The relationship of body mass index to intra-abdominal pressure as measured by multichannel cystometry

Abstract

The aim of the study was to identify the possible relationship between body mass index and intra-abdominal pressure as measured by multichannel cystometry. A retrospective chart review of patients presenting for urodynamic evaluation between January 1995 and March 1996 was carried out. Variables identified included weight, height, intra-abdominal pressure and intravesical pressure as recorded on multi-channel cystometrogram at first sensation in the absence of detrusor activity. Body mass index was defined as weight in kilograms divided by height in square meters. Intra-abdominal pressure was measured intravaginally except in those cases of complete procidentia or severe prolapse, where it was measured transrectally. Adequate data were available on 136 patients. The mean age was 60.6 years (range 30-91); mean body mass index was 27.7 kg/m2 (range 12.7-47.7); and mean intra-abdominal pressure was 27.5 cmH2O (range 9.0-48.0). A strong association between intra-abdominal pressure and body mass index was demonstrated, with a Pearson coefficient correlation value of 0.76 (P<0.0001). Strong correlation was still demonstrated when those patients who had had the intra-abdominal pressure measured transrectally were separated out, thus eliminating any possible confounding factors between measurements of intra-abdominal pressure measured transvaginally versus transrectally. In addition a strong correlation between intravesical pressure and body mass index was also demonstrated, with a Pearson coefficient correlation value of 0.71 (P<0.0001). Of the 136 patients, 65 (47.8%) were ultimately diagnosed as having genuine stress urinary incontinence (GSUI), 35 (25.7%) with GSUI and a low-pressure urethra (maximum urethral closure pressure of less than 20 cmH2O), and 18 (13.2%) with detrusor instability. The remaining 13.2% had severe prolapse. Our data demonstrate a significant correlation between body mass index and intra-abdominal pressure. These findings suggest that obesity may stress the pelvic floor secondary to chronic state of increased pressure, and may represent a mechanism which supports the widely held belief that obesity is a common factor in the development and recurrence of GSUI.

Body weight through adult life and risk of urinary incontinence in middle-aged women: results from a British prospective cohort

“…Across adult life, high BMI may lead to mechanical stress on the urogenital tissues. Noblett et al 36 has found strong correlations between BMI and intra-abdominal pressure and intravesical pressure that suggested obesity may cause a chronic state of increased pressure that stresses the pelvic floor. This supports the theory that BMI acts as an aggravating condition rather than a true risk factor.…”

Sexual function in obese women: impact of lower urinary tract dysfunction

“…6 Although the precise mechanisms behind the association between body weight and stress incontinence remain undecided, abdominal adiposity gives rise to increased intraabdominal pressure 27 and subsequently urethral sphincter closing pressure may be compromised. The increased prevalence and bother of urgency in obese women is not so readily explained and may be associated with hormonal and metabolic factors, increased fluid intake or may be secondary to somatic diseases.…”

Influence of Obesity on Short-term Surgical Outcome of the Transobturator Tape Procedure in Patients with Stress Urinary Incontinence

“…Higher intra-abdominal pressures have been observed in patients with greater BMI, and this may stress the pelvic floor secondary to a chronic state of increased pressure [3]. Increased intra-abdominal pressure elevates pressure at maximum cystometric capacity, and decreases cough pressure transmission from the bladder to the urethra, as well as decreasing VLPP, which may contribute to the development of SUI in obese patients [7].…”

“…Obesity is one of the important risk factors for the development of urinary incontinence with old age, in addition to vaginal delivery, history of gynecological surgery, body mass index, menopausal status, smoking, and coffee and alcohol consumption [1,2]. Some authors have described an increase of intra-ab-dominal pressure in obese patients [3], and this phenomenon may stress the pelvic floor, possibly causing nerve and muscular injury that might lead to a higher prevalence of SUI [4]. Also, increased body mass index (BMI) is known to be associated with urge and mixed urinary incontinence [5].…”