title: Risk factors for acute endophthalmitis after cataract surgery: a population-based study.
abstract: OBJECTIVE
  To identify risk factors for suspected acute endophthalmitis after cataract surgery.
  
  
  METHODS
  Population-based retrospective cohort.
  
  
  METHODS
  Administrative data from more than 440,000 consecutive cataract surgeries in Ontario, Canada, from April 1, 2002, to March 31, 2006.
  
  
  METHODS
  Consecutive physician billing claims for cataract surgery and specific intraoperative and postoperative procedures related to complications of cataract surgery were identified. Acute endophthalmitis was defined using surrogate markers for intraocular infection, including vitrectomy, vitreous injection, or aspiration procedures not in combination with air/fluid exchange or dislocated lens extraction, performed 1 to 14 days after cataract surgery. Anterior vitrectomy performed on the day of surgery was used as a surrogate marker for capsular rupture.
  
  
  METHODS
  Overall rates of endophthalmitis were calculated and grouped by patient demographics, surgical facility, season, year, and association with capsular rupture.
  
  
  RESULTS
  There were 617 suspected acute endophthalmitis cases of 442,177 cataract surgeries over the 4 years. The overall unadjusted and adjusted rates of suspected acute endophthalmitis were both 1.4 per 1000 cataract surgeries. Men had higher rates than women (1.70 vs. 1.19/1000 surgeries, P<0.0001) with an adjusted odds ratio of 1.40 (95% confidence interval, 1.19-1.64).The oldest age group (>or= 85 years) had the highest rate (2.18/1000), and the youngest group (20-64) had the second highest rate (1.76/1000). The endophthalmitis rates for these age groups were significantly different from those aged 65 to 84 years. The endophthalmitis rate was approximately 10-fold higher in those with capsular rupture compared with those without (13.11 vs. 1.34/1000, P<0.0001), with an adjusted odds ratio of 9.56 (95% confidence interval, 6.43-14.2).
  
  
  CONCLUSIONS
  The overall rates of suspected acute endophthalmitis are low but significantly higher in certain patient groups. Our population-based analysis can be used as a benchmark for quality-improvement initiatives and can assist clinicians in educating their patients regarding the risks associated with cataract surgery. Future work is required to address the higher rate of endophthalmitis in men, those with capsular rupture, and the oldest patients undergoing cataract surgery.
authors.affiliation: Ophthalmology and Vision Sciences at the University of Toronto, Toronto, Canada.
authors.forename: Wendy V
authors.initials: WV
authors.lastname: Hatch
authors.forename: Geta
authors.initials: G
authors.lastname: Cernat
authors.forename: David
authors.initials: D
authors.lastname: Wong
authors.forename: Robert
authors.initials: R
authors.lastname: Devenyi
authors.forename: Chaim M
authors.initials: CM
authors.lastname: Bell
mesh_terms: D000208:Acute Disease; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002387:Cataract Extraction; D016208:Databases, Factual / Q000706:statistics & numerical data; D009877:Endophthalmitis / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D015817:Eye Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009313:National Health Programs / Q000706:statistics & numerical data; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D011183:Postoperative Complications; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution