Pelvic-floor strength in women with incontinence as assessed by the Brink scale.

The pelvic-floor muscles (PFMs) are considered important in maintaining pelvic organ support and bowel and bladder continence. Several studies with small numbers of subjects have shown that women with urinary incontinence have decreased PFM thickness, (1,2) decreased PFM electromyographic activity, (3) and less muscle strength (4,5) (force-generating capacity) compared with control subjects without urinary incontinence. Women with fecal incontinence also demonstrate decreased PFM strength compared with controls. (6) Denervation, weakening, and thinning of the PFMs are thought to occur as a consequence of normal aging and to be amplified or accelerated by neuromuscular damage that occurs during vaginal childbirth. (7-10) In line with these observations, PFM strengthening is standard therapy for both urinary and fecal incontinence. (11,12)

Clinical assessment of PFM strength is by transvaginal or transrectal digital palpation of the PFMs during contraction, and PFM strength is scored according to several validated methods, (13) none of which is generally accepted as the gold standard. Although studies with small numbers of subjects (1-6) suggest that PFM strength is altered in women with urinary and fecal incontinence, the association of PFM strength and pelvic symptoms has not been well studied using validated measures in a large sample of women. The purpose of this article is to describe the relationship among patient characteristics, symptoms, and a clinical measure of PFM strength in a large cohort of women whose pelvic strength and symptoms were well characterized using validated clinical instruments.

Method

The Urinary Incontinence Treatment Network is a collaborative research group comprising 9 clinical sites and 1 biostatistical coordinating center with sponsorship from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and the National Institute of Child Health and Human Development (NICHD). The Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr) study is an ongoing randomized surgical trial comparing the modified Tanagho Burch procedure with the autologous rectus fascial sling procedure for the treatment of stress urinary incontinence (SUI). The primary aim of the SISTEr study is to compare the efficacy of these procedures 2 years after surgery. A detailed description of the SISTEr study, including study design, has been published previously. (14) In brief, the SISTEr study included female patients who had pure or predominant SUI symptoms, who were clinically eligible for both procedures, and who had a positive standing cough stress test at a bladder volume of 300 mL. Patients were recruited from the clinical practices of the participating urologic and urogynecologic centers as well as in response to public advertising at some centers. Patients were excluded if they had predominant urge incontinence symptoms, a history of a medical disorder known to affect bladder function, or a history of pelvic irradiation. Written informed consent was obtained from all study participants.

Subjects

A total of 655 women were enrolled in the SISTEr study. We present data for the 643 women with complete baseline Brink scale scores. Of these women, 197 (31%) reported that they had undergone a prior hysterectomy, and 92 women (14%) reported that they had undergone prior incontinence surgery. Table 1 describes the sample by ethnicity, stage of pelvic organ prolapse, genital hiatus size, and Brink scale scores.

Procedure

The data for this analysis were obtained from information collected during the baseline clinical assessment, which contained clinical information related to the pelvic floor, sociodemographic information, and general medical history. Patient demographic variables included self-reported age, race, parity, prior history of incontinence surgery, and hysterectomy status. The baseline symptom questionnaires included the Medical, Epidemiological, and Social Aspects of Aging (MESA) urinary incontinence questionnaire, (15) which records the frequency with which different stress and urge incontinence symptoms occur. The MESA items ask about how urine loss occurs in the patient's activities of daily living. Stress urinary incontinence is defined by positive responses to questions about loss of urine at times of exertion, such as laughing, sneezing, lifting, or bending. Urge incontinence is defined by positive responses to questions about urine loss preceded by an urge to void, or uncontrollable voiding with little or no warning. Mixed incontinence is defined by positive responses to both urge incontinence and stress incontinence subscale items. Validity of the MESA questionnaire as a screen for urinary incontinence type has been established previously, with 87% agreement between the MESA questions and a clinician's assessment. (15) In order to calculate the MESA score, each of the stress incontinence and urge incontinence subscale items was scored as described elsewhere, (15) and the scores were summed to give stress incontinence and urge incontinence subscale scores.

