title: Characteristics of Endophthalmitis after Cataract Surgery in the United States Medicare Population.
abstract: OBJECTIVE
  Endophthalmitis is a rare but sight-threatening infection after cataract surgery. Roughly one third of eyes remain blind after treatment. We report United States population-based data on microbiological investigations and treatment patterns plus risk factors for poor outcomes.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Medicare beneficiaries from 5 states in whom endophthalmitis developed within 6 weeks after cataract surgery in 2003 and 2004.
  
  
  METHODS
  We identified endophthalmitis cases occurring after cataract surgery using Medicare billing claims. We contacted treating physicians and requested they complete a questionnaire on clinical and microbiological data and submit relevant medical records. Two independent observers reviewed materials to confirm that cases met a standardized definition.
  
  
  METHODS
  Positive culture results, vitrectomy status, microbiology spectrum, and final visual acuity.
  
  
  RESULTS
  In total, 615 cases met our case definition. Initial visual acuity was counting fingers or worse for 72%. Among 502 cases with known culture results, 291 (58%) had culture positive results. Twelve percent had positive results for streptococci. More than 99% of cases were treated with intravitreal vancomycin. Vitrectomy was performed in 279 cases (45%), including 201 cases with initial acuity better than light perception. Rates of vitrectomy varied across states, with California having the highest rate and Michigan having the lowest (56% and 19% of cases, respectively). Overall, 43% of individuals achieved visual acuity of 20/40 or better. Poor initial acuity (adjusted odds ratio [OR], 1.08; 95% confidence interval [CI], 1.04-1.12 per 0.10 logarithm of the minimum angle of resolution units), older age at diagnosis (OR, 1.22; 95% CI, 1.03-1.45 per 5-year increase), and more virulent organisms were important predictors of poor final visual acuity. Cases with streptococci infection were 10 times more likely to have poor final acuity than coagulase-negative staphylococci cases (adjusted OR, 11.28; 95% CI, 3.63-35.03). Vitrectomy was not predictive of final visual acuity (adjusted OR, 1.26; 95% CI, 0.78-2.04).
  
  
  CONCLUSIONS
  Population-based data on the microbiology of acute postoperative endophthalmitis in the United States after cataract surgery are consistent with prior reports. Vitrectomy usage is higher than that recommended from the Endophthalmitis Vitrectomy Study, with no evidence of increased benefit.
authors.affiliation: Departments of Epidemiology and Ophthalmology, Wake Forest School of Medicine, Winston-Salem, North Carolina; Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: egower@wakehealth.edu.
authors.forename: Emily W
authors.initials: EW
authors.lastname: Gower
authors.affiliation: The George Institute for Global Health, University of Sydney, Sydney, Australia.
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Keay
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Dianne E
authors.initials: DE
authors.lastname: Stare
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Arora
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Sandra D
authors.initials: SD
authors.lastname: Cassard
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Ashley
authors.initials: A
authors.lastname: Behrens
authors.affiliation: George Washington University School of Public Health and Health Services, Washington, District of Columbia.
authors.forename: James M
authors.initials: JM
authors.lastname: Tielsch
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Oliver D
authors.initials: OD
authors.lastname: Schein
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001419:Bacteria / Q000302:isolation & purification*; D016022:Case-Control Studies; D002387:Cataract Extraction; D014487:Centers for Medicare and Medicaid Services, U.S. / Q000706:statistics & numerical data; D016208:Databases, Factual; D004363:Drug Utilization / Q000706:statistics & numerical data; D009877:Endophthalmitis / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D015818:Eye Infections, Bacterial / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D011183:Postoperative Complications; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States; D014792:Visual Acuity / Q000502:physiology; D014821:Vitrectomy / Q000706:statistics & numerical data
chemical_list: D000900:Anti-Bacterial Agents