Validity of cuff-uroflow as a diagnostic technique for bladder outlet obstruction in males

OBJECTIVE: To investigate the validity of the cuff-uroflow method as a diagnostic technique for bladder outlet obstruction (BOO) in males. MATERIAL AND METHODS: A cross-sectional study was carried out on a consecutive series of 93 males (mean age 54.1 years) referred on presenting with lower urinary tract symptoms. The patients were subjected to measurement of the isovolumetric pressure (Pcuff.op) and its corresponding flow (Qcuff.op) by means of the cuff-uroflow method. Subsequently, a study was carried out of the conventional pressure-flow, calculating the degree of BOO according to the provisional International Continence Society (ICS) nomogram. RESULTS: There was a statistical relationship between the Pcuff.op and Qcuff.op values and the degree of BOO according to the provisional ICS nomogram: patients with BOO had a lower value of Qcuff.op and a higher value of Pcuff.op than those without BOO. Using a logistic regression model a nomogram was constructed to link Pcuff.op with Qcuff.op. This nomogram was divided into three areas (obstructed, indeterminate and not obstructed). Most patients (44.1% of the sample) were situated in the indeterminate area. If those patients were excluded, the nomogram gave a sensitivity for the diagnosis of obstruction of 100% and a specificity of 55.6%. The overall rate of correct diagnosis was 84.6%. CONCLUSIONS: The parameters obtained using the cuff-uroflow method were related to the presence of BOO. According to the provisional ICS nomogram, this method showed a better sensitivity than specificity for the diagnosis of BOO.