Investigator bias in urodynamic studies for functional urinary incontinence

In the setting of the European Bladder Dysfunction Study, a multicenter, randomized, controlled trial of treatment options for functional incontinence in children, we assessed the concordance between reported and reviewed urodynamic scores.

A total of 97 children with clinically diagnosed urge syndrome and 105 with clinically diagnosed dysfunctional voiding enrolled in the European Bladder Dysfunction Study and underwent full urodynamic studies before and immediately after treatment for urinary incontinence. Photocopies of 72% of the original urodynamic recordings were available for blinded review.

The concordance for detrusor overactivity throughout the filling phase was 37% in urge syndrome cases and for increased pelvic floor activity during voiding it was 81% in dysfunctional voiding cases. Differences in original and reviewed scores were equally distributed among participating centers.

Concordance between original and reviewed urodynamic scores was low for detrusor overactivity. Concordance was acceptable for increased pelvic floor activity during voiding but was not specific for dysfunctional voiding. Since interpreting urodynamic studies is based on pattern recognition, investigator bias can only be compensated for by blinded review of the actual recordings.