Hospitalizations of older people in an emergency department related to potential medication-induced hyperactive delirium: a cross-sectional study

Background Although delirium is one of the most common adverse drug reactions observed in hospitalized older people, it remains underdiagnosed. Aim To estimate the prevalence of hospitalization of older people with potential medication-induced hyperactive delirium in the emergency department (ED); to identify the risk factors and the medicines frequently associated with the occurrence of the syndrome. Method A cross-sectional, retrospective study was performed with older people (age ≥ 60) admitted in 2018 to a Brazilian ED. The hospitalizations with suspected hyperactive delirium were screened with the aid of trigger-tools: International Code of Diseases-10th Revision, intra-hospital prescriptions of antipsychotics, and trigger-words related to the syndrome. A chart-review and medication review were developed to establish the causality assessment between adverse event and medicine. Logistic regression was used to determine risk factors for occurrence. Results Among the hospitalizations included, 67.5% (193/286) were screened by at least one trigger-tool. Of these, potential medication-induced hyperactive delirium was observed in 26.0% (50/193). The prevalence estimated in the ward was 17.5% (50/286). Opioids (31.9%), benzodiazepines (18.8%) and corticosteroids (10.6%) were the commonest medicines associated with delirium. Long-lived patients (p = 0.005), potentially inappropriate medicines (PIMs) (p = 0.025), and high weighted deliriogenic load (p = 0.014) were associated with potential medication-induced hyperactive delirium. Conclusion Approximately one in six hospitalizations of older people in the ED showed potential medication-induced hyperactive delirium. Data suggest PIMs and high weighted deliriogenic load, rather than polypharmacy or anticholinergic burden, are considered the most important characteristics of pharmacotherapy associated with avoidable hyperactive delirium among long-lived patients.