Urodynamic classification of patients with symptoms of overactive bladder

Purpose: We describe a new classification of patients with overactive bladder symptoms. Materials and Methods: The office records of 132 patients who presented for evaluation of symptoms of urinary frequency, urinary urgency and/or urge incontinence, and who underwent videourodynamics were identified. All patients completed a 24-hour voiding diary and 24-hour pad test. Data collection included age, sex, hormone status, number of voids and incontinence episodes per 24 hours, functional bladder capacity, pad weight and associated genitourinary conditions. Videourodynamics were reviewed and patients were divided into 4 clinical categories, including type 1-no evidence of involuntary detrusor contractions on videourodynamics, type 2-involuntary detrusor contractions present, and patient aware and able to abort them, type 3-contractions present, patient aware and able to contract the sphincter but not abort contractions and type 4-contractions present and patient unaware but unable to contract the sphincter or abort contractions. Results: Average patient age +/- SD was 64 years +/- 13. There were an average of 13 +/- 5 voids and 3 +/- 5 incontinence episodes per 24 hours. Average functional bladder capacity was 306 +/- 146 cc and average pad weight was 94 +/- 165 gm. Associated diagnoses included benign prostatic hypertrophy in 28% of cases, sphincteric incontinence in 17%, idiopathic urge incontinence in 29% and uterovaginal or bladder prolapse in 17%. Another 11% of patients had bladder outlet obstruction, impaired detrusor contractility or neurogenic bladder conditions. Of the cases 72 (55%), 32 (25%), 23 (17%) and 5 (4%) were categorized as classes 1 to 4, respectively. ANOVA revealed no statistically significant differences in the number of voids or incontinence episodes, functional bladder capacity or pad test when individual categories were compared to each other. Conclusions: This overactive bladder classification stratifies patients according to degrees of awareness, and control of bladder and sphincter function. It may prove useful as a guide for prognosis and therapy. Patients can be stratified into clinical groups based on the presence or absence of involuntary detrusor contractions, the ability to abort contractions and the ability to contract the urinary sphincter in response to contractions. Limiting the definition of overactive bladder to apply only to patients with no proved infection or other pathological condition would have eliminated more than 75% of those in this sample with symptoms of urinary urgency, frequency and/or urge incontinence.