Variables affecting maximum urethral closure pressure (MUCP) and abdominal leak point pressure (ALPP) measurements.

introduction and hypothesisThe relationship between pelvic floor muscles and measurements of urethral function is not well studied. It is not known whether adjusting for clinical, demographic and urodynamic parameters would improve the association between MUCP and ALPP. Our hypothesis was that pelvic floor muscle strength (PFMS) influences the relationship between MUCP and ALPP.

methodsThis was a retrospective study of women who underwent a complex urodynamic study with evaluation of MUCP and ALPP using ICD-9 codes with documentation of PFMS.

resultsUrodynamic stress incontinence was confirmed in 478 patients, of whom 323 had MUCP recorded and 263 had both MUCP and ALPP recorded. Women with higher PFMS had a higher MUCP. In regression analysis ALPP at 150 mL and MUCP were weakly associated (coefficient 0.43, 95% CI 0.08-0.78; p = 0.02), whereas ALPP at capacity and MUCP were moderately associated (coefficient 0.60, 95% CI 0.25-0.95; p < 0.001).

conclusionsThis study showed that MUCP and ALPP at 150 mL were weakly associated and that this improved to a moderate association for ALPP at capacity. MUCP increased with increasing PFMS among women with stress urinary incontinence and decreased with increasing age. There was no evidence that ALPP was associated with PFMS or age. The relationship between MUCP and ALPP was unchanged when accounting for covariates of PFMS (age, parity, BMI, prior procedure, urethral mobility, bladder capacity, stage of cystocele, or stage of uterine or apical prolapse).