The relationship between health-related quality of life, pain and coping strategies in juvenile idiopathic arthritis

M. G. Sawyer, J. N. Whitham, D. M. Roberton1, J. E. Taplin2, J. W. Varni3 and P. A. Baghurst4

Research and Evaluation Unit and 1Rheumatology Clinic, Women's and Children's Hospital and Department of Paediatrics, University of Adelaide, South Australia, 2Department of Psychology, University of Adelaide, South Australia, 3Colleges of Architecture and Medicine, Texas A&M University, College Station, Texas, USA and 4Public Health Research Unit, Women's and Children's Hospital, South Australia.

Correspondence to: M. Sawyer, Research and Evaluation Unit, Women's and Children's Hospital, 72 King William Rd, North Adelaide, South Australia 5006, Australia. E-mail: michael.sawyer{at}adelaide.edu.au


    Abstract
 Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 References
 
Objectives. To investigate the relationship between health-related quality of life (HRQL), experience of pain and pain coping strategies in children with juvenile idiopathic arthritis (JIA). To compare reports describing these variables obtained from children and their parents.

Methods. Participants were 59 children aged 8 to 18 yr with JIA and their parents. Parents and children completed the PedsQLTM generic core scales and arthritis module, the visual analogue scale of the Varni–Thompson Pediatric Pain Questionnaire, and the Waldron/Varni Pediatric Pain Coping Inventory. Parents rated children's functional disability using the Childhood Health Assessment Questionnaire.

Results. Parents reported significantly lower scores (indicating worse HRQL) than children on five of the eight PedsQLTM scales rating children's HRQL. Parents and children reported a significant negative relationship between pain levels and the PedsQLTM scores assessing children's physical, emotional and social functioning. They also reported a significant negative relationship between scores on several pain coping scales and scores on the PedsQLTM scales. However, the pattern of these relationships varied for reports from parents and children.

Conclusions. Pain intensity and pain coping strategies have a significant and independent relationship with several domains that comprise the HRQL of children with JIA. However, parents and children have differing perceptions of the nature of these relationships. The differences emphasize the importance of clinicians obtaining information about children's HRQL, pain levels and pain coping strategies from both parents and children.

KEY WORDS: Juvenile idiopathic arthritis, Health-related quality of life, Functional disability, Paediatric pain, Coping strategies.


    Introduction
 Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 References
 
Juvenile idiopathic arthritis (JIA) can persist over many years with children often experiencing disability and dysfunction into adult life [1]. Although medical treatment can alter the degree of inflammatory joint disease, it is not curative and only occasionally induces remission. As a result, JIA has the potential to have an adverse impact on the development of children and adolescents.

Recent research has begun to examine this broader impact of JIA on children's physical, psychological and social functioning. This reflects increasing concern in paediatric medicine about the potential impact of chronic illness on the development of children in a range of areas and the importance of taking a holistic approach to address these problems [2]. The term health-related quality of life (HRQL) is employed to describe this approach to assessing children's development and functioning [3]. The approach focuses on the patients’ own views of their health assessed across physical, psychological and social domains.

Assessments of childhood HRQL generally utilize information from both parents and children [4]. For example, the Pediatric Quality of Life Inventory (PedsQL) [58] is designed to obtain independent ratings from children and parents describing problems with children's physical, emotional, social and school functioning. It also provides ratings of problems in areas particularly relevant to JIA such as pain levels, difficulties with daily activities and problems with treatment activities. The availability of new measures such as the PedsQL makes it possible to obtain reliable assessments of children's functioning in a range of areas without imposing an unreasonable assessment burden on children and parents.

Several investigators have suggested that musculoskeletal pain, and strategies adopted by children to cope with this pain, play an important role in determining children's HRQL [7, 9]. For example, the Biobehavioural Model of Paediatric Pain developed by Varni et al. [7] hypothesizes that there is a significant relationship between children's HRQL, their experience of pain and their use of pain coping strategies. The model suggests that coping strategies are a key intervening factor in the relationship between pain perception and children's functional status.

The present study was designed to investigate the relationship between children's HRQL, their experience of pain and the strategies they employ to cope with pain. We hypothesized that children with higher levels of pain would report a worse HRQL in a range of areas. We also hypothesized that children who made greater use of pain coping strategies would have a better HRQL. Finally, we hypothesized that when both pain and coping were included as independent variables in a statistical model examining the impact of these variables on children's HRQL, the strength of the relationship between children's experience of pain and their HRQL would be greatly attenuated, reflecting the influence of pain coping strategies on this relationship.


    Subjects and methods
 Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 References
 
Subjects
All children aged 8 to 18 yr who had been diagnosed with JIA at least 6 months prior to the study and who were attending the rheumatology clinic at the Women's and Children's Hospital in South Australia, and their parents, were approached to participate in the study (for brevity, the term ‘children’ will be used to describe both children and adolescents). Families were excluded from the study if they did not have sufficient command of the English language to complete the study questionnaires.

A total of 81 children aged 8 to 18 yr were identified as potential participants from the patient files at the rheumatology clinic. Sixty-four families (79%) agreed to participate in the study. Amongst those who did not participate, five families could not be contacted. Reasons stated by other families who declined to participate included the child's unwillingness to participate and a lack of time. Results from a further five families were treated as outliers and not included in the analysis of results. In these latter families, at the time of their interview, children and parents indicated that although the children continued to attend the clinic, they experienced no pain and made no use of the coping strategies being investigated in the study.

There was no significant difference in the age, gender, diagnosis and duration of care in the rheumatology clinic between the study participants, the outliers and those who did not participate in the study. For children in the study, diagnoses were oligoarthritis (44%), enthesitis related arthritis (19%), polyarthritis (17%), psoriatic arthritis (14%) and systemic arthritis (7%). All children met the International League of Associations for Rheumatology (ILAR) criteria for JIA and its subcategories [10]. The demographic characteristics of participating children are shown in Table 1.


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TABLE 1. Demographic characteristics of participating children (n = 59)

 
Measures
Health-related quality of life (HRQL) was assessed using the PedsQLTM 4.0 generic core scales [8] and the PedsQLTM 3.0 arthritis module of the Pediatric Quality of Life Inventory (PedsQLTM) [6]. The generic core scale consists of 23 items which can be completed independently by children and parents. It includes four scales that measure physical, emotional, social and school functioning. The arthritis module consists of 22 items and is specifically designed to assess the HRQL of children with arthritis. It uses the same answering format as the generic module and has five scales labelled pain and hurt, daily activities, treatment, worry and communication. To avoid methodological confounding, the pain and hurt scale was not utilized in the present study. For ease of interpretability, raw scores on both scales are transformed into a score between 0 to 100 with a higher score indicating a better HRQL (i.e. less problems or fewer symptoms).

Children's experience of pain was assessed using the visual analogue scale (VAS) in the Varni–Thompson Pediatric Pain Questionnaire (PPQ) [11]. The PPQ-VAS is designed so that parents and children can give an independent assessment of the intensity of children's present pain and their worst pain during the last week. It has been shown to be a reliable and valid measure of pain perception in paediatric populations [7, 12]. Higher scores indicate greater pain intensity.

Children's level of functional disability was assessed by means of the Childhood Health Assessment Questionnaire (CHAQ) completed by parents [13]. The CHAQ is a 30-item questionnaire which is suitable for parents of children between the ages of 1 and 19 yr. It assesses children's performance over the past week in eight areas of functioning (dressing and personal care, rising, eating, walking, hygiene, reach, grip and activities). Higher scores indicate worse functioning.

Parents and children independently completed the Waldron/Varni Pediatric Pain Coping Inventory (PPCI) [7] to identify the strategies children used to cope with pain. The PPCI consists of 41 items in which the respondent is asked to rate, on a three-point response scale, how frequently coping skills are used in five areas: (i) cognitive self-instruction, e.g. ‘pretending that I don’t have any pain or hurt’, ‘tell myself to be brave’, (ii) seek social support, e.g. ‘have a parent or friend sit with me’, ‘ask someone to tell me that the pain will go away and I’ll feel better’, (iii) strive to rest and be alone, e.g. ‘sit quietly’, ‘ask to stay by myself’, (iv) cognitive refocusing, e.g. ‘watch TV/read a book’, ‘think about happy things’, (v) and problem-solving/self-efficacy, e.g. ‘tell my parents’, ‘know I can ask for something that will make it feel better’. Higher scores indicate more frequent use of the particular coping strategy.

Procedure
Families were contacted by letter and by telephone. A research assistant brought the questionnaires to the families’ homes. After written consent was obtained from all subjects participating in the study according to the Declaration of Helsinki (Br Med J 1996; 313:1448–9), children and parents independently completed their questionnaires with help being provided by the research assistant if this was requested. The design of the study was approved by the Women's and Children's Hospital Research Ethics Committee.

Statistical analysis
A series of regression analyses were used to identify the strength of the relationship between the PedsQL and CHAQ scores (assessing children's HRQL), and the pain and coping strategy scores. In these analyses, significant univariate predictors of HRQL were initially identified. Subsequently, multiple regression analyses were used to determine whether individual predictor scores retained a significant relationship with HRQL scores after controlling for the other predictors in the model. In these analyses, the pain score was entered as the first independent variable followed by those coping scores which showed a significant univariate relationship with the relevant HRQL score. The strength of the association between the dependent and individual predictor variables is shown as standardized regression coefficients. This makes it possible to categorize the strength of these relationships as small (0.10–0.29), medium (0.30–0.49) and large (>=0.50) effect sizes based on the recommendations of Cohen [14]. In the presentation of results, the term significant is used to refer to P <= 0.05.


