Risk Factors for Photodynamic Therapy of Predominantly Classic Choroidal Neovascularization in Age-related Macular Degeneration

Purpose: To investigate the influence of various risk factors for age-related macular degeneration (AMD) on the rate of undergoing photodynamic therapy (PDT). Design: An observational population based cohort study. Methods: settings: A district of the largest health maintenance organization (HMO) in Israel. Study Population: All HMO members in the district, older than 50 years on January 1, 2001, who did not terminate their membership until May 31, 2005 (139,894 members); of those, 283 underwent PDT for AMD during the study period (775 procedures). Observation Procedures: We extracted information from the chronic disease registry of the HMO as well as demographic information including age, gender, country of birth, place of residency, and social security economic status. Main Outcome Measures:Effect of various risk factors for AMD on the rate of PDT. Results: The age-adjusted proportion of patients requiring PDT was significantly higher in hypertensives (P = .03, χ² test), in hyperlipidemics (P = .002), in ischemic heart disease patients (P = .002) and among males (P = .03) and Ashkenazi Jews (P = .02). No significant difference in PDT rates was noted in diabetics, congestive heart failure (CHF), and chronic renal failure (CRF) patients. PDT rates were lower in the lower socioeconomic class (P = .002). Logistic regression found a significant effect of age, hyperlipidemia, hypertension, socioeconomic status, and gender on the rate of PDT, while ischemic heart disease (IHD), diabetes, CHF, CRF, place of birth, and place of residence did not contribute significantly to the model. Conclusions: Advanced age, hypertension, hyperlipidemia, male gender, and socioeconomic status are risk factors for undergoing PDT for predominantly classic neovascular AMD.