Pediatric Rheumatology Online Journal

Vol 2, No. 2   2004

http://www.pedrheumonlinejournal.org

 

Quality of life in children with systemic lupus erythematosus: The search for appropriate measurement tools.

 

L. Nandini Moorthy1, Melanie J. Harrison2, Peterson, Margaret2, Karen B. Onel2, Thomas J.A. Lehman2

 

Affiliations:

1.      Robert Wood Johnson Medical School-UMDNJ, Dept. of Pediatrics, New Brunswick, NJ

2.      Hospital For Special Surgery, New York, NY

 

Keywords: Quality of life, Systemic lupus erythematosus, Children, Physical function, proxy respondents

 

Contact: 

L. Nandini Moorthy, MD MS

Robert Wood Johnson Medical School-UMDNJ, Dept. of Pediatrics, MEB 396 A, New Brunswick, NJ  08903

Phone: (732) 235 9378 (Work) 

Email: LNMoorthy@mac.com;

 

 

Abstract

Systemic lupus erythematosus (SLE) in children is a chronic multi-system disease with wide ranging effects on their quality of life (QOL).  While SLE’s impact on different arenas of life and well-being has been extensively examined in the adult population, its effect on children has not received adequate attention. This article briefly discusses the multidimensional aspect of QOL, the biopsychosocial implications of SLE, factors complicating QOL measurement in the affected population, and the different generic and disease-specific scales used for measuring QOL and related constructs, thereby highlighting the need for a SLE-specific pediatric QOL instrument.

 

Introduction

There is no single definition for quality of life (QOL), as it is a global, dynamic and personal construct, encompassing physical, psychological and social domains [1-3].  Health-related QOL (HRQOL), distinct from QOL and health status, is defined as “optimum levels of mental, physical, role and social functioning, including relationships, and perceptions of health, fitness, life satisfaction and well-being,” incorporating the “assessment of patient’s satisfaction with treatment, outcome and health status and with future prospects” [2, 4]. Although its relevance to children has been questioned, the revised International Classification of Impairments, Disabilities, and Handicaps published by the World Health Organization provides a new framework delineating parameters of health and disability as body structure and function, activities, participation, and environmental factors [5].

QOL, as impacted by health or disease becomes especially relevant in children with chronic illnesses such as systemic lupus erythematosus (SLE).  In children, SLE is associated with significant morbidity consequential to their disease and treatment, and comprises a wide-ranging spectrum of physical, psychosocial and economic implications.  Impact of specific organ involvement, especially the skin, renal and central nervous systems, requires in-depth examination.  There is sufficient evidence from research on adults, that SLE affects multiple dimensions (including psychological) of QOL, thus emphasizing the importance of determining a reliable instrument to measure QOL in children with SLE [6-21]. Despite recognizing the considerable effect of SLE on children and their families, very few pediatric studies explore the widespread impact of SLE on QOL or the ideal methods of measuring the same.

 

Difficulties encountered in measuring QOL in pediatric SLE

SLE’s chronic, episodic and unpredictable course, its extremely varied presentations within and between patients, associated psychosocial factors, and patient/family expectations complicate the measurement of QOL in children. The use of a generic versus a disease-specific instrument for evaluating a specific disease with wide-ranging effects such as SLE poses a great dilemma [22]. 

Generic instruments developed for use within a general population or for patients with a variety of diseases may be limited to assessing the overall aspects of all diseases and may lack responsiveness to clinical changes [23-25].  As such, these instruments may not adequately capture and measure the extent of the impact on a particular organ system especially in case of central nervous or renal involvement, where cognitive function, psychiatric, financial and logistic effects require consideration. Self-esteem and body image may be affected in children with widespread skin rash, cushingoid features, alopecia and/or fatigue affecting their peer relationships.  Conversely, disease-specific instruments may lack sensitivity for the particular condition and may not adequately measure QOL in children with mild SLE, those in remission, or those with more than one chronic condition [26].  Despite the restrictions that generic and disease-specific instruments impose within the context of a multisystemic disease such as SLE, their combined use may allow measurement of the global and SLE-specific impact on QOL in children.

QOL measures are developed with a particular focus and/or for a specific population and therefore, should not be expected to adequately assess all aspects of health and/or wellbeing in another population [27]. For example, in pediatric rheumatology, outcome measures are primarily focused on impact of physical disability on various domains of well-being because the majority of the children have juvenile idiopathic arthritis (JIA). Although physical function is an important

domain affected in SLE, a true measure of SLE-related QOL would have to take into consideration other domains of well-being, and adequately assess the impact of renal and central nervous system involvement, as well as the effect of medication.

Children’s evolving needs and expectations is another impediment.  Several QOL scales---adapted from the adult scales---may not account for children’s developmental stages that affect cognitive function, autonomy, body image and recall [22].  Given that small numerical differences in children’s age translate into important psychosocial changes of great clinical significance, it is crucial to develop age-adjusted formats for children that consider their changing cognitive skills [28].

Since QOL is a uniquely personal construct, it is best for children to evaluate their own QOL.  However, the limitations in using children as their own respondents include unreliable or invalid results based on their varying degrees of long-term perspective, memory, age, health, mood, and communication skills [29].  Therefore, the parents, as proxy respondents may be useful  in these circumstances. However, they may be influenced by their personal expectations and experiences, as well as their own health and mental status [29].  Moreover, parents' perception of the child’s QOL, often based on areas that they deem important and of value to their children, greatly motivates seeking health care for the child, resulting in a selection bias [30].  Studies examining parent-child concordance and have found that the level of agreement varies and is dependent on the domain studied, and also patients’ and parents’ physical and mental health status [31-33].  In order to maximize accuracy and to explore the determinants of parent-child concordance, an argument can be made for using parallel parent and child versions for assessing QOL in chronic, ever-changing, potentially life-threatening and deforming multi-systemic illnesses such as SLE.

 

Assessment of QOL and health status in pediatric rheumatic diseases

The majority of pediatric studies use descriptive QOL measures, which explore various domains of QOL, instead of utilities or preference-based measures, which quantitatively estimate individual preferences of children [34, 35]. A description of some of the QOL measures will provide insight into the various domains that comprise QOL and enable assessment of measures in pediatric rheumatic disease.  Since results with utility scales have been shown to vary widely in  children with musculoskeletal diseases, this account will focus on descriptive measures [36].  An attempt is made to categorize scales commonly used in pediatric rheumatic diseases into generic, disease/system-specific measures, and generic measures with disease/system-specific modules. 

 

Generic measures

Short-Form-36 (SF-36) and Short Form-20 (SF-20)

         The SF-36 and SF 20 are reliable and valid health status measures widely used in clinical studies of both healthy and sick adults, including those rheumatic diseases, and are sometimes used in older children [6-8, 13, 19, 21, 42-46]. The SF-36 assesses domains of physical functioning, role limitations due to physical health and emotional problems, bodily pain, social functioning, general mental health covering psychological distress and well-being, vitality, energy or fatigue, and general health perceptions, areas that are relevant in all healthy and sick individuals. The major limitation of studies using SF-36 or SF-20 is that they claim to be measuring QOL when they are actually measuring health status. Additionally, in the case of children, they exhibit ceiling effects and do not show adequate variability and discriminant validity [47].  Therefore, a cautious review of studies using these instruments is critical.

 

Child Health Questionnaire (CHQ)

A widely used global health status measure in children is the CHQ, which was derived along the lines of the SF-36, and has domains adapted for children [48].   Although there are parent-reports (for children over 5 years) and child-reports (over 10 years), they are not entirely parallel.  The CHQ is valid, reliable and has been found to be responsive to clinical changes in children with JIA [48, 49].  It has been used widely as a health status measure and is being adapted cross-culturally in different countries [48, 50-53]. Although the CHQ has domains (physical functioning, role/social – emotional, role/social – behavioral, role/social – physical, bodily pain, general behavior, mental health, self esteem, general health perceptions, change in health, parental impact – emotional, parental impact – time, family activities, family cohesion) that would be relevant for all children including those with SLE, further testing is necessary to determine if the scale captures the SLE-specific impact on QOL.  The major limitations are the lack of parallel versions, lack of validity for children under 5 years of age and lack of child-report for ages under 10 years.