    Results
 Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 References
 
The mean score on the Childhood Health Assessment Questionnaire completed by parents was 0.6 (S.D. = 0.5). This is very similar to the scores reported in previous studies of children attending rheumatology clinics in England and Italy [15, 16]. It suggests that, on average, the children in the present study were experiencing mild disability.

Parent and child ratings of children's health-related quality of life, perceived pain and coping strategies are shown in Table 2. Across the four generic HRQL domains assessed by the PedsQL, the highest level of problems (i.e. the lowest HRQL scores) were reported by parents in the areas of emotional and physical functioning. Children reported the highest level of problems in the area of physical functioning. Parents and children both reported that children had the fewest problems in the area of social functioning. On all these scales children reported significantly higher scores (indicating better HRQL) than were reported by their parents. On the disease-specific scales children reported the highest level of problems on the scale rating the quality of children's communication with health professionals. Parents reported the highest level of problems on this scale and the scale rating the extent to which children worry about their illness. With the exception of the communication scale, children consistently reported higher scores on these scales (indicating better HRQL) than parents. However, only the child-reported daily activities score was significantly higher than the equivalent parent-reported score.


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TABLE 2. Mean scores (SD) for HRQL, functional disability and coping scales, and pain intensity completed by parents and children

 
Problem solving/self-efficacy was the coping strategy most frequently identified by parents. Cognitive self-instruction and problem solving/self-efficacy were the strategies most frequently reported by children. Parents reported that children used problem solving/self-efficacy, strive to rest and be alone, and seek social support significantly more often than was reported by the children. Children reported more frequent use of cognitive self-instruction than parents, but this difference was not statistically significant.

Only the rating of worst pain intensity differed significantly in reports from parents and children (Table 2). There was also a very high correlation between the three VAS pain scores reported by parents (r >=0.76) and between the scores reported by children (r >=0.49). In light of this, only the VAS worst pain score was included in the analyses examining the relationship between pain, coping and HRQL.

For parents’ reports there was a significant positive correlation between the pain score and the strive to rest and be alone (r = 0.3, P = 0.03) and problem solving/self-efficacy (r = 0.3, P = 0.02) scores. For children's reports there was a significant positive correlation between the pain score and the problem solving/self-efficacy (r = 0.3, P = 0.03), cognitive self-instruction (r = 0.4, P = 0.001) and seek social support (r = 0.3, P = 0.009) scores.

The strength of the univarate relationships between the HRQL scores and the predictor variables are shown in Tables 3 and 4. For parent reports there was a significant negative relationship between the pain intensity score and the PedsQL physical functioning, emotional functioning and social functioning scores. The pain intensity score also had a significant negative relationship with the PedsQL treatment scale score, and a significant positive relationship with the CHAQ score. Child-reported scores also showed a significant negative relationship between the pain intensity score and the PedsQL physical functioning, emotional functioning, social functioning and treatment scale scores. For child-reported scores there was also a significant negative relationship between the pain intensity score and the PedsQL worry and communication scale scores.


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TABLE 3. Standardized regression coefficients showing association between parent-reported HRQL scores, pain intensity and coping scoresa

 

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TABLE 4. Standardized regression coefficients showing association between child-reported HRQL scores, pain intensity and coping scoresa

 
For parents’ reports (Table 3) there was a significant negative relationship between the strive to rest and be alone score and the PedsQL physical functioning, emotional functioning and social functioning scores. There was also a significant negative relationship between the score on this coping scale and the PedsQL daily activities score, and a significant positive relationship with the CHAQ score. One relationship which was inconsistent with this general pattern was that between cognitive self-instruction and social functioning where there was a significant positive relationship which was also evident in the multivariable analyses. For children's reports (Table 4), the seek social support score had a significant negative relationship with the PedsQL emotional functioning and social functioning scores, and with three of the four PedsQL disease-specific scale scores. The cognitive self-instruction score had a significant negative relationship with the PedsQL physical functioning score and with three of the four PedsQL disease-specific scale scores.

In the multivariable analyses of parents’ reports (Table 3), after adjusting for the other independent variables in the model, the pain score and the strive to rest and be alone score had a significant negative relationship with the PedsQL physical functioning, emotional functioning and social functioning scores, and a significant positive relationship with the CHAQ score. For children's reports, the pain score had a significant negative relationship with the PedsQL physical functioning and social functