Serial measurements of C-reactive protein in patients hospitalized for community-acquired pneumonia: is less more?
Brief project description
Background
Community-acquired pneumonia (CAP) is a frequent reason for hospitalization. C-reactive protein (CRP) is commonly used to support diagnosis and monitor the course of infection. While CRP levels 3–4 days after starting antibiotics have been proposed as a prognostic indicator, a small retrospective study suggested that fewer CRP measurements were associated with an earlier switch to oral antibiotics, without impacting readmission or mortality—indicating that less frequent testing may be sufficient. However, there is a lack of data on how repeated CRP testing influences clinical decision-making, including potential unnecessary or even harmful diagnostic and treatment interventions.
Aims
The primary aim is to evaluate the impact of serial CRP measurements—beyond clinical assessment—on the management of CAP in non-immunocompromised hospitalized adults.
The secondary aim is to develop practical, evidence-based recommendations for the use of CRP in CAP management for this patient population.
Summarized Methods
Primary Aim:
We will conduct a retrospective chart review of non-immunocompromised adults hospitalized for CAP at the Department of General Internal Medicine, Bern University Hospital (Inselspital), and Spitalzentrum Biel. Data collected will include clinical symptoms, lab values, medications, imaging and procedures. Physician notes will be reviewed to evaluate whether CRP monitoring influenced management decisions—categorized as favorable (e.g., switch to oral antibiotics) or unfavorable (e.g., ordering additional, possibly unnecessary tests or interventions). Statistical analyses will include Cox regression and time-to-event models to assess the association between CRP testing and changes in management.
Secondary Aim:
Based on findings from the chart review, we will develop clinical practice recommendations in collaboration with an expert panel. These guidelines will be available in German, French, and English. They will be pilot-tested over three months with end-users (residents and chief residents) working in emergency departments and general internal medicine wards—settings where CRP testing is frequently ordered. Feedback will be gathered through surveys and semi-structured interviews. Pilot testing will be conducted at both Inselspital and Spitalzentrum Biel, including French- and German-speaking clinicians to enhance generalizability. The final recommendations will be made freely accessible online.
Expected Impact
This project will provide crucial insight into the clinical relevance of serial CRP testing in managing a common condition like CAP. If found to be a low-value practice, unnecessary CRP testing can be targeted by Smarter Medicine initiatives aimed at reducing overuse in clinical care.
Benefit for Patients and the Public
By offering clear guidance on when repeat CRP testing is clinically justified, this study will support more effective, safer, and patient-centered care. Reducing unnecessary blood tests and follow-up procedures can lower the risk of patient harm and decrease healthcare costs, improving overall care quality for patients with CAP.