Nonintubated uroflowmetry as a predictor of normal pressure flow study in women with stress urinary incontinence

Objectives. To determine whether a normal nonintubated uroflowmetry test (NIF) is predictive of a normal pressure flow study (PFS) in women with stress urinary incontinence. Methods. Women evaluated with multichannel urodynamics from December 1998 to October 2002 who had urodynamic stress urinary incontinence, an NIF with voided volume of at least 150 mL, no more than grade 2 cystocele, and a PFS were included (n = 92). Voiding parameters obtained in the NIF performed without catheterization were compared with those obtained after catheterization and mechanical bladder filling. The sensitivity, specificity, positive predictive value, and negative predictive value of using a normal NIF to predict a normal PFS were calculated. Results. No statistically significant differences were found in the mean volume voided and postvoid residual volume between the NIF obtained spontaneously and the NIF obtained after mechanical bladder filling. The mean maximal urinary flow rate, however, was greater in the spontaneous NIF group than in the mechanical fill group (23. 9 mL/s versus 19.6 mL/s, P = 0.041). A strictly defined normal NIF resulted in a normal PFS in 57.7% of cases in women who had no history of urethral or bladder surgery and in 42.9% of women who had such a prior surgical history. Conclusions. The low positive predictive value for both groups of women suggests that a normal NIF cannot exclude an abnormal PFS in this patient population. NIF and PFS should, therefore, be interpreted with caution and should always be compared with one another when assessing voiding dynamics in women with stress urinary incontinence.