Characterizing CRP dynamics during acute infections

C-reactive protein (CRP) is a common proxy of inflammation, but accurate characterizations of its dynamics during acute infections are scant. The goal of this study was to examine C-reactive protein (CRP) trajectories in hospitalized patients with viral infections, confirmed bacteremia (stratified by Gram-negative or Gram-positive bacteria), and non-bacteremic infections/inflammations, considering antibiotic treatment.

Electronic medical records from Tel Aviv Sourasky Medical Center (July 2007-May 2023) were analyzed. Patients with blood cultures or positive viral tests were included. CRP levels were modeled using generalized additive mixed-effects models (GAMMs) and observed up to 150 h after initial infection diagnosis. Patients with initial CRP levels > 31.9 were excluded, to remove individuals already in a highly active inflammatory process. The shapes of the CRP curves were characterized and peak CRP as well as area under the CRP curve were the primary variables of interest.

Viral infections had the lowest and flattest CRP curves. Non-bacteremic infections showed intermediate levels, while bacteremia (especially Gram-negative under antibiotic treatment) had the highest CRP peaks. For instance, peak CRP ranged from 15.4 mg/L in viral infections without antibiotics to 140.9 mg/L in Gram-negative bacteremia with antibiotics.

CRP trajectories significantly differ based on infection type and antibiotic treatment. Frequent CRP measurement could be a valuable diagnostic and risk stratification tool in hospitalized patients.