High C-reactive protein levels associated with AMD risk

Elevated levels of high-sensitivity C-reactive protein may be associated with a higher risk of both early and late age-related macular degeneration, according to a study by researchers in the Netherlands.

Sharmila S. Boekhoorn, MD, PhD, and colleagues investigated serum high-sensitivity C-reactive protein (HsCRP) levels in 4,914 patients enrolled in the Rotterdam Study who were at risk of AMD. They published their results in the October issue of Archives of Ophthalmology.

At 7.7 years mean follow-up, the researchers identified 561 cases of early AMD and 97 cases of late AMD in the patient population, according to the study.

Among all patients, HsCRP levels averaged 2.67 mg/L (range, 0.20 mg/L to 33.60 mg/L). Specifically, HsCRP levels averaged 2.69 mg/L (range, 0.20 mg/L to 31.50 mg/L) in patients with early AMD and 3.04 mg/L (range, 0.20 mg/L to 16.80 mg/L) in patients with late AMD.

After adjustment for age and sex, hazard ratios were 1.11 for early AMD development and 1.28 for late AMD development per standard deviation increase in HsCRP level, the authors reported.

The risk of developing early AMD increased per quartile increase in HsCRP level. Specifically, hazard ratios were 1.19 in the second quartile, 1.29 in the third quartile and 1.33 in the fourth quartile.

In addition, the risk of developing late AMD rose per standard deviation increase in HsCRP level and was higher in all upper quartiles of HsCRP, the authors found.

"Persons with a high HsCRP level (greater than 1.73 mg/L) within the normal range have a statistically significant higher risk of early and late AMD. We consider HsCRP level a potential useful biological marker in profiling the risk of AMD for individual persons," the authors said.