Evaluation of a noninvasive uroflowmetry parameter (Delta Q value) in detrusor underactivity and bladder outlet obstruction

Abstract

Purpose To determine the significance of the Delta Q value in discrimination between detrusor underactivity (DU) and bladder outlet obstruction (BOO) in adult male patients. Methods A total of 238 patients in this cohort study underwent pressure-flow study. Patients were divided into two groups based on UDS outcomes: DU (n = 121) and BOO (n = 117). From uroflowmetry, 5 variables including maximal flow rate (Qmax), average flow rate (Qave), voiding volume (VV), postvoid residual urine (PVR), and the difference between (Qmax) and (Qave) known as (Delta Q) were obtained. Diagnostic prediction of these variables was evaluated with DU and BOO. Results Delta Q was less in the DU group compared with the BOO group 2.9 ml/s and 6.2 ml/s, respectively. Delta Q showed a promising diagnostic value in the discrimination between DU and BOO. A cut-off value of 6.1 ml/s was found to be discriminatory between the two groups with a sensitivity of 96.58% and specificity of 92.79%. Conclusion Delta Q value has proven to be a useful noninvasive screening and diagnostic tool in differentiating between DU and BOO in men with obstructive lower urinary tract symptoms.