Impact and preventability of adverse events in Spanish public hospitals: results of the Spanish National Study of Adverse Events (ENEAS)

To determine the impact and preventability of adverse events (AEs) associated with health care in Spanish hospitals. Retrospective cohort study. Twenty-four Spanish hospitals. Patients of any age with a clinical record indicating an inpatient stay of > 24 h and a discharge between 4 and 10 June 2005 (n = 5908). None. Percentage of AEs considered preventable. We were able to identify 525 patients suffering AEs associated directly with medical care, who accumulated 655 AEs with 43% of these AEs considered preventable. Overall, 45% (295 AEs) were considered minor, 39% (255 AEs) moderate and 16% (105 AEs) severe. There were no significant differences in AE severity by hospital size, but AEs associated with surgical services were more likely to be severe than those associated with medical services. Some 31.4% of AEs resulted in a longer stay and 23.4% led to hospital admission. AEs associated with medical care caused 6.1 additional days per patient. Of the patients, 66.3% required additional procedures and 69.9% required additional treatments. Incidence of death in patients with AEs was 4.4% (CI 95%: 2.8-6.5). Age over 65 was associated with a higher incidence of preventable AEs. The highest percentages of preventable AEs were related to diagnosis (84.2%), to nosocomial infections (56.6%) and to care (56%). In Spanish hospitals, AEs associated with health care cause distress, disability, death, lengthen hospital stay and cause increased consumption of health-care resources. A relatively high percentage of AEs in Spain may be preventable with improvements in medical care.