The Urogenital Distress Inventory (UDI), with its stress symptoms, irritative symptoms, and obstructive symptoms subscales, (16) also was included at baseline. The UDI contains 19 questions about lower urinary tract symptoms and the degree to which they are bothersome. The UDI has been shown to be valid, reliable, and responsive in a community-dwelling population of women with incontinence. (16) The stress symptoms subscale describes bother with symptoms of SUI. The irritative symptoms subscale describes bother with urinary urgency, frequency, and urge incontinence. The obstructive symptoms subscale describes bother related to bladder emptying and symptoms of pelvic heaviness or discomfort.

We also determined whether women experienced fecal incontinence by asking them "Do you have leaking or loss of control of gas?" (and, if so, how often?) and similar questions concerning lost control of liquid and solid stool. Subjects underwent urodynamic testing in the standing position, with urodynamic diagnoses made according to International Continence Society definitions. 17 Subjects completed a urinary diary for 1 week (recording number and type of incontinence episodes) and completed a standardized pad test. Pelvic organ support was assessed using the Pelvic Organ Prolapse Quantification (POP-Q) system. (18)

Pelvic-floor muscle strength was determined through transvaginal digital palpation during the performance of a voluntary PFM contraction and rated using the Brink scoring system, (19) which has been reported to yield scores with reasonable interrater reliability, test-retest reliability, and validity. (19) Pelvic-floor muscle strength was assessed with each subject in the dorsal lithotomy position, while the tester placed 1 or 2 lubricated fingers 4 to 6 cm into the subject's vagina with the palm facing down. The subject was instructed that the tester would be counting to 3 and would then ask her to "squeeze your pelvic muscles, the ones that you use to stop your urine stream, as strong as you can. I want you to hold the contraction for as long as possible or until I tell you to stop. As you do this, I want you to try to avoid contracting your tummy, bottom, or thigh muscles." Once the subject demonstrated the ability to contract her PFMs, formal assessment took place. The expected co-contraction of the abdominal wall and PFMs was permitted.

The Brink scale evaluates 3 PFM contraction variables: vaginal pressure or muscle force, elevation or vertical displacement of the examiner's fingers, and duration of contraction. Each muscle contraction variable is rated on a 4-point ordinal scale. The pressure felt by examining fingers is rated 1 ("no response"), 2 ("weak squeeze"), 3 ("moderate squeeze"), or 4 ("strong squeeze"). The vertical displacement is rated 1 ("none"), 2 ("finger base moves anteriorly"), 3 ("whole length of fingers move anteriorly"), or 4 ("whole fingers move anteriorly, are gripped and pulled in"). Duration of contraction (in seconds) is timed and scored 1 ("none"), 2 ("<1 second"), 3 ("1-3 seconds"), or 4 (">3 seconds"). Ratings are summed to obtain total scores, with a possible range of scores of 3 to 12.

The PFM strength testers were certified in the assessment using the Brink scale by the principal investigator at each site. All testers were either physicians or registered nurses, and several testers were certified at each clinical site.

Data Analysis

A priori, we predicted that PFM strength would be related to subject characteristics (including age, race, parity, hysterectomy status, and history of prior surgery for urinary incontinence) and to subject symptoms of urinary and fecal incontinence. After descriptive statistics were tabulated for all variables, bivariate analysis of factors associated with the Brink scale score was done using analysis of variance with categorical variables and simple linear regression with continuous measures, with results considered significant at the .05 level. For inclusion in the multivariate analysis, we selected subject variables that were statistically significant on bivariate analysis and that could reasonably be thought to predict PFM strength. Subjects' symptoms that were likely to be a result of altered PFM strength, rather than a cause of altered PFM strength, were not included in the multivariate analysis.

Results

The sample's mean Brink scale total score was 9 (SD=2). The relatively small variation in Brink scale scores arose because there was relatively little variation in clinical findings as described by the Brink scoring system. For example, 84% of the subjects had a rating of 3 on the duration of their PFM contraction, 75% of the subjects had a rating of either 2 or 3 on the pressure assessment, and 70% of the subjects had a rating of 2 or 3 on displacement in the vertical plane. Classifying the women in quartiles of their Brink scale score, 33 women were in the lowest quartile and 285 women were in the highest quartile. Incontinence of flatus was present more than once a month in 313 (49%) of the women. Incontinence of liquid stool occurred more than once a month in 85 women (13%), and incontinence of solid stool was present more than once a month in 37 women (6%).

