Intraoperative clinical practice and risk of early complications after cataract extraction in the United States, Canada, Denmark, and Spain

Objective: To examine variation in intraoperative clinical practice and rates of adverse events after cataract surgery across four different healthcare systems. Design: Multicenter cohort study. Participants: Patients were recruited from ophthalmic clinics in the United States (n = 75); in the Province of Manitoba, Canada (n = 12); in Denmark (n = 17); and the City of Barcelona, Spain (n = 10). In all, 1420 patients undergoing first eye cataract surgery were enrolled, with preoperative, perioperative, and postoperative clinical data collected on 1344 patients (95%). Main Outcome Measures: Occurrence of 23 specified intraoperative and early postoperative adverse events was measured. Four-month postoperative visual acuity outcome also was measured. Results: Phacoemulsification was performed in two thirds of the extractions in the United States and Manitoba, in one third in Denmark, and in 3% in Barcelona (P < 0.001). More than 96% of extractions in North America and Denmark were performed with the patient under local anesthesia, whereas general anesthesia was used for 38% of extractions in Barcelona (P < 0.001). Rates of intraoperative adverse events were 11% to 12.8% in Manitoba, Denmark, and Barcelona and significantly lower in the United States (6%), mainly because of a lower rate of capsular rupture (P < 0.01). Significantly higher rates of early postoperative events were seen in the United States (18.8%) and Manitoba (20.4%) compared to Denmark (7.9%) and Barcelona (5%) (P < 0.001). The differences among sites in rates of events could not be explained by differences in recorded patient characteristics or surgical techniques. The occurrence of perioperative events was significantly associated with a worse 4-month visual outcome. Conclusion: The observed variation in clinical practice might represent a general trend of a slower diffusion of new medical technology in Europe compared with that of North America. Rates of intraoperative and early postoperative events varied significantly across sites.