measuring fecal incontinence
TRANSCRIPT
Diseases of the Volume Number
CozoN 46 12 DECEMBER 2003
CURRENT STATUS
Measuring Fecal Incontinence Nancy N. Baxter, M.D., Ph.D., David A. Rothenberger, M.D., Ann C. Lowry, M.D.
From the Division of Colorectal Surgery, University of Minnesota, Minneapolis, Minnesota
The measurement of fecal incontinence is challenging. Be- cause fecal incontinence is a symptom, the subjective per- ception of the patient must be the foundation of any eval- uation of incontinence or the impact of incontinence. The lack of a criterion standard makes testing measures for reliability and validity more difficult. Despite this, many measures are available and can be divided into three broad categories: descriptive measures that do not provide sum- mary scores; severity measures that assess the frequency and type of incontinence; and impact measures that assess the effect of incontinence on quality of life. The strengths and weaknesses of currently available measures are pre- sented in this review. [Key words: Fecal incontinence; Mea- surement; Quality of life; Function; Outcome assessment]
Baxter NN, Rothenberger DA, Lowry AC. Measuring fecal incontinence. Dis Colon Rectum 2003;46:1591-1605.
F ecal incontinence is common and can be severely
debilitating to those affected. 1 Improvements in
the understanding, diagnosis, and treatment of the
disorder have occurred over the past 20 years, and
research in the area is active and ongoing. In the past,
such research was hindered by difficulties defining and measuring incontinence. 2 Significant progress has
been made in measuring incontinence with increased
understanding of both the disease and measurement
principles.
What Is Fecal Incontinence?
The American Society of Colon and Rectal Surgeons
defines incontinence as the impaired ability to control
gas or stool, ranging in severity from mild difficulty
with gas control to complete loss of control over liquid and formed stools. 3 Although this definition has
limited clinical utility, it does emphasize an important
point. Fecal incontinence is a symptom, and as such,
it must be measured through subjective assessment.
Physiologic studies, although clinically important in
determining causes and guiding treatment, have lim-
ited utility in grading severity or evaluating outcomes.
Objective measures such as anal manometry, nerve
conduction studies, electromyography, defecogra-
phy, and endoanal ultrasonography do not measure
incontinence. Although findings on any of these stud-
ies may be associated with incontinence, they are
inadequate measures to determine incidence and se-
verity of incontinence or response to therapy. For
example, in a study of 468 consecutive people under-
going endoanal ultrasonography, including 335 in-
continent patients, 115 continent patients, and 18
asymptomatic female volunteers, the prevalence of
sphincter defects was 65, 43, and 22 percent, respec-
tively. 4 From this study, the presence of an anal
sphincter defect on ultrasonography would have a
sensitivity of 0.65 and a specificity of 0.59 for fecal
incontinence. Although this does not undermine the
importance of endoanal ultrasonography in diagnosis
and management guidance, it demonstrates that this
test is at best a poor surrogate measure for inconti-
nence. Similarly, in a study that compared the results
of anal manometry in 40 volunteers and 23 patients
with fecal incontinence, one-fourth of incontinent pa-
tients had resting and squeeze pressures within the
normal range, which highlights the limitations of mea-
suring incontinence with manometry. 5
How Should Incontinence Be Measured?
N o reprints are available.
DOI: 10.1097/01.DCR.0000098906.61097.1C
Incontinence could be measured simply as present
or absent. The limitations of such an approach for
1591
1592 BAXTER E T A L Dis Colon Rectum, December 2003
clinical or research purposes, however, are clear.
Such a measure would not differentiate between
groups with important differences or allow detection
of clinically important change, two key aspects of
validity. In fact, such a measure is unlikely to accu-
rately reflect patient experience, because inconti-
nence type and frequency and the duration of symp-
toms are not specified. More detailed measures are
therefore necessary.
The evaluation of fecal incontinence requires con-
sideration of two different yet related components,
severity and impact. Two forms of severity measures
are available: grading scales that assign a value to
specific types of incontinence and summary measures
that assign values for certain categories of inconti-
nence and produce summary scores based on the
addition of values for each category. Impact measures
attempt to evaluate the effect of incontinence on emo-
tional, social, occupational, and physical functioning
and are best thought of as disease-specific quality-of-
life measures. Although measurement of disease-spe-
cific quality of life is challenging from a design per-
spective, it is extremely important, because many
salient aspects of disease and treatment will not be
reflected in or measured by quality-of-life measures
developed for the general population. Additionally,
the impact of incontinence may vary not only with
severity but also with myriad individual factors, such
as gender, age, lifestyle, occupation, cultural issues,
and personal values. 6~ Patients may limit the severity
of their incontinence by altering their lifestyle, i .e. , a
patient might have only infrequent episodes of incon-
tinence by severely restricting activities. Such a pa-
tient would be considered to have "severe" inconti-
nence by a quality-of-life measure but not by a
standard measure of incontinence frequency. Thus,
measuring impact in addition to severity enriches
studies of this disorder. Also, it is possible that small
changes in severity lead to greater changes in terms of impact.
Severity and impact measures both attempt to eval-
uate a subjective phenomenon in a reliable and valid
manner. Given the lack of objective measures, there is
no criterion standard for comparison. Evaluation of
the instruments must therefore rely on measurement
principles established for the assessment of clinical
and psychologic phenomena. Because of the lack of a
criterion standard, measurement evaluation is an on-
going process, and evidence for the reliability and
validity of a measure evolves over time. Having said
this, few measures of incontinence have been submit-
ted to a rigorous evaluation.
Re l i ab i l i ty
Useful measures must be reliable; that is, scores
must reflect the underlying phenomenon and not
measurement error. The ratio between total score
variation and variation related to error gives an as-
sessment of the reliability of a measure (ff most of the
variation in score is caused by error, the measure
would have poor reliability). For research purposes, a
measure should achieve a reliability of at least 0.70,
whereas for use with individuals, a reliability level of
0.90 is recommended. 9
There are several ways in which reliability can be
evaluated. 10 The reproducibility of a measure, or test-
retest reliability, is an easily understood assessment.
In patients who have not had clinical changes, repeat
administrations of a measure (or measurement by
different evaluators in the case of a grading scale)
should produce equivalent results. Differences in
scores between the test and retest correspond to ran-
dom fluctuations in responses over time and thus are
an estimate of the amount of variation in the observed
score that is caused by random error. The intraclass
correlation coefficient is the most appropriate statistic
to determine the degree of concordance between test
and retest. 11
Internal consistency is another established mea-
surement of reliability. Items included in any measure
can be considered a random sample of all possible
items that evaluate a particular attribute. Because the
sample of items is limited in any measure, the ob-
served score will always differ from the true score by
an amount of error related to item selection. Variation
in the observed score on an incontinence scale will be
related to a combination of true differences in incon-
tinence and differences caused by the limited sam-
piing of all possible items measuring all possible as-
pects of incontinence. Measures of internal
consistency estimate reliability on the basis of the
average correlation among items within a measure. 9'12
In a measure of a single condition or single aspect of
a condition, all the items should be measuring the
same thing, and the average correlation between the
items should be high, i .e. , items in such a measure should "hang together. "13 If the average correlation
between items is not high, the selection of items has
introduced significant error (or the instrument is mea-
Vol. 46, No. 12 MEASURING FECAL INCONTINENCE 1593
suring more than 1 thing). The most commonly used
measure of internal consistency is coefficient alpha.
V a l i d i t y
The lack of a criterion standard for any subjective
phenomenon such as incontinence makes assessment
of validity particularly challenging. Simply stated, a
valid instrument measures what it purports to mea- sure. Validation of a subjective phenomenon may be
divided into four aspects: face validity, content valid- ity, construct validity, and sensitivity to change. 1~
Face Validity. Classically, face validity evaluates
"the extent to which the test taker or someone else
(usually someone who is not trained to look for for- mal evidence of validity) feels the instrument mea- sures what it is intended to measure. ''14 This has been
extended to also include the suitability of response categories used in a measure and the suitability of
aggregate ratings. If a measure fails to pass this "eye-
ball" test, it is unlikely to perform well under more rigorous evaluation and is unlikely to be acceptable to
users.
Content Validity. Closely related to face validity, content validity is the systematic evaluation of a mea-
sure to ensure that all important aspects of the phe- nomenon have been included and that unrelated ar- eas have not. 15 In assessing content validity, it is
important to consider the method of choosing items, because some methods are more susceptible to inap-
propriate inclusions or exclusions than other meth- ods. For instance, if item generation for an inconti-
nence measure did not include patient input,
important aspects of incontinence might be omitted.
There may be some aspects of incontinence (for ex- ample, urgency) that would be more likely to have
been included if incontinent individuals participated in measurement development. This is important to note, because with only a few exceptions, incontinent
patients have not been involved in development of
incontinence measures, particularly in the item-gen- eration phase.
Construct Validity. No criterion standard for the
measurement of incontinence exists, and thus new
measures cannot be validated by comparison with
such a standard. Other indirect methods of assessing validity must therefore be used. To demonstrate con- struct validity, hypotheses regarding the predicted behavior of a valid measure are generated and then
tested through research. Evidence of validity is pro- vided if the research findings support the proposed
hypothesis. Several different types of hypotheses may
be generated. A significant difference in incontinence score should be found be tween groups expected to
differ in terms of continence. For example, construct
validity could be evaluated by comparing females who had a fourth-degree obstetric tear with a group
of nulliparous females. Finding a difference in score
be tween these two groups would support the con-
struct validity of a fecal incontinence measure. In addition, scores on related measures should have
significant correlations. For example, results of a dis-
ease-specific fecal incontinence measure such as the Fecal Incontinence Quality of Life Scale 16 should have
significant correlations with a generic quality-ofqife measure such as the Short Form (SF)-36.17 This is
termed convergent validity. Construct validation is a gradual process and requires the testing of multiple
hypotheses by numerous independent researchers. Sensitivity to Change. Even a valid measure may
not adequately reflect change, particularly when
change is anticipated to be small despite being clini-
cally important. If a measure has not been adequately
evaluated for sensitivity, the failure to find differences
in studies using the measure may be the result of a
lack of difference or may be related to the inability of the measure to detect change. Although sensitivity to change may be considered an aspect of construct validation, it is particularly important to clinicians and
researchers when determining the effect of treatment and thus should be considered separatelyJ 8
AVAILABLE MEASURES
There are many measures of fecal incontinence available. These can be broadly categorized into de-
scriptive measures, severity measures (grading scales, summary scores), and impact measures.
Descriptive Measures. Descriptive measures include
numerous questions that relate to various aspects of
fecal incontinence. No summary score is calculated
for these measures, and thus each item must be eval- uated separately. This approach may be useful for populat ion-based research, for example, to determine
the incidence of incontinence symptoms. However,
because no single score or small number of scores is calculated, these measures are difficult to use in re-
search studies. Multiple comparisons lead to prob- lems with Type I error. 19 In addition, answers to single items are inherently less reliable than well- developed multi-item scales, 9 and with few response
categories for each item, differences be tween individ-
1594 BAXTER ETAL Dis Colon Rectum, December 2003
uals and change within an individual are difficult to detect, particularly when differences are small. Hav-
ing said that, the large number of widely varied items
used by descriptive measures provides a rich sam-
piing of incontinence symptoms and in certain cir-
cumstances may be very useful. In addition, with further research, summary scores for these measures
might be developed. Three descriptive measures have been used for research purposes.
Mayo Clinic Fecal Incontinence Questionnaire. This questionnaire was designed to measure preva-
lence of fecal incontinence in the community and risk
factors associated with incontinence. 2~ It assesses nu-
merous aspects of incontinence, including stool leak- age, frequency, timing, urgency, pad usage, and rectal
discrimination. Incontinence of flatus, however, is not
included in the measure, and this could be considered
an inappropriate exclusion. Experts in the field devel- oped questions for the measure without input from
incontinent patients. The authors tested the question- naire on 94 individuals and assessed validity by com-
paring self-report responses with responses from tele-
phone interviews in 41 individuals. Agreement between self-report and interview was high for some
items but surprisingly low for others. This may be the
result of problems with instrument wording or reluc- tance to discuss incontinence on the phone. Other
authors have not used the measure, and further re- search would be r ecommended before wide accep- tance.
Osterberg Assessment of Patients With Fecal Incon- tinence and Constipation. A group of Swedish inves-
tigators developed this self-report measure to assess
patients with fecal incontinence and constipation. 21 The measure consists of 47 questions, 15 related to constipation, 12 related to incontinence, 10 relating to
other symptoms, 7 regarding obstetric events, and 3
about social and physical impact. The method of item generation is not described. The questionnaire was evaluated in 36 incontinent patients, 38 constipated
patients, and 16 controls. Most items relating to in- continence demonstrated good reproducibility in in-
continent patients. However, frequency of inconti-
nence to solid stool demonstrated low
reproducibility, perhaps because in the majority of patients, retesting occurred after a delay of more than
2 months. The lack of reproducibility may reflect a
change in the underlying condition. Responses of incontinent patients to the majority of incontinence items differed from those of constipated patients and
controls. In addition, 15 patients underwent surgical
treatment for incontinence, and statistical improve-
ment was found in the responses to five incontinence items. The responses on items related to frequency of
incontinence of flatus, loose stool, and solid stool
have been summed, and the summary score was
found to be sensitive to change when patients with
neurogenic fecal incontinence were compared before and after electrostimulation of the pelvic floor. This
measure may be particularly useful in the evaluation
of patients with multiple symptoms; however, reliabil-
ity needs to be established. Further research develop- ing summary scores for this measure and translation
of the measure to other languages would be useful. Malouf Postoperative Questionnaire. Malouf et al. 22
designed a questionnaire to be administered to pa- tients after sphincteroplasty. Details of item genera-
tion are not given. The questionnaire addresses sev-
eral items relating to incontinence, including fecal urgency/urge fecal incontinence, passive inconti-
nence, and postdefecation incontinence. In addition,
there are several questions that ask the respondent to
compare current symptoms with those before sur- gery. No assessment of reliability was performed. As a
purely descriptive tool, the measure appeared useful; however, further research and development of sum-
mary scales should be pursued before widespread
use of this postoperative measure.
Severity Scores Grading Systems. Numerous fecal incontinence
scales, both grading and summary scales, exist and
have been reviewed in detail elsewhere, z'z~3a In
grading scales, various categories of incontinence are assigned a particular grade in an ordinal fashion (Ta- ble 1). Although there are individual nuances in cat-
egorization, the similarities of these scales far out-
weigh the differences. All of them have issues with face validity. The scales lack any real assessment of
frequency, and the scores mainly reflect an evaluation of sphincter performance, i.e., the worse the sphincter
function, the higher the score. Thus, incontinence to
solid stool is always considered worse than inconti-
nence to liquid stool. Although this is clinically intu- itive, it does not necessarily reflect the subjective experience of incontinent patients. For example, an
individual incontinent to liquid stools on a daily basis
could rightfully consider themselves to have severe incontinence, even though this would not be reflected
on grading scales. Because of the limited number of
categories, these scales lack the ability to differentiate
Vol. 46, No. 12
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between patients with minor differences in inconti-
nence or to detect small but clinically important
changes. In fact, the majority of researchers using these scales have done so in a descriptive fashion.
The scales are simple to use and may be applied to historical information, although the reliability of the
use of historical data has not been evaluated and is of
questioned reliability and validity. To avoid bias, pa- tient completion of any incontinence measure is strongly r ecommended and should be required for
purposes of publication.
When choosing a grading scale, one should avoid ambiguous grading categories ("unsatisfactory with
major incontinence") and scales that do not allow all patients to be categorized (minor = fecal leakage no
more than once a month, usually associated with
diarrhea; moderate -- incontinent at least once per
week and could not control a solid stool; severe =
wear a perineal pad because of incontinence on most
days). A simple and easily understood scale, such as that of Parks 23 (4 grades ranging from normal to no
control of solid stool) or Womack et al. 31 (4 grades
ranging from fully continent to incontinent to solid or liquid stool and gas) is likely best. However, because
of the many inconsistencies, inadequacies, and lack of precision of the grading scales, they are not to be
r ecommended as the sole method of categorizing patients or monitoring outcome.
S u m m a r y Scales. Summary scales attempt to ad- dress some of the deficiencies of grading scales.
These scales acknowledge that incontinence is not an "all or none" phenomenon and that various aspects of
incontinence, including frequency, contribute to se-
verity. In addition, by producing multilevel summa- tive scores, they are much more likely to enable dif- ferentiation be tween groups and detection of
clinically important change. Twelve summary scales 32-43 have been identified; however, two of the scales 42'43 include objective measurement (e.g.,
squeeze pressure) and thus are not included in this evaluation. For the remaining ten scales, similarities again far outweigh differences. Nine of the scales
include an assessment of incontinence to gas, incon-
tinence to liquid stool, and incontinence to solid stool
(Table 2). Values for each type of incontinence are assigned according to the frequency of incontinent episodes. Frequency scales differ. The highest fre-
quency category varies from more than once per week to more than twice per day. The lowest fre-
quency category (other than never) also varies, from less than once per month to up to three times per
month. Thus, some scales may better differentiate
patients with frequent episodes of incontinence, whereas others may be more useful in patients with infrequent episodes. The number of categories for
frequency range from three to six, with most having
four categories (including never). The number and
range of frequency categories may be important if one
is looking for small differences in severely incontinent
groups. For example, if the highest frequency in- cludes one or more times per week, improvement
after treatment from daily to weekly incontinence will
not be detected. No scale relates the frequency of
incontinent episodes to the number of total bowel movements , and this may lead to an underestimation
of severity in those patients who stool less frequently.
Scores on the summary scales range from 0 to 6 to 0 to 120, and one scale 39 has reversed scoring (higher
score = better function). The assignment of values to
types and frequencies of incontinence varies be tween
scales. Some scales value all types of incontinence
equally; for example, in the Jorge/Wexner Conti- nence Grading Scale, 34 all types of incontinence are
weighted equally (0 to 4), and therefore, the same
frequencies of incontinence of gas and incontinence
of solid stool contribute equally to the severity score. Three other scales use this method, assigning equal
values to the same frequencies of different types of incontinence. 33'36'41 Although these scales have
proven useful, they are unlikely to reflect the subjec- tive experience of the patient, because both a patient
incontinent to gas once per week (value = 3) and
liquid stool three times per year (value = 1) and a patient with daily incontinence to solid stool only
(value = 4) would have the same total score of 4. In fact, the distinction be tween solid and liquid stool made by most scales has not been validated and again
may not reflect the subjective experience of the in-
continent individual. Other authors have chosen a different approach,
giving variable weights to the same frequencies of
different types of incontinence. The manner of assign- ing values varies. Most authors have arbitrarily chosen
values that tend to reflect severity of sphincter impair- ment. For example, in Rothenberger 's scale, 4~ incon-
tinence to liquid stool receives twice the value of incontinence to gas at the same frequency. Similarly, incontinence to solid stool is worth three times the
value of incontinence to gas at the same frequency. On this scale, the patient with incontinence to gas once per week (value -- 3) and incontinence to liquid
stool three times per year (value = 4) would score
Vol. 46, No. 12 MEASURING FECAL INCONTINENCE 1597
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1598 BAXTER E T A L Dis Colon Rectum, December 2003
seven, whereas an individual incontinent to solid stool only on a daily basis would score nine. How- ever, again, such a method of assigning values may not reflect the subjective experience of incontinence. An individual who is incontinent to liquid stools daily would likely consider incontinence to be severe, but their score would be lower than someone incontinent to solid stool less than once per month. This lack of patient perspective in the assignment of values limits
the comparability and validity of the scales. To address this problem, Rockwood e t a l . 32 devel-
oped a severity measure (the Fecal Incontinence Se- verity Index (FISI)) that assigns values to various fre- quencies and types of incontinence on the basis of subjective ratings of severity. The scale has six fre- quency categories ranging in score from 0 to 61, with the lowest frequency (other than none) being one to three times per month and the highest frequency being two or more times per day. To assign values, 34 patients were asked to rate the severity of various frequencies of gas, mucus, liquid stool, and solid stool incontinence using a 4 • 6, type • frequency matrix. Twenty-six colorectal surgeons also completed the matrix. Interestingly, liquid stool incontinence was considered almost or as severe as solid stool inconti- nence by both groups. Patient values for incontinence to gas tended to be higher than those of the surgeons. Again, surgeon ratings tended to reflect sphincter function more than patient ratings. Mthough the au- thors do not endorse the use of the values of one group over the other, one can argue that because incontinence is a symptom, the subjective experience of the patient should be considered most important. As an example of the scoring of the FISI, a patient incontinent to solid stool daily with no other inconti- nence would score 16. A patient incontinent to gas weekly and to liquid stool three times per year would score 6 + 0 = 6. Although this research has certainly increased the understanding of patient values, the small number of patients queried is somewhat con- cerning; this study should be replicated in other pop- ulations before widespread adoption of these partic- ular values.
Although almost all severity measures evaluate gas, liquid, and solid stool incontinence, six scales evalu- ate other aspects of incontinence, including inconti- nence of mucus, soiling, urgency, and difficulty clean- ing. 32'33'36'37'39'41 In addition, three scales include an
item that relates to the use of pads, 33'34'36 and five include an item or items measuring lifestyle alter- ations related to incontinence. 33'34'36'37'4~ The appro-
priateness of these inclusions (or exclusions) be- comes an issue of content validity. For example, many would argue that any measure of incontinence should include an evaluation of urgency, because this is a particularly important and bothersome symptom to the patient. 44 Because urgency may be as limiting to an individual as frank incontinence, urgency would be inappropriately excluded from an incontinence measure. On the other hand, several severity scales include an item that measures lifestyle alteration or impact of incontinence. The inclusion of items that measure impact would be expected to introduce error into a measure of incontinence severity, adversely affecting reliability and validity. Similarly, some scales include items to determine frequency of pad usage. The wearing of a pad may reflect the degree of indi- vidual fastidiousness vs. severity of incontinence and therefore may represent an inappropriate inclusion. Scale users must determine the salient aspects of con- tinence for measurement in a particular patient or a
particular study and choose a severity score accord- ingly.
Relatively little research has evaluated the reliability of incontinence severity measures. One study evalu- ated test-retest reliability for four incontinence scales in 13 incontinent patients. 36 The scales evaluated in- cluded the Vaizey scale 36 (a 5-category scale ranging
in score from 0-24, with frequencies ranging from once monthly to daily), the Jorge/Wexner scale 34 (a 5-category scale ranging in score from 0-20, with frequencies ranging from less than once per month to more than daily), the American Medical Systems scale 37 (a 6-category scale ranging in score from
0-120, with frequencies ranging from once monthly to at least twice per day), and the Pescatori scale 35 (a 3-category scale ranging in score from 0--6, with fre- quencies ranging from less than once per week to daily; Table 2). Acceptable reliability (intraclass cor- relation coefficient = 0.75-0.87) was found for three 34'36'37 of four scales. In this study, one measure
had unacceptably low reliability. 35 There are no stud-
ies evaluating reliability for other scales. Unlike simple grading scales, summary measures
have been used quantitatively in a variety of studies, and there is evidence of validity. Some of the scales have been shown to correlate with quality-of-life measures. 32'45'46 The ability to discriminate between
groups with expected differences in continence has been demonstrated. Higher scores were found in pa- tients with a clinically good outcome after sphinctero- plasty than in those with a clinically poor outcome. 47
Vol. 46, No. 12 MEASURING FECAL INCONTINENCE 1599
In addition, some measures have been demonstrated
to be sensitive to change, with significant score im-
provement after sphincteroplasty or biofeedback and worsening scores after sphincterotomy. 33'35'36'41'48'49
Summary scales may be calculated from patient recall or directly from diary entry. Diaries allow pa-
tients to record incontinent events in real time and
thus may reduce the bias introduced by relying on
patient memory. This has not been demonstrated in the fecal incontinence literature. In fact, in a study
evaluating compliance with article diaries for pain
assessment by use of a time-recording binder, many
patients entered data for times when the binder was not opened. 5~ Most patients (75 percent) in this study
were found to hoard information for at least one day, i.e., the diary was completed for days on which the
binder was not opened, which introduces the poten-
tial for recall bias when diary entry is used. Palm
handheld computers and electronic entry may im- prove compliance and satisfaction with diaries. 51 In-
continence should never be limited to a measure of
frequency based on diary entries, because individuals
often make dramatic lifestyle changes to avoid incon- tinence. Because of this, measurements of frequency
may be a poor measure of severity in many individ-
uals. All studies using summary scales should specify whether scores were calculated on the basis of patient recall or evaluation of diaries, and further research to
evaluate the effect of the data collection method on
reliability is needed.
Because of limited data on the reliability and valid- ity of these scales, it is difficult to recommend the use
of one over any others. If assessment of urgency were
believed to be important for content validity, then Vaizey's measure, 36 which has some evidence of re-
liability and validity, would be suitable. The Jorge/ Wexner measure 34 is the most frequently used and is
simple and reliable and appears to be sensitive to
change. However, the equal weighting of all types of incontinence and the inclusion of pad usage may limit
the face and content validity of the measure. Given the subjective nature of incontinence, the incorpora- tion of patient values into severity measurement has
been a major step forward. Although more research
with the tool is necessary, the Fecal Incontinence Severity Index 32 is r ecommended for use when incon-
tinence occurs frequently; however, the lack of as- sessment of urgency in this measure may limit appli-
cability. Impact Measures. Although it is important to know
the severity of fecal incontinence, it is also important
to understand and measure the impact of fecal incon-
tinence on patients, or rather the effect of fecal incon- tinence on quality of life. Small changes in severity of incontinence may have large changes in terms of
impact of incontinence on quality of life. In addition,
the impact likely varies not only with severity but also with individual factors such as occupational status,
social support, and psychologic functioning. To fully
understand our patients' experience and the impact of
treatment, it is essential that measurement of quality
of life be incorporated into incontinence research.
Although the exact definition of quality of life, or
health-related quality of life, remains elusive and de-
bated, generally most questionnaire-based quality-of- life measures evaluate the impact of disease and treat- ment on physical, social, and emotional function and may include perception of overall well-being. 52 Ge-
neric questionnaires, such as the SF-36, include items
of relevance to broad populations of individuals and
may be applied to both the ill and the well. Such measures often have a long history of use with estab-
lished reliability, validity, and population norms. In
addition, generic measures allow comparisons be-
tween disease groups and measurement of unex- pected consequences of disease and treatment.
Although so-called generic quality-of-life measures
have proved useful when various normal and dis- eased groups are compared, in many disease states
these measures are not specific enough to detect
small changes or differentiate be tween individuals with varying severity of the same disease. 53 Disease-
specific measures allow evaluation of individuals within disease groups, and in the case of fecal incon-
tinence, several specific measures exist and appear
highly useful. Nonetheless, functional impairment caused by fecal incontinence appears to be severe
and global enough to be measured with generic qual- ity-of-life instruments. Patients with fecal inconti-
nence have significantly worse scores on the SF-36 than continent individuals. 46 In addition, the SF-36 is
sensitive enough in this populat ion to detect change in quality of life after treatment. 54-s7 Further research
using generic quality-of-life measures in the study of incontinence and the effect of treatment would enrich
our understanding of the impact of this disorder and facilitate comparison of the functional impairment of
patients with fecal incontinence to other groups of patients.
Disease-Specific Measures. Three disease-specific measures of the impact of fecal incontinence have been developed for the adult populat ion and are
1600 BAXTER E T A L Dis Colon Rectum, December 2003
freely available for use. Two of these produce sum-
mary scores. The measures are self-administered and generally require five to ten minutes to complete. This
may limit applicability in some instances. The Fecal Incontinence Quality of Life Scale
(FIQLS) was developed by The American Society of Colon and Rectal Surgery. 16 A panel of experts se-
lected aspects (or domains) of quality of life likely to
be affected by fecal incontinence. Forty-one items relating to these domains were generated and tested
by a group of 50 patients for comprehension and
acceptability. A technique termed factor analysis was
used to develop four subscales representing four do-
mains of quality of life (lifestyle, coping-behavior, depression, and embarrassment), and 12 items not
fitting into this domain structure were eliminated. The
number of items for each subscale ranges from 3 to 10, with 29 items in total. Internal consistency was
calculated for the subscales and was above 0.8 for all
scales, which indicates good reliability. Test-retest re- liability was assessed by te lephone responses of 47
individuals. Unfortunately, no reliability coefficient
was calculated; however, the test and retest scores did
not differ statistically. Scores of continent and incon-
tinent patients were compared to assess the construct validity of the measure, and incontinent patients had
significantly lower scores for all four subscales. Scores on the measure correlated with scores on the SF-36 in a predicted fashion 16 and also correlated with incon- tinence severity measures, 45'58'59 which provides evi-
dence of convergent validity. The measure has been
found to be sensitive to change, with statistically sig-
nificant improvements in scores after artificial sphinc- ter implantation 58'6~ and biofeedback. 62 This mea-
sure is well studied and appears very useful. Support for the validity of the measure is accumulating, and given the demonstrated sensitivity of this instrument
to change, use of the FIQLS as a primary end point for
research is supportable. Instructions for appropriate
scoring of the FIQLS are given in Table 3. The Manchester Health Questionnaire (MHQ; Table
4) was adapted to measure the condition-specific
quality of life related to fecal incontinence from a
validated measure of urinary incontinence (the King's Health Quest ionnaire)Y '64 The basic structure of the
original questionnaire was maintained, including as-
sessment of physical limitations (2 items), social lim- itations (3 items), role limitations (2 items), emotions (3 items), sexual function (2 items), s leep/energy (2 items), general health perceptions (1 item), inconti-
nence impact (1 item), and incontinence severity (5
items). A ten-item symptom inventory accompanies
the questionnaire but is not scored. The items for the
questionnaire were developed by the researchers but
modified from comments of 45 females with inconti- nence. The final questionnaire was evaluated for face validity by 15 females with incontinence and tested
for comprehension in a group of 15 females without
incontinence. Interestingly, during testing, females had difficulty understanding words such as "fecal"
and "stool" and thus, wording was changed to "bowel
leakage." Internal consistency was evaluated with the
