Elevated baseline CRP was frequent in patients with acute myocarditis but was not consistently associated with 90-day adverse outcomes, suggesting that a single CRP measurement at presentation has limited value for risk stratification in this setting.
The study identified 3615 adults hospitalised with acute myocarditis between 2005 and 2025 using the TriNetX Research Network.
In the unmatched cohort, patients with CRP <10 mg/L had a numerically higher but statistically non-significant 90-day incidence of the primary composite outcome compared with those with CRP ≥10 mg/L.
In the unmatched cohort, tachyarrhythmia incidence was borderline higher in the CRP <10 mg/L group compared with the CRP ≥10 mg/L group.
All-cause mortality at 90 days was similar between the CRP <10 mg/L and CRP ≥10 mg/L groups in the unmatched cohort.
After propensity score matching, the 90-day incidence of the primary composite outcome was virtually identical between the CRP <10 mg/L and CRP ≥10 mg/L groups.
A single CRP measurement at presentation appears to have limited value for risk stratification in patients hospitalised with acute myocarditis.
This research suggests that measuring C-reactive protein (CRP), a common blood marker of inflammation, at the time a patient is admitted to hospital with acute myocarditis (inflammation of the heart muscle) does not reliably predict who will experience serious complications over the following 90 days. The study analyzed data from 3,615 hospitalized adults with acute myocarditis, dividing them into those with lower CRP levels (below 10 mg/L) and those with higher CRP levels (10 mg/L or above). Surprisingly, patients with lower CRP levels actually had slightly higher rates of the combined outcome of death and dangerous heart rhythm disturbances, though this difference was not statistically significant and essentially disappeared after accounting for differences in patient characteristics between the two groups. After using a statistical technique called propensity score matching to create more comparable groups, outcomes were nearly identical regardless of CRP level: 16.4% of patients with lower CRP and 16.9% of patients with higher CRP experienced the primary combined outcome within 90 days. This research suggests that a single CRP test at hospital admission does not help doctors identify which myocarditis patients are at higher or lower risk for death or serious heart rhythm problems in the near term. The practical implication is that clinicians should not rely heavily on a single CRP measurement taken at admission to guide risk assessment or treatment decisions in acute myocarditis. This does not mean CRP is useless in general, but rather that this one snapshot in time appears insufficient on its own for predicting short-term outcomes in this specific condition. Further research may be needed to determine whether serial CRP measurements, other biomarkers, or combinations of factors might better identify high-risk patients.
Marchetta M, Filomia S, Golino M, Morini S, Sicignano L, Narducci M, et al.. (2026). C-reactive protein and 90-day adverse clinical outcomes in acute myocarditis: a retrospective database analysis of patients requiring hospitalisation.. Open heart. https://doi.org/10.1136/openhrt-2026-004028