Pseudomonas aeruginosa keratitis: outcomes and response to corticosteroid treatment

Abstract

Purpose: To compare the clinical course and effect of adjunctive corticosteroid therapy in Pseudomonas aeruginosa with those of all other strains of bacterial keratitis.

Methods: Subanalyses were performed on data collected in the Steroids for Corneal Ulcers Trial (SCUT), a large randomized controlled trial in which patients were treated with moxifloxacin and were randomly assigned to 1 of 2 adjunctive treatment arms: corticosteroid or placebo (4 times a day with subsequent reduction). Multivariate analysis was used to determine the effect of predictors, organism, and treatment on outcomes, 3-month best-spectacle-corrected visual acuity (BSCVA), and infiltrate/scar size. The incidence of adverse events over a 3-month follow-up period was compared using Fisher's exact test.

Results: SCUT enrolled 500 patients. One hundred ten patients had P. aeruginosa ulcers; 99 of 110 (90%) enrolled patients returned for follow-up at 3 months. Patients with P. aeruginosa ulcers had significantly worse visual acuities than patients with other bacterial ulcers (P = 0.001) but showed significantly more improvement in 3-month BSCVA than those with other bacterial ulcers, adjusting for baseline characteristics (-0.14 logMAR; 95% confidence interval, -0.23 to -0.04; P = 0.004). There was no significant difference in adverse events between P. aeruginosa and other bacterial ulcers. There were no significant differences in BSCVA (P = 0.69), infiltrate/scar size (P = 0.17), and incidence of adverse events between patients with P. aeruginosa ulcers treated with adjunctive corticosteroids and patients given placebo.

Conclusions: Although P. aeruginosa corneal ulcers have a more severe presentation, they appear to respond better to treatment than other bacterial ulcers. The authors did not find a significant benefit with corticosteroid treatment, but they also did not find any increase in adverse events. (ClinicalTrials.gov number, NCT00324168.).

Figure 1.

Visual acuity comparison of P. aeruginosa and all other bacterial ulcers at enrollment and 3 months. The line in the middle of each box represents the median, and the lower and upper bounds of the box represents the 25th and 75th percentiles, the span of which is the interquartile range (IQR). Whiskers extend to the lowest data point within 1.5× IQR below the 25th percentile and to the highest data point within 1.5× IQR above the 75th percentile. Individually plotted points represent outliers or values falling outside the whiskers. P values were obtained by rank sum test.

Figure 2.

Kaplan-Meier curves comparing time to reepithelialization in corticosteroid versus placebo treatment arms within the P. aeruginosa subgroup (n = 110). Curves are right-censored at 21 days; tick marks represent censoring. One patient in the corticosteroid arm was censored at day 1; 8 patients in the placebo arm and 14 patients in the corticosteroid arm were censored at day 21.