Effectiveness of non-pharmacological and pharmacological interventions on delirium duration in older adults with delirium: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND: Delirium is a severe neuropsychiatric syndrome common in older adults and linked to adverse outcomes, especially when prolonged and in the presence of cognitive deficits. While preventive multicomponent strategies are well established, the effectiveness of interventions for treating delirium in older adults remains unclear. OBJECTIVE: To evaluate the efficacy of non-pharmacological and pharmacological interventions for treating delirium after onset in older adults (≥65 years), with delirium duration as primary outcome and length of stay as secondary. METHODS: We conducted a systematic review and meta-analysis of randomised controlled trials evaluating interventions for treating delirium across settings, excluding ICU-only studies. MEDLINE, Cochrane, Web of Science and PsycINFO were searched through October 2024. Comparators included usual care, placebo or other drug treatments. Random-effects meta-analyses with subgroup analyses by setting and drug type were performed. Sensitivity analyses excluded high risk-of-bias studies. PROSPERO registration: CRD42024500346. RESULTS: Seventeen trials (3765 randomised patients) were included. Non-pharmacological multicomponent interventions (k = 6, n = 2634) reduced delirium duration by -1.79 days [95% confidence interval (CI): -3.08 to -0.51] compared to usual care, with high heterogeneity (I2 = 97%). Effects were significant in medical and mixed settings. Pharmacological interventions (k = 7, n = 259) showed no significant effect (mean difference: -0.58 days; 95% CI: -1.24 to 0.08), and subgroup analyses revealed no differences. Neither intervention type significantly reduced length of stay. CONCLUSIONS: Non-pharmacological multicomponent interventions may reduce delirium duration in older adults, but evidence is limited by heterogeneity and the few studies focused on treatment. Pharmacological and single-component interventions showed unclear benefit, underscoring the need for more high-quality trials in this population.