Inflammatory bowel disease can impact on a patient's ability to maintain normal physical and mental function, and fulfil their social, family and work roles. Aspects of disability in IBD have received little attention.
Inflammatory bowel disease can impact on a patient's ability to maintain normal physical and mental function, and fulfil their social, family and work roles. Aspects of disability in IBD have received little attention.
To develop, validate and apply a questionnaire directed towards evaluating these disease aspects.
A literature review on disability in IBD was undertaken, and opinion about aspects of disability to measure was sought from six IBD-specialised gastroenterologists. A questionnaire was developed, and IBD patients completed the new disability questionnaire, the SF-36 and the short-IBD (SIBDQ - 10 point). A subgroup of patients completed the questionnaire again 4 weeks later. Healthy volunteers were studied as a control group.
A total of 116 IBD out-patients were approached, of whom 81 (52 Crohn's disease and 28 ulcerative colitis) participated. Nineteen patients were re-evaluated at 4 weeks. Twenty-five controls were studied. All subscales demonstrated good Cronbach's alpha reliability and reproducibility. There was a significant inverse correlation between the disability score and the SIBDQ and between the disability score and the SF36 and a positive correlation with the Crohn's Disease Activity Index (CDAI) (all P < 0.001). Disability differed between ulcerative colitis and controls, but not between active and inactive disease.
The new disability questionnaire is sensitive for detecting disability, is reliable and reproducible, and correlates with disease activity in Crohn's disease, but not ulcerative colitis. Further prospective testing is now needed in the longer term, larger patient populations and in different countries and ethnicities.
The inflammatory bowel diseases (IBD), Crohn's disease (CD) and Ulcerative Colitis (UC), are chronic disorders with a variable clinical course.[1, 2] In Crohn's disease, there is often a progressive decline in the proportion of patients with pure inflammatory disease and an increase in those who develop complications.[3, 4] In the case of ulcerative colitis, disease may become more extensive with time, and the cumulative incidence of complications, such as colectomy and development of cancer increases.
The onset of disease is often in childhood, teens or early adulthood. Recent epidemiological studies have suggested an increase in the incidence of childhood-onset IBD, particularly for Crohn's disease.[5, 6] Preliminary data suggest that disease behaviour in those with childhood onset may be more severe than those with adult-onset CD.[7-9] The young age of onset, more severe disease in those with young onset and the propensity to develop complications progressively all have consequences for the long-term prognosis, and impact on future disability and quality of life.
To appreciate the impact of disease progression, it is necessary to understand the natural history of these conditions. In a population-based inception cohort study of ulcerative colitis in Norway in the 10 years after diagnosis, the cumulative rate of colectomy was approximately 10%, relapsing disease was present in over 80% of patients and approximately 20% had progressed from proctitis or left sided colitis to extensive colitis.
In a recent study, the cumulative relapse rate during the first 10 years of Crohn's disease was 90%, and the cumulative probability of surgery was 38%. Independent predictors for the requirement for surgery were terminal ileal disease location (P < 0.001), stricturing disease (P = 0.004), penetrating behaviour (P < 0.001) and age younger than 40 years (P = 0.03). More severe physical disease, termed ‘disabling’ disease, arose through chronic inflammation, frequent clinical relapses and the clinical consequences of irreversible intestinal lesions or resections. The predictors of such physical, disease-related, gut ‘disabling’ Crohn's disease at diagnosis for the subsequent 5 years, in a referral centre, were age below 40 years, the presence of perianal disease and an initial requirement for systemic steroids. The rate of ‘disabling’ disease within 5 years was reported to be 58% and the rate of severe disease 37%, with stricturing disease and weight loss at diagnosis representing independent poor prognostic risk factors.
The symptoms associated with active inflammation, the development of gut-related complications[13, 14] and adverse effects from medications are just one part of a patient's life. Despite the increased use of biological therapies, the rates of major abdominal surgery and hospitalisation(s) remain high in the long term. The disease itself may have major effects on psychological well-being. In addition, the disease, through its physical and mental effects, can substantially impact on quality of life, both in Crohn's disease[18, 19] and UC.[20, 21] Finally, inflammatory bowel disease may directly or indirectly impact on a patient's ability to maintain normal physical and mental day-to-day functions, and fulfil their roles as a social individual, worker and family member. These conditions also have significant economic consequences for the individual and for society.
A more holistic approach to chronic disease management carries with it more intense consideration of quality of life and disability. Disease-related quality of life is generally regarded as the subjective experiences and feelings of the patient in relation to their condition. In contrast, disability is regarded as the limitations and restrictions to normal activity that a patient may experience as a result of their disease. Disability can manifest along several domains, including impaired body function and structures, activity limitation, and participation restrictions, in the interaction with environmental factors.
The World Health Organisation has attempted to standardise the definition and measurement of disability in a range of diseases, within a disease-specific framework termed the International Classification of Functioning (‘ICF’), with such measurements complementing the medical diagnoses. The ICF-based definition of disability is addressed in the United Nation Convention on the Rights of Persons with disabilities in 2006. The data collected regarding disability are objective descriptions that differ from subjective appraisals, such as quality of life, well-being and personal satisfaction with life. The WHO has developed ICF core sets for various disease states, including ischaemic heart disease, chronic obstructive pulmonary disease and pain.[25-27]
The ability to define and measure disability in inflammatory bowel diseases remains an unmet need. Such measures would enable a focused approach in the provision of medical and social services to patients with these disorders. A working group has recently reported on the initial attempts to develop tools for the measurement of disability in inflammatory bowel diseases. The goals of the current study were to develop further means for measurement of disability in IBD.
This study involved the following components:
A detailed search and review encompassing the medical literature from January 2004 to January 2010 was undertaken. The databases Medline and Embase, and abstracts from the American Digestive Disease Week (DDW) and United European Gastroenterology Week (UEGW), were searched to include the terms: functioning and disability, cross-referencing with Crohn's disease, ulcerative colitis and inflammatory bowel diseases.
Their opinion about the disabilities suffered by patients with IBD was sought from five specialist gastroenterologists (SJB, SB, WRC, PRE and MAK) at St Vincent's Hospital in Melbourne, Australia, and one French specialist gastroenterologist working in the USA at that time (LPB). These opinions were incorporated into the preliminary questionnaire.
A questionnaire was developed, using items identified from articles on disability in IBD, the expert survey and the ICF checklist for functioning and disability. The questionnaire comprised the following domains; demographics, mobility, gastrointestinal-related problems, self-care, major life activities, mental health and interaction with the environment.
The majority of questions were scored by patients according to a 5-point Lickert scale (no limitation, slight limitation, moderate limitation, severe limitation, worst limitation), and a visual analogue scale (zero = no limitation to ten = maximum limitation). Some questions were a choice between a yes or no answer.
Patients aged 18 or over were recruited from the inflammatory bowel disease clinic at St Vincent's Hospital Melbourne. Any patient with an established diagnosis of IBD, based on the revised criteria by Lennard-Jones and Shivananda, and who could speak adequate English, was asked to participate. Patients completed the newly developed disability questionnaire, the SF-36 and the short-IBD (SIBDQ - 10 point).
Data were collected about patients’ current disease state with respect to disease activity, using the Crohn's Disease Activity Index (CDAI) and a modified (excluding sigmoidoscopy) ulcerative colitis disease activity index (UCDAI). Laboratory data were collected to complete the CDAI. Within 4 weeks after they first completed the new disability questionnaire a subgroup of patients were asked to complete the identical questionnaire again.
Healthy volunteers, largely hospital employees, without IBD or other medical conditions were studied.
This study was approved by the Research and Ethics Committee at St Vincent's Hospital, Melbourne. All patients gave informed consent to participate.
Data were analysed using spss (Version 17; SPSS Inc., New York, NY, USA). Cronbach's alpha was calculated to assess the internal consistency/reliability of the 5- and 10-point Likert scale questionnaires. Pearson's correlation coefficient was used to assess convergent validity of the IBD index and the correlation between the IBD index score and the UCDAI. A reliability coefficient by Bland and Altman was used to assess reproducibility of the total IBD index and subscales. Finally, independent sample t-tests were used to compare the mean IBD index scores between patients and controls and subscale means between active and inactive patients.
One hundred and sixteen consecutive patients with inflammatory bowel disease were approached to participate in the study. Of these, 81 patients were successfully recruited (response rate: 70%) and form the basis of this study.
Forty-one patients were male subjects (51%) and 40 (49%) female subjects, with a median age of 39 (range: 18–75) years. Fifty-two patients had Crohn's disease (64%), 28 ulcerative colitis (35%) and one indeterminate colitis (1%).
The number of operations that the patients had experienced included: none (n = 36); one operation (n = 16); two operations (n = 7); three operations (n = 6), four operations (n = 4) and greater than four operations (n = 12 patients). Six patients had a current stoma in situ.
The number who had received steroid treatment were: ‘currently prescribed steroids’ n = 37; ‘previously taking steroids’ n = 32; and ‘no steroids in the past 1 year’ n = 12. Medications currently and previously prescribed were: azathioprine currently (n = 23) and previously (n = 24), methotrexate currently (n = 15) and previously (n = 13) and anti-TNF therapy currently (n = 15) and previously (n = 15).
Self-scoring of current health was (total n = 81): very good (n = 1), good (n = 21); moderate (n = 33); bad (n = 16) and very bad (n = 6). Four patients did not respond to this question.
Twenty-four patients had a coexistent condition, including diabetes (n = 5), unspecified cancer (n = 3), treated depression (n = 4), asthma (n = 4) and arthritis (n = 5). Of the 81 participants, three patients received a disability pension. Nineteen patients (11 Crohn's disease and eight UC) were re-evaluated at 4 weeks.
Twenty-five healthy control volunteers were studied. Their median age was 41 years (range: 42–63) and their median BMI 24.1 (Range: 19.1–41.1). Self-scoring of current health was: very good n = 14, good n = 9 and moderate n = 2.
For the different subscales, there was good internal consistency/reliability on the 5-point Likert scale and the 10-point visual analogue scale for cases (see Table S2, values correspond to Cronbach's alpha reliability score between the two scales). All alpha scores were greater than 0.839 demonstrating good internal consistency for all subscales when cases and controls were combined (Table S2). The Cronbach's alpha scores were comparable for both scales; hence, the 5-point Likert scale was used in all further analysis.
Data on 25 controls were added to the case data and internal consistency assessed for both groups. Convergent validity for the individual factors on the 5-point Likert scale was assessed using Pearson's correlation (Table S3).
Using the repeatability coefficient adopted by the British Standards Institution by Bland and Altman, the total score and subscale scores showed good repeatability between the first and repeated questionnaire (Table S4).
Repeatability for the SIBDQ and SF36 between the first and second application of questionnaires (Table S5) showed good repeatability for quality of life measurement (SIBDQ and SF-36) in patients for the two assessments.
To determine whether the degree of support affected the degree of disability, for example, patients with greater support or facilitation (spouse, doctor, nurse, etc.) having different disability as measured in this questionnaire, the support subscale was compared with total IBD-disability score. There was no correlation identified between support and the total IBD-disability score (P = 0.741).
When the SIBDQ score was compared with the total IBD-disability score, a statistically significant (P < 0.001) inverse correlation was observed (Table S3). That is a lower SIBDQ score (lower quality of life - QOL) correlated with a higher IBD-disability total score (higher degree of disability). When comparing the SF36 with the IBD-disability score, there was an inverse correlation with the SF36 and IBD-disability score (P < 0.001). There was also a statistically significant (P < 0.001) inverse correlation present between the mental subscale of SF36 and the mental scale from the IBD-disability score. The self-care section was only two questions and therefore was not analysed and its meaning could not be quantified.
There was a statistically significant positive correlation between Crohn's Disease Activity Index and the IBD-disability score (P < 0.001).
Total IBD-disability score differed significantly between the overall IBD-disability score in Crohn's disease and controls (P < 0.001, t-test) (Table 1).
|Number||Mean||Standard deviation||95% confidence interval of the difference||P-value|
|Crohn's disease||35||115.74||26.85||17.224||36.161||P < 0.001|
In patients with Crohn's disease, there were significant differences (t-test) between active disease (CDAI >150 points) and inactive disease (CDAI <150 points) with regard to the disability index subscales (Table 2): support (P = 0.038), major life areas (P = 0.003), gastrointestinal symptoms (P < 0.001) and mental symptoms (P < 0.001). There was no statistically significant difference between active and inactive disease in the categories of self-care (P = 0.362) and environmental support (P = 0.071).
|Subscale||Mean difference||Standard error of difference||95% CI of the difference||Significance (P-value)|
|Major life activities||−11.866||3.536||−19.225, −4.506||0.003|
|Gastrointestinal-related symptoms||−14.715||2.369||−19.499, −0.993||<0.001|
|Mental-related symptoms||−10.648||1.788||−14.305, −6.993||<0.001|
|Environmental-related issues||−4.108||2.187||−8.586, 0.370||0.071|
There was a significant difference in overall score (P < 0.001) when comparing total IBD-disability score in Ulcerative colitis patients with the control group (Table 3).
|Number of patients||Mean disability score||Standard deviation||95% CI of the difference||P-value|
The overall IBD-disability scores did not differ between patients with active and inactive UC (Spearman's correlation, correlation coefficient 0.355, P = 0.136).
We have developed a questionnaire addressing disability in patients with IBD. It appears to be sensitive for detecting disability. We have demonstrated a significant difference in total disability score (IBD-DS) between patients with IBD (Ulcerative colitis and Crohn's disease) when compared to controls. This tool appears to be sensitive to disease activity in Crohn's disease, but not in ulcerative colitis.
This questionnaire has been shown to have good correlation between a 5-point Likert scale and 10-point visual analogue scale. It has also demonstrated good repeatability with regard to retesting. In this study, we observed an inverse correlation between the IBD-disability score and the SIBDQ and SF36, suggesting that patients with inflammatory bowel disease have significant impairment of quality of life (how they perceive this ‘disability’) and functional disability (how patients perform in their daily lives). We did not detect a correlation between patients’ support (e.g. from family, medical staff, nurses etc.) and their overall disability.
This study attempted to develop a questionnaire based on several components; a literature review, expert consensus and questionnaires. Although the tool appears to be relatively stable, reproducible, repeatable and sensitive to disease activity (Crohn's disease, but not ulcerative colitis) in the short term, it needs to be validated prospectively in the longer term. The correlation with disease activity in Crohn's disease, but not in ulcerative colitis may relate to the more chronic nature of Crohn's disease, with its associated permanent structural changes, compared with the often more transient nature of symptoms in ulcerative colitis. In this study, we did not collect information on disease phenotype - such a process may refine the information on which disease characteristics are associated with the greatest disability.
The current study was conducted in a secondary and tertiary centre for inflammatory bowel disease. Patients’ disease activity and previous surgeries may therefore have been higher than in a primary or secondary setting. However, this should not have affected the final validation or reproducibility of this study. This study evaluated patient-reported disability and disease activity, but a physician rating score may be of further value in the future.
A group which overlaps with that performing the current study have recently aimed to develop a disability index for IBD using a slightly different approach, selecting the most relevant ICF categories that are affected by IBD. Using ICF categories, a questionnaire to be filled in by clinicians, called the ‘IBD-disability index’, has been developed. This involved the selection of 19 ICF core sets categories that were used to develop the IBD-disability index: seven on body functions, two on body structures, five on activities and participation and five on environmental factors. This index has not yet been tested prospectively or validated in patients.
Inflammatory bowel disease has economic consequences for patients and society.[35, 36] In a sample of nearly 20 000 children and adults in the United States, the mean treatment costs of Crohn's disease and ulcerative colitis in the United States were estimated at $8265 and $5066, respectively, per year. For Crohn's disease, 31% of costs were attributable to hospitalisation, 33% to out-patients care and 35% to pharmaceutical claims. The corresponding distribution for UC was 38%, 35% and 27% respectively. A striking finding was that costs were significantly greater for children (less than 20 years old) than adults.
In a recent study, to assess the influence of symptoms or disease characteristics on the awarding of Social Security Benefits in Spain, the authors found that an adequate description of the disease, faecal incontinence, the number of associated diseases and the presence of a stoma were independent predictors for a benefit award. A similar study from the United States reported that the number of hospitalisations, the number of surgical interventions and low quality of life scores were associated with the awarding of benefits. Several large population-based studies have suggested that disease activity may be greatest in the 2 years after diagnosis of IBD and then plateau.[1, 2, 39] From the Olmsted Markov model, it is estimated that less than 10% of the disease duration will be spent in phases of active disease either responsive or refractory to treatment, in steroid-dependent states, or undergoing or recovering from surgery.
In a Danish study, patients were able to work every year during the disease course except during the first year, in 90% of the UC patients and 80% of the Crohn's disease patients.[1, 2] In a Dutch study, 59% of patients with UC and 69% of patients with CD had at least one episode of absence from work in the preceding year, as compared to 53% of controls. Although employment rates for patients with IBD vs. controls appears similar, there appears to be a relatively high disability pension rate in patients with CD. This relatively high health economic burden of permanent working disability in IBD is in some way explained by the relatively young age of disease and subsequent disability compared to other diseases. A negative association between quality of life and unemployment, sick leave and disability pension has been reported in patients with IBD.
In conclusion, we have developed and tested a questionnaire to quantitate the extent of disability in patients with inflammatory bowel disease. Both Crohn's disease and ulcerative colitis are associated with significant disability across a range of domains. Further prospective testing is now needed in the longer term, larger patient populations and in different countries and ethnicities.
Guarantor of the article: M. A. Kamm.
Author contributions: All authors approved the final version of the manuscript.
Declaration of personal and funding interests: None.