Objective

Previous studies have identified a higher prevalence of diabetes mellitus (DM) among patient cohorts with nonarteritic anterior ischemic optic neuropathy (NAION). We sought to determine the development of incident NAION among a group of newly diagnosed patients with DM and to estimate the incidence of NAION among the elderly.

Design

Medicare 5% database study.

Participants

A total of 25 515 patients with DM and an equal number of age- and gender-matched nondiabetic patients.

Methods

Query of Medicare 5% claims files identified patients with a new diagnosis of DM in 1994. A randomly selected control group was created using 1-to-1 propensity score matching. Patients with a diagnosis of giant cell arteritis, preexisting DM, and age 68 years or older or >95 years were excluded. Patients with DM and controls were followed for the development of NAION over the following 4745 days.

Main outcome measures

Incidence of NAION among patients with and without DM.

Results

In each group, 85% were white, 11% were black, and 4% were other race. Patients were aged 76.4 years, and 40% were male. Mean follow-up was 7.6 years. In the diabetes group, 188 individuals developed NAION (0.7%) compared with 131 individuals (0.5%; P < 0.01) in the control group. In unadjusted Cox regression analysis, having DM was associated with a 43% increased risk (hazard ratio [HR]: 1.431; 95% confidence interval [CI], 1.145-1.789) of developing NAION. After adjusting for other covariates, the risk of developing NAION among individuals with DM was reduced to 40% (HR 1.397; 95% CI, 1.115-1.750). Male gender increased an individual's risk of developing NAION by 32% (HR 1.319; 95% CI, 1.052-1.654). No other covariate was statistically significantly associated with developing NAION. The annual incidence of NAION was 82 per 100 000 persons.

Conclusions

Diabetes mellitus significantly increased the risk of the diagnosis NAION. The incidence of NAION among patients aged more than 67 years may be higher than previously reported.