Respiratory tract infections in primary care: narrative review of CRP point-of-care testing and antibacterial use

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In our feature article series, we take a look at publications of particular relevance to point-of-care testing (POCT), providing summaries and expert commentary on the key aspects of the paper and within the wider context of POCT systems.In this article, we cover the below publication by Professor Cooke and co-authors


Antimicrobial resistance is a major global problem

Antimicrobial resistance (AMR) remains a global problem and continues to be addressed through national strategies to improve diagnostics, develop new antimicrobials and promote antimicrobial stewardship. In this context, respiratory tract infections (RTIs) are among the most common acute conditions leading to general practitioner (GP) consultations and to antibiotic prescribing in primary care, even if 70% are viral and many others are minor self-limiting bacterial infections. 

Thus, the use of antibiotics in such situations is deemed to be mostly inappropriate, and there is concern that a lack of new antibiotics will threaten global efforts to contain AMR infections if used indiscriminately. In primary care, prescribing antibacterials is mainly empirical and based on non-specific clinical signs and symptoms rather than more precise diagnostic tools that are readily available in secondary care, for example, radiology, immunology, microbiology and chemical pathology testing.

The authors reviewed the evidence for the use of C-reactive protein (CRP) point-of-care testing (POCT) in reducing antimicrobial prescribing in primary care by prescribers who see patients presenting with symptoms of RTI. A narrative review of the evidence on CRP POCT for adults presenting to GPs with symptoms of RTI was performed in order to determine whether CRP POCT can reduce antibacterial prescribing, ascertain the safety and acceptability of CRP POCT for patients and GPs, and determine the cost-effectiveness of CRP POCT in a National Health Service (NHS) setting.

Point-of-care testing reduces antibiotic prescribing in ambulatory care

The 21 most relevant studies included systematic reviews of randomised controlled trials, cluster randomised controlled trials, and observational and economic evaluations. The most comprehensive evidence of the value of CRP POCT in patients presenting with symptoms of RTI in primary care in reducing antimicrobial prescribing is reported in a systematic review (Cochrane Review) that concluded ‘”Performing a point-of-care CRP test in ambulatory care accompanied by clinical guidance on interpretation reduces the immediate antibiotic prescribing in both adults and children”.

Nineteen studies used CRP POCT (11 RCTs and 8 non-randomised studies on 16,064 patients). The Forest plots from this study show highly significant difference towards CRP POCT for antibiotic prescribing at index consultation for all patients, RCTs; all patients, non-randomised studies, RCTs; adults only, if cut-off guidance applied; and RCTs, children only, if cut-off guidance applied. This remains a pivotal publication and included studies until March 2017. 

Widespread adoption of point-of-care strategies is imperative

Another narrative review of factors affecting antibiotic prescribing for acute RTIs in primary care concluded that widespread adoption of successful strategies in primary care is imperative. In addition, a multicentre, open-label, randomised, controlled trial investigated the use of CRP POCT in lower RTI in participants aged at least 1 year with a documented fever or a chief complaint of fever. The study showed that there was a modest but significant reduction in antibiotic prescribing, with patients with high CRP being more likely to be prescribed an antibiotic. 

A multicentre, open-label, randomised, controlled trial involving patients with a diagnosis of COPD CRP-guided prescribing of antibiotics for exacerbations of chronic obstructive pulmonary disease in primary care clinics resulted in a lower percentage of patients who reported antibiotic use and who received antibiotic prescriptions from clinicians, with no evidence of harm. 

Adopting systems that reduce antibiotic consumption is a “no-brainer”

A mixed-methods UK study with CRP POCT confirmed that costs and funding are important barriers to implementation of POCT. In addition, physical and operational constraints as well as training and the value of a local champion were cited as enablers. In a US study to ascertain which POCTs would be most beneficial to add to clinical practice, incorporating CRP POCT with clinical guidelines was felt to strengthen the utility of POCT testing when there is diagnostic uncertainty. In a South African study, clinicians saw POCTs as potentially useful to positively address both clinical and social drivers of overprescribing of broad-spectrum antibiotics. 

In summary, the main barriers to adoption of POCT appear to be financial constraints from the central government and the reluctance of, or lack of incentives for, primary care clinicians to adopt new diagnostic processes. However, the authors highlight that adopting systems that markedly reduce antibiotic consumption is a “no-brainer” for governments that are struggling to address the rise in AMR.

There has been plenty of advocacy, but action is now needed, the authors advocate:

“There is now overwhelming evidence that CRP POCT can offer a significant strengthening of the diagnostic precision of primary care clinicians in addressing whether or not a patient presenting with symptoms of RTI needs antibiotics or not”

This is relevant since with the rapid development of artificial intelligence, patients expect greater precision in diagnosing and managing their illnesses. Accordingly, adopting systems that markedly reduce antibiotic consumption is a no-brainer for governments that are struggling to address the rise in AMR.

Reference:

Cooke, et al. BMJ Open Respir Res 2020;7(1):e000624

Respiratory tract infections (RTIs) in primary care: narrative review of C-reactive protein (CRP) point-of-care testing (POCT) and antibacterial use in patients who present with symptoms of RTI

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