[Adverse events associated with the healthcare of patients with multimorbidity admitted to medium-long stay hospitals]

Background: Since medical practice involves risks, the aim of the health system is to promote and preserve health and to avoid, relieve and treat disease, while ensuring the quality of care. Patient safety is an essential component of the quality of care.

Objectives: To determine the incidence and prevalence of adverse events in hospitalized patients with multimorbidity in a medium-long stay hospital, to analyze the patients and healthcare characteristics associated with adverse events, to assess their impact, and to identify the possibilities for prevention.

Material and methods: We performed a retrospective cohort study in a medium-long stay hospital in 2004, and a prevalence study once a year from 2005 to 2008.

Results: The incidence of patients with adverse events directly related to hospital care was 3.3%, and the prevalence of patients with adverse events associated with health care was 5.8%. In both studies, extrinsic risk factors and length of stay were related to a greater risk of adverse events. In the incidence study, most of the adverse events (68.7%) were moderate, while in the cross-sectional study, most (84%) were mild. Fifty percent of the AE increased the length of hospital stay, and 14.5% led to readmission to the incidence study. Most of the adverse events detected in both studies required additional treatments and procedures to be performed. Between 30% and 49% of the adverse events were considered avoidable.

Conclusions: The incidence and prevalence of patients with adverse events in medium-long stay hospitals were lower than those found in acute-stay hospitals. The most frequent adverse events were related to medication in the incidence studies and with healthcare in the prevalence studies. Cohort studies are the most suitable type of study to assess the impact of adverse events. Sequential cross-sectional studies seem to be useful for identifying and performing surveillance of adverse events and allow strategies to reduce these events to be prioritized and the effectiveness of improvement programs to be assessed. Consequently, we recommend the introduction of this type of design to study adverse events in hospitals specializing in the care of patients with chronic diseases.