RESUMEN
OBJECTIVE: To analyze the incidence and preventability of adverse events related to health care in adult patients admitted to a Brazilian teaching hospital. METHODS: A retrospective cohort study, in which the incidence and preventability of adverse events related to health care were based on a two-stage retrospective review of 368 medical records (nurses and pharmacist review of medical records, followed by physicians review of triggered medical records) of adult patients whose hospitalizations occurred during 2015 in a high-complexity public teaching hospital located in Brazil. Data were collected from February 2018 to February 2019. RESULTS: A total of 266 adverse events were observed in 124 patients. The incidence of adverse events related to health care was 33.7% (95% CI 0.29-0.39), and the incidence density was 4.97 adverse events per 100 patient-days. Adverse events were responsible for 701 additional days of hospitalization, and the estimated length of additional hospital stay attributable to them was, on average, 6.8 days per event. The most common types of events were related to general care (60; 22.6%), medications (50; 18.8%), nosocomial infection (35; 13.2%), any other type (11; 4.1%), and diagnoses (2; 0.8%). Regarding the severity of adverse events, it was found that 168 (63.2%) were mild, 55 (20.7%) were moderate, and 43 (16.2%) were severe. In addition, it was estimated that 155 (58.3%) events were preventable. The length of a patient's hospital stay was identified as a risk factor for the occurrence of adverse events (RR 1.20; 95% CI 1.04-1.39). CONCLUSIONS: Through knowledge of the incidence, nature, severity, preventability, and risk factors for the occurrence of adverse events, it is possible to create the opportunities to prioritize the implementation of strategies for mitigating specific events based on reliable data and concrete information.