Topical Brimonidine Is Associated With Trabeculectomy Failure in Glaucoma Patients

To evaluate the role of preoperative glaucoma medication in the surgical outcomes of trabeculectomy.

Retrospective observational cohort study.

A total of 501 eyes of adult glaucoma patients who underwent primary trabeculectomy.

Using data from a single academic center, we identified adult trabeculectomy patients by procedure codes between January 1, 2015, and March 21, 2022. Preoperative and postoperative electronic medical records, up to 3 years, were extracted and included demographics, diagnoses, intraocular pressure (IOP), and medications. Preoperative medications were matched to 43 unique formulations, incorporating all concentration variants, brand names, and generic equivalents. Data accuracy was validated with a manual chart review.

Surgical success was defined by IOP between 6 and 15 mm Hg or greater than 20% reduction from baseline without reoperation. Surgical failure from high IOP was determined by IOP > 15 mm Hg or < 20% reduction from baseline on 2 consecutive visits, or reoperation due to high IOP.

Preoperative brimonidine was associated with an increased risk of high IOP trabeculectomy failure (hazard ratio [HR] 2.87; p = .002), as was higher baseline IOP (HR: 1.33; p = .014). Other topical agents, such as beta blocker, prostaglandin, or carbonic anhydrase inhibitors, age, sex, race, or glaucoma severity, did not show an increased or decreased hazard of high IOP surgical failure. At 3 years, survival analysis showed the probability of success from high-IOP failure was 81.9% in the brimonidine group versus 93.36% in the non-brimonidine group (p < .00, log-rank test).

Brimonidine is associated with a near 3-fold increase in trabeculectomy failure from high IOP. Further study is needed to understand the underlying mechanisms and to optimize preoperative medication.