Factors affecting the outcome of trabeculectomy: an analysis based on combined data from two phase III studies of an antibody to transforming growth factor beta2, CAT-152.

PURPOSE: To determine the factors affecting trabeculectomy success.
DESIGN: Retrospective analysis of 2 randomized controlled trials comparing an antibody against transforming growth factor beta2 (TGF-beta2) with vehicle (placebo) for prevention of fibrosis after trabeculectomy, in which there was no significant difference between the treatment groups. PARTICIPANTS: Data were from patients (n = 726) with a diagnosis of primary open-angle glaucoma, chronic angle-closure glaucoma, pseudoexfoliative glaucoma, or pigmentary glaucoma (PG) who had an intraocular pressure (IOP) > 21 mmHg and visual field or optic disc changes characteristic of glaucoma and were taking the maximum tolerated dose of medication before trabeculectomy.
METHODS: Patients had trabeculectomy and 4 subconjunctival injections of a human monoclonal antibody to TGF-beta2 (CAT-152) or a placebo. The definition of trabeculectomy success in the protocols was an IOP between 6 and 16 mmHg inclusive at months 6 and 12. Analyses of success used factors identified by ophthalmic experts. MAIN OUTCOMES MEASURES: Covariates analyzed included patient age, black race, gender, time since diagnosis, primary diagnosis, country, diabetes, mean defect, cup-to-disc (C/D) ratio, suture type, anesthetic, flap type, IOP at listing for surgery, suture release/lysis, needling, reformed anterior chamber, wound leak, severe bleb vascularity, and bleb microcysts.
RESULTS: A stepwise logistic regression model found the following predictors of treatment success: PG (odds ratio [OR], 4.11; 95% confidence interval [CI], 1.41-11.99), high C/D ratio (OR, 2.84; 95% CI, 1.15-6.99), and use of a corneal traction suture (OR, 1.67; 95% CI, 1.09-2.56). A negative relationship was found for black race (OR, 0.28; 95% CI, 0.13-0.62); treatment in France (OR, 0.35; 95% CI, 0.17-0.70), Sweden (OR, 0.17; 95% CI, 0.05-0.58), Spain (OR, 0.37; 95% CI, 0.21-0.68), Poland (OR, 0.53; 95% CI, 0.32-0.88), or Hungary (OR, 0.14; 95% CI, 0.06-0.34); and suture release/lysis (OR, 0.34; 95% CI, 0.22-0.53). The effect of needling was marginally statistically significant (OR, 0.56; 95% CI, 0.31-1.01).
CONCLUSIONS: Successful trabeculectomy outcome was associated with PG, higher C/D ratio, and corneal traction suturing. Factors associated with surgical failure were black race and suture release/lysis. Intercountry differences also were observed.