Predictors of Endophthalmitis after Intravitreal Injection: A Multivariable Analysis Based on Injection Protocol and Povidone Iodine Strength

Purpose: To determine the incidence of endophthalmitis after anti-vascular endothelial growth factor (VEGF) therapy at our institution and to identify potential risk factors for endophthalmitis occurring after injection.

Design: Retrospective, single-center cohort study.

Participants: All patients who received an intravitreal injection of an anti-VEGF medication between January 1, 2014, and March 31, 2017.

Methods: Current Procedural Terminology and International Classification of Diseases billing codes were used to identify instances of anti-VEGF administration and cases of endophthalmitis. Medical records and injection technique were reviewed carefully in each case. Multivariable logistic regression analysis was performed in a stepwise fashion to determine independent predictors of endophthalmitis based on injection protocol.

Main outcome measures: Incidence of endophthalmitis after injection and odds of endophthalmitis by injection technique with 95% confidence intervals (CIs).

Results: A total of 154 198 anti-VEGF injections were performed during the period of interest, resulting in 58 cases of endophthalmitis (0.038% [1:2659]). After adjustment for confounders, both 2% lidocaine jelly (odds ratio [OR], 11.28; 95% CI, 3.39-37.46; P < 0.001) and 0.5% Tetravisc (Ocusoft, Richmond, TX; OR, 3.95; 95% CI, 1.15-13.50; P = 0.03) use were independent risk factors for endophthalmitis after injection. Lid speculum use, povidone iodine strength (5% vs. 10%), injection location (superior or inferior), conjunctival displacement, use of provider gloves, use of a strict no-talking policy, use of subconjunctival lidocaine, and topical antibiotic use were not statistically significant predictors of endophthalmitis after injection. There was no difference in endophthalmitis rate among the anti-VEGF agents (bevacizumab, ranibizumab 0.3 mg, ranibizumab 0.5 mg, and aflibercept).

Conclusions: The incidence of endophthalmitis after anti-VEGF injections is low. Use of lidocaine jelly or Tetravisc may increase the risk of endophthalmitis after injection.