responses of 154 incontinent patients and ranged
from 0.73 to 0.91 for the scales. Of these patients, 121
completed a second questionnaire, which allowed
test-retest reliability to be assessed. The authors com- pared the scores on the two administrations of the
questionnaire using Pearson's correlation coefficient, a measure that would tend to overestimate reliability,
and this ranged from 0.81 to 0.93 for the scales. Scores
on the MHQ were compared with scores on the SF-36. The authors state there were modest to strong corre-
lations of domains between the MHQ and the SF-36;
however, the pattern of correlation be tween the indi-
vidual scales of the measures was not specified. Two
items were selected from the symptom inventory as representing frank incontinence (bowel leakage when coughing or sneezing and bowel leakage when walking). Scores on these items were added and cor-
related to scores on the scales of the MHQ. Modest to strong correlations were found between these items
and the scales, the lowest (0.30) between general health perceptions and frank incontinence and the
highest (0.65) be tween incontinence severity and
frank incontinence. Given that the measure of frank
incontinence used was not an established instrument, this offers only limited validation. No other authors have reported the use of the instrument. Further re-
search is required to validate the measure and test
sensitivity to change before the measure could be
used as a primary end point for studies; however, the measure does appear promising. The addition of a
s leep/energy scale in the MHQ may produce useful insight into the impact of incontinence. The sampled
content of the MHQ and the FIQLS is similar, and
research comparing the two measures would be use-
ful. The TyPE specification (Table 5) was developed to
measure fear of incontinence and activities affected by incontinence. 54 Very little information is available
about development of the measure. There are no summary scores for the measure, and thus, each item
Vol. 46, No. 12 MEASURING FECAL INCONTINENCE 1601
Table 3. Items in the Fecal Incontinence Quality of Life Scale*
Scale 1: Lifestyle Que3B: I cannot do many of the things I want to do (agreement, 4 points) Que2A: I am afraid to go out (frequency, 4 points) Que2G: It is important to plan my schedule (daily activities) around my bowel pattern (frequency, 4 points) Que2E: I cut down on how much I eat before I go out (frequency, 4 points) Que2D: It is difficult for me to get out and do things like going to a movie or church (frequency, 4 points) Que3L: I avoid traveling by plane or train (agreement, 4 points) Que2H: I avoid traveling (frequency, 4 points) Que2B: I avoid visiting friends (frequency, 4 points) Que3M: I avoid going out to eat (agreement, 4 points) Que2C: I avoid staying overnight away from home (frequency, 4 points)
Scoring -- (Que3B + Que2A + Que2G + Que2E + Que2D + Que3L + Que2H + Que2B + Que3M + Que2C)/ 10
Scale 2: Coping--Behavior Que3H: I have sex less often than I would like to (agreement, 4 points) Que3J: The possibility of bowel accidents is always on my mind (agreement, 4 points) Que2J: I feel I have no control over my bowels (frequency, 4 points) Que3N: Whenever I go someplace new, I specifically locate where the bathrooms are (agreement, 4 points) Que21: I worry about not being able to get to the toilet in time (frequency, 4 points) Que3C: I worry about bowel accidents (agreement, 4 points) Que2M: I try to prevent bowel accidents by staying very near a bathroom (agreement, 4 points) Que2K: I can't hold my bowel movement long enough to get to the bathroom (frequency, 4 points) Que2F: Whenever I am away from home, I try to stay near a restroom as much as possible (frequency, 4 points)
Scoring = (Que3H + Que3J + Que2J + Que3N + Que21 + Que3C + Que2M + Que2K + Que2F)/9 Scale 3: Depression
Quel: In general, would you say your health is (excellent-poor, 5 points) Que3K: I am afraid to have sex (agreement, 4 points) Que31: I feel different from other people (agreement, 4 points) Que3G: I enjoy life less (agreement, 4 points) Que3F: I feel like I am not a healthy person (agreement, 4 points) Que3D: I feel depressed (agreement, 4 points) Que4: During the past month, have you felt so sad, discouraged, hopeless, or had so many problems that you wondered if anything was worthwhile? (extremely so-not at all, 6 points)
Scoring + [(Quel • 4/5) + Que3K + Que31 + Que3G + Que3F + Que3D + (Que4 • 4/6)]/7 Scale 4: Embarrassment
Que2L: I leak stool without even knowing it (frequency, 4 points) Que3E: I worry about others smelling stool on me (agreement, 4 points) Que3A: I feel ashamed (agreement, 4 points)
Scoring = (Que2L + Que3E + Que3A)/3
Que = question. * Adapted with permission from Rockwood et aL TM
Published copies of the Fecal Incontinence Quality of To improve proper completion of the questionnaire, this
Life Scale include a "not applicable" endorsement category. endorsement category should be excluded.
is evaluated individually. No reliability information has been published. In a group of 88 patients who
had fecal incontinence treated with dynamic gracilo-
plasty, significant improvement from preoperative status was noted for all items of the TyPE specifica- tion. Although too little is known about this measure
to endorse its widespread use, it may prove very useful and certainly warrants further investigation.
Utility-BasedMeasures. Utility-based measures pro- vide an alternative and perhaps more individualized method to evaluate the impact of disease and treat-
ment on quality of life. 65 Initially created for eco-
nomic analysis, utility-based measures assess an indi-
vidual's preference for a given state relative to death
and perfect health. Complete wellness is given a util- ity value of 1.0 and death, a value of 0.0. A health state
other than complete wellness receives a value some- where be tween these extremes. There are several
standard methods available to determine utilities. One of the more intuitive methods is the time tradeoff method, which is calculated on the basis of the num-
ber of years an individual is willing to give up to
1602 BAXTER E T A L Dis Colon Rectum, December 2003
Table 4. Items in the Manchester Health Questionnaire*
General health How would you describe your health? (very good- very poor)
Incontinence impact How much do you think your bowel problem affects your life? (not at all-extremely)
Role function Does your bowel problem affect you doing jobs within the home? (frequency) Does your bowel problem affect your job, or your normal daily activities outside the home? (frequency)
Physical function Does your bowel problem affect your ability to travel? (frequency) Does your bowel problem affect your physical activities (e.g., going for a walk, running, sport, gym)? (frequency)
Social function Does your bowel problem limit your social life? (frequency) Does your bowel problem limit your ability to see and visit friends? (frequency) Does your bowel problem affect your family life? (frequency)
Personal function Does your bowel problem affect your relationship with your partner? (frequency) Does your bowel problem affect your sex life? (frequency)
Emotional problems Does your bowel problem make you feel depressed? (frequency) Does your bowel problem make you feel anxious or nervous? (frequency) Does your bowel problem make you feel bad about yourself? (frequency)
Sleep/energy Does your bowel problem affect your sleep? (frequency) Does your bowel problem make you feel worn out and tired? (frequency)
Severity measures (do you do any of the following?) Wear pads to keep clean? (frequency) Be careful how much food you eat? (frequency) Change your underclothes because they get dirty? (frequency) Worry in case you smell? (frequency) Do you get embarrassed because of your bowel problem? (frequency)
* Adapted with permission from Bugg et aL 6a
achieve a perfect health state. As an example, using
this method, an incontinent patient would choose
be tween the current level of incontinence for life and a shortened life expectancy with normal continence. The difference is increased or decreased until the
Table 5. Items Included in the TyPE Specification Scale*
During the past 4 weeks, did fear of bowel accidents or leakage limit your participation in the following activities? (using frequency scale)
Walking Vigorous exercise Household chores Visiting friends Driving Sexual relations Employment Traveling Church or temple attendance Shopping * Adapted with permission from Wexner et aL s"
point of equivalence is reached. If the patient reached
this point at 25 years of perfect health vs. 35 years of incontinence, then the utility of incontinence would
be 25/35 = 0.7 (if all future years of health are con- sidered to have equal utility). Utilities may be com-
bined with estimates of life expectancy to produce
quality-adjusted life-years. Utility measures produce a highly individualized
assessment of the impact of a disease state on quality
of life and also produce a single value (vs. several
values from several subscales), an attractive feature for research. They are, however, labor and cost inten-
sive and are cognitively quite complex. This limits the use of utility measures as outcome measures for most
research. Utility measures have not been used in in-
continence research, and the routine use of such mea- sures cannot be recommended. However, for studies
focused on the impact of incontinence on quality of
life, utility-based measures may be particularly suit- able, and certainly research using these types of mea-
sures has the potential to enrich our understanding of
the impact of fecal incontinence and provide infor- mation for cost-effectiveness studies and decision analysis.
A quality-of-life measure that can be thought of as
a hybrid between standard questionnaires and utility
measures is the Direct Questioning of Objectives (DQO) 66'67 measure. The DQO has been used in the
gastroenterology literature to assess quality of life in patients on home parenteral nutrition, 66 after surgery for inflammatory bowel disease, 67-69 and after the
Whipple procedure 7~ and has recently been used to
assess the impact of neuropathic fecal incontinence on quality of life. 62'71 Briefly, to calculate the DQO, a
patient spontaneously lists various objectives that are
Vol. 46, No. 12 MEASURING FECAL INCONTINENCE 1603
important to them, such as shopping, traveling, or
working. The patient then rates the importance of
each objective on a scale from zero to ten and their ability to perform the objective on a scale from zero to
ten. The product of ability and performance for each
objective is calculated and divided by ten. This num-
ber is added for all objectives and divided by the importance scores for all objectives. This produces a
score from 0 to 1.0. The score may be recalculated at
any time by measuring current ability to perform the listed objectives, enabling before and after compari-
sons. The initial generation of objectives and impor-
tance/ability ratings requires assistance by trained personnel, and this is cognitively a more complex task
than completing a questionnaire. The result, however,
is a highly personal assessment that includes only
aspects of incontinence of importance to an individ-
ual patient and is therefore more directly relevant to the specific individual. Such a measure may be more
sensitive to change than other measures, although this is untested.
Because the measure is a hybrid, it is difficult to
assess the reliability and validity of the DQO. Results of the measure do not produce true utilities, and thus,
use of the DQO in economic or decision analysis is
suspect. From a psychometric perspective, that the measure is more individualized does not necessarily improve the construct validity over more conven-
tional measures. If quality of life for patients with fecal incontinence is a single definable concept or group of
concepts, measuring only certain individualized ob- jectives may in fact decrease the validity of the mea-
sure, particularly when groups of patients are being
compared. However, the DQO may be more useful than standard measures in the treatment of individual patients, for w h o m goals of therapy may be defined
by individual objectives and the success of treatment
in achieving these goals may be assessed directly.
C O N C L U S I O N S
The measurement of incontinence has improved
significantly but continues to evolve. Because fecal
incontinence is a symptom, the subjective perception of the patient must be the foundation of any evalua- tion of incontinence or the impact of incontinence. There are a large number of measures available to
evaluate symptom severity and a growing number to measure disease impact. When possible, existing
measures should be chosen for end points in research studies. Precious resources should be invested in de-
veloping new measures only when a clear need is
established. More fundamental research evaluating
the reliability and validity of the measures and com- paring various measures would enrich our under-
standing of these tools and improve our ability to
evaluate fecal incontinence and response to treatment
both for research and clinical use. To better under-
stand the impact of fecal incontinence on patients, researchers should incorporate QOL assessments into
any intervention studies.
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