Longitudinal Rates of Postoperative Adverse Outcomes after Glaucoma Surgery Among Medicare Beneficiaries: 1994 to 2005
Received 17 October 2007; received in revised form 25 March 2008; accepted 31 March 2008.
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 ≥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.
1Kellogg Eye Center, University of Michigan Department of Ophthalmology, Ann Arbor, Michigan.
2Duke University Center for Health Policy, Durham, North Carolina.
3Duke University Department of Ophthalmology, Durham, North Carolina.
Correspondence to: Frank A. Sloan, PhD, Center for Health Policy, Rubenstein Hall 114, Box 90253, Duke University, Durham, North Carolina, 27708.
Manuscript no.: 2007-1362.
The authors have no financial interest in any material presented in this manuscript.
Funded in part by grants from the National Institute on Aging (NIA) (grant no. 2R 37-AG-17473-05A1) and InHealth Institute for Health Technology Studies.
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