Design: Prospective multicentre diagnostic accuracy study with independent validation
Population: 601 men with LUTS in 67 UK general practices
Primary outcome: Urodynamic diagnosis of obstruction, underactive or overactive bladder
Effect: C index: obstruction 0.82, underactivity 0.63, overactivity 0.62 (validation)

A diagnostic accuracy study in the BJGP (1 October) recruited 601 men with lower urinary tract symptoms (LUTS) from 67 general practices in England and Wales. Each had a symptom score, a bladder diary, examination, PSA, a urine flow rate and a post-void residual volume, and then invasive urodynamics as the reference standard.

A model combining the simple tests identified bladder outlet obstruction well, with a C index of 0.80 in development and 0.82 in an independent validation cohort. Models for an underactive bladder (0.63) and an overactive bladder (0.62) performed only moderately.

This supports doing more of the work-up in primary care — enough to start treatment for likely obstruction with confidence, and to recognise when symptoms point elsewhere. Flow meters and bladder scanners are not in every practice, so access to these tests decides how far it applies.

Combine a symptom score, a three-day bladder diary, examination and PSA as a starting work-up
Add flow rate and residual volume where available; together they predict obstruction well
Be less confident about overactive or underactive bladder from simple tests alone
Refer when symptoms do not fit, or when first-line treatment fails

Why it matters

Most men with urinary symptoms can be assessed and started on treatment without waiting for a urology clinic.

The statistics, in plain English

A C index of 0.80 means the model ranks a man with obstruction above one without it 80% of the time; 0.62 is only modestly better than chance. Holding up in a separate validation cohort makes the obstruction model more trustworthy.