Delirium and in-hospital falls in older adults: factors associated with fall occurrence and number of falls.

purposeTo examine the association between delirium and in-hospital falls in older adults, including fall occurrence and number of falls, and to assess whether fall-related factors differ according to delirium status.

methodsWe conducted a retrospective cohort study of patients aged ≥ 65 years hospitalized in acute geriatric units between 2022 and 2024. Delirium was identified using ICD-10 codes, Confusion Assessment Method (CAM) documentation, and physician-entered diagnoses. Fall occurrence (≥ 1 fall) was analysed using multivariable logistic regression and number of falls using negative binomial regression. Analyses were stratified according to delirium status.

resultsAmong 12,866 hospitalizations, 1751 patients (13.6%) experienced at least one in-hospital fall. Delirium occurred in 2889 patients (22.5%) and was independently associated with fall occurrence (OR 1.51, 95% CI 1.32-1.72). Male sex (OR 1.56, 95% CI 1.39-1.74), Parkinson's disease (OR 1.52, 95% CI 1.23-1.89), and antipsychotic exposure were also associated with falls. Baseline functional status showed a significant interaction with delirium status (p = 0.0002): higher functional independence was associated with lower fall risk in patients without delirium (OR per 10-point FIM increase 0.91, 95% CI 0.89-0.94), but not in those with delirium (OR 0.99, 95% CI 0.95-1.03). Delirium was also independently associated with a higher fall count (IRR 1.47, 95% CI 1.31-1.66).

conclusionDelirium is independently associated with both the occurrence and number of in-hospital falls. Once delirium develops, fall risk appears to reflect a state of acute neurocognitive instability in which baseline functional status loses much of its discriminative value for risk stratification.