Acute urinary retention (AUR) is a severe complication of benign prostatic hyperplasia (BPH). Several studies have found associations with major morbidity and propose that AUR may be a harbinger of severe systemic disease.

A study in the BMJ has now shown that patients with AUR have an increased mortality rate.

This retrospective cohort study used data from the hospital episode statistics database and the mortality database of the Office for National Statistics. All men aged over 45 years who were admitted to NHS hospitals in England for a first episode of AUR during the seven-year study period were included, a total of 176,046 men. Episodes of AUR were categorised as spontaneous or precipitated (eg postoperative).

In the spontaneous AUR group, overall one-year mortality was 14.7%, increasing with age, with a rate of 32.8% in patients aged 85 and over. In precipitated AUR, overall mortality was 25.3%, and 45.4% in patients aged 85 and over. However, compared with the general population, the highest relative increase in mortality was in patients aged 45-54 (standardised mortality ratio 10.0 for spontaneous and 23.6 for precipitated AUR) and lowest in patients aged 85 and over (1.7 and 2.4 respectively).

The comparable mortality rates for patients with AUR treated in the community are not known, but one would suspect them to be significantly lower, as these patients are likely to have less comorbidity. Furthermore, it is unclear whether preventing episodes of AUR by treating lower urinary tract symptoms with 5-alpha-reductase inhibitors, which are known to reduce the risk of AUR in those with large prostates, will make any difference to these mortality rates.

However, given that AUR represents the first symptom of BPH in many cases, it is going to be difficult to make a substantial impact on AUR rates in primary care.

It is reasonable to conclude, however, that AUR is a useful warning sign of possible comorbidity and patients with this condition should have a review of their general health.

Prevention of AUR with appropriate use of 5-alpha-reductase inhibitors and improving patients' awareness of treatments available for lower urinary tract symptoms are important areas on which GPs can focus.

Armitage JN, Sibanda N, Cathcart PJ et al. Mortality in men admitted to hospital with acute urinary retention: database analysis. BMJ 2007 doi: 10.1136/bmj.39377.617269.55