Table 2 details descriptive statistics for continuous measures. In summary, the women had a mean age of 51.9 years (SD=10.3) and had a mean of 2.6 (SD=1.6) vaginal deliveries. As expected in this sample of women who were incontinent with stress-predominant symptoms, MESA stress incontinence subscale scores were higher than the urge incontinence subscale scores. A higher degree of distress associated with stress compared with overactive bladder syndrome symptoms also was reflected in the UDI subscale scores.

Table 3 lists the results of the bivariate analyses. Age, number of vaginal deliveries, ethnicity, and history of hysterectomy all showed a statistically strong association with Brink scale total score. For example, Brink scale scores were inversely related to age (P<.0001). Those subjects with Brink scale scores in the lowest quartile had a mean age of 54.77 (SD=11.61) years, and those subjects with scores in the highest quartile had a mean age of 50.36 (SD=9.99) years. Similarly, Brink scale scores decreased with an increasing number of vaginal deliveries (P=.01). Brink scale scores were lowest for women of "other" racial and ethnic groups, which include those who reported multiple categories, and highest for non-Hispanic black women (P=.04). Women with prior hysterectomy had lower Brink scale scores (P=.004). The association between prolapse stage and Brink scale scores approached but did not reach statistical significance, probably because there were too few women with advanced pelvic organ prolapse in this study cohort. No significant associations were found between Brink scale scores and SUI severity measures of pad test weight and number of urinary diary daily leakage episodes.

There was an association between higher UDI and MESA total scores and lower Brink scale scores (P=.02 and P=.02, respectively). For example, among the 33 subjects with Brink scale scores in the lowest quartile, the mean UDI total score was 173 (SD=63), whereas among the 285 subjects with Brink scale scores in the highest quartile, the mean UDI total score was 150 (SD=51). This relationship between UDI and Brink scale scores was primarily due to the presence of a relationship between Brink scale scores and the UDI irritative symptoms subscale scores. Similarly, the MESA urge continence subscale scores were inversely related to Brink scale scores (P=.004).

The presence of incontinence of flatus (P=.01) or liquid stool (P=.001) was related to lower Brink scale scores. Incontinence of flatus at least once a month was present in 19 (58%) of the subjects with Brink scale scores in the lowest quartile and in 133 (47%) of the subjects with Brink scale scores in the highest quartile. Similarly, incontinence of liquid stool at least monthly was present in 9 (27%) and 37 (13%) of those subjects with low quartile and high quartile Brink scale scores, respectively. Finally, although incontinence of solid stool was seldom reported and thus we could find no statistical relationship, it was present at least monthly in 5 (15%) of the subjects with Brink scale scores in the lowest quartile and in 13 (5%) of the subjects with Brink scale scores in the highest quartile.

As detailed in Table 4, multivariate analysis confirmed age (P<.O01) as a subject characteristic that significantly predicted Brink scale score after correcting for other factors, but the model explained only 7% of the variability seen and did not add to our understanding of factors influencing Brink scale score.

Discussion

Perhaps the most important aspect of our analysis is the simple finding that, in general, women undergoing surgical treatment for SUI had relatively good PFM function, as assessed by the Brink scale. Only a minority of patients had very low Brink scale scores. Until the results of the SISTEr study are available, we will not know whether PFM strength relates to eventual surgical success.

Although our large sample size allowed us to discern several statistically important relationships, it is clear from Tables 2 and 3 that the variation in absolute Brink scale scores was very small. We were able to support the findings of Rizk et al, (20) who demonstrated racial differences in PFM morphology in women who were nulliparous and healthy, and our findings also confirmed the results of prior studies that suggested there is weakening and thinning of the PFMs with aging. (11,21)

We found no relationship between PFM strength and the number of vaginal deliveries after controlling for age and other factors. The relationship between PFM strength and vaginal parity has been examined previously with mixed results. Electromyographic evidence of denervation at the time of vaginal delivery has been found, with longer second stage of labor and larger birth weight associated with more evidence of denervation. (7) One study of postpartum Brink scale scores in a small number of primigravidas (22) showed that PFM strength was highest in women who delivered by Cesarean section and was incrementally lower in women with vaginal delivery without episiotomy, followed by vaginal delivery with episiotomy and vaginal delivery with laceration. Another study (2) also showed a reduction in PFM strength 3 to 8 days postpartum and lower scores in women who were multiparous than in women who were primiparous. However, follow-up testing 6 to 10 weeks postpartum showed resolution of function to antepartum levels. Conversely, a study using the Oxford Digital Rating Scale (23) did not show differences in PFM strength between women who were nulliparous and women who were parous.

The UDI obstructive symptoms subscale measures symptoms related to lower abdominal pressure or pain, heaviness or dullness in the pelvic area, dysuria, or the need to push on the vaginal walls to have a bowel movement. Our finding of a weak relationship between decreased PFM strength and those symptoms is pathophysiologically reasonable, as many women with a weakened pelvic floor may have a widened genital hiatus and feel pelvic pressure. Again, because this relationship is weak and the multivariate model was able to explain only 7% of the variability in Brink scale scores, we are anxious not to overinterpret this finding.

In the present study, all women had stress incontinence, yet we did not find the expected negative relationship between PFM strength and measures of SUI severity, including Valsalva leak point pressure, pad test weight, and number of incontinence episodes recorded in the urinary diary. Our lack of ability to show this relationship may have been due to the relative homogeneity of the study sample, with a relatively small range of Brink scale scores and lack of a continent control group. However, other studies investigating the relationship between PFM strength and urinary symptoms are divided in their results. Some studies have shown differences in PFM strength measured by digital palpation between women with and without incontinence. (22) Other studies have not found associations between subjects' perception of urine loss and PFM strength determined by vaginal digital palpation or the Oxford Digital Rating Scale. (24)

Several factors may have interfered with the ability to show stronger associations between Brink scale scores and these demographic and clinical variables. Although the Brink method of muscle testing has been found to be a fairly reliable clinical measure, (19,25) like other current measures of PFM strength, it cannot fully characterize PFM function. It does provide the clinician with a crude measure of a woman's ability to contract her PFMs over a brief time period, but it does not determine whether the woman's muscle function is adequate to fulfill its role in maintaining continence. The sphincteric and supportive roles of the PFMs require that they have good endurance and the ability to contract with adequate force and sufficient timing to anticipate increases in intra-abdominal pressure. Additionally, to prevent urine leakage during a functional task, such as standing from a sitting position, adequate recruitment of the PFMs must be coordinated with that of other muscles needed for that specific task.

It is probably unrealistic to expect that a simple digital measure of PFM strength could strongly predict whether these motor control and coordination demands can be met to prevent stress incontinence or urge incontinence when encountered during a functional task. The finding that this sample of women with incontinence had fairly good PFM strength, as defined by a mean Brink scale score of 9 out of a possible 12 points, provides support for the notion that adequate muscle function depends on several factors, including the ability to perform a muscle contraction under a variety of environmental circumstances. For example, a woman may have good PFM strength but lack the skill to activate her muscles under certain situations, such as during a sneeze as she runs to her car in the rain while carrying her child. Support for this notion is provided by the finding of Devreese and colleagues (26) that women who were continent had significantly better coordination between the PFMs and the lower abdominal muscles during coughing compared with women who were incontinent.

Another variable that limits the functional generalizability of digital strength test results is the test condition itself. Both tactile and verbal examiner feedback is provided to the patient during the assessment. This feedback has the potential to enhance the patient's ability to understand the task and thus contract her muscles. In real life, without feedback and instruction, the woman's ability to use her PFMs to prevent a stress incontinence or urge incontinence episode may be more limited.

The fact that the Brink scale scores of women in our sample fell within a narrow range also may have limited our ability to find stronger associations between PFM strength and symptoms of pelvic dysfunction. To further explore these relationships, additional studies may need to include women with a broader range of PFM strength and with a greater diversity of clinical symptoms. Other strength rating systems also may better reflect the diversity of clinical findings and allow more sophisticated exploration of this interesting relationship.

Conclusion

Our analysis confirms that PFM strength is related to patient age but also raises questions about the ability of the Brink scale to describe clinically obvious differences in PFM function.

Dr FitzGerald, Dr Schaffer, Dr Kraus, and Dr Mallett provided concept/idea/research design. Dr FitzGerald, Dr Burgio, Dr Borello-France, Dr Menefee, Dr Kraus, and Dr Mallett provided writing. Dr FitzGerald and Dr Schaffer provided data collection. Dr Kraus and Ms Xu provided data analysis. Dr FitzGerald provided project management. Dr FitzGerald, Dr Kraus, and Dr Mallett provided subjects. Dr Kraus provided facilities/ equipment. Dr FitzGerald, Dr Borello-France, and Dr Kraus provided consultation (including review of manuscript before submission).

The institutional review boards at all participating clinical centers approved the study.

This work was presented orally at the 26th Annual Scientific Meeting of the American Urogynecologic Society; September 15-17, 2005; Atlanta, Ga. An abstract of this research was published in Journal of Pelvic Surgery (2005;11[suppl 1]:15).

This article was submitted March 6, 2006, and was accepted May 21, 2007.

DOI: 10.2522/ptj.20060073

References

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(2) Hoyte L, Jakab M, Warfield S, et al. Levator ani thickness variations in symptomatic and asymptomatic women using magnetic resonance-based 3-dimensional color mapping. Am J Obstet Gynecol. 2004;191: 856-861.

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(10) DeLancey JO, Kearney R, Chou Q, et al. The appearance of levator ani muscle abnormalities in magnetic resonance images after vaginal delivery. Obstet Gynecol. 2003;101:46-53.

(11) Henalla S, Kirwan P, Castleden C, et al. The effect of pelvic floor exercises in the treatment of genuine urinary stress incontinence in women at two hospitals. Br J Obstet Gynaecol. 1988;95:602-606.

(12) Kegel A. Progressive resistance exercise in the functional restoration of the perineal muscles. Am J Obstet Gynecol. 1948;56: 238-248.

(13) Bo K, Sherburn M. Evaluation of female pelvic floor muscle function and strength. Phys Ther. 2005;85:269-282.

(14) The Urinary Incontinence Treatment Network. Design of the Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr). Urology. 2005;66:1213-1217.

(15) Herzog AR, Diokno AC, Brown MB. Two-year incidence, remission, and change patterns of urinary incontinence in noninstitutionalized older adults. J Gerontol. 1990;45:M67-M74.

(16) Shumaker S, Wyman J, Uebersax J, et al. Health-related quality of life measures for women with urinary incontinence: the Incontinence Impact Questionnaire and the Urogenital Distress Inventory. Qual Life Res. 1994;3:291-306.

(17) Abrams P, Cardozo L, Fall M, et al; Standardisation Sub-committee of the International Continence Society. The standardisation of terminology of lower urinary tract function: report from the Standardisation Sub-committee of the International Continence Society. Neurourol Urodyn. 2002;21:167-178.

(18) Bump RC, Mattiasson A, Bo K, et al. The standardization of terminology of female pelvic organ prolapse and pelvic floor dysfunction. Am J Obstet Gynecol. 1996; 175:10-17.

(19) Brink C, Wells T, Samplselle C, et al. A digital test for pelvic muscle strength in women with urinary incontinence. Nurs Res. 1994;43:352-356.

(20) Rizk D, Czechowski J, Ekelund L. Dynamic assessment of pelvic floor and bony pelvis morphologic condition with the use of magnetic resonance imaging in a multiethnic, nulliparous, and healthy female population. Am J Obstet Gynecol. 2004; 191:83-89.

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(24) Sartore A, Pregazzi R, Bortoli P, et al. Assessment of pelvic floor muscle function after delivery: clinical value of different tests. J Reprod Med. 2003;48:171-174.

(25) Hundley A, Wu J, Visco A. A comparison of perineometer to Brink score for assessment of pelvic floor muscle strength. Am J Obstet Gynecol. 2005;192:1583-1591.

(26) Devreese A, Staes F, De Weerdt W, et al. Clinical evaluation of pelvic floor muscle function in continent and incontinent women. Neurourol Urodyn. 2004;23: 190-197.

Mary P FitzGerald, Kathryn L Burgio, Diane F Borello-France, Shawn A Menefee, Joseph Schaffer, Stephen Kraus, Veronica T Mallett, Yan Xu; for the Urinary Incontinence Treatment Network

MP FitzGerald, MD, is Associate Professor, Division of Female Pelvic Medicine and Reconstructive Pelvic Surgery, Loyola University Medical Center, 2160 S First Ave, Bldg 103, Room 1004, Maywood, IL 60153 (USA). Address all correspondence to Dr FitzGerald at: [e-mail].

KL Burgio, MD, is Professor of Medicine, Division of Gerontology, Geriatrics, and Palliative Care, University of Alabama at Birmingham, Birmingham, Ala, and Associate Director for Research, Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs, Birmingham, Ala.

