Helping to hold back the rising tide of antimicrobial resistance by testing for C-reactive protein in respiratory tract infections is a natural extension of a pharmacist’s role, says Ash Soni, president of the Royal Pharmaceutical Society.

Technological advances allow a growing number of diagnostic tests to be performed in pharmacies, including assessing renal function and measuring levels of C-reactive protein (CRP) to reduce inappropriate antibiotic use.

I am one of the authors of a recent report, ‘Straight to the Point’, which summarises the compelling evidence that measuring CRP using point-of-care testing helps to differentiate viral and selflimiting bacterial respiratory tract infections from more serious infections that require antibiotics. The report makes recommendations targeted at policy makers, clinical commissioning groups and healthcare professionals, including highlighting ways in which CRP point-of-care testing can help pharmacists deliver enhanced services that improve antibiotic prescribing.

Growing problem

Antimicrobial resistance could undermine several mainstays of modern medicine (including cancer treatments and orthopaedic surgery), drive potentially unsustainable rises in expenditure and dramatically increase mortality and morbidity from common infections. Indeed, antimicrobial resistance was recently added to the National Risk Register for Civil Emergencies. “The numbers of infections complicated by antimicrobial resistance are expected to increase markedly over the next 20 years,” the Register notes.

“If a widespread outbreak were to occur, we could expect around 200,000 people to be affected by a bacterial blood infection that could not be treated effectively with existing drugs, and around 80,000 of these people might die.”¹ Overprescribing for respiratory tract infections is an important driver of antimicrobial resistance in the community. A study from 26 European countries reported a linear correlation between outpatient antibiotic prescribing and antimicrobial resistance in Streptococcus pneumoniae.²

Approximately 60 per cent of antibiotics prescribed in general practice are probably for respiratory tract infections³ but most acute uncomplicated respiratory tract infections are viral or self-limiting bacterial infections, which patients can self-manage^4-6 and for which antibiotics are inappropriate. Despite educational initiatives aimed at healthcare professionals and the public, antibiotic use in primary care in England increased by 4 per cent between 2010 and 2013, while total use increased by 6 per cent.⁷

In addition, one in 10 people taking antibiotics develop sideeffects, commonly gastrointestinal disturbances, and approximately one in 15 develop a hypersensitivity reaction.⁸ Clearly, new initiatives are needed to reduce inappropriate antibiotic prescribing.

Role of CRP

Normally, blood contains only trace amounts of CRP, but levels increase rapidly following infection or injury.⁹ High CRP levels in the blood are often associated with potentially serious bacterial infections. In contrast, CRP does not usually increase to high levels in viral or self-limiting bacterial infections.

Healthcare professionals consider the results of CRP point-of-care testing alongside signs, symptoms and the patient’s history to identify ‘low risk’ patients who do not require antibiotics and those at highrisk of having a bacterial infection who need antibiotics. Importantly, CRP point-of-care testing can reassure worried patients and parents or those demanding antibiotics.¹⁰

In some cases, GPs might issue a prescription for an antibiotic that patients fill only if self-care fails to improve symptoms or their condition worsens (delayed prescribing). Overall, patients are satisfied with receiving a low CRP point of-care testing result rather than an antibiotic prescription.¹¹ We found no evidence that patients demand CRP pointof- care testing regardless of clinical relevance. A Cochrane review of randomised or cluster randomised trials reported that CRP point-of-care testing significantly reduced antibiotic prescriptions in primary care for acute respiratory tract infections.¹²

The number-needed-to-test to save one antibiotic prescription at the index consultation ranged from six to 20. In one study, the use of CRP point-of-care testing showed a difference of 41 per cent in antibiotic prescribing for respiratory tract infections in primary care.¹³ No difference in clinical recovery (at least a substantial improvement at day seven and 28 or re-consultation by day 28) emerged between the CRP point-of-care testing and standard care groups.¹²

NICE advocates CRP point-of-care testing in people presenting in primary care with symptoms of lower respiratory tract infection if pneumonia cannot be diagnosed clinically and it is unclear whether antibiotics should be prescribed.

NICE suggests:

• Not offering antibiotics routinely if the CRP concentration is less than 20mg/L
• Considering a delayed antibiotic prescription when the CRP level is between 20mg/L and 100mg/L
• Offering antibiotics if the CRP concentration is greater than 100mg/L.¹³

Public Health England now suggests considering CRP point-of-care testing as part of the differential diagnosis of community-acquired pneumonia.¹⁴ Draft NICE guidelines concluded that CRP point-of-care testing might assist antimicrobial stewardship.¹⁵

Implementing testing

The report argues that pharmacists should work with other healthcare professionals (including nurses, GPs and public health doctors) and CCGs to develop clinical and business plans to implement CRP point-of-care testing. Such testing could form part of the proposed Common Ailments Scheme in England and any equivalent local schemes. Pharmacists could also use CRP point-of-care testing to reduce pressure on general practice, especially out-of-hours.

Antibiotic use by current out-of-hours services is rising more rapidly than in other parts of the NHS.⁷ CRP point-of-care testing would allow pharmacists to offer low-risk patients symptomatic self-care advice and refer high-risk patients or those with red-flag symptoms to their GP or an out-of-hours service. To deliver on this potential, the report calls for CCGs to develop funding mechanisms that encourage uptake, such as locally incentivised enhanced services.

Over three years and compared with current standard practice, CRP pointof- care testing delivered by a healthcare professional (GP or practice nurse) in the UK increases quality adjusted life years and reduces costs.¹⁶ Some of the point-of-care CRP tests use the same devices as other income-generating tests, such as lipids (NHS Health Check), HbA1c and urine albumin-to-creatinine ratio. As the report shows, community pharmacy has an important responsibility in ensuring appropriate use of antimicrobials.

Point-of-care testing is already part of many pharmacists’ offering. CRP point-of-care testing is a natural evolution of our clinical role.

 

 

• The report, 'Straight to the Point', was supported by a grant from Alere International and can be accessed here. The author would like to acknowledge the editorial support of Pharmacy Magazine clinical editor, Mark Greener.