Inouye · The New England journal of medicine 1999 · prospective matched controlled trial · n=852

A multicomponent intervention to prevent delirium in hospitalized older patients.

Cited 2935 times in the scientific literature.

Level 3 - non-randomized controlled study

Prospective matched controlled trial with non-randomized allocation by hospital unit

PubMed 10053175 · doi:10.1056/NEJM199903043400901 · record verified 2026-08-29

What was done

Researchers conducted a prospective matched trial among 852 general-medicine inpatients aged 70 years or older at a teaching hospital. Patients were allocated by unit (one intervention unit vs. two usual-care units) and matched. The intervention consisted of standardized protocols targeting six delirium risk factors: cognitive impairment, sleep deprivation, immobility, visual impairment, hearing impairment, and dehydration. Delirium was assessed daily until discharge.

What was found

Delirium developed in 9.9% of intervention patients compared to 15.0% of usual-care patients (matched odds ratio 0.60; 95% CI, 0.39 to 0.92). Total delirium days were lower in the intervention group (105 vs. 161 days, P=0.02), as were total episodes (62 vs. 90, P=0.03). Intervention adherence was 87%, and sleep medication use decreased. However, delirium severity and recurrence rates did not differ significantly between groups.

Why it matters

This landmark study demonstrates that non-pharmacological, multicomponent risk-factor modification can prevent incident delirium in hospitalized older adults, though it does not reduce the severity or recurrence once delirium occurs.

Limits

Allocation was by hospital unit rather than individual randomization, introducing potential unit-level confounding despite prospective matching. The study was conducted at a single teaching hospital on general-medicine wards, limiting direct generalizability to other settings or surgical populations. Long-term post-discharge outcomes and mortality were not reported in the abstract.

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