 

Childhood Health Assessment Questionnaire (CHAQ)

The CHAQ, the most extensively administered measure of physical function in children with rheumatic diseases, is modified from the Health Assessment Questionnaire (HAQ) [54-57].  The domains of the CHAQ are similar to that of the adult HAQ, which in addition to disability and discomfort, evaluates drug side effects, death and dollar costs. The CHAQ consists of brief, easily administered, parallel child-  (8-19 years) and parent-reports (2-19 years), with the chief areas of focus being disability and discomfort. The 30 items on the questionnaire estimate disability in areas of dressing and grooming, arising, eating, walking, hygiene, reach, grip, and activities.  Although found to be reliable and valid, studies are mixed in terms of its responsiveness to clinical change [54, 58, 59].  The CHAQ is a widely employed, functional assessment tool in diverse studies of children with arthritis and is being cross-culturally adapted and translated into different languages [50].  The minimal clinically important change to enable prospective follow-up of physical function in children with JIA has been determined for the CHAQ scores [60].  CHAQ is also valid, reliable, and sensitive to clinical change in children with idiopathic inflammatory myositis [61]. The CHAQ may be useful in children with SLE with physical disability such as avascular necrosis, severe arthritis or fatigue.

           

Other questionnaires

The EuroQOL, a generic health utility index widely used in adult studies has demonstrated validity in assessing children with JIA [62-64]. The TNO AZL Children's Quality of Life questionnaire (TACQOL) is a generic QOL instrument in children aged 6-15 years limited by lack of validity in older and younger children [29].  This questionnaire assesses the domains of pain and symptoms, basic motor functioning, autonomy, cognitive functioning, social functioning, global positive emotional functioning, global negative and emotional functioning, many of which are affected in children with chronic diseases such as SLE.   Quality of My Life Visual Analog Scale has been used for measuring the overall QOL in children, but there are very few studies published using this instrument [4].

 

Disease/System-specific measures

Although most of the instruments described in this section are more relevant to children with arthritis, they may be relevant in children with SLE with severe fatigue, musculoskeletal involvement including arthritis or avascular necrosis where physical function is compromised.

 

Juvenile Arthritis Quality of Life Questionnaire (JAQQ)

The JAQQ is a valid and responsive disease-specific instrument assessing physical and psychosocial function in children with juvenile arthritis, including spondyloarthropathies [65-68].  Despite its strong psychometric properties, including content validity, the JAQQ lacks the ability to discriminate between groups [69].

 

Childhood Arthritis Health Profile (CAHP)

The CAHP was designed as a parent-report to assess the overall physical and psychosocial health status of children over 13 years with arthritis through the domains of physical functional status, psychosocial functioning, behavior, general health perceptions, family functioning and impact of disease [70, 71]. General health status is evaluated by the CHQ, and the disease-specific impact is assessed by a focused section on juvenile arthritis [48, 72].  Despite the desirable combination of global and disease-specific aspects of rheumatic illness and relevant domains for children, the CAHP is not widely used as there are too few studies published using the measure, there is no parallel child-report, and it lacks validity in children under 13 years of age.

 

Juvenile Arthritis Functional Assessment Scale (JAFAS), Juvenile Arthritis Functional Assessment Report (JAFAR) and Juvenile Arthritis Functional Status Index (JASI)

         The JAFAS and the JAFAR are valid and reliable scales of physical function in children above 7 years of age [73, 74].  JAFAS has not gained popularity because of its length, the need for trained health professional and standardized equipment, lack of established responsiveness, and lack of validity in younger children.  The JAFAR child- and parent-reports has been found to be responsive and used in several clinical studies of children with JIA, limited only because of lack of validity for younger children [74-77].  The JASI is a reliable and valid measure of activities of daily living and functional mobility in children with arthritis less than 8 years of age [78, 79].  Despite good psychometric properties and a patient-specific part, it is not widely used due to increased time of administration, lack of established responsiveness and the lack of validity in children greater than 8 years of age.

