Delirium, Dementia, and In-Hospital Mortality: The Results From the Italian Delirium Day 2016, A National Multicenter Study

Background There is little evidence about the prevalence of cognitive disorders and their effect on in-hospital mortality in large multicenter studies. The objectives of the 2016th edition of the "Italian Delirium Day," a large multicenter study on in-hospital older patients, were to assess (i) the point prevalence of cognitive impairment/no dementia, dementia, delirium, and delirium superimposed on dementia and (ii) the effect of these conditions on in-hospital mortality. Methods This multicenter study and included 2,037 older patients (aged ≥65 years) admitted to acute medical and surgical wards across 205 acute hospitals. The four cognitive disorders groups were defined with a structured approach including the four AT and the presence of a documented diagnosis of dementia. The outcome measure was in-hospital mortality, as reported by the researchers involved in the study in each center. Results The mean age was 81.17 ± 7.7 years. Overall, 893 patients (43.8%) had neither delirium nor dementia nor cognitive impairment, 483 (23.7%) had cognitive impairment/no dementia, 230 (11.3%) dementia alone, 187 (9.2%) delirium alone, and 244 (12.0%) delirium superimposed on dementia. Overall, 99 (4.8%) patients died. Participants with delirium alone (odds ratio 2.56; 95% confidence interval: 1.29-5.09) and those with delirium superimposed on dementia (odds ratio 2.60; 95% confidence interval: 1.39-4.85) had higher mortality risk compared with the reference group of patients with "no cognitive impairment." Conclusions Delirium and delirium superimposed on dementia were highly prevalent among older hospitalized patients and significantly increased in-hospital mortality. Clinicians should systematically assess these conditions and recognize them as markers of critical conditions and predictors of imminent death.