Correlation between Bladder Wall Thickness and Uroflowmetry in West African Patients with Benign Prostatic Enlargement

Abstract

ABSTRACT Background: Pressure flow urodynamic study remains the gold standard for the diagnosis of bladder outlet obstruction; however, their use is limited by their relative unavailability in our environment, cost, and invasiveness. Measurement of bladder wall thickness (BWT) by transabdominal ultrasonography is a promising tool that can be used to diagnose bladder outlet obstruction in our environment where pressure-flow urodynamic study is not readily available. Objective: The study aimed to correlate BWT with uroflowmetry and to establish a BWT cut-off in patients with lower urinary tract symptoms (LUTS) due to benign prostatic enlargement. Materials and Methods: This was a prospective one-year study of patients with LUTS due to benign prostatic enlargement. The patients were divided into obstructed and non-obstructed groups with Q- max of 10 ml/s serving as the cut-off value. Receiver Operator Curve (ROC) was used to evaluate the performance of BWT in diagnosing BOO. Statistical significance was set at P < 0.05. Results: The mean BWT and Q-max were 4.53 ± 2.70 mm and 15.06 ± 9.43 ml/s. There was a negative correlation between BWT and Q-max (r = -0.452, P = 0.000), Q-average (r = -0.336, P = 0.000), and voided volume (r = -0.228, P = 0.046). A BWT cut-off of 5.85 mm was found to be the best threshold to differentiate obstructed from non-obstructed patients with a sensitivity and specificity of 70 and 88.2 percent respectively. Conclusion: Bladder wall thickness showed an inverse relationship with maximum flow rate with high sensitivity and specificity. This non-invasive test can be used as a screening tool for BOO in our setting, where the pressure flow urodynamic study is not readily available.