C-Reactive Protein (CRP) - Page 3

Will lowering my CRP level reduce my risk of stroke?

Reducing CRP levels with statins— cholesterol-lowering medication that also lowers CRP levels—has been associated with up to a 25% reduction in the incidence of stroke.^{8, 9} It is believed that this is due to the medication's effect on CRP levels, and not on its lowering of cholesterol.⁹

However, lowering high CRP levels may not reduce your risk of stroke any further if you do not have detectable atherosclerosis ( plaque buildup) in your carotid artery (the main artery leading to your brain). Several studies show that CRP level is a good predictor of cardiovascular events in patients who have plaque buildup that is extensive enough to detect through imaging, with higher CRP levels predicting worse outcomes for these patients. In cases where plaque is minimal, CRP levels do not appear to indicate future stroke risk independently of other well-known risk factors.^{10, 11}

How is high CRP treated?

In general, statins lower CRP levels by 15% to 25%, but there is a wide variation in how people respond to statin therapy—it has no effect on CRP levels in some men and women. Aspirin,¹² exercise, weight loss, moderate alcohol consumption, and following the Mediterranean diet all lower CRP levels, but, more importantly, have beneficial effects on other risk factors for stroke, such as high blood pressure and obesity.

Does CRP level affect my outcome after having a stroke?

After a stroke, CRP levels are usually elevated for a period of several days to several months.¹³ Some, but not all, studies indicate that CRP levels following a stroke may be useful in determining the risk of future events. One study of about 200 stroke patients (half were women) found that those with high CRP levels at hospital discharge were 7 times more likely to experience another vascular event or death within 1 year.¹⁴ A different study that followed 467 stroke patients for up to 5 years found that having high levels of CRP did not independently predict recurrent stroke, but did double the risk of death during follow-up. It may be that the inflammation indicated by high levels of CRP interferes with healing, or predisposes the patient to other problems.¹⁵

References

1. Rost NS, Wolf PA, Kase CS, et al. Plasma concentration of C-reactive protein and risk of ischemic stroke and transient ischemic attack: the Framingham study. Stroke. Nov 2001;32(11):2575-2579.
2. Ridker PM, Rifai N, Rose L, Buring JE, Cook NR. Comparison of C-reactive protein and low-density lipoprotein cholesterol levels in the prediction of first cardiovascular events. N Engl J Med. Nov 14 2002;347(20):1557-1565.
3. Groschel K, Ernemann U, Larsen J, et al. Preprocedural C-reactive protein levels predict stroke and death in patients undergoing carotid stenting. AJNR Am J Neuroradiol. Oct 2007;28(9):1743-1746.
4. Blake GJ, Ridker PM. High sensitivity C-reactive protein for predicting cardiovascular disease: an inflammatory hypothesis. Eur Heart J. Mar 2001;22(5):349-352.
5. Wang CH, Li SH, Weisel RD, et al. C-reactive protein upregulates angiotensin type 1 receptors in vascular smooth muscle. Circulation. Apr 8 2003;107(13):1783-1790.
6. Lakoski SG, Cushman M, Criqui M, et al. Gender and C-reactive protein: data from the Multiethnic Study of Atherosclerosis (MESA) cohort. Am Heart J. Sep 2006;152(3):593-598.
7. Di Napoli M, Schwaninger M, Cappelli R, et al. Evaluation of C-reactive protein measurement for assessing the risk and prognosis in ischemic stroke: a statement for health care professionals from the CRP Pooling Project members. Stroke. Jun 2005;36(6):1316-1329.
8. Endres M. Statins: potential new indications in inflammatory conditions. Atheroscler Suppl. Apr 2006;7(1):31-35.
9. Plutzky J, Ridker PM. Statins for stroke: the second story? Circulation. Jan 23 2001;103(3):348-350.
10. Lorenz MW, Karbstein P, Markus HS, Sitzer M. High-sensitivity C-reactive protein is not associated with carotid intima-media progression: the carotid atherosclerosis progression study. Stroke. Jun 2007;38(6):1774-1779.
11. Cao JJ, Arnold AM, Manolio TA, et al. Association of carotid artery intima-media thickness, plaques, and C-reactive protein with future cardiovascular disease and all-cause mortality: the Cardiovascular Health Study. Circulation. Jul 3 2007;116(1):32-38.
12. Ridker PM, Cushman M, Stampfer MJ, Tracy RP, Hennekens CH. Inflammation, aspirin, and the risk of cardiovascular disease in apparently healthy men. N Engl J Med. Apr 3 1997;336(14):973-979.
13. Eikelboom JW, Hankey GJ, Baker RI, et al. C-reactive protein in ischemic stroke and its etiologic subtypes. J Stroke Cerebrovasc Dis. Mar-Apr 2003;12(2):74-81.
14. Di Napoli M, Papa F, Bocola V. C-reactive protein in ischemic stroke: an independent prognostic factor. Stroke. Apr 2001;32(4):917-924.
15. Elkind MS, Tai W, Coates K, Paik MC, Sacco RL. High-sensitivity C-reactive protein, lipoprotein-associated phospholipase A2, and outcome after ischemic stroke. Arch Intern Med. Oct 23 2006;166(19):2073-2080.