DF Borello-France, PT, PhD, is Associate Professor, Department of Physical Therapy, Duquesne University, Pittsburgh, Pa.

SA Menefee, MD, is Associate Clinical Professor, Department of Reproductive Medicine, University of California-San Diego, San Diego, Calif, and Director, Division of Female Pelvic Medicine & Reconstructive Surgery, Kaiser Permanente, San Diego, Calif.

J Schaffer, MD, is Professor, Chief of Gynecology and Urogynecology, Department of Obstetrics/ Gynecology, University of Texas Southwestern Medical Center, Dallas, Tex.

S Kraus, MD, is Assistant Professor, Department of Surgery, Division of Urology, and Head, Section of Female Urology, Neuro-Urology and Voiding Dysfunction, University of Texas Health Services Center at San Antonio, San Antonio, Tex.

VT Mallett, MD, is Professor and Chair, Department of Obstetrics and Gynecology, University of Tennessee Health Science Center, Memphis, Tenn.

Y Xu, MS, is Statistician, New England Research Institute, Watertown, Mass.

The Urinary Incontinence Treatment Network is funded by the National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Md, and the National Institute of Child Health and Human Development, Rockville, Md.

[FitzGerald MP, Burgio KL, Borello-France DF, et al; for the Urinary Incontinence Treatment Network. Pelvic-floor strength in women with incontinence as assessed by the Brink scale. Phys Ther; 2007;87:1316-1324.]

Table 1.
Patient Demographics, Stage of Pelvic Organ Prolapse, and Brink Scale
Score

Elements (N=643)                                      N (%)

Demographics
  Ethnicity
    Hispanic                                        72 (11)
    Non-Hispanic white                             469 (73)
    Non-Hispanic black                              44 (7)
    Non-Hispanic "other"                            58 (9)
  Stage of pelvic organ prolapse
    0                                               30 (5)
    1                                              131 (20)
    2                                              377 (59)
    3                                             8603 (13)
    4                                              190 (3)
Pelvic-floor muscle assessment
  Pressure
    1-no response, cannot perceive                  37 (6)
    2-weak squeeze, felt as a flick                243 (38)
    3-moderate squeeze, felt all around finger     240 (37)
    4-strong squeeze, full fingers compressed      123 (19)
  Pelvic contraction assessment (duration)
    None                                            27 (4)
    [greater than or equal to] 1 and [less          75 (12)
      than or equal to] 3 seconds
    >3 seconds                                     541 (84)
  Displacement of vertical plane
    1-none                                          86 (13)
    2-fingertips may move anteriorly               251 (39)
    3-whole length of forgers move anteriorly      197 (31)
    4-whole fingers move anteriorly                109 (17)

Table 2.
Descriptive Statistics for Continuous Measures (N=643) (a)

Variable                    n     Mean    SD      Minimum
                                                  Value
Age                         643    51.9   10.3    27
No. of pregnancies          643     3.3    1.7     0
No. of vaginal deliveries   643     2.6    1.6     0
Genital hiatus (cm)         641     3.6    1.2     1
Brink scale total score     643     9.0    2.1     3
MESA total score            643    25.8    7.4     4
MESA stress incontinence    643    19.3    4.6     4
  subscale score
MESA urge incontinence      643     6.5    3.9     0
  subscale score
UDI total score             639   151.1   49.0     0
UDI obstructive symptoms    640    25.2   21.8     0
  subscale score
UDI irritative symptoms     640    47.8   25.3     0
  subscale score
UDI stress symptoms         639    78.0   22.0     0
  subscale score
Pad test weight (g)         633    43.6   79.8     0.1
Diary: average leaks/day    642     3.2    3.0     0

Variable                    Median   Maximum
                            Value    Value

Age                          50         81
No. of pregnancies            3         12
No. of vaginal deliveries     2         10
Genital hiatus (cm)           3.5       10
Brink scale total score       9         12
MESA total score              26        43
MESA stress incontinence      20        27
  subscale score
MESA urge incontinence        6         17
  subscale score
UDI total score             150.5      290.9
UDI obstructive symptoms     18.2       97.0
  subscale score
UDI irritative symptoms      50        100
  subscale score
UDI stress symptoms          83.3      100
  subscale score
Pad test weight (g)          15.1    1,022.6
Diary: average leaks/day      2.3      26

(a) MESA-Medical, Epidemiological, and Social Aspects of Aging
urinary incontinence questionnaire; UDI=Urogenital Distress Inventory.

