Measuring Fecal Incontinence

Diseases of the Volume

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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. Because fecal incontinence is a symptom, the subjective perception of the patient must be the foundation of any evaluation 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 summary 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 presented in this review. [Key words: Fecal incontinence; Measurement; Quality of life; Function; Outcome assessment] Baxter NN, Rothenberger DA, Lowry AC. Measuring fecal incontinence. Dis Colon Rectum 2003;46:1591-1605. ecal incontinence is c o m m o n 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.

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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 reprints are available. DOI: 10.1097/01.DCR.0000098906.61097.1C No

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 limited utility in grading severity or evaluating outcomes. Objective measures such as anal manometry, nerve conduction studies, electromyography, defecography, and endoanal ultrasonography do not measure incontinence. Although findings on any of these studies may be associated with incontinence, they are inadequate measures to determine incidence and severity of incontinence or response to therapy. For example, in a study of 468 consecutive people undergoing endoanal ultrasonography, including 335 incontinent patients, 115 continent patients, and 18 asymptomatic female volunteers, the prevalence of sphincter defects was 65, 43, and 22 percent, respectively. 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 incontinence. Similarly, in a study that compared the results of anal manometry in 40 volunteers and 23 patients with fecal incontinence, one-fourth of incontinent patients had resting and squeeze pressures within the normal range, which highlights the limitations of measuring incontinence with manometry. 5

How Should Incontinence Be Measured? Incontinence could be measured simply as present or absent. The limitations of such an approach for 1591

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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 accurately reflect patient experience, because incontinence type and frequency and the duration of symptoms are not specified. More detailed measures are therefore necessary. The evaluation of fecal incontinence requires consideration 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 incontinence and produce summary scores based on the addition of values for each category. Impact measures attempt to evaluate the effect of incontinence on emotional, social, occupational, and physical functioning and are best thought of as disease-specific quality-oflife measures. Although measurement of disease-specific quality of life is challenging from a design perspective, 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 incontinence by severely restricting activities. Such a patient would be considered to have "severe" incontinence 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 evaluate a subjective p h e n o m e n o n 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 ongoing process, and evidence for the reliability and validity of a measure evolves over time. Having said

Dis Colon Rectum, December 2003

this, few measures of incontinence have been submitted to a rigorous evaluation.

Reliability Useful measures must be reliable; that is, scores must reflect the underlying p h e n o m e n o n and not measurement error. The ratio between total score variation and variation related to error gives an assessment 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 testretest reliability, is an easily understood assessment. In patients w h o 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 random 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 measurement 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 observed 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 incontinence and differences caused by the limited sampiing of all possible items measuring all possible aspects of incontinence. Measures of internal consistency estimate reliability on the basis of the average correlation a m o n g 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-

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suring more than 1 thing). The most c o m m o n l y used measure of internal consistency is coefficient alpha. Validity The lack of a criterion standard for any subjective p h e n o m e n o n such as incontinence makes assessment of validity particularly challenging. Simply stated, a valid instrument measures what it purports to measure. Validation of a subjective p h e n o m e n o n may be divided into four aspects: face validity, content validity, construct validity, and sensitivity to change. 1~ Face Validity. Classically, face validity evaluates "the extent to which the test taker or s o m e o n e else (usually s o m e o n e w h o is not trained to look for formal evidence of validity) feels the instrument measures what it is intended to measure. ''14 This has b e e n 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 "eyeball" 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 measure to ensure that all important aspects of the phen o m e n o n have b e e n included and that unrelated areas have not. 15 In assessing content validity, it is important to consider the method of choosing items, because some methods are more susceptible to inappropriate inclusions or exclusions than other methods. For instance, if item generation for an incontinence measure did not include patient input, important aspects of incontinence might be omitted. There may be some aspects of incontinence (for example, urgency) that would be more likely to have b e e n included if incontinent individuals participated in measurement development. This is important to note, because with only a few exceptions, incontinent patients have not b e e n involved in development of incontinence measures, particularly in the item-generation phase. Construct Validity. No criterion standard for the measurement of incontinence exists, and thus n e w measures cannot be validated by comparison with such a standard. Other indirect methods of assessing validity must therefore be used. To demonstrate construct validity, hypotheses regarding the predicted behavior of a valid measure are generated and then tested through research. Evidence of validity is provided if the research findings support the p r o p o s e d

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hypothesis. Several different types of hypotheses may be generated. A significant difference in incontinence score should be found b e t w e e n groups expected to differ in terms of continence. For example, construct validity could be evaluated by comparing females w h o had a fourth-degree obstetric tear with a group of nulliparous females. Finding a difference in score b e t w e e n these two groups would support the construct validity of a fecal incontinence measure. In addition, scores on related measures should have significant correlations. For example, results of a disease-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 m a y not adequately reflect change, particularly w h e n change is anticipated to be small despite being clinically important. If a measure has not b e e n adequately evaluated for sensitivity, the failure to find differences in studies using the measure m a y b e the result of a lack of difference or m a y 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 w h e n determining the effect of treatment and thus should be considered separatelyJ 8 AVAILABLE MEASURES There are m a n y measures of fecal incontinence available. These can be broadly categorized into descriptive 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 s u m m a r y score is calculated for these measures, and thus each item must be evaluated separately. This approach m a y be useful for population-based research, for example, to determine the incidence of incontinence symptoms. However, because no single score or small n u m b e r of scores is calculated, these measures are difficult to use in research studies. Multiple comparisons lead to problems with Type I error. 19 In addition, answers to single items are inherently less reliable than welldeveloped multi-item scales, 9 and with few response categories for each item, differences b e t w e e n individ-

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uals and change within an individual are difficult to detect, particularly w h e n differences are small. Having said that, the large n u m b e r of widely varied items used by descriptive measures provides a rich sampiing of incontinence symptoms and in certain circumstances m a y be very useful. In addition, with further research, summary scores for these measures might be developed. Three descriptive measures have b e e n used for research purposes.

Mayo Clinic Fecal Incontinence Questionnaire. This questionnaire was designed to measure prevalence of fecal incontinence in the community and risk factors associated with incontinence. 2~ It assesses numerous aspects of incontinence, including stool leakage, 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 develo p e d questions for the measure without input from incontinent patients. The authors tested the questionnaire on 94 individuals and assessed validity by comparing self-report responses with responses from telep h o n e 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 reluctance to discuss incontinence on the phone. Other authors have not used the measure, and further research would be r e c o m m e n d e d before wide acceptance. Osterberg Assessment of Patients With Fecal Incontinence and Constipation. A group of Swedish investigators 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 incontinence demonstrated g o o d reproducibility in incontinent patients. However, frequency of incontinence 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 m a y 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

Dis Colon Rectum, December 2003

treatment for incontinence, and statistical improvement 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 b e e n summed, and the summary score was found to be sensitive to change w h e n patients with neurogenic fecal incontinence were c o m p a r e d before and after electrostimulation of the pelvic floor. This measure may be particularly useful in the evaluation of patients with multiple symptoms; however, reliability needs to be established. Further research developing 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 patients after sphincteroplasty. Details of item generation are not given. The questionnaire addresses several items relating to incontinence, including fecal urgency/urge fecal incontinence, passive incontinence, and postdefecation incontinence. In addition, there are several questions that ask the respondent to compare current symptoms with those before surgery. No assessment of reliability was performed. As a purely descriptive tool, the measure a p p e a r e d useful; however, further research and d e v e l o p m e n t of summary scales should be pursued before widespread use of this postoperative measure.

Severity Scores Grading Systems. Numerous fecal incontinence scales, both grading and s u m m a r y scales, exist and have b e e n reviewed in detail elsewhere, z'z~3a In grading scales, various categories of incontinence are assigned a particular grade in an ordinal fashion (Table 1). Although there are individual nuances in categorization, the similarities of these scales far outweigh 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 incontinence to liquid stool. Although this is clinically intuitive, 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 n u m b e r of categories, these scales lack the ability to differentiate

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MEASURING FECAL I N C O N T I N E N C E

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between patients with minor differences in incontinence 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 b e e n evaluated and is of questioned reliability and validity. To avoid bias, patient completion of any incontinence measure is strongly r e c o m m e n d e d 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 w e e k and could not control a solid stool; severe = wear a perineal p a d 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 W o m a c k 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 m a n y inconsistencies, inadequacies, and lack of precision of the grading scales, they are not to be r e c o m m e n d e d as the sole method of categorizing patients or monitoring outcome. S u m m a r y Scales. Summary scales attempt to address some of the deficiencies of grading scales. These scales acknowledge that incontinence is not an "all or none" p h e n o m e n o n and that various aspects of incontinence, including frequency, contribute to severity. In addition, by producing multilevel summative scores, they are m u c h more likely to enable differentiation b e t w e e n groups and detection of clinically important change. Twelve summary scales 32-43 have b e e n 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, incontinence 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 frequency category varies from more than once per w e e k to more than twice per day. The lowest frequency category (other than never) also varies, from less than once per month to up to three times per

Dis Colon Rectum, December 2003

month. Thus, some scales m a y better differentiate patients with frequent episodes of incontinence, whereas others may be more useful in patients with infrequent episodes. The n u m b e r of categories for frequency range from three to six, with most having four categories (including never). The n u m b e r and range of frequency categories m a y be important if one is looking for small differences in severely incontinent groups. For example, if the highest frequency includes one or more times per week, i m p r o v e m e n t after treatment from daily to weekly incontinence will not be detected. No scale relates the frequency of incontinent episodes to the n u m b e r of total bowel movements, and this may lead to an underestimation of severity in those patients w h o 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 b e t w e e n scales. Some scales value all types of incontinence equally; for example, in the J o r g e / W e x n e r Continence 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 subjective experience of the patient, because both a patient incontinent to gas once per w e e k (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 b e t w e e n solid and liquid stool made by most scales has not b e e n validated and again may not reflect the subjective experience of the incontinent individual. Other authors have chosen a different approach, giving variable weights to the same frequencies of different types of incontinence. The manner of assigning values varies. Most authors have arbitrarily chosen values that tend to reflect severity of sphincter impairment. For example, in Rothenberger's scale, 4~ incontinence 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 w e e k (value -- 3) and incontinence to liquid stool three times per year (value = 4) would score

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MEASURING FECAL INCONTINENCE

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seven, whereas an individual incontinent to solid stool only on a daily basis would score nine. However, 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 developed a severity measure (the Fecal Incontinence Severity Index (FISI)) that assigns values to various frequencies and types of incontinence on the basis of subjective ratings of severity. The scale has six frequency 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 incontinence 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 authors 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 incontinence 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 concerning; this study should be replicated in other populations before widespread adoption of these particular values. Although almost all severity measures evaluate gas, liquid, and solid stool incontinence, six scales evaluate other aspects of incontinence, including incontinence of mucus, soiling, urgency, and difficulty cleaning. 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 alterations related to incontinence. 33'34'36'37'4~The appro-

Dis Colon Rectum, December 2003

priateness of these inclusions (or exclusions) becomes 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 individual fastidiousness vs. severity of incontinence and therefore may represent an inappropriate inclusion. Scale users must determine the salient aspects of continence for measurement in a particular patient or a particular study and choose a severity score accordingly. Relatively little research has evaluated the reliability of incontinence severity measures. One study evaluated test-retest reliability for four incontinence scales in 13 incontinent patients. 36 The scales evaluated included 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 frequencies ranging from less than once per week to daily; Table 2). Acceptable reliability (intraclass correlation 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 studies 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 patients with a clinically good outcome after sphincteroplasty than in those with a clinically poor outcome. 47

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In addition, some measures have b e e n demonstrated to be sensitive to change, with significant score improvement 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 patients to record incontinent events in real time and thus may reduce the bias introduced by relying on patient memory. This has not b e e n 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, m a n y patients entered data for times w h e n 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 potential for recall bias w h e n diary entry is used. Palm handheld computers and electronic entry may improve compliance and satisfaction with diaries. 51 Incontinence should never be limited to a measure of frequency based on diary entries, because individuals often make dramatic lifestyle changes to avoid incontinence. Because of this, measurements of frequency may be a p o o r measure of severity in m a n y individuals. 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 validity of these scales, it is difficult to r e c o m m e n d 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 reliability 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 p a d usage may limit the face and content validity of the measure. Given the subjective nature of incontinence, the incorporation of patient values into severity m e a s u r e m e n t has b e e n a major step forward. Although more research with the tool is necessary, the Fecal Incontinence Severity Index 32 is r e c o m m e n d e d for use w h e n incontinence occurs frequently; however, the lack of assessment of urgency in this measure may limit applicability. Impact Measures. Although it is important to k n o w the severity of fecal incontinence, it is also important

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to understand and measure the impact of fecal incontinence on patients, or rather the effect of fecal incontinence 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 m e a s u r e m e n t 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 debated, generally most questionnaire-based quality-oflife measures evaluate the impact of disease and treatment on physical, social, and emotional function and may include perception of overall well-being. 52 Generic questionnaires, such as the SF-36, include items of relevance to broad populations of individuals and m a y be applied to both the ill and the well. Such measures often have a long history of use with established reliability, validity, and population norms. In addition, generic measures allow comparisons between disease groups and m e a s u r e m e n t of unexpected consequences of disease and treatment. Although so-called generic quality-of-life measures have proved useful w h e n various normal and diseased groups are compared, in m a n y disease states these measures are not specific enough to detect small changes or differentiate b e t w e e n individuals with varying severity of the same disease. 53 Diseasespecific measures allow evaluation of individuals within disease groups, and in the case of fecal incontinence, several specific measures exist and a p p e a r highly useful. Nonetheless, functional impairment caused by fecal incontinence appears to be severe and global enough to be measured with generic quality-of-life instruments. Patients with fecal incontinence have significantly worse scores on the SF-36 than continent individuals. 46 In addition, the SF-36 is sensitive enough in this population 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 b e e n d e v e l o p e d for the adult population and are

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freely available for use. Two of these produce summary 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 selected 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 domains of quality of life (lifestyle, coping-behavior, depression, and embarrassment), and 12 items not fitting into this domain structure were eliminated. The n u m b e r 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 g o o d reliability. Test-retest reliability was assessed by telephone responses of 47 individuals. Unfortunately, no reliability coefficient was calculated; however, the test and retest scores did not differ statistically. Scores of continent and incontinent patients were c o m p a r e d 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 incontinence severity measures, 45'58'59 which provides evidence of convergent validity. The measure has b e e n found to be sensitive to change, with statistically significant improvements in scores after artificial sphincter implantation 58'6~ and biofeedback. 62 This measure 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 Questionnaire)Y '64 The basic structure of the original questionnaire was maintained, including assessment of physical limitations (2 items), social limitations (3 items), role limitations (2 items), emotions (3 items), sexual function (2 items), sleep/energy (2 items), general health perceptions (1 item), incontinence impact (1 item), and incontinence severity (5

Dis Colon Rectum, December 2003

items). A ten-item s y m p t o m 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 incontinence. 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. O f these patients, 121 completed a second questionnaire, which allowed test-retest reliability to be assessed. The authors compared 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 c o m p a r e d with scores on the SF-36. The authors state there were modest to strong correlations of domains between the MHQ and the SF-36; however, the pattern of correlation b e t w e e n the individual scales of the measures was not specified. Two items were selected from the s y m p t o m inventory as representing frank incontinence (bowel leakage w h e n coughing or sneezing and bowel leakage w h e n walking). Scores on these items were a d d e d and correlated 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) b e t w e e n 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 research 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 a p p e a r promising. The addition of a sleep/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 useful. 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

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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 Life Scale include a "not applicable" endorsement category. To improve proper completion of the questionnaire, this endorsement category should be excluded.

is evaluated individually. No reliability information has b e e n published. In a group of 88 patients w h o had fecal incontinence treated with dynamic graciloplasty, significant i m p r o v e m e n t from preoperative status was noted for all items of the TyPE specification. Although too little is k n o w n about this measure to endorse its widespread use, it may prove very useful and certainly warrants further investigation. Utility-BasedMeasures. Utility-based measures provide an alternative and perhaps more individualized method to evaluate the impact of disease and treat-

ment on quality of life. 65 Initially created for economic analysis, utility-based measures assess an individual's preference for a given state relative to death and perfect health. Complete wellness is given a utility value of 1.0 and death, a value of 0.0. A health state other than complete wellness receives a value somewhere b e t w e e n 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 number of years an individual is willing to give up to

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Table 4. Items in the Manchester Health Questionnaire*

Table 5. Items Included in the TyPE Specification Scale*

General health How would you describe your health? (very goodvery 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

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 e t aL s"

achieve a perfect health state. As an example, using this method, an incontinent patient would choose b e t w e e n the current level of incontinence for life and a shortened life expectancy with normal continence. The difference is increased or decreased until the

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 considered to have equal utility). Utilities m a y be combined 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 intensive and are cognitively quite complex. This limits the use of utility measures as outcome measures for most research. Utility measures have not b e e n used in incontinence research, and the routine use of such measures cannot be recommended. However, for studies focused on the impact of incontinence on quality of life, utility-based measures may be particularly suitable, and certainly research using these types of measures has the potential to enrich our understanding of the impact of fecal incontinence and provide information 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 D Q O has b e e n used in the gastroenterology literature to assess quality of life in patients on h o m e parenteral nutrition, 66 after surgery for inflammatory bowel disease, 67-69 and after the Whipple procedure 7~ and has recently b e e n 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

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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 number 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 m a y be recalculated at any time by measuring current ability to perform the listed objectives, enabling before and after comparisons. The initial generation of objectives and importance/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 individual 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 D Q O 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 conventional measures. If quality of life for patients with fecal incontinence is a single definable concept or group of concepts, measuring only certain individualized objectives may in fact decrease the validity of the measure, particularly w h e n groups of patients are being compared. However, the D Q O 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 m a y be assessed directly. CONCLUSIONS The m e a s u r e m e n t 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 evaluation of incontinence or the impact of incontinence. There are a large n u m b e r of measures available to evaluate s y m p t o m severity and a growing n u m b e r to measure disease impact. When possible, existing measures should be chosen for end points in research studies. Precious resources should be invested in de-

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veloping n e w measures only w h e n a clear n e e d is established. More fundamental research evaluating the reliability and validity of the measures and comparing various measures would enrich our understanding of these tools and improve our ability to evaluate fecal incontinence and response to treatment both for research and clinical use. To better understand the impact of fecal incontinence on patients, researchers should incorporate QOL assessments into any intervention studies.

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