Correlation between bladder wall thickness and uroflowmetry in West African patients with benign prostatic enlargement.

Abstract

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. 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. 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. 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. 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.