Our objective was to determine the effect of cough strength on pressure transmission ratios and establish quantitative and qualitative intra-observer test-retest reproducibility of pressure transmission ratios calculated from dynamic urethral pressure profilometry. The study included 242 consecutive urodynamic evaluations on women without pelvic organ prolapse. Dynamic urethral pressure profiles were performed in duplicate with coughs of different intensities. The analysis included pressure transmission ratios from the proximal 3 urethral quartiles (Q1 through Q3) and the mean pressure transmission ratio calculated from these quartiles. The final diagnoses were stratified into genuine stress incontinence, 135 (56%), and stress continence, 107 (44%).
Correlations were strong for pressure transmission ratios from the first versus the second dynamic urethral pressure profile (K ס 0.712 for mean). While the variation in cough intensity between hard and soft coughs averaged 30 cm H 2 O (P < 0.001), correlation's were equally strong between hard and soft cough pressure transmission ratios (K ס 0.712 for mean). When mean pressure transmission ratios were stratified into below 90% and at least 90% categories, 83.5% of subjects had test-retest concordance (K ס 0.671). Concordance rates were less for stress continent subjects (80.0%; K ס 0.527) than for genuine stress incontinence subjects (86.4%; K ס 0.679).
Pressure transmission ratios appear to have reasonable quantitative and qualitative reproducibility which is unaffected by cough strength. The degree of individual variability limits the utility of pressure transmission ratios to diagnose genuine stress incontinence independent of other, equally variable clinical and urodynamic parameters, but this measure is sufficiently reproducible to be useful in characterizing stress sphincteric function in population studies.