C-reactive protein may predict risk of recurrent stroke

Researchers have shown that elevated levels of C-reactive protein (CRP) and CRP-related gene variations are associated with risk of recurrent stroke. This finding holds the potential to predict patients’ risk of a second stroke using only a blood test and their genetic profile. The study was published online March 2, 2016 in the journal Neurology.

“The biggest risk of death for someone who has already had a stroke is to have another one,” said Stephen Williams, PhD, a researcher at the University of Virginia School of Medicine’s Center for Public Health Genomics, in Charlottesville, VA. “So it’s really important to be able to try and target those individuals who are at the highest risk for the thing that very well may kill them.”

For this study, Dr. Williams and colleagues investigated whether genetic contributors to cerebrovascular disease affect the levels of inflammatory biomarkers associated with stroke risk. They analyzed genome-wide association scans among a population of 2,100 people who already had an ischemic stroke, and searched for genetic determinants of variation in 6 biomarkers: CRP, fibrinogen, creatinine, prothrombin fragments F₁₊₂, thrombin-antithrombin complex, and thrombomodulin.

Of these biomarkers, the researchers found that genetic variants of CRP were associated with elevated levels of CRP in the blood at a genome-wide significance level.

“So we have the genetics influencing [CRP] levels, which then increases the risk of having a recurrent stroke,” Dr. Williams said. “Then we went back and said, ‘All right, can we predict the increased risk purely based on the genetics?’ which we were able to do. There’s this shared genetic susceptibility not only for increased C-reactive protein but for increased risk for stroke.”

Increased risk for recurrent stroke ranged from 1.25-fold to 1.8-fold, depending on the subjects’ particular genetic contributor.

Elevated levels of fibrinogen in the blood were also associated with recurrent stroke, although no genetic variants of fibrinogen were associated with ischemic stroke or recurrent stroke risk.

“These findings are critical to our understanding of genetic risk for vascular disease and could prove useful in risk stratification for prevention of both incident and recurrent stroke,” the researchers concluded in their article.

Dr. Williams foresees a day when doctors can test CRP levels and a patient’s genetic makeup to determine the patient's overall risk for a second stroke. But even CRP levels alone could be a useful tool in assessing risk after the initial stroke, he noted.