Additive Effect of Risk Factors for Trabeculectomy Failure in Glaucoma Patients: A Risk-group From a Cohort Study.

Abstract

The purpose of the study was to assess the role of significant risk factors and develop a risk-group category related to the trabeculectomy (Trab) failure. A retrospective cohort study was developed between January 2009 and June 2014. In total, 120 eyes included in this study had a glaucoma diagnosis and undergone to Trab with mitomycin. The main outcome measures were surgical success and failure rate. Multivariate (Cox proportional hazards regression model) analyses were used to examine the predictive value of significant factors. A risk-group category was build based on the number of significant risk factors for patients. The risk group category was tested using the Kaplan-Meier method and log-rank test. With a median follow-up of 33 months (3 to 72 mo), the complete surgical success in 1, 2, 3, and 4 years was 82%, 63.5%, 52%, and 27.6%, respectively. The probability of freedom from a complete surgical failure was 88%, 84.5%, 78%, and 70% in 1, 2, 3, and 4 years, respectively. Glaucoma type (P=0.008), previous ophthalmic surgery (P=0.04), glaucoma medication use ≥3 years (P=0.010) and 4 glaucoma medication use pre-Trab (P=0.038) were identified as risk factors for surgical failure. The probability of freedom of surgical failure in 3 years was 93%, 83%, and 37.6% (P=0.003), for low (no factors), intermediate (1 to 2 factors), and high-risk group (3 to 4 factors). Trab with mitomycin produces satisfactory intraocular pressure control over time. However, several risk factors influence the efficacy of the surgical procedure. Our data show that there seems to exist an additive effect among risk factors with similar pathophysiology.