Postoperative serious adverse events in a teaching hospital

To the Editor: The article by Bellomo et al,1 with its alarmist conclusions, received a lot of media attention. However, the authors' methodology is flawed and their conclusions are unsupported by their data. They describe postoperative adverse events in a group of largely elderly patients (median age, 65.5 years) who stayed in hospital more than 48 hours after inpatient surgery. These selective criteria were used "to exclude patients having day surgery or minor procedures".

Stratifying the severity of operations according to duration of stay is fundamentally flawed. This would have excluded many major, short-stay operations if the patient had had an uneventful postoperative course (eg, laparoscopic cholecystectomy and complex endoscopic procedures), and included others simply because a complication prolonged the patient's stay. The result is a selective bias towards a high complication rate. A more valid approach would have been to stratify all inpatient operations by severity and to include all major operations in the denominator for the study. This strategy would undoubtedly have shown significantly lower complication and mortality rates than those reported by Bellomo et al.

The "silent epidemic" referred to in the study is neither silent nor an epidemic. An epidemic refers to a disease normally absent but liable to outbreaks. What the authors describe is an endemic situation (habitually present, of common occurrence); it is quite obvious and already extensively documented. Elderly patients undergoing major operations (especially in an emergency — "unscheduled surgery" in the authors' pejorative lexicon) are likely to have complications, and, when they do, need to stay in hospital longer.

The authors did not analyse whether the adverse events were preventable, and therefore they cannot justify their conclusion that "there is much scope for improving postoperative care".