sign of an exacerbation: This study has shown that doctors can use a simple finger-prick test in a consultation to better identify those instances where antibiotics will probably do no good and may even do some harm. This can help us focus on other treatments that may be more helpful for some with exacerbations.”
Our paper explains the guidance we gave to clinicians: “The guidance noted that for patients with a CRP level lower than 20 mg/L, antibiotics are unlikely to be beneficial and usually should not be prescribed; for those with a CRP level from 20 mg/L to 40 mg/L, antibiotics may be beneficial, mainly if purulent sputum is present; and for those with a CRP level higher than 40 mg/L, antibiotics are likely to be beneficial.”
Q: How is point-of-care CRP testing currently being used in clinical practice?
A: In Scandinavian countries, just about everyone consulting in primary care with a suspected chest infection gets a CRP test. However, CRP testing in most other countries is rare, including the United States, although things are beginning to change, with CRP testing increasing rapidly in countries such as the Netherlands.
Q: Are there any issues that clinicians may face when deciding to implement CRP testing into clinical practice?
A: The CRP test does not give you a definite yes or no answer about antibiotic treatment, but it gives another piece of information that contributes to decision-making. Patients do not want clinicians to treat the numbers alone; rather, they want clinicians to take their whole picture into account, including test results. Effectively communicating the meaning of the test results is a skillful business and should be part of a shared decision-making process with patients.
Q: Do you have anything that you would like to add?
A: Most antibiotics are prescribed in primary medical care, and many of these prescriptions do not benefit patients: Point-of-care testing is being vigorously promoted as a critical solution for better targeted antibiotic prescribing. However, there have been virtually no trials of point-of-care tests that measure impact on clinician behavior, patient behavior and patient outcomes. Acute exacerbations of chronic pulmonary disease account for a considerable proportion of unnecessary antibiotic use, but a good solution to the problem in ambulatory care (where most of the antibiotics are prescribed) has not been identified until now. Ours is the first trial of biomarker-guided management of acute COPD exacerbations in ambulatory care and has found an effect that should be practice-changing.
Reference:
Butler CC, et al. N Engl J Med. 2019;doi:10.1056/NEJMoa1803185.
For more information:
Christopher C. Butler, FMedSci, can be reached at christopher.butler@phc.ox.ac.uk; Twitter: @Christo63544930.
Disclosures: Afinion desktop devices (Abbott) for CRP point-of-care testing were loaned to the clinical practices for the trial. Butler reports he was supported by funding from an NIHR Protection Research Unit on Health Care Associated Infections and Antimicrobial Resistance, by the NIHR MedTech and In Vitro Diagnostics Co-Operative at Oxford NHS Foundation Trust and by an NIHR Senior Investigator Award. He also reports receiving advisory board fees from Roche Molecular Systems and grant support from Roche Molecular Diagnostics.