The incidence of endophthalmitis after cataract surgery among the U.S. Medicare population increased between 1994 and 2001.

Objective: To estimate the annual incidence rate of presumed endophthalmitis after cataract surgery, evaluate any changes in this rate over time, and examine demographic risk factors for endophthalmitis after cataract surgery.

Design: Population-based review of Medicare beneficiary claims data.

Data Source: Medicare 5% sample beneficiary data files for inpatient and outpatient claims from 1994 through 2001 were examined to identify all cataract surgeries and subsequent cases of presumed endophthalmitis after cataract surgery.

Methods: All cataract surgery and presumed endophthalmitis cases after cataract surgery were identified based on claims submitted. The annual rate of presumed endophthalmitis after cataract surgery was calculated, and demographic risk factors for endophthalmitis were examined using multivariate models.

Main Outcome Measures: Incidence rate of endophthalmitis after cataract surgery and prevalence of demographic risk factors for endophthalmitis over an 8-year period.

Results: One thousand twenty-six cases of presumed endophthalmitis occurred after 477,627 cataract surgeries, yielding an incidence rate of 2.15 per 1000 for this 8-year period. Rates of endophthalmitis adjusted for age, gender, and race were significantly higher in 1998 to 2001 than in earlier years (relative risk [RR], 1.41; 95% confidence interval [CI], 1.24-1.60). Older age and black race also were associated with increased risk of endophthalmitis (RR, 1.83; 95% CI, 1.19-2.81; age, > or =90 years, and RR, 1.30; 95% CI, 1.02-1.65, respectively).

Conclusions: Analysis of Medicare claims data suggests that the incidence of endophthalmitis after cataract surgery has been increasing, but does not provide an explanation for this occurrence. An increase in the incidence of endophthalmitis after cataract surgery is of concern, because cataract surgery is the most commonly performed operation in the United States, and the number of cataract surgeries performed annually will likely increase substantially over the coming decades due to the aging of the U.S. population.