Longitudinal rates of postoperative adverse outcomes after glaucoma surgery among medicare beneficiaries 1994 to 2005

Abstract

Purpose: To determine longitudinal rates of postoperative adverse outcomes after incisional glaucoma surgery in a nationally representative longitudinal sample.

Design: Retrospective, longitudinal cohort analysis.

Participants: Medicare beneficiaries >or=68 years who underwent a primary trabeculectomy (PT), trabeculectomy with scarring (TS), or glaucoma drainage device (GDD) implantation from 1994 to 2003 with follow-up through 2005.

Intervention: Primary trabeculectomy, TS, and GDD were identified from International Classification of Diseases (ICD-9-CM) and Current Procedural Terminology (CPT) procedure codes. Change in rates of postoperative adverse outcomes associated with these 3 surgical interventions was analyzed by cumulative incidence rates and Cox proportional hazards model regression; regression analysis controlled for prior adverse outcome measures (3-year run-up) and demographic variables.

Main outcome measures: First-, second-, and sixth-year cumulative rates and probability of experiencing serious adverse outcomes (retinal detachment, endophthalmitis, suprachoroidal hemorrhage), less serious adverse outcomes (choroidal detachment, corneal edema, hypotony), and receipt of additional glaucoma surgery were identified through Medicare claims for each treatment group.

Results: At the 1-year follow-up, rates of severe adverse outcomes were higher among beneficiaries in the GDD group (2.0%) relative to the PT (0.6%) and TS groups (1.3%). Controlling for prior adverse outcomes to the surgery and demographic factors in Cox proportional analysis, differences were often reduced, but generally remained statistically and clinically significant. Rates of severe outcomes, less severe outcomes, corneal edema, and low vision/blindness were higher for persons undergoing GDD than PT or TS. However, rates of reoperation were higher for TS than GDD.

Conclusions: The risk for adverse outcomes was higher in GDD than in PT surgery or TS, controlling for a number of important case mix and demographic factors.

Figure 1

Cumulative incidence (Table 4). (♦) GDD = glaucoma drainage device; (■) PT = primary trabeculectomy; (▲) TS = trabeculectomy with scarring.

Figure 2

Hazard ratios (HR), 95% confidence intervals (CI) from Cox proportional hazards models of adverse outcomes. GDD = glaucoma drainage device is the omitted reference group; PT = primary trabeculectomy; TS = trabeculectomy with scarring.