Hearing aids did not significantly reduce progression from MCI to dementia, but more people returned to normal cognition

Design

Multicentre, open-label, randomised clinical trial (CHOICE)

Population

703 adults aged 60 and over in Shanghai with mild cognitive impairment and moderate to severe hearing loss

Primary outcome

Conversion to dementia-level impairment (CDR ≥1) over 24 months

Effect

3.1% vs 4.7%; RR 0.59 (95% CI 0.25 to 1.38); return to normal cognition 15.3% vs 2.4%

Hearing loss is an established modifiable risk factor for dementia in population studies, but trials of hearing intervention have been mixed. CHOICE randomised 703 adults aged 60 and over (mean 74.5) in Shanghai with mild cognitive impairment (CDR 0.5) and moderate to severe hearing loss to hearing aids or hearing care education, open label, for 24 months.

The primary outcome, conversion to dementia-level impairment (CDR 1 or more), occurred in 3.1% with hearing aids and 4.7% with education (risk difference −2.1%, 95% CI −4.7% to 0.6%; relative risk 0.59, 0.25 to 1.38). The difference was not statistically significant. A prespecified secondary outcome, return to normal cognition (CDR 0), was much more common with hearing aids: 15.3% vs 2.4% (relative risk 5.94, 2.46 to 14.37). No study-related adverse events were reported.

Two honest readings follow. Hearing aids were not shown to prevent dementia in people who already had mild cognitive impairment, and patients should not be told they will. But the trial was small for its primary outcome, conversion was low in both groups, and the secondary result suggests some people labelled as having mild cognitive impairment were partly impaired by not hearing. Correcting hearing is worth doing for its own sake, and may clarify the cognitive diagnosis.

• Check hearing in every patient assessed for mild cognitive impairment.
• Refer patients with moderate or severe hearing loss for hearing aid fitting.
• Reassess cognition after hearing has been corrected before confirming a diagnosis of mild cognitive impairment.
• Do not promise patients that hearing aids will prevent dementia; this trial did not show that.

Why it matters

Some mild cognitive impairment may be partly hearing loss, and correcting it changes the diagnosis as well as the experience.

Don't overread it

The primary outcome was negative; the improvement in cognition is a secondary finding from an open-label trial.

The statistics, in plain English

The relative risk of 0.59 points towards benefit, but its interval (0.25 to 1.38) crosses 1, so the trial cannot rule out no effect. Few people converted in either group, which left the trial underpowered. The secondary result is large, but secondary outcomes are less reliable than the primary one, and an open-label design may influence how cognition was rated.

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.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.