I read with interest the article by Dossarps and associates, in which they reported the results of their multicenter (25 centers) retrospective study, including incidence and characteristics of endophthalmitis after 316 576 intravitreal injections (IVI). Antibiotic prophylaxis was based on topical 1.5% azithromycin for 3 days either before or after IVI; antiseptic prophylaxis, topical 0.05% picloxydine 3 days before and 3 days after IVI. They reported that in univariate analysis, use of an antibiotic or antiseptic was statistically associated with an increased incidence of endophthalmitis ( P = .011 and P = .021, respectively). In multivariate analysis, use of prophylaxis with an antibiotic or antiseptic remained statistically associated with an increased incidence of endophthalmitis (interrater reliability = 2.77, 95% confidence interval 1.54–5.00, P = .001). Likewise, they concluded that “the endophthalmitis rate was higher with antibiotic prophylaxis or antiseptic use.”
However, their Table 1 delivers some opposite data. It is shown there that “no prophylaxis with antibiotic or antiseptic” influenced the incidence of endophthalmitis after IVI in 2 centers (8%) in univariate analysis ( P = .021) and multivariate analysis ( P = .001). Topical antiseptic use in 2 centers (8%) was not related with incidence of endophthalmitis in univariate analysis ( P = .534); the multivariate analysis was not done in this case.
Moreover, topical antibiotics started before IVI in 10 centers (40%) and after IVI in 11 centers (44%) were shown not to be related with endophthalmitis incidence in univariate analysis ( P = .844 and P = .645, respectively); the multivariate analysis was not done.
Thus, analysis of Table 1 shows that the use of topical antibiotics or antiseptics before or after IVI did not influence the incidence of endophthalmitis, whether “no prophylaxis with antibiotic or antiseptic,” although based only on 8% of centers, was significantly related with increased incidence of endophthalmitis.
Interestingly, another earlier French study, not discussed within the paper and probably based at least partly on the same data, reported quite opposite results; that is, the incidence of endophthalmitis post–intravitreal injections to be lower when using antibiotics (0.03% vs 0.23%, P = .024). This study included 11 450 patients who received intravitreal injections between January 2007 and October 2012, and the discussed study included patients between January 2008 and June 30, 2013. The similarities and differences between the 2 studies should be commented upon.