- Design
- Systematic review and meta-analysis
- Population
- 1,190 hospitalised adults in 8 studies
- Primary outcome
- Incidence of delirium
- Effect
- RR 0.64 (0.38-1.07), P = 0.09; very low certainty
This systematic review and meta-analysis included eight randomised, controlled or pilot studies, 1,190 hospitalised adults, testing bright light therapy to prevent delirium. Most gave morning light of 5,000 lux or more for one to two hours over three to four days.
The pooled risk ratio for delirium was 0.64 (95% CI 0.38 to 1.07; P = 0.09), with moderate heterogeneity. Certainty was very low because of risk of bias, inconsistency, imprecision and possible publication bias. Adherence and adverse events were inconsistently reported. Two of three studies measuring circadian rhythm reported changes after light therapy.
Restoring a normal day-night pattern is already part of good delirium prevention: daylight, curtains open in the day, lights low at night. A dedicated light device adds cost and staff time for an effect that is not yet shown. It is reasonable to keep the simple measures and wait for better trials before buying equipment.
- Open curtains and expose patients to daylight in the morning as part of routine care.
- Reduce light and noise at night, and avoid unnecessary overnight observations.
- Do not invest in bright light devices for delirium prevention on current evidence.
- Keep light therapy within research or audit settings for now.
Why it matters
It stops a plausible but unproven device being added to delirium bundles ahead of the evidence.
Don't overread it
The confidence interval crosses 1 and certainty is very low; no benefit has been shown.
The statistics, in plain English
A risk ratio of 0.64 would mean about a third fewer cases of delirium, but the interval runs from 0.38 to 1.07, so the data are also compatible with no effect or a slight increase.
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for geriatrics, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free