Clinical usefulness of very high and very low levels of C-reactive protein across the full range of Framingham Risk Scores.
Level 3 - non-randomized controlled study
Prospective cohort study of cardiovascular outcomes.
PubMed 15051634 · doi:10.1161/01.CIR.0000125690.80303.A8
What was done
Baseline levels of high-sensitivity C-reactive protein (hsCRP) were assessed in 27,939 apparently healthy women followed prospectively for incident cardiovascular events (myocardial infarction, stroke, coronary revascularization, or cardiovascular death). Crude and Framingham Risk Score (FRS)-adjusted relative risks (RRs) were computed across nine strata of hsCRP (<0.5, 0.5 to <1.0, 1.0 to <2.0, 2.0 to <3.0, 3.0 to <4.0, 4.0 to <5.0, 5.0 to <10.0, 10.0 to <20.0, and ≥20.0 mg/L), with additional stratification by FRS and adjustment for diabetes.
What was found
In the cohort, 15.1% of women had hsCRP <0.50 mg/L and 5.4% had hsCRP >10.0 mg/L. Cardiovascular risk increased linearly with hsCRP. Crude RRs across the nine ascending tiers were 1.0 (referent), 2.2, 2.5, 3.1, 3.7, 4.2, 4.9, 6.3, and 7.6 (P for trend <0.001). After adjustment for FRS, the RRs were 1.0, 1.6, 1.6, 1.7, 1.9, 2.2, 2.3, 2.8, and 3.1 (P for trend <0.001). All risk estimates remained statistically significant after stratifying by FRS and controlling for diabetes.
Why it matters
This study demonstrates that the prognostic value of hsCRP extends beyond standard clinical cutpoints (1 to 3 mg/L), showing that very low (<0.5 mg/L) and very high (>10 mg/L) levels continue to stratify cardiovascular risk across all FRS categories.
Limits
The study included only apparently healthy women, limiting direct generalizability to men or individuals with pre-existing cardiovascular conditions. The abstract does not report the duration of follow-up, total event counts, or confidence intervals around the relative risk estimates.
Cited by
- supports A high-sensitivity C-reactive protein (hs-CRP) level above 1 to 2 mg/L indicates a chronic inflammatory condition.