Characterizing CRP dynamics during acute infections

Purpose: 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. Methods: 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. Results: 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. Conclusions: 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.