Observational Outcomes of Initial Trabeculectomy With Mitomycin C in Patients of African Descent vs Patients of European Descent: Five-Year Results

Importance There is evidence that patients of African descent (AD) experience higher surgical failure rate after trabeculectomy without antimetabolites. Objective To compare outcomes of initial trabeculectomy with mitomycin C in AD patients with those of patients of European descent (ED) and to identify prognostic factors for failure. Design, Setting, and Participants In this retrospective matched cohort study, 135 eyes of 105 AD patients were matched with 135 eyes of 117 ED patients by age (within 5 years), surgeon, lens status, and follow-up time (within 1 year) from a single tertiary academic center. Interventions Initial trabeculectomy with mitomycin C. Main Outcomes and Measures Criteria A, B, and C defined qualified success rates as final intraocular pressure of 18 mm Hg or less, 15 mm Hg or less, and 12 mm Hg or less, respectively, in addition to 20% or more, 25% or more, and 30% or more reduction of intraocular pressure or reduction of 2 or more medications. Kaplan-Meier survival curves were compared with log-rank test in AD and ED patients, and Cox proportional hazard models were used to estimate the influence of race/ethnicity on surgical success accounting for confounding variables. Results Of the 105 AD patients, 56 (53.3%) were female, and the mean (SD) age was 67.5 (10.4) years; of the 117 ED patients, 64 (54.7%) were female, and the mean (SD) age was 68.2 (10.0) years. For AD patients compared with ED patients, the qualified success rates at 5 years for criteria A were 61% and 67%, respectively (difference, 7.3%; 95% CI, 4.4-10.4); for criteria B, 43% and 60% (difference, 17.6%; 95% CI, 15.2-20.0); and for criteria C, 25% and 40% (difference, 15.8%; 95% CI, 11.1-20.5). On multivariable Cox regression analyses, AD was associated with higher failure rate with criteria B and C for qualified success and with all criteria for complete success (ie, no need for medications). Incidence of bleb leaks was higher in the AD group (29 vs 11 eyes; P  = .002). Additionally, AD patients required additional glaucoma surgeries more often than ED patients (47 vs 26 eyes; P  = .004). Conclusions and Relevance African descent was associated with higher failure rates and higher incidence of bleb leaks after initial trabeculectomy with mitomycin C compared with European descent. If this is subsequently shown to be a cause and effect, the findings need to be considered when surgical treatment of glaucoma is contemplated in AD patients.