Adverse events in older hospitalized patients with cognitive impairment.

Objectives As an increasing number of hospitalized inpatients are older and frail, cognitive impairment is becoming more common. Cognitive impairment may increase susceptibility to adverse events (AEs). This study aimed to identify the prevalence of AEs, potentially preventable AEs, and deaths in patients with and without cognitive impairment and the nature, causes, and prevention strategies. Design We analyzed data from 1959 records of a nationwide retrospective record review study of hospitalized older deceased patients. Setting and participants The cognitive impairment group included those with documented International Classification of Diseases, 10th Revision codes for delirium, dementia, mild cognitive impairment, and unspecified cognitive impairment. Methods Records were reviewed in 2 stages to assess AEs, their preventability, nature, causes, and prevention strategies. Results Of the 1959 included older patients, 428 patients (21.8%) were cognitively impaired. The Charlson comorbidity index was scored ≥5 in ≥90% of all patients. AE prevalence was 13.1% in patients without cognitive impairment vs 17.0% in cognitively impaired patients (P = .071). Potentially preventable AE prevalence was 4.0% in patients without cognitive impairment vs 5.1% in cognitively impaired patients (P = .369), and potentially preventable death prevalence was 3.3% vs 2.7%, respectively (P = .458). Cognitively impaired patients registered as delirium experienced more AEs than those with dementia. The nature of AEs in cognitively impaired patients was most often related to "other clinical management," that is, nursing clinical activities, nursing, and paramedical care. Organizational causes were more common in patients with cognitive impairment. Most AEs with a human cause were deemed potentially preventable in both groups. The recommended prevention strategies mainly included reflection and evaluation. Conclusion and implications This study shows no significant difference in AE prevalence between patients with documented cognitive impairment and those without; however, we did find differences in the nature and causes of AEs. Future research is needed to better understand the relationship among frailty, multimorbidity, cognitive impairment, and patient safety risks.