C-reactive protein levels, complement factor H polymorphism together create high risk for AMD progression

Researchers conducted a 2-arm, case-control study to determine the effect of elevated level of C-reactive protein (CRP) and its joint effect with the complement factor H (CFH) polymorphism on prevalent age-related macular degeneration and progression of the condition.

One arm included 312 patients with early or late AMD, and 232 controls; the other, 254 early AMD patients followed up for seven years. A combination of elevated CRP and the CC (Y402H) genotype combined to create a super-additive risk, increasing the odds of developing late AMD 19-fold, and the risk for progression almost seven-fold.  This CRP-CFH interaction accounted for 26 percent of the risk for prevalent late AMD and 22 percent for AMD progression.

Elevated CRP levels were associated with a three-fold increase in the odds for late AMD. An association of elevated CRP with AMD progression was weaker, with and odds ratio of 1.90.

Given these findings, the researchers call for testing of this risk factor combination to help predict those at high risk for AMD and its progression. These individuals should be the first in line for studies on intervention to prevent the progression of this disease.