Factors Associated with Success in First-Time Trabeculectomy for Patients at Low Risk of Failure with Chronic Open-Angle Glaucoma

Purpose: To examine the relationships between study factors and trabeculectomy outcome in a representative sample of United Kingdom ophthalmology surgeons and patients. Design: Cross-sectional observational study by questionnaire. Participants: All ophthalmic surgeons performing trabeculectomy in the National Health Service were invited to select their 4 most recent consecutive trabeculectomy cases satisfying study eligibility criteria before June 1996. Three hundred eighty-two surgeons supplied baseline data for 1450 patients and 1-year follow-up data for 1240 (85.3%) patients. All patients had undergone first-time trabeculectomy for chronic open-angle glaucoma. Methods: Data were collected by self-administered questionnaires at baseline and 6 and 12 months postoperatively. Univariate analysis of the relationships between study factors and success was performed by chi-square test (categorical variables) and Student's t or Mann-Whitney U tests (continuous variables). Multiple logistic regression modeling of explanatory variables significant at a P value of ≤0.1 was then performed. Main Outcome Measure: Trabeculectomy success, defined as a final intraocular pressure (IOP) less than two thirds of the preoperative IOP, excluding patients on antiglaucoma medications. Results: After multiple logistic regression modeling, diabetes (odds ratio [OR] = 0.485, 95% confidence interval [CI] = 0.271-0.868, P = 0.015), superior rectus traction suture (OR = 0.580, 95% CI = 0.348-0.959, P = 0.034), subconjunctival anesthetic (OR = 0.172, 95% CI = 0.065-0.459, P<0.0001), and nonspecialist surgeons (OR = 0.539, 95% CI = 0.335-0.865, P = 0.010) remained significantly associated with poorer outcome. Conclusions: In this nationally representative sample of glaucoma patients undergoing first-time trabeculectomy, we have identified important associations between diabetes, superior rectus traction suture, subconjunctival anesthetic, nonspecialist surgeons, and diminished trabeculectomy success. These associations merit further examination.