Risk factors for acute urinary retention among community-dwelling men

While acute urinary retention is a serious sequelae of benign prostatic hyperplasia, relatively little is known about the occurrence of and risk factors for acute urinary retention in the community-setting. We use longitudinal followup of the men participating in the Olmsted County Study of Urinary Symptoms and Health Status among Men to determine the incidence of acute urinary retention and the role of lower urinary tract symptoms, depressed peak flow rates and enlarged prostate play in predicting risk. A cohort of 2115 men ages 40 to 79 years was randomly selected from an enumeration of the Olmsted County, Minnesota population (55% response rate). These men completed a previously validated baseline questionnaire that assessed symptom severity and voided into a portable urometer to measure peak urinary flow rates. A one-quarter random subsample underwent transrectal sonographic imaging of the prostate to determine prostate volume. Followup was performed through a retrospective review of community medical records to determine the occurrence of acute urinary retention in the subsequent four years. During the 8,344 person-years of followup, 57 men had a first episode of acute urinary retention (incidence = 6.8/1,000 person-years, 95% confidence interval = 5.2,8.9). Among men with none to mild symptoms (International Prostate Symptom Score (IPSS) of ≤ 7) the incidence of acute urinary retention increased from 2.6/1,000 person-years among men aged 40-49 years to 9.3/1,000 person-years among men aged 70-79 years. Among men with moderate to severe symptoms (IPSS > 7) rates increased from 3.0/1,000 person-years for men aged 40-49 years to 34.7/1,000 person-years among men aged 70-79 years. Men with depressed peak urinary flow rate (<12 ml/sec) were at four times the risk of acute urinary retention compared with men with urinary flow rates >12 ml/sec (95% confidence interval = 2.3, 6.6). Men with an enlarged prostate (30 ml) experienced a three-fold increase in risk (95% confidence interval = 1.0, 9.0). the area under the receiver operator characteristic curve of a risk score based on age, symptom score, and peak flow rate was 0.74. Lower urinary tract symptoms, depressed peak urinary flow rates, and enlarged prostates are all associated with an increased risk of acute urinary retention in community-dwelling men. These findings may help to identify men at increased risk of acute urinary retention in whom closer evaluation may be warranted.