Identifying and Classifying Quality of Life Tools for Assessing Neurogenic Bowel Dysfunction After Spinal Cord Injury

A systematic review of the literature published between January 1975 and June 2016 was conducted using multiple online databases (MEDLINE/PubMed, CINAHL, and PsycInfo). No limit was set on publication date to ensure that all relevant articles on the topic could be identified. To identify relevant articles presenting QoL tools for assessing NBD in adults with SCI, we used the key words “spinal cord injuries” and its variants, along with the following terms: neurogenic bowel dysfunction, quality of life, participation, personal or life satisfaction, and activities of daily living. The reference lists of identified articles were also reviewed. Studies eligible for inclusion were written in English, included adult participants of whom at least 50% of the sample were persons with SCI, and contained one or more tools assessing the influence of NBD on QoL (or a related construct, such as social participation). Studies that examined global constructs of QoL post SCI, did not link QoL with NBD, contained pediatric populations or pediatric-onset SCI, or were primary qualitative studies were excluded.

Two raters independently conducted searches and then rated the titles and abstracts. Consensus on the selected abstracts was attained, and then relevant full-text articles were abstracted. If consensus could not be reached regarding article inclusion, a third rater was available for consultation. Descriptive information related to study design, participants, outcomes, and related findings were abstracted into a summary table (see Table 1). QoL outcomes were then classified according to Dijkers' theoretical framework by one rater and verified by a second rater.19,22 

Similar to previous studies that classified QoL tools used to assess the influence of different SCI-related secondary conditions,23–25 Dijkers' QoL framework was used to categorize outcome measures as being either objective or subjective and was used to provide a deeper understanding of the QoL constructs underlying each measure (see Figure 1).19,22 Briefly described, the model categorizes measures into three categories: QoL as “utility,” “achievements,” and “subjective well-being.”

QoL as utility reflects the desirability and preferences of life valuations (box A, Figure 1) and is obtained by judging one's tradition, achievements, and status in terms of societal norms and standards (box B). Hence, QoL as utility is expressed as an outsider's viewpoint (objective) and provides a metric framing QoL, typically used to support health economic analyses.22 Similarly, QoL as achievements is an objective perspective that takes into account the individual's possessions, accomplishments, status, and so on (box C), while excluding the subjective reactions to these qualities.22 Therefore, QoL is predicted by what a person has obtained in his or her life (ie, good health, marriage, etc; box C), which society generally views as indicative of what one needs to have a “good life” (box B). QoL as subjective well-being recognizes that humans develop individual priorities/wants (box E), which may range in relative importance (box D). When these needs/wants are compared to reality (box C), the resulting reactions by respondents might range from positive to negative and are likely to affect morale, life satisfaction, and other expectations (box E).22 QoL as “subjective well-being” can therefore be explained as “feelings of well-being as influenced by the good things in life.”27(p1) 

This methodology was used to classify QoL outcomes specific to NBD as objective or subjective, and the relevant constructs of QoL that comprised each tool were identified (ie, A, B, C, D, E) (Figure 1). Each QoL measure was mapped to one or more QoL constructs (Figure 1) by a first reviewer and verified by a second reviewer. The psychometric properties and sensitivity of each tool to capture the impact on QoL were also summarized (Table 2).

Following duplicate removal and screening of titles and abstracts, 82 full-text articles were assessed for eligibility and 35 met the inclusion criteria. Figure 2 provides a flow diagram illustrating the search and selection of studies. The details of two randomized controlled trials,28,29 11 pre-post interventions studies,6,8,30–38 4 comparison studies,10,39–41 16 cross-sectional observational and comparative studies,4,5,42–55 1 longitudinal study,56 and 1 mixed-methods study57 are presented in Table 1.

A total of 13 QoL outcome tools were identified (5 objective, 8 subjective). Table 2 presents each QoL tool with details about the underlying QoL constructs,19,22 psychometric properties, format and scoring, administrative burden, and sensitivity of the tool to NBD.

The Medical Outcomes Survey Short Form (SF-36) was the most commonly used objective measure of health-related QoL33,34,51,52,54 (used in 5 of 35 studies). The SF-12, a shortened version of the SF-36 measuring the same QoL constructs, was also used in one study.39 Both the SF-36 and the SF-12 provide a generic assessment of physical and mental health status, derived across eight domains of health and functioning (boxes B and C, Figure 1). Specific to individuals with SCI, the SF-36 has documented reliability and validity,58 and the SF-12 has construct validity.59 Although both the SF-36 and SF-12 were sensitive to changes in QoL that were related to NBD (Table 2), neither tool has items specific to SCI or NBD. As measured by the SF-36 or SF-12, studies identified in this review showed that NBD was associated with decreased health-related QoL,54,59 with more severe cases of NBD associated with lower QoL and more mild case of NBD associated with higher QoL.51 Improvements in bowel function after sacral neuromodulation were also associated with improved health-related QoL in two studies.33,34 

The Modified Barthel Index (MBI), a measure of functional status, was used in one study.47 The MBI is an objective tool comprised of 10 items of activities of daily living that are scored for level of dependency on a scale ranging from 0 (unable to perform task) to 15 (fully independent) (boxes B and C, Figure 1). The MBI is not a measure of QoL per se but does assess key activities of daily living that have implications for QoL, and it might be a useful tool to help further validate other measures of QoL since it has been found to be a reliable tool for SCI,60 with a good internal consistency (alpha 0.88–0.90) and sufficient interrater agreement (intraclass correlation coefficient [ICC] = 0.77).61,62 The correlations between the MBI and the American Spinal Injury Association Impairment Scale (AIS) motor and sensory scales were moderate to high as expected, providing evidence of convergent validity.61 There has been limited evidence of construct validity for the bowel and bladder items in SCI.61 MBI scores have been documented to be responsive to environmental changes.61,62 However, bowel function was not associated with functional status as measured by the MBI.47 

The Health Utility Index Mark III (HUI-III) was used in one study to ascribe the burden of various secondary health conditions, including NBD, following SCI.46 The HUI-III is a comprehensive system for describing the health status of individuals and for assigning a preference (or utility) score.63 A preference score is a societal representation of well-being, which is typically reported as a single metric anchored at 0 (death) with 1 (perfect health) at the end of the ranking, thus representing a preference for a health state.64 These health state morbidities are measured across a group of individuals and combined into a utility score, which can then be used as a quality metric for calculating the number of quality adjusted life-years gained in cost-utility analyses65 (boxes A, B, and C, Figure 1). Although Craven et al46 provided some evidence with regard to QoL as utility for NBD, only preliminary evidence of concurrent validity has been established to date.66 Individuals without NBD or with mild NBD reported higher HUI-III scores than those who had moderate or severe NBD, suggesting the HUI-III is sensitive to the influence of NBD on QoL.46 An important limitation of this study was that bowel dysfunction was assessed via self-report using the Secondary Conditions Scale, which asked participants if they had bowel problems and, if so, to rate its severity (mild, moderate, or severe). Further work on the sensitivity of the HUI-III to this secondary condition is required to determine if it is sensitive to other self-reported measures or objective assessments of bowel problems.

The Craig Handicap Assessment and Reporting Technique (CHART) was used in one study to assess the degree of handicap experienced by individuals with SCI due to NBD.39 The CHART is a 32-item scale assessing the degree of handicap experienced across six areas, including orientation, physical independence, mobility, occupational functioning, social integration, and economic self-sufficiency (boxes B and C, Figure 1). The CHART is reliable and valid for use in SCI52,67 and is sensitive to the impact of NBD on QoL. Individuals who were dependent on others for bowel management reported lower satisfaction and higher perceived handicap, specifically in the physical independence, mobility, and occupational functioning domains.39 

The NBD score, the most commonly used subjective QoL tool in 5 of 35 studies,28,29,49,51,55 was developed to assess the influence of NBD on QoL in persons with SCI.49 Ten items related to symptoms of constipation and fecal incontinence and their impact on QoL are evaluated, with scores ranging from 0 (very minor bowel dysfunction) to 47 (very severe bowel dysfunction)49 (boxes C, D, and E, Figure 1). Although the questionnaire is primarily comprised of items that assess NBD symptoms from an objective standpoint, the development of this tool was based on subjective perceptions of the impact of NBD on QoL in people with SCI, and the scale has a subjective QoL item. The developers of the scale acknowledge that that their tool is vague with regard to which aspects of QoL are impacted but believe that it is likely social activities.49 Based on the tool development process, along with the inclusion of the single subjective QoL item, we have classified it as a subjective measure of QoL.

The reliability and validity of the NBD score have been established for SCI.49 The results of two experimental trials using the NBD score showed that transanal irrigation lead to improved bowel function and improved QoL (NBD score decreased by 4.5; p < .0001).28,29 More severe symptoms of constipation or fecal incontinence were associated with lower QoL in other cross-sectional studies.49,51,55 

The Burwood QoL Questionnaire was developed as a study-specific measure to assess the QoL related to bowel function after SCI and was used in two studies.10,41 The questionnaire comprises 26 items, covering five domains of functioning, including systemic symptoms and emotional, social, work, and bowel function (boxes C and E, Figure 1).41 Only preliminary face validity has been established for use in SCI populations.4,10 According to the Burwood QoL Questionnaire, incontinence influenced QoL in 62% of individuals with SCI.10 However, when used to detect the impact of colostomy on QoL, there were no differences observed between those who received a colostomy and those who did not.41 

The Survey of Neurogenic Bowel Characteristics (SNBC) contains questions about health-related (bowel program management) and non-health-related (demographic status) factors that may affect QoL (boxes C and E, Figure 1). This self-administered survey focuses on demographic aspects surrounding QoL after SCI. The SNBC seems to be sensitive to the influence of NBD on QOL, as satisfaction with bowel management was associated with higher QoL and dissatisfaction with bowel management was associated with lower QoL.8 Only face and content validity have been established for the SNBC to date.8 

The SCI-QoL Bowel Management Difficulties assesses the impact of bowel management difficulties on QoL (box E, Figure 1).57 This tool evaluates how often 26 various bowel management difficulties are experienced on a scale ranging from 1 (never) to 5 (always). Reliability and validity assessment of the final item banks have been documented.57 Furthermore, the tool can be easily administered using computer adaptive testing or short forms. The sensitivity of the SCI-QoL Bowel Management Difficulties is unknown, as the tool has not yet been used outside of this validation study.57 

The Impediments to Community Integration (ICI) Scale evaluates the impact of NBD on community participation after SCI (box E, Figure 1) through 16 statements that reflect three general areas of life (leisure activity, socializing, and feeling bad about oneself). Preliminary reliability has been established for SCI, but further evaluation is required.53 The findings of the study assessing bowel dysfunction in 103 persons with SCI suggest the ICI Scale is sensitive to the influence of NBD on QoL, as severity of bowel dysfunction significantly influenced personal relationships and feelings about oneself.53 

The Inflammatory Bowel Disease Questionnaire (IBDQ) comprises 32 questions covering the activities of daily living, intestinal function, social performance, personal interactions, and emotional status (box E, Figure 1).40 Similar to the ICI, preliminary reliability has been established for the IBDQ in SCI, but the tool was not found to be sensitive to differences in bowel function between individuals with SCI who had a colostomy and those who did not.40 

Related constructs used to assess the influence of NBD on QoL included social support (Reciprocal Social Support [RSS] Scale) and affect (Hospital Anxiety and Depression Scale). The RSS scale evaluates levels of reciprocal social support from families, friends, and the community in four areas (ie, social interaction, material assistance, emotional support, and non-paid personal assistance) (boxes C and E, Figure 1). Frequency of incontinence and material support given and received were shown to be significantly correlated in one study, but there is no evidence of the impact of bowel function and emotional support given or received.44 The RSS has acceptable internal consistency for use in SCI, but further validation is needed.68 

The HADS was developed with a focus on the patient and their mood state to screen for anxiety (7 items) and depression (7 items) (box E, Figure 1). The frequency that each of the 14 items is experienced is rated on a 4-point scale from 0 (not at all) to 3 (very often). Although not a measure of QoL per se, it is arguable that the HADS taps into the construct of affect, which would qualify it as a QoL measure of subjective well-being. Psychometric properties of the HADS in SCI have been documented,69 and HADS scores were significantly correlated with time required for bowel management.4 

The purpose of this systematic review was to identify, classify, and summarize existing tools for assessing the influence of NBD on QoL (and related constructs) after SCI. The findings of this review support efforts toward an improved conceptual understanding of QoL to ensure that investigators employ appropriate research designs and suitable outcome measures to assess this prevalent secondary health condition. The summary of QoL outcome tools may also aid clinicians in the selection of appropriate tools for assessing the impact of NBD on QoL in patients with SCI, which may guide practice.

Findings from this review show that existing tools are representative of Dijkers's three QoL domains of utility, achievements, and subjective well-being.19,22 Although no objective tool was developed specifically for SCI, all tools have been validated for use in the SCI population. Likewise, no objective tools have specific items related to NBD in SCI, but four of five tools have shown sensitivity to the impact of NBD (CHART, HUI-III, SF-36, SF-12). Five of the eight subjective tools were developed specifically to assess the influence of NBD on QoL in SCI (Burwood QoL Questionnaire, ICI Scale, NBD score, SCI-QoL Bowel Management Difficulties, and SNBC). At least some psychometric evidence has been generated for all five of these tools, and all five tools have shown sensitivity to impact of NBD. The goal of classification in this review is to assist researchers and clinicians in the outcome tool selection process, not to endorse the use of one tool over another.

Constantly evolving conceptualizations and definitions of QoL and related constructs (eg, social participation, life satisfaction) make measurement difficult and confusing for both researchers and clinicians.70 In addition to providing clear definitions and conceptualizations of QoL (eg, QoL specific to a secondary health condition in SCI),70 the inclusion of both objective and subjective tools has been suggested.28 Objective tools provide insight on what society agrees is important to health, but does not consider what is important to the individual. Conversely, subjective measures expose individuals' feelings and perceptions about their health-related issues but may overlook societal norms.71 Recommendations moving forward are that QoL assessments include a combination of psychometrically sound, objective and subjective QoL tools that cover the three QoL domains described in Dijkers' model (utility, achievement, subjective well-being) and that have shown sensitivity to NBD in SCI.

The SF-36 is among the most widely used measures of health-related QoL in the field of medicine72,73 and was the most commonly used objective measure of NBD-specific QoL in this review. The strengths of the SF-36 include that it can be administered in 10 minutes or less to provide a relatively valid and responsive tool for assessing health-related QoL according to society. Although the SF-36 has documented reliability and validity specific to SCI, there is limited evidence of its sensitivity to the impact of NBD on QoL. This limitation could potentially be minimized by pairing the SF-36 with a condition-specific tool,74 such as the NBD.

Like the SF-36, the HUI-III contains no items specific to NBD or SCI and psychometric evidence for SCI is preliminary. However, the HUI-III represents a comprehensive and potentially promising objective tool for assessing preference-based health state (ie, utility; boxes A, B, and C, Figure 1).19 Objective measurement of health utility is becoming of increasing interest in medicine and rehabilitation science, as evidence of cost utility and cost-effectiveness is most likely to inform decisions regarding resource allocation.75 Use of validated utility tools, such as the HUI-III, may help to promote evidence-based practice specific to NBD treatment in SCI.

With regard to subjective measures, the NBD score was the most comprehensive tool, incorporating both subjective domains of QoL (subjective well-being, achievements) (boxes C, D, and E, Figure 1).19 The NBD score takes 5 minutes or less to administer, has strong psychometric properties,49 and has shown sensitivity to impact of NBD on QoL in five studies (including two RCTs).28,29,49,51,55 In fact, the NBD score is the only QoL outcome tool identified in this review that showed responsiveness to change in QoL due to changes in bowel function.28,29 As noted, the majority of items on the scale reflect those typically seen in objective measures, but the underlying design of the scale, along with the inclusion of the subjective QoL items, suggests that its resulting score is reflective of subjective perceptions of the impact of NBD on QoL after SCI. Further work to determine its subjective properties should be explored by using it with other subjective measures of QoL (general and condition-specific) to confirm this assumption.

The Burwood QoL Questionnaire, ICI Scale, and SNBC captured QoL constructs related to achievements and subjective evaluations (boxes C and E, Figure 1),19 which are important for understanding whether patients' expectations are met and whether individuals are satisfied with their life, happy, and have overall perceived well-being. The SCI-QoL Bowel Management Difficulty was developed using a patient-centered approach to develop three subjective QoL outcome tools that include items about neurogenic bowel in SCI.57 From a clinical and statistical perspective, the SCI-QOL Bowel Management Difficulties items bank shows promise for measuring overall well-being and life satisfaction (Subjective Evaluations and Reactions, box E, Figure 1).19 

Three other subjective tools were identified to assess the impact of NBD on QoL (HADS, IBDQ, RSS) in this review. While the IBDQ was developed specifically to measure QoL related to bowel dysfunction, it was developed for use in individuals with inflammatory bowel diseases such as Crohn's and colitis.76 Although the IBDQ has been validated for use in SCI, the tool was not sensitive to the impact of NBD. It is likely that the items touch on condition-specific issues of NBD, but lack a comprehensive assessment of SCI-related impairments (eg, paralysis). Both the HADS and RSS are validated for use in SCI and showed sensitivity to the impact of NDB but are not QoL measures per se nor do they have condition-specific items (NBD and/or SCI).

The recent development of NBD-specific tools for SCI is timely in the advancement of SCI treatments for NBD and for revolutionizing QoL measurement. This review identified both objective and subjective tools and provided recommendations for their use based on existing psychometric properties and evidence of responsiveness to NBD impact. However, the quality of evidence to date is quite low, as most studies were cross-sectional designs. Moreover, the variability in QoL between individuals with upper motor neuron versus lower motor neuron bowel dysfunction may have important implications on QoL that have not yet been addressed.77,78 For example, individuals with upper motor NBD have a hyperreflexive bowel and experience normal or increased sphincter tone, constipation and fecal retention, with reflexive defecation. Bowel care is recommended every 1 to 3 days, and rectal suppositories or digital stimulation can be used to assist in evacuation. Conversely, individuals with lower motor NBD experience constipation and incontinence, reduced anal sphincter tone, and the defecation reflex is absent. Daily bowel care is recommended, and neither suppositories nor digital stimulate are effective. Therefore, it seems that upper motor NBD symptoms may impact less on QoL; however, current tools are not able to detect the discussed differences.

Future studies should continue to validate existing tools and provide evidence of responsiveness and clinical significance in experimental trials. More research that examines the associations between QoL and changes in NBD over time would also help to clarify whether QoL changes in persons with SCI as bowel function improves. A broader understanding of how NBD impacts QoL of individuals with SCI would facilitate better planning of services, treatment, and rehabilitation.14 In the current practice, clinicians largely direct their efforts toward addressing the health condition (ie, NBD) and its associated impact on body functions and structures (eg, loss of volitional control, bowel transit times). Better measurement of QoL and related constructs will address the expressed need for consideration of activities, participation, and contextual factors (personal, environmental) that reflect the whole lived experiences of individuals living with NBD after SCI.14 

A limitation of this review is that samples with <50% of individuals with SCI were excluded, which may introduce bias in the results. Further, information on cross-cultural applications were not available. It is also possible that we did not identify all relevant articles for inclusion.

Accurate assessment of NBD impact on QoL should be an important consideration in rehabilitation practice, as it influences the extent and nature of the treatments applied. Based on this review, promising objective (HUI-III) and subjective (NBD score, ICI Scale, Survey of Neurogenic Bowel Characteristics, and SCI-QoL Bowel Management Difficulties) outcome tools were identified for assessing the impact of NBD on QoL in SCI. Further work is recommended to increase evidence of their validity, reliability, and clinical utility. A combination of objective and subjective QoL tools are recommended to best understand the impact of NBD over time, treatments effects, clinical practice, and resource allocation issues within the health care system.