Objectives: Many older men with voiding symptoms do not have bladder outlet obstruction (BOO) but have conditions amenable to medical treatment. If primary care providers could reliably exclude men who have BOO, then they could initiate appropriate evaluation and treatment in a substantial proportion of the remainder. Urine flow rate, although widely used, is insufficiently sensitive to exclude BOO reliably. We investigated whether the decline in flow rate with age could be utilized to improve the utility of flow rate for excluding BOO in symptomatic men, especially when combined with knowledge of the patient's postvoiding residual volume (PVR).
Design: Prospective study using two patient cohorts.
Settings: A Veterans Affairs urology clinic serving community-dwelling and institutionalized healthy older men.
Participants: 111 men with voiding symptoms (mean age 72.4 +/- 9.2 years).
Measurements: Maximum urine flow rate, measured with standard flowmeter, and PVR, measured by catheterization. BOO was determined by multichannel videourodynamic testing.
Results: The sensitivity of flowrate for BOO increased significantly with age (P = .0001) and did not appear to be confounded by comorbid conditions. An algorithm incorporating age, flow rate, and PVR had a sensitivity of 90%, specificity of 43%, and accuracy of 74% in screening for BOO. The algorithm's sensitivity was better than that of flow rate alone (55%); its sensitivity was also similar to a "refer all" strategy (100%) but had improved specificity (41% vs 0%).
Conclusions: Flow rate alone is insufficiently sensitive as a screening test to exclude BOO, but a simple diagnostic algorithm using age, flowrate, and PVR was more sensitive and accurate. This algorithm allows primary care evaluation and initial management of men with voiding symptoms while potentially reducing unnecessary referrals and costs.