High-Sensitivity CRP Testing Underutilized

Among these patients, 38% had persistently high residual inflammatory risk (hsCRP >2 mg/L) despite high-quality care, and another 10% developed residual inflammatory risk over time. Following these patients for more than a year afterward, investigators found that for those with hsCRP above 2 mg/L, rates of recurrent myocardial infarction and all-cause mortality were 7.5% and 2.6% respectively, compared with much lower rates of 4.3% and 0.7% found in patients with lower hsCRP. Investigators in subgroup analyses also found a link between elevated hsCRP and poor outcomes in both men and women, and among those with LDL cholesterol levels above and below 70 mg/dL.

Paul M. Ridker, MD, MPH, the lead author of the study and his colleagues, wrote, “Multiple trials have shown that the benefits of statin therapy relate to both lipid lowering and inhibition of inflammation, with on-treatment hsCRP levels as important a prognostic factor as on-treatment levels of low-density lipoprotein (LDL) cholesterol. Very recent data suggest that low levels of hsCRP but not low levels of LDL cholesterol are protective for stroke.”

They added that other key clinical trials illustrate the significance of measuring hsCRP levels in secondary prevention. The CANTOS trial provided proof of principle that targeting innate immunity, at least with a monoclonal antibody that reduces the critical interleukin-1β to interleukin-6 to CRP pathway, significantly lowers recurrent rates of myocardial infarction and cardiovascular death among patients already treated with high-intensity statins.

The authors concluded that physicians can only address the biological processes they measure. Without measuring hsCRP, it is unclear how we will effectively identify and manage residual inflammatory risk. While some reject the idea of using hsCRP as a screening tool, this controversy has resulted in less than optimal preventive care for millions of high-risk European patients. The editorial was published on January 17, 2019, in the journal Clinical Laboratory News.

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