Postoperative Risk Factors Influencing Corneal Graft Survival in the Singapore Corneal Transplant Study

Abstract

To determine postoperative risk factors that influence long-term corneal graft survival. Prospective cohort study. Nine-hundred one consecutive penetrating keratoplasty procedures for optical, therapeutic, or tectonic indications from the Singapore Corneal Transplant Study. Univariate and multivariate analysis was performed for postoperative risk factors; Cox proportional hazards regression with a time-dependent covariate was used for preoperative, intraoperative, donor, and postoperative risk factors in a combined model. Raised intraocular pressure (20.7%) was the most common complication, followed by rejection (18.2%), whereas glaucoma surgery (7.9%) and repeat grafting (7.3%) were the most common procedures after penetrating keratoplasty. The primary graft failure rate was 1.4%, and late failure was seen in 9.4% of eyes. In the combined regression model, rejection (hazard ratio [HR], 3.4; P = .00), microbial keratitis (HR, 3.6; P = .00), endophthalmitis (HR, 7.7; P = .00), primary disease recurrence (HR, 73.9; P = .00), wound dehiscence (HR, 2.8; P = .02), lid surgery (HR, 2.3; P = .02), glaucoma surgery (HR, 2.46; P = .02), and repeat grafting (HR, 3.2; P = .00) were the significant postoperative failure predictors; the significant preoperative and intraoperative factors identified were female gender, graft size of less than 7 mm and more than 9 mm, primary diagnosis, preoperative inflammation, and preexisting perforation. Postoperative complications and operative procedures after grafting have an adverse effect on graft survival.