Hospitalisation-associated disability: 27%, and how you measure it decides the number

Design

systematic review and meta-analysis of 46 studies with random-effects pooling

Population

439,406 older adults across 15 regions

Primary outcome

prevalence of hospitalisation-associated disability

Effect

pooled prevalence 27% (95% CI 24 to 31), 95% prediction interval 7% to 48%

A systematic review pooled 46 studies covering 439,406 older adults across 15 regions to estimate how often an older person leaves hospital less functionally able than before the illness. Individual studies ranged from 5% to 57%; the pooled prevalence was 27% (95% CI 24% to 31%), with a 95% prediction interval of 7% to 48%.

The subgroup findings are as informative as the headline. Prevalence was higher in randomised trials, in patients admitted with lower respiratory tract infection, in those aged 75 to 89, where the modified Barthel index was the instrument, and - critically - where function was measured against a pre-admission baseline rather than an admission-day assessment. That last point is a measurement artefact with clinical meaning: by the time someone is admitted they have often already lost function to the illness, so an admission-day baseline hides a large part of the decline and makes the discharge comparison look reassuring.

What follows is not a new intervention but a change to the question asked on the ward round. Ask what the patient could do two weeks ago - walk to the shop, manage the stairs, wash unaided - and record it on day one. Without that, nobody can tell whether the person in front of them is improving or has simply stopped deteriorating, and rehabilitation gets planned against the wrong target.

• Record pre-admission function on day one, from the patient or a relative, not admission-day ability
• Name the specific tasks - stairs, shopping, washing, toileting - rather than a global impression
• Flag patients aged 75 to 89 with respiratory infection as the highest-risk group in this analysis
• Mobilise early and deliberately; bed rest is the exposure that produces the outcome
• Set the rehabilitation target against pre-admission function, not against admission function

Why it matters

Whether a hospital appears to cause functional decline depends largely on whether it recorded what the patient could do before admission.

Don't overread it

Pooled observational prevalence with wide heterogeneity; it describes how often disability is recorded, not how much of it hospital care caused.

The statistics, in plain English

The 95% confidence interval of 24% to 31% describes how precisely the average was estimated; the prediction interval of 7% to 48% describes what the next study would likely find, and it is the honest measure of how much these studies disagree. In practice that means 27% is a planning figure for a service, not a risk to quote to a patient. Much of the spread comes from measurement - which instrument, which baseline - rather than from real differences between populations.

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