Fourteen retrospective record review studies (approximately 16,424 patients) were included in the review.
A median of 14.4% (IQR 12.5% to 20.1%) of surgical patients experienced at least one event (six studies); the severity of adverse events was mostly minor (median 40.5%, IQR 28.6% to 42.4%) or moderate (median 35.3%, IQR 34.5% to 44.3%).
The median frequency of adverse events per surgical patient was 11.6% (IQR 6.1% to 16.2%; six studies). A median of 5.2% of surgical patients (IQR 4.2% to 7.0%; four studies) had one or more potentially preventable adverse events and a median of 4.4% of surgical patients (IQR 3.2% to 5.7%; two studies) had preventable adverse events.
The most frequent consequences of surgical adverse events were wound problems and genitourinary, cardiovascular and gastrointestinal consequences (three studies). The most frequent potentially preventable surgical adverse event consequences were wound problems, followed by bleeding, sepsis (including abscess) and cardiovascular consequences) (two studies).
The most frequent causes of surgical adverse events included non-operative management errors. These included monitoring, incorrect or delayed treatment and diagnostic error or delay. Other secondary outcome results were reported in the review.