Management of patients with respiratory infections in primary care: procalcitonin, C-reactive protein or both?

Abstract

Use of inflammatory biomarkers to guide antibiotic decisions has shown promising results in the risk-adapted management of respiratory tract infections, mainly in the inpatient setting. Several observational and interventional trials have investigated the benefits of procalcitonin (PCT) and C-reactive protein (CRP) testing in primary care. Both markers have shown promising results, although CRP is an inflammatory biomarker while PCT is more specific for bacterial infections. For CRP, point-of-care testing is widely established. Recently, sensitive point-of-care testing for PCT has also become available. A high-quality trial comparing these two markers for the management of patients in primary care is currently lacking. The aim of this paper is to review the existing literature investigating the use of PCT and CRP in primary care. The authors compare their performance for guiding antibiotic stewardship and analyze the cut-off values and endpoints to put these parameters into context in a low-acuity environment.

Keywords:

• ambulatory care
• antibiotic guidance
• biomarker
• C-reactive protein
• general practice
• primary care
• procalcitonin

Financial & competing interests disclosure

P Schuetz has received grants from the Swiss National Science Foundation (SNSF Professorship, PP00P3_150531/ 1). P Schuetz and B Müller have received grants and assay-related supplies from B•R•A•H•M•S AG (now Thermo Fisher Scientific Biomarkers) (ProHosp 00231, TRIAGE-00256). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• Respiratory tract infections in ambulatory care are the most frequent reason for antibiotic prescriptions despite the mostly viral etiology.

• Misuse of antibiotic agents boosts microbial resistance, creating a major public health issue with far-reaching socio-economic consequences.

• Procalcitonin (PCT)-guided antibiotic stewardship has shown impressive results in numerous clinical trials optimizing antibiotic therapies in inpatients.

• C-reactive protein (CRP) testing is an already well-established point-of-care test in primary care practices and is used similarly with good results.

• Data from primary care settings comparing PCT with CRP are sparse, but existing trial data point toward considerable reduction of antibiotic use and increasing prognostic accuracy without compromising clinical outcome.

• Further emphasis on point-of-care PCT testing in primary care practices appears to be an important next step.

• More data directly comparing PCT and CRP will be needed to better understand the best use of these markers.

• Once established in primary care practices, PCT testing will help to accurately identify patients in need of antibiotics.

Notes