Which Adverse Events Are Related to Health Care during Hospitalization in Elderly Inpatients?

Background: Adverse events result in longer hospital stays and increase costs and mortality. We aimed to assess incidence of adverse events occurring during hospitalization in a post-emergency unit and to describe their characteristics. Methods: All adverse events occurring in patients during their hospitalization in a post-emergency unit in a French university hospital (20 beds) were systematically and consecutively recorded from September 2009 to February 2011. Patients with adverse events were compared to up to three control patients, matched for date of admission +/- age in the same unit. Results: We identified 56 patients with 64 adverse events, giving an incidence of 3.0/100 patients admitted/year. Fifty-one adverse events were drug-related. Patients had a median age of 82.5 years with a male/female ratio of 1/1.4. They presented a median Charlson score of 1 and the median number of medications was 6. The drugs most frequently involved in drug-related events were nervous system drugs (47%) and anti-infectives (22%). In multivariate analysis, a Charlson score >= 2 was associated with the occurrence of adverse events (OR 0.4; 95% CI [0.21 - 0.80]). Conclusions: Systematic recording showed that adverse events were not rare in a post-emergency unit. Patients with comorbid conditions were less likely to present an adverse event, possibly because of greater precautions taken by the medical team.