Quality measurement of quality of life

                  Alimentary tract and pancreas

                  Alimentari trakt i pankreas

                 ARCH GASTROENTEROHEPATOL 2001: 20 ( No 3 - 4):

               Review

            

             Quality measurement of quality of life in IBD

              Procena kvaliteta zivota u IBD

            

                  ( accepted December 6th, 2001 )     

              Ioannis Al. Mouzas

                 Gastroenterology Department, University Hospital, Medical         

                 Faculty, University of Crete, Greece

Address correspondence to: Dr.  I.A. Mouzas

                                                   Assist. Professor of Gastroenterology

                                                   Medical School, University of Crete

                                                   P.O. Box 1393

                                                   71110 Heraklion, Greece

                                                    FAX +30 81 542085

                                                     E-Mail: mouzas@med.uoc.gr

………………..                         ………………………………………

Quality of life in IBD               Gastroenteroloska sekcija SLD-

                                                  01715, 2001.

ABSTRACT 

Quality of life, and in particular Health Related Quality of Life (HRQOL), is an crucial aspect of illness perception from the part of patient, incorporating social, psychological, and disease related factors.  Instruments assessing HRQOL became very important in the setting of clinical trials on Inflammatory Bowel Disease (IBD).

We need valid and reliable instruments as HRQOL assessment tools. We need instruments of high quality that can reliably measure important changes in the global health status of patients with IBD. 

Among disease-specific instruments that have been proposed for the assessment of HRQOL in IBD, two have been so far widely used, being validated in several linguistic and cultural milieus: the Inflammatory Bowel Disease Questionnaire and the Rating Form of Inflammatory Bowel Disease Patient Concerns.

Quality instruments measuring HRQOL help to identify the needs of IBD patients and therefore to improve patient care but are at the same time important tools in evaluating the outcome of therapeutic interventions. Measuring HRQOL in an objective and reliable way is a prerequisite of well-designed IBD medical trials and will be much more important in the future.

Key words: IBD, quality of life, measurement.

SAZETAK

Procena kvaliteta zivota, i to posebno kvaliteta zivota kroz prizmu stanja zdravlja jedne osobe ( HRQOL ) je bitna strana dozivljavanja bolesti od strane pacijenata. Ona obuhvata socijalne, psiholoske, i cinioce vezane za samu bolest. Sredstva procene HRQOL su postala veoma znacajan deo sarzaja klinickih proba u inflamatornim bolestim creva (IBD). U cilju sagledavanja HRQOL nama su potrebna solidna i pouzdana sredstva procene. Ona moraju da budu visokog kvaliteta da bi  sa njima mogli pozdano da merimo znacajne promene opsteg zdravstvenog stanja bolesnika sa IBD.   

Medju metodama HRQOL koje su predpostavljeno specificne za grupu bolesti kao sto je IBD dve su stekle poverenje svojom pouzdanoscu i to u jezickim i kulturoloski razlicitim sredinama: IBD upitnik i Formular procene stepena pozornosti IBD pacijenata prema svojoj bolesti.

Instrumenti kvaliutativne procene u HRQOL pomazu da se otkriju potrebe pacijenata sa IBD te da se briga o njima poboljsa i da se proceni ishod terapijskih postupaka. Merenje HRQOL je objektivan i pouzdan preduslov svih IBD terapijskih protokola ispitivanja i njegov znacaj ce se u buducnosti sve vise povecavati. 

Kljucne reci: IBD, kvalitet zivota, merenje.

INTRODUCTION

The primary aim of treatment, particularly in chronic disease, is to reduce the impact of the disease, thus enhancing quality of life. At first sight, quality of life is a highly individual concept. Its assessment has been compared with the assessment of the beauty of a rose(1). No matter how many measurements are made, e.g. of color, smell, volume, the full beauty of the rose can never be captured. General quality of life measurement cannot capture all aspects of life that are important to an individual because general quality of life is linked to the specific person. However, the concept of health-related quality of life (HRQOL) limiting the field of measurement of quality to the implications of a chronic disease on every-day life of the individual, i.e. the attitudes and behaviors of daily life that are influenced by the degree of good health, has gained relevance in medicine(2).  Over the last two decades we have seen HRQOL to  develop from an ill-defined and rather indeterminate concept to a concrete and dominant indicator of health status. We can now reliably measure HRQOL as an index of subjective health status and we hope that this measurement will be even more  qualitative and reliable in the years to come.  HRQOL has been defined as "a global measure of the patient's perceptions, illness experience, and functional status that incorporates social, cultural, psychological, and disease-related factors"(3). The main practical utilization of  HRQOL consists in monitoring changes and evaluating therapeutic interventions, facilitating health-care planning and shared decision making in chronic disease, screening for hidden problems, helping patients to  identify and communicate their problems.

Inflammatory bowel disease (IBD) has an important impact on HRQOL. As long as the rationale of the management of  IBD is to get the utmost possible reduction of the impact of the disease on general well being, it is of particular importance to perform measurements of quality of life with a high quality, reliable method.

Qualitative and semi-quantitative measurements of HRQOL had been used mainly in the past. In a review on quality of life assessment in all illnesses that dates from 1987, 95% of all surgical trials reviewed used qualitative and semi-quantitative methods in a retrospective design(4). This situation has now changed in favor of randomized, controlled and prospective trials, both surgical and medical, using reliable HRQOL instruments(5), (6).

PREREQUISITES FOR A SOUND INSTRUMENT FOR MEASURING QUALITY OF LIFE

Following criteria are significant for assessing an instrument that measures quality of life in chronic disease.

Reproducibility: instruments used for HRQOL assessment should allow replication of findings(7).

  Validity: as there is no “gold standard” for HRQOL, instruments should show construct validity by correlation with other measures of function or by comparison with independently validated general instruments (8).

  Reliability: instruments for general and disease specific HRQOL measurement should have test-retest reliability in populations whose condition is stable over time. 

Understandable: instruments should be ease to use, written in understandable words and not too time consuming in their use.

Responsiveness to change: optimal measures of HRQOL should be as sensitive as possible to changes in subjective state.  Reliable but relatively insensitive measures are unable to detect changes in state before and after interventions(7).

Meaningfulness of results: the results of HRQOL measurement should be interpretable.   Semi-quantitative categories (good, fair, poor) provide little and unreliable information.

TYPES OF INSTRUMENTS FOR MEASURING HRQOL

There are three basic types of instruments (or questionnaires) for assessing the HRQOL, each one with its own advantages and limitations (table 1). These are global assessments, general or generic instruments and disease specific instruments. Global assessments provide a general impression of the patient’s HRQOL, but they do not identify specific domains of dysfunction. They are based on a single attribute, in other words they are unidimensional. General or generic instruments are multidimensional and may be applicable to many chronic diseases. Some of the most commonly used tools in chronic diseases studies are the Sickness Impact Profile (SIP), the EuroQoL and the MOS SF-36 questionnaire (SF-36). General instruments may provide comparisons between groups of patients with different chronic diseases and are useful in health service planning.  They may be used to detect similarities or differences between patient groups, but they are insensitive to changes after therapy in groups of patients with specific diseases. Disease-specific instruments are focused on identifiable aspects of HRQOL and have been specifically designed for a disease, population subgroup, a condition or a problem. Disease specific instruments are derived from general instruments and are tested against them in terms of validity.Finally, disease-specific questionnaires provide more information about particular concerns or worries of a patient group and are the most sensitive in detecting changes over time or after therapy in the HRQOL of patients (9).

GENERIC INSTRUMENTS FOR MEASURING QUALITY OF LIFE IN IBD

The Sickness Impact Profile (SIP) is a questionnaire that measures the sickness-related dysfunction of patient's performance in 12 areas of every-day life. It consists of 136 questions or items or questions divided into 12 domains. The SIP has been  used in IBD patients showing a more pronounced dysfunction in Crohn's disease (CD) than in ulcerative colitis (UC) patients, and  an overall dysfunction that was more marked in all IBD patients in comparison to a control group. Dimensions of greatest impact were worries, leisure and recreation, elimination, sleep and rest (10), (11).

The EuroQol is a standardized, non-disease-specific instrument for health states. It contains 5 items representing the following dimensions: mobility, personal care, daily activities, pain and anxiety-depression. It was developed by means of postal surveys in England, The Netherlands and Sweden and was intended to describe and value 14 different health states and to complement other quality-of-life measures.  The items are scored using a visual analogue scale ranging from no problem to extreme problem (12). EuroQol has been the object of severe criticism due to flaws in its construction and design which result to very different response rates in similar groups (13).

The Medical Outcomes Study 36-Item Short Form Questionnaire (SF-36) is another generic instrument containing 36 items divided into 9 domains. SF-36 has been used in several chronic disease patients (14),(15),(16),(17). It has been used in IBD patients resulting in a poorer score compared to a control group with mild chronic illness. The CD subgroup scored poorer than the UC one. General health perception, vitality and psychosocial were the domains where most of the differences were observed(18).

DISEASE-SPECIFIC INSTRUMENTS FOR MEASURING QUALITY OF LIFE IN IBD

The two leading disease-specific instruments for measuring HRQOL, specifically designed for IBD patients are: the Inflammatory Bowel Disease Questionnaire and the Rating Form of IBD Patients Concerns.

Inflammatory Bowel Disease Questionnaire (IBDQ)

The IBDQ is a 32- item questionnaire that was designed as an evaluative instrument for clinical trials. The first step for the development of the IBDQ was to construct a list of problems important to IBD patients, by asking 77 of them for their opinion. At a second phase the number of items was reduced by determining the items chosen most commonly and rated most important by 97 IBD patients. Serial testing to improve wording and consultation with experienced clinicians resulted in the 32-item questionnaire (7;19). These items can be grouped into four domains : gastrointestinal symptoms, systemic symptoms, emotional function and social function (Table 2). The response to each item is ranged in a 7 point Likert type scale. In this scale, 7 corresponds to "best function" and 1 to "worst function". The overall score of the IBDQ ranged from 32 to 224 (worst to best). The final version of the IBDQ was tested for reproducibility, responsiveness, and validity and scored well. The responsiveness was better than the one of a general health status measure (19). The results obtained by IBDQ are not influenced whether the questionnaire is self-administered or administered by a health-care professional or when answering it a second time by the same patient. Further, IBDQ results were not different between novice and experienced to the questionnaire IBD patients, suggesting that IBDQ is a reliable questionnaire, useful in clinical trials(20).

Gastrointestinal symptoms (diarrhea, abdominal pain) and systemic symptoms (fatigue, malaise) had the most powerful impact on HRQOL. Emotional and social dimensions were less influenced compared to intestinal and systemic symptoms, with social functions being the least influenced by IBD.

From the authors of IBDQ a short version of the questionnaire has been developed intended for application by general practitioners, called SIBDQ. (21) From the original IBDQ, 10 items-questions were selected as best predictors of the score. The same 7-point scale was used. The SIBDQ was tested for convergent and discriminant validity as well as test-retest reliability with excellent results. Additional test of SIBDQ in outpatients in an ambulatory care office gave very good results concerning validity and reliability.  Thus, the short form of IBDQ may be used in routine practical ambulatory care of IBD patients, while the original 32-items version is more research oriented.

Several studies have validated IBDQ into different language versions and have further proved its validity and reliability for different cultural and linguistic milieus (22), (23), (24), (25), (26), (27), (28). In the Dutch validation study a high reliability was observed between  both measurements of the IBDQ in patients who reported no change in bowel complaints. Construct validity was assessed by calculating Pearson correlation coefficients between IBDQ dimensional scores and both SF-36 and two Visual Analogue Scales (VAS) concerning general well being and bowel function.  Correlations were reasonable (0.40 - 0.71) for VAS and higher for SF-36 (0.50 - 0.91) (23). In the North-East England validation test-retest reliability and internal consistency were tested. Construct validity was assessed by using Colitis Activity Index (CAI) and SF-36. There was moderately high Pearson correlations between IBDQ and both CAI and SF-36 (0.30 - 0.84) (24). The Spanish version of the IBDQ was also highly reliable when  repeated in clinically stable patients with UC and CD. In the Spanish version correlations between the IBDQ (Short Version), EuroQoL, Psychological General Well Being Index and clinical indices of activity were all positive and comparable for both diseases (Spearman’s r = -0.50 to r = -0.70, p<0.01) (25). In the Korean version a strong correlation between IBDQ scores and St.Mark’s Activity Index was observed (r = -0.708, p<0.001) in UC patients.  IBDQ scores were also highly correlated both with Crohn’s Disease Activity Index (CDAI) and Harvey-Bradshaw Index (HBI) (Spearman’s r = -0.506, p<0.001 for CDAI; r = -0.600, p<0.001 for HBI) in CD patients (26). In the Swedish version of the IBDQ 300 consecutive patients with ulcerative colitis completed the IBDQ and three other HRQOL instruments. The dimensional scores had sufficient convergent validity, but low discriminant validity. Test-retest correlations were 0.40-0.76 and the sensitivity to change was also good (27). In Crete, Greece we performed a validation study of the Greek version of the IBDQ  in 114 patients with IBD. Reliability outcomes were tested by measuring intraclass correlation coefficients (ICC) between two consequent sets of measurement in stable patients. High ICC were observed for all IBDQ dimensional scores (ICC range from 0.94 to 0.99) and in both diseases.  Construct validity was tested by Pearson and Spearman correlation coefficients between the four IBDQ dimensional scores and both the SF-36 total score and a Visual Analogue Scale for general well being. Correlations were high in CD patients (0.74 - 0.88) and lower in UC patients (0.25 -0.84) regarding to both indices (28). AAs illustrated by the example of all these validation studies of IBDQ in several languages and cultural environments, this instrument has been proved to be valid and reliable. Therefore, IBDQ can reliably been applied for multicenter, multilingual, multicultural clinical trials in IBD patients.

Rating Form of IBD Patient Concerns (RFIPC)

The Rating Form of Inflammatory Bowel Disease Patient Concerns is a 25-item, self-administered questionnaire (3). The RFIPC derived from a list of 12 concerns and worries expressed by 150 IBD patients. The rest of the items were generated by video-taped patient interviews designed to encourage the expression of subjective concerns.  The validity of the RFIPC was initially tested against the Sickness Impact Profile (SIP) and the Symptom Check List (SCL-90, indicator of psychological distress) (10). A large mail survey of 320 UC and 671 CD patients followed with similar results. Correlation of the RFIPC to the SIP was 0.46 for UC and 0.48 for CD patients (Spearman’s r).  Test-retest reliability was tested over a two to ten-week period. Factor analysis yielded four significant factor domains: impact of disease, sexual intimacy, complications of disease, and body stigma. After comparison between all factor domains and subscales of the SIP, the SCL-90 and to several global ratings of well being, only the factor domain of impact of disease yielded significant correlations.  Furthermore a strong correlation between RFIPC and both overall SIP score (Spearman’s r = 0,43) and test-retest reliability had been shown. There was a fair correlation between RFIPC and measures of disease activity such as stool frequency (Spearman’s r = 0,28) and sigmoidoscopic grading in a Swedish study in which RFIPC was translated and validated (29). The RFIPC in its extended form, with 25 instead of 21 items, was used in a study on 105 Austrian patients with IBD.  A low correlation was observed between the disease related worries and concerns, as measured by the RFIPC and indices such as actual disease activity, severity of the course of IBD, diagnosis, disease duration or location, and medication (30). A possible reason for this poor correlation is that this tool is based on individual concerns which may not be influenced by external parameters such as relapses and remissions, or therapeutic interventions. 

In the different studies in IBD patients were RFIPC was used, the main concerns of the patients were: requirement of an ostomy bag, effects of medication, the possibility of surgery and developing cancer, loose bowel control, the uncertainty about the disease and the low energy level. Worries and concerns were similar in UC and CD patients. Especially in the Austrian study the significance of patient information became manifest: a positive association between poorer perceived information regarding their disease and greater concerns was found in IBD patients.

The RFIPC has been translated following an adequate process of translation and has been validated into other linguistic and cultural milieus, such as French and Swedish (31), (27). In these validation studies the RFIPC has been proven to be a valid, reliable and consistent instrument. It is important to bear in mind that whenever RFIPC has been used, and this in different countries, the IBD patients' concerns have been found similar for UC and CD patients, and patients with disease in regression consistently scored poorer and communicated similar worries and concerns.

CONCLUSIONS

The measurement of HRQOL in IBD is an increasingly important factor especially in clinical research but also in every-day patient care. It represents a major achievement in the management of IBD patients. Quality measurement of HRQOL, which means HRQOL measured in an objective and reliable way, is a prerequisite for a well-designed IBD therapeutic trial. This high quality measurement will be a self-evident request in the future. The use of validated questionnaires will become more wide in the years to come.

The IBD-specific questionnaires that have been shown to have adequate validity and reliability so far are the IBDQ and the RFIPC.  The IBDQ has been proved to have strong correlation with disease activity indexes  in several studies and adequate correlation with other general well being assessing instruments. It is a valid and reliable HRQOL assessment tool in IBD patients, and has been extensively validated in different languages. The RFIPC is an instrument oriented towards the  patients’ worries and concerns, mainly focused on the psychological area. When tested against general well being assessing instruments, showed significant correlation. Instruments measuring HRQOL help to identify the concerns and needs of IBD patients and therefore to improve patient care and are important tools in evaluating the outcome of therapeutic interventions.

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TABLES

Table 1. Types of instruments (questionnaires) for measuring health related quality of life.

Instrument

Attributes

Examples

GLOBAL

One

Good, bad, score

on a Likert-skale

GENERIC (GENERAL)

Multiple

SIP, EuroQol, SF-36

DISEASE-SPECIFIC

Multiple, focused on specific disease

IBDQ, RFIPC

Table 2. The Inflammatory Bowel Disease Questionnaire

Dimensions

Items

Examples

Score range

Bowel symptoms

10

Diarrhoea, pain, abdominal distension

10-70

Systemic symptoms

  5

Fatigue, troubles in sleep, feeling unwell

5-35

Social

5

Avoid events without WC

5-35

Emotional

12

Worried, angry, aggressive, irritable, embarrassed

12-84

Total

32

32-224

1