Elevated C-reactive protein levels in patients with polypoidal choroidal vasculopathy and patients with neovascular age-related macular degeneration

Abstract

Purpose: To determine the relationship between systemic C-reactive protein (CRP) levels and polypoidal choroidal vasculopathy (PCV) and advanced neovascular age-related macular degeneration (AMD) in Japanese patients.

Design: Case-control study.

Participants: Ninety-seven patients with PCV, 176 with advanced neovascular AMD, and 262 control subjects without any macular abnormality were studied.

Methods: Color fundus photographs of the macular area were taken from both eyes in all subjects. Indocyanine green angiography and fluorescein angiography were performed for diagnosis. The CRP level was measured by a high-sensitivity assay using a latex aggregation immunoassay, and the levels in patients with PCV and neovascular AMD were compared with that in the control group using the Kruskal-Wallis test. Associations between CRP and PCV or neovascular AMD were compared using logistic regression analysis by computing the odds ratios (ORs) and 95% confidence intervals (CIs) after the study populations were divided into quartiles.

Main outcome measures: The CRP levels in patients with PCV, patients with neovascular AMD, and control subjects. Standard univariate and multivariate analyses between groups.

Results: Median CRP levels were significantly higher in cases with PCV (0.94 mg/l) or with advanced neovascular AMD (0.95 mg/l) than in control subjects (0.43 mg/l) (P<0.001 for Kruskal-Wallis test). After adjusting for baseline characteristics such as age, gender, smoking status, alcohol use, body mass index, history, and use of antiinflammatory drugs, the increase in risk was significant for the highest quartile of CRP for both PCV (OR, 3.53; 95% CI, 1.49-8.40) and neovascular AMD (OR, 4.08; 95% CI, 1.94-8.56), and for the third quartile of CRP for neovascular AMD (OR, 2.29; 95% CI, 1.07-4.91). The trends for an increase in risk of disease with increase in CRP were statistically significant for both PCV (P = 0.001) and neovascular AMD (P<0.001).

Conclusions: The significant associations between elevated serum CRP levels and PCV or neovascular AMD in the Japanese strongly suggest that inflammatory processes are involved in the pathogenesis of PCV and neovascular AMD.