Table 3.
Bivariate Analysis, With Brink Scale Score as Dependent Variable
(N=643) (a)

Independent Variable         N    [beta]   SE      P          Adjusted
                                                              Mean
Age                         643   -0.03    0.008   <.0001 *
No. of pregnancies          643   -0.05    0.05     .33
No. of vaginal deliveries   643   -0.14    0.05     .01 *
Pad test weight             633   -0.001   0.001    .17
Voiding diary:              642    0.02    0.03     .53
    accidents/day
UDI obstructive symptoms    640   -0.01    0.004    .0001 *
    subscale score
UDI irritative symptoms     640   -0.008   0.003    .01*
    subscale score
UDI stress symptoms         639    0.006   0.004    .12
    subscale score
UDI total score             639   -0.004   0.002    .02 *
MESA total score            643   -0.03    0.01     .02 *
MESA stress incontinence    643   -0.02    0.02     .16
    subscale score
MESA urge incontinence      643   -0.06    0.02     .004 *
    subscale score
Ethnicity                   643
  Hispanic                         0.41    0.37     .04 *     8.82
  Non-Hispanic white               0.59    0.29               9.00
  Non-Hispanic black               1.18    0.41               9.59
  Non-Hispanic "other"                                        8.41
Previous urinary            643
    incontinence surgery
  Yes                             -0.27    0.23     .25       8.74
  No                                                          9.01
Hysterectomy                643
  Yes                             -0.52    0.18     .004 *    8.61
  No                                                          9.13
Incontinence of flatus      643
  Yes                             -0.42    0.16     .01 *     8.77
  No                                                          9.19
Incontinence of             643
    liquid stool
  Yes                             -0.65    0.19     .001 *    8.47
  No                                                          9.12
Incontinence of             643
    solid stool
  Yes                             -0.38    0.30     .21       8.62
  No                                                          9.00
Pelvic organ                643
    prolapse stage
  0 and 1                          0.46    0.26     .14       9.24
  2                                0.14    0.23               8.91
  3 and 4                                                     8.77

(a) Results of analysis of variance include the adjusted mean, which
gives the mean Brink scale score for each category of the explanatory
variable. The P value is for the test of the hypothesis that all the
means are equal (asterisk indicates P value is <.05). MESA= Medical,
Epidemiological, and Social Aspects of Aging urinary incontinence
questionnaire; UDI=Urogenital Distress Inventory.

Table 4.
Results of Multivariate Regression Analysis (a)

                            Slope    SE       P     Mean Brink
                                                    Scale Score

Age                         -0.03    0.01    .001
No. of vaginal deliveries   -0.08    0.05    .16
UDI obstructive symptoms    -0.01    0.004   .008
    subscale score
UDI irritative symptoms     -0.001   0.004   .80
    subscale score
MESA urge incontinence      -0.03    0.02    .27
    subscale score
Ethnicity
  Hispanic                   0.19    0.36    .14    8.74
  Non-Hispanic white         0.41    0.29           8.96
  Non-Hispanic black         0.89    0.41           9.44
  Non-Hispanic "other"                              8.55
Hysterectomy
  Yes                       -0.31    0.18    .09    8.77
  No                                                9.08
Incontinence
    of liquid stool
  Yes                       -0.07    0.25    .78    8.89
  No                                                8.96
Pelvic organ
    prolape stage
0 and 1                      0.02    0.28    .46    9.00
2                           -0.19    0.24           8.79
3 and 4                                             8.98

(a) The table details the slope of the association of each
explanatory variable and the Brink scale scores, which
represents the average change in the Brink scale scores
for a one-unit change in the explanatory variable. The P
value is for the test of the hypothesis that the slope is
equal to 0 or that there is no association. When all
variables were included simultaneously, age and obstructive
pelvic symptoms remained significantly associated with Brink
scale scores, but other measures were no longer significant.
[R.sup.2]=.074 for this model (ie, the model explained only
7% of the variance seen). MESA=Medical, Epidemiological, and
Social Aspects of Aging urinary incontinence questionnaire;
UDI=Urogenital Distress Inventory.