To estimate the annual incidence of endophthalmitis after cataract surgery from January 1, 1996, through December 31, 2005, in Quebec, Canada.
Deidentified data were obtained from an outpatient physician billing database (Quebec State Control for Health Insurance [RAMQ]) with regard to all cataract surgical procedures performed from January 1, 1996, through December 31, 2005, in Quebec. For this cohort, records of an International Classification of Diseases, Ninth Revision (ICD-9) code for endophthalmitis during the same years were requested from 2 sources: the RAMQ outpatient database and an inpatient hospital discharge database (Maintenance and Exploitation of Data for the Study of Hospitalized Patients [MED-ECHO]). Endophthalmitis after cataract surgery was assumed if it occurred within 90 days of the surgery. Risk factors were examined using χ2 tests and logistic regression.
After exclusions, 490 690 cataract surgical procedures were performed from January 1, 1996, through December 31, 2005. A total of 754 cases of endophthalmitis occurred within 90 days after surgery for an overall incidence rate of 1.5 per 1000 surgical procedures (95% confidence interval [CI], 1.4-1.7). Factors associated with endophthalmitis included age of 85 years or older (odds ratio [OR], 1.34; 95% CI, 1.06-1.70), male sex (1.44; 1.24-1.66), later year of surgery (0.94; 0.92-0.97), and region of cataract surgery, because regions 6 (2.21; 1.91-2.55) and 9 (4.00; 2.48-6.43) had higher rates compared with all other regions.
Reasons that explain the apparent decrease in endophthalmitis, especially in 2005, should be explored and further research performed to understand why certain patients and regions have higher risks of endophthalmitis after cataract surgery.