Mortality in men admitted to hospital with acute urinary retention
Authors: Katia M C Verhamme, Miriam C J M Sturkenboom
Journal: BMJ (2007)

Acute urinary retention is the sudden inability to micturate; it is usually painful and requires treatment with a urinary catheter.1 Risk factors are increasing age, especially in men; urological conditions such as benign prostatic hyperplasia, prostate cancer, and urethral stricture; medical conditions such as constipation and diabetes mellitus; bed rest; surgery; and the use of certain drugs.2 Its incidence in the general population has mostly been studied in men, and it varies between 2.2 and 6.8 per 1000 person years. Acute urinary retention is generally treated immediately with a urinary catheter. After the acute period, most men will be offered a trial without catheter, often in combination with α adrenergic blockers. Prostate surgery will be considered if this trial fails.3,4,5,6,7

Few data are available on mortality in patients with acute urinary retention. A retrospective cohort study in this week’s BMJ by Armitage and colleagues is the first to study long term mortality in men admitted to hospital for a first episode of acute urinary retention.8 The study uses data from the hospital episode statistics database and the mortality database of the Office for National Statistics in the United Kingdom. The authors found that mortality was high—one in seven men with spontaneous acute urinary retention (no evidence of precipitating factors other than benign prostatic hyperplasia) and one in four men with precipitated acute urinary retention (all cases that were not spontaneous) died in the first year. The risk of dying increased with age and comorbidity (measured by the Charlson score). In the first year after hospital admission, 16% of men with precipitated acute urinary retention and no comorbidity died compared with 38% of similar men who also had comorbidity.

The study also compared mortality at one year with mortality in the general male population of the UK. Overall, mortality at one year in men admitted to hospital for acute urinary retention was two to three times higher than for the general male population. The highest relative increase in mortality was seen in men aged 45-54 and in those with precipitated acute urinary retention (standardised mortality ratio 10.0 for spontaneous acute urinary retention and 23.6 for the precipitated form).

Benign prostatic hyperplasia has been associated with comorbidities such as diabetes mellitus, hypertension, and the metabolic syndrome.9 Armitage and colleagues’ study is important, not only because it is the first to study mortality after hospital admission for acute urinary retention, but also because it confirms the high prevalence of comorbidities such as cardiovascular disease, diabetes mellitus, and chronic pulmonary disease in people with urinary retention. Because mortality was highest in the presence of comorbid conditions, people presenting with acute urinary retention should be given a urological examination and a multidisciplinary review to identify and treat comorbidity early.

Several questions remain unanswered. Firstly, Armitage and colleagues focused on the effects of comorbidity and did not consider the effects of concomitant drugs. Opioids and drugs with anticholinergic or adrenergic activity increase the risk of acute urinary retention. Thus, the association between comorbidity and acute urinary retention could be partly explained by the use of drugs for the treatment of chronic conditions, such as inhaled anticholinergics for chronic obstructive pulmonary disease and opioids for the relief of chronic severe pain. Secondly, it would be interesting to know whether mortality at one year varies with the type of treatment (trial without catheter versus prostate surgery) and whether the increase in mortality is seen not only in people admitted to hospital but also in those receiving care in the community. Finally, the conclusion that people with acute urinary retention should be screened for comorbidity at the time of admission seems sensible, but prospective studies are needed to measure the effect of this approach on mortality rates.

If mortality really is higher in men admitted to hospital for acute urinary retention, we should try to prevent acute urinary retention in people with benign prostatic hyperplasia. Randomised controlled trials have shown that 5α reductase inhibitors reduce the risk of acute urinary retention, especially in men with severe symptoms, large prostates, and high concentrations of prostate specific antigen. Risk was reduced most in men treated with a 5α reductase inhibitor combined with an α1 adrenergic blocker.10 11 A retrospective cohort study of men with benign prostatic hyperplasia, however, showed that about 50% of those with acute urinary retention presented with urinary retention as the first symptom of their underlying prostatic hyperplasia.12 For these men, pharmacological prevention will be too late.

In conclusion, because the increased mortality seen in men admitted to the hospital for acute urinary retention is probably the result of comorbid conditions and frailty, multidisciplinary care is warranted in these men.