 

Generic measures with disease/system-specific modules

Pediatric QOL Inventory (PedsQL)

            The PedsQL-Generic module (version 4.0), a descriptive measure in the form of a brief, easily administered questionnaire, is designed to assess QOL in healthy and sick children and can be used to compare different populations.  It is both a reliable and valid measure of QOL in children between ages 2-18 years in different pediatric settings [28, 37-39].  The initial PedsQL (version 1.0) was developed from a pediatric cancer database and has been modified since [28, 40, 41].  The most recent version, PedsQL4.0, which measures the essential domains as specified by the WHO, has both child- and parent-reports with separate language-adjusted formats for different ages 5-7, 8-12 and 13-18 years.  The parent-report has an additional questionnaire for toddlers aged 2-4.  The generic core module consists of four domains: physical, emotional, social, and school functioning, which are scored to yield total, physical, and psychosocial summary scores. 

The most current version of the PedsQL-Rheumatology module (3.0), formatted similar to the Generic module, is comprised of five domains: pain and hurt, daily activities, treatment, worry, and communication [39].  Only the domain scores are reported and not the total mean score, which limits its use in pediatric rheumatic disease studies, where sample sizes are often small.  The PedsQL should be suitable for the measurement of QOL in children with all rheumatic diseases including SLE since it appears to take into account both global and specific domains impacted by a chronic rheumatic disease.

 

General limitations of current measures and proposals for future development

 The various questionnaires described above have been used widely in studies of children with rheumatic diseases; they have different limiting features when considered in the context of pediatric SLE.  First, many of these instruments are heavily weighted towards determining the impact of arthritis, which is not the single major complaint in children with SLE.   Secondly, these instruments may not adequately capture all the relevant domains in pediatric SLE unless used in conjunction with other measures [80].  Thirdly, not all the instruments are valid, reliable and responsive over time to clinical changes.  Lastly, some instruments do not have parallel self- and parent-reports and they are not applicable to all pediatric age-groups.  Those that do not have parent-reports, limit their use to children who are older and are well enough to complete them.  The majority of the children with SLE are adolescents, but it is preferable to have a measure that will be able to assess younger children as well. Instruments that lack self-report versions may not accurately measure the child’s QOL and require parents to be used as proxies.  Some measures are not validated for the complete pediatric age group, and therefore cannot be widely used for data collection where patient population spans a wide spectrum of ages.  Certain measures have both child and parent versions but the versions are not in parallel, thus limiting accurate estimation of concordance between child- and proxy-respondents. 

A generic QOL tool could be valuable in comparing children with SLE to other disease/healthy groups.  A SLE-specific tool that would assess impact on QOL would be very useful especially if used in conjunction with tests validated for assessing disease activity, damage and neuropsychiatric status [81-83].  Until there are SLE-specific QOL scales available, a combination of previously validated scales may be used for pediatric SLE.

Recently conducted qualitative research in children with SLE and their families has yielded important information regarding critical domains affecting QOL in children with SLE [84].  An adequate measure QOL in pediatric SLE should have domains that are based on patient’s attitudes and expectations in order to incorporate the patient-perceived global and disease-specific impact of SLE, so that the health domains measured would be relevant for them.

Qualitative research would be the next step to confirm the validity and completeness of the health domains.   Additionally, it should be brief, easy to administer, with complete scoring coupled with having parallel child and parent versions with language-adjusted formats for different age groups.  Finally, it should have validity and reliability across a wide age-range, which will facilitate clinical comparisons and long-term prospective outcome studies in this population. It is not realistic to develop a single tool that fulfills all the criteria mentioned above.  However, the development of a SLE-specific tool that measures at least most of the domains is critical for optimizing care in these children.

 

Conclusion

            Although many of the instruments developed to assess QOL and related constructs such as health status and physical function have demonstrated utility in specific population groups, inherent problems complicate the accurate and comprehensive assessment of QOL in children with SLE.  Some of the problems of current instruments include emphasis on other diseases, specific age group limits, non-availability of corresponding child or parent version, length and difficulty of administration.  Such limitations compromise the measurement of QOL, thus restricting the effort to fully meet the growing challenges and needs of children with SLE.  The need for a disease-specific instrument specifically applicable for children with SLE becomes particularly evident in this context.  Understanding issues critical to QOL and developing effective measures of disease impact can help to mitigate distress secondary to medical and psychosocial impact of SLE in children and their families.

 

 

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