1. Introduction
Traditional medicine was focused on the physical side of the illness and death rates and life expectancy were the main measures used to evaluate people’s health. This excludes the fact that, in most diseases, the state of health is deeply influenced by mood, coping mechanisms to different situations and social support. The higher prevalence of chronic conditions, as a consequence of the decline of infectious diseases, as well as the development of new technologies that reduced pain, have made necessary newer and more sensitive outcomes beyond morbidity and biological functioning
[1]. Quality of life (QoL) has been considered as a component of health since 1947 when the World Health Organization (WHO) began to define health not only as the absence of disease, but also as a state of physical, mental and social well-being
[2]. Health-related quality of life (HRQoL) has been defined as the value assigned to the duration of life influenced by health, which is modified by impairments, functional state, perceptions and opportunities that are in turn influenced by diseases, injury and treatments
[3]. HRQoL only includes components that are part of an individual’s health and, therefore, excludes other aspects of QoL, as political or economic factors
[4].
Inflammatory bowel diseases (IBD) are chronic, progressive and disabling conditions affecting young people that have a negative impact on their HRQoL
[5]. For years, the main endpoints of IBD treatment had been clinical remission and response. Afterwards, new targets like biomarkers and mucosal healing have been introduced in new drug evaluations and, in the last decades, the use of patient-reported outcome (PRO) has also become especially important. In 2015 the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) program was initiated by the International Organization for the Study of Inflammatory Bowel Diseases (IOIBD). It examined potential treatment targets for IBD to be used for a “treat-to-target” clinical management strategy using an evidence-based expert consensus process. In these first recommendations, improvement of HRQoL was only suggested as part of PRO
[6]. In the recently published STRIDE II consensus, HRQoL has more weight and it is recommended as an important endpoint for IBD management
[7].
2. How Can We Measure HRQoL in IBD?
There are two main types of HRQoL tools to evaluate patients with IBD: disease-specific and generic. Disease-specific tools evaluate symptoms and compare the effect of different treatments, while generic tools allow for comparisons between different population and illnesses.
It is important to take into account two psychometric considerations for choosing which instrument to measure HRQoL:
-
− Reliability is the probability that a questionnaire will perform its intended function adequately. A reliable measure is one that provides consistent and accurate information.
-
− Validity is how accurately a method measures what it is intended to measure. A tool is valid when it measures the characteristic that it claims to measure.
Plenty of IBD-specific HRQoL tools have been developed and validated for IBD patients
[8]. Nevertheless, the majority of these instruments have had no patient involvement in their development
[9]. In
Table 1, we summarize the main characteristics of the most widely used tools and some other options designed for specific IBD cohorts.
Table 1. Characteristics of tools for measure HRQoL in IBD.
+ Poor, ++ Fair, +++ Good.
The Inflammatory Bowel Disease Questionnaire 32 (IBDQ-32) and Inflammatory Bowel Disease Questionnaire 36 (IBDQ-36) are the most commonly used
[10]. IBDQ-32 is a 32-item questionnaire that has been demonstrated to be reliable and valid. It includes four aspects of the patients’ life and the main domains are intestinal symptoms (10 items), systemic symptoms (five items), social (12 items) and emotional domains (five items). Häuser et al. conducted a validation study of the German version of the IBDQ (IBDQ-D) for patients with ileal pouch anal anastomosis (IPAA) for UC, and they observed that it was a reliable tool in this setting although it had some limitations in terms of validity
[11]. The short version of IBDQ-32 is the Short Inflammatory Bowel Disease Questionnaire (SIBDQ). SIBDQ also contains symptom, social and emotional sections. IBDQ-36 is a 36-item questionnaire that has also been proven to be valid and reliable. It comprises the following points: intestinal symptoms (eight items), systemic symptoms (seven items), social (6 items) and emotional domains (eight items), and functional impairment (seven items). The short version of IBDQ-36 is IBDQ9. IBDQ9 only contains one domain (total score) and the comprehensiveness is lower than IBDQ-36
[9].
Another tool, Crohn’s Life Impact Questionnaire (CLIQ), composed of 27 dichotomous items, is focused on how the impairments affect need fulfilment. It has demonstrated good validity and reproducibility, and it is easy to complete in a few minutes
[12]. Recently, the Crohn’s Anal Fistula Quality of Life (CAF-QoL) has been developed to evaluate the impact of anal fistula. It is a new PRO measure for Crohn’s perianal fistula that has been validated. CAF-QoL is a 28-item questionnaire that has demonstrated to be internally consistent, reliable, stable and valid
[13]. Among them, the best questionnaires related to relevance, comprehensiveness and comprehensibility are IBDQ-32 and CLIQ. In
Table 1, we summarize the main characteristics of the most widely questionnaires used.
Other examples of disease-specific instruments are the Crohn’s and Ulcerative Colitis Questionnaire (CUCQ), Inflammatory Bowel Disease Questionnaire 30 (IBDQ-30), Norwegian Inflammatory Bowel Disease Questionnaire (IBDQ-N), Cleveland Global Quality of Life (CGQL), Short Health Scale (SHS), Edinburgh Inflammatory Bowel Disease Questionnaire (EIBDQ), short Inflammatory Bowel Disease Questionnaire 10 (sIBDQ-10) and Inflammatory Bowel Disease Disability Index (IBD-DI). In paediatric IBD patients, the IMPACT series tools (IMPACT, IMPCT-II and IMPACT III) were used to evaluate the HRQoL. IMPACT was proven to be valid and contains 4 domains: symptoms, physical, emotional and social domains
[8][14].
The generic questionnaires most commonly used are the Generic 36-item Short Form Survey (SF-36) and The EuroQoL–dimension (EQ-5D). SF-36 was developed in the USA for use in the Medical Outcomes Study (MOS). It is a generic scale that provides quantitative information related to HRQoL and has good validity and reliability. It is frequently reported as two separate figures, a physical component score (PCS) and a mental component score (MCS), which included a total of 36 items allocated in eight domains: physical functioning (10 items), role physical (four items), social functioning (two items), bodily pain (two items), mental health (five items), role emotional (three items), general health perceptions (five items) and one item about general health
[15]. EQ-5D is a generic, reliable and valid instrument developed by the EuroQoL group. It can be used to assess HRQoL but also the cost-utility analysis of health care interventions
[16]. Other similar instruments can be World Health Organization Quality of Life (WHOQOL)-BREF, Short Form SF-12, Satisfaction with Life Scale (SWLS), EORTC Quality of Life Questionnaire C-30, Quality of Well Being Scale or Health Utilities Index
[17][18]. In paediatrics, the generic tools more widely used are PedsQ1, Child Health Questionnaire (CHQ), KINDL, KINSCREEN 27, DISABKIDS HRQOL
[19].
3. Quality of Life Studies in UC
To date, multiple studies have reported that UC impairs QoL, which can also be affected by demographic, psychological and socioeconomic factors
[20][21]. Clinical activity was pointed out as the factor with the most negative impact in HRQoL
[22], although it has been shown that it’s still compromised during quiescent disease as compared to the general population
[23]. Rasmussen et al. observed that bowel frequency, urgency and rectal bleeding are the symptoms that most significantly affect these patients’ HRQoL
[24]. Apart from the physical symptoms, IBD patients complain about an important emotional burden which is barely addressed during follow-up appointments
[25][26]. Different therapies have been proved to be effective to treat UC and improve the HRQoL of those who suffer from it (
Table 2) although its administration schedules and side effects can also negatively affect HRQoL.
Table 2. IBD treatments that have been shown to improve HRQoL.
AZA: azathioprine. IFX: infliximab. GLM: golimumab. VDZ: vedolizumab. ADA: adalimumab. USK: ustekinumab. TFC: tofacitinib.a Remission Crohn’s disease. b Active Crohn’s disease. c Healthy controls.
4. Quality of Life Studies in CD
There are several studies that have shown an association between CD and significant disability and impaired HRQoL. There is a systematic review and meta-analysis that compared HRQoL between CD and UC including physical (2375 participants) and mental scores (2664 participants). The HRQoL scores were shown to be lower in patients with CD compared with UC, but these differences were borderline significant
[50].
In the systematic review of Van der Have et al. including 5735 patients with CD, the HRQoL was consistently impaired by the occupational disability, number of flares, disease activity, need for hospital admission and use of corticosteroids. Furthermore, the biological treatment had a beneficial impact in the HRQoL. The majority of the studies included in this review employed both generic and disease-specific HRQoL measures, the IBDQ and the SF-36 being the most commonly used
[51].
Despite the thinking that HRQoL is mainly related with clinical activity in CD, in a study performed in 92 CD patients in remission, scores on the SF-36 were lower than in the general population of similar age and sex. Age, colonic location and previous surgery was related with worse HRQoL
[52].
The effectiveness of different treatments improving HRQoL in patients with CD has been evaluated in clinical trials of new drugs, but also real-life studies (
Table 2). Only a few studies have been conducted to assess the impact of thiopurines in HRQoL. A prospective study that included 92 IBD patients (68 CD) who started thiopurines showed a significant impairment HRQoL at week 0 with a basal median IBDQ score of 4.99 (range 2.37–6.84) as compared to patients in remission. In the first year after starting treatment, all dimensions of the IBDQ demonstrate a statistically significant improvement that was more pronounced in those patients receiving steroids at the beginning of the study
[30]. In a case-control study it was shown a restoration of HRQoL in patients with CD in remission under thiopurines without differences with healthy controls
[31].