Demographic, Systemic, and Ocular Factors Associated with Nonarteritic Anterior Ischemic Optic Neuropathy.

Objective: Nonarteritic anterior ischemic optic neuropathy (NAION) is a devastating ocular condition causing permanent vision loss. Little is known about risk factors for developing this disease. We assessed demographic, systemic, and ocular factors associated with NAION.

Design: Retrospective longitudinal cohort study.

Participants: Beneficiaries between 40 and 75 years old without NAION at baseline enrolled in a large U.S. managed care network.

Methods: Enrollees were monitored continuously for ≥2 years between 2001 and 2014 to identify those newly diagnosed with NAION (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] code 377.41). All persons were under ophthalmic surveillance and all cases had ≥1 confirmatory ICD-9-CM code for NAION during follow-up.

Main Outcome Measures: Multivariable Cox regression modeling was used to generate hazard ratios (HRs) with 95% confidence intervals (CIs) to describe the statistical relationship between selected demographic characteristics, systemic and ocular conditions, and the hazard of developing NAION.

Results: Of 1 381 477 eligible enrollees, 977 (0.1%) developed NAION during a mean ± standard deviation (SD) follow-up of 7.8±3.1 years. The mean ± SD age for NAION cases at the index date was 64.0±9.2 years vs. 58.4±9.4 years for the remainder of the beneficiaries. After adjustment for confounding factors, each additional year older was associated with a 2% increased hazard of NAION (HR = 1.02; 95% CI: 1.01-1.03). Female subjects had a 36% decreased hazard of developing NAION (HR = 0.64; 95% CI: 0.55-0.74) compared with male subjects. Compared with whites, Latinos had a 46% decreased hazard of developing NAION (HR = 0.54; 95% CI: 0.36-0.82), whereas African ancestry was not significantly associated with NAION (HR = 0.91; 95% CI: 0.72-1.15). Systemic diseases associated with NAION included hypertension (HR = 1.62; 95% CI: 1.26-2.07) and hypercoagulable states (HR = 2.46; 95% CI: 1.51-4.00). Although diabetes mellitus (DM) was not significantly associated with NAION compared with those without DM (P = 0.45), patients with end-organ involvement from DM had a 27% increased hazard of NAION relative to those with uncomplicated DM (HR = 1.27; 95% CI: 1.01-1.59). Ocular diseases associated with NAION were age-related macular degeneration (HR = 1.29; 95% CI: 1.08-1.54) and retinal vein occlusion (HR = 3.94; 95% CI: 3.11-4.99).

Conclusions: Our study identified several modifiable risk factors that may be associated with NAION. Should future studies confirm these findings, they may offer opportunities to prevent or treat this debilitating condition.