This is the first report of AEs in a respiratory hospital and one of the first studies ever performed in developing countries to assess their frequency and consequences. Overall, the prevalence of AEs was 9.1%, which would mean 415 cases of a total of 4,555 patients admitted to the study hospital in the year 2001. Of all the patients with AEs, 22% had some kind of disability; 52% had a protracted hospitalization; in 26%, the AE was considered to be an important contributor to the death of the patient; and 26% of these patients had more than one AE. The clinical condition most strongly related to an AE was a diagnosis of empyema, mainly due to delayed surgical treatment producing a prolonged hospital stay.
Our findings are consistent with those reported in studies from general hospitals from developed countries. Steel et al reported AEs in 36% of the patients admitted to university hospitals; in 25% of these cases, the events were life-threatening. Brennan et al observed AEs in 3.7% of hospitalizations, and 27.6% were caused by negligence; of these, 70% induced a transient disability of < 6 months and 2% caused a permanent disability. An additional study performed in Colorado and Utah revealed similar results, and the 3% prevalence of AEs mainly affected patients undergoing surgery or childbirth. A study performed in two British hospitals reported that 10.8% of patients experienced AEs. Andrews et al reported that AEs affected 480 of 1,047 patients (45.8%), with 17.7% of severe episodes causing disability or even death. Finally, the publication with the greatest public impact to date is the book by the US Institute of Medicine, which estimated that medical errors kill some 98,000 Americans each year.