Detrusor wall thickness as a test for detrusor overactivity in women

The measurement of detrusor wall thickness has been used as a screening test for detrusor overactivity and bladder outlet obstruction in men and women. The aim of this study was to determine, using receiver-operating characteristics (ROC) analysis, the diagnostic value of detrusor wall thickness in predicting detrusor overactivity in women.

The records of 686 women who attended a tertiary urodynamics service from November 2002 to January 2006 were retrospectively reviewed. The patients had undergone an interview, clinical examination, multichannel urodynamic studies and translabial ultrasound examination. Detrusor wall thickness measurements were taken at the bladder dome, after bladder emptying. ROC analysis was used to identify the optimal cut-off of detrusor wall thickness in predicting detrusor overactivity.

Average detrusor wall thickness in the detrusor overactivity group was 4.7 +/- 1.9 mm (mean +/- SD), compared to 4.1 +/- 1.6 mm in the non-detrusor overactivity group (P < 0.001). Using a cut-off of detrusor wall thickness of 5.0 mm gave a sensitivity of 37% and a specificity of 79% for diagnosing detrusor overactivity. The ROC analysis revealed an area under the curve (AUC) of 0.606 (95% CI, 0.56-0.65).

There is a statistically significant association between detrusor wall thickness and detrusor overactivity (P < 0.001). However, ROC analysis demonstrated that detrusor wall thickness as measured by translabial ultrasound is of little use as a diagnostic test for detrusor overactivity, giving an AUC of only 0.606. Measurement of detrusor wall thickness should therefore not be used as a diagnostic parameter for detrusor overactivity in women.