High-Sensitivity C-Reactive Protein (hs-CRP) Levels and Cardiac Risk Assessment

Risk Stratification Using hs-CRP

The American Heart Association recommends that an hs-CRP level above 3 mg/L indicates high cardiovascular risk, while levels between 1-3 mg/L suggest moderate risk, and levels below 1 mg/L represent low risk, with the high-risk tertile having approximately twice the relative risk compared to the low-risk tertile 4
hs-CRP is an independent marker of cardiovascular risk that can be used to enhance risk assessment beyond traditional risk factors, with established risk categories for hs-CRP in primary prevention being low risk: <1 mg/L, and high risk: >3 mg/L 2, 3, 4

The American College of Cardiology recommends hs-CRP measurement for refining risk assessment in individuals at intermediate risk (10-20% 10-year risk of coronary heart disease), with two separate measurements of hs-CRP being adequate to classify a person's risk level due to within-individual variability 2, 6, 1, 7
Persistently elevated hs-CRP levels ≥10 mg/L after repeated testing should prompt evaluation for non-cardiovascular causes of inflammation, with several factors increasing hs-CRP levels independent of cardiovascular risk, including elevated blood pressure, elevated body mass index, cigarette smoking, metabolic syndrome/diabetes, low HDL/high triglycerides, estrogen/progestogen hormone use, and chronic infections and inflammation 2, 8, 1, 9

The American Heart Association recommends that hs-CRP measurement is most beneficial in patients at intermediate cardiovascular risk (10-20% 10-year risk) to help guide further evaluation or therapy decisions, with finding a high hs-CRP level (>3 mg/L) in intermediate-risk patients justifying intensification of medical therapy and lifestyle modifications 2, 3, 6, 4
High-risk individuals (>20% 10-year risk) or those with established atherosclerotic disease should receive intensive treatment regardless of hs-CRP levels, with hs-CRP helping to assess likelihood of recurrent events, including death, myocardial infarction, or restenosis after percutaneous coronary intervention 3, 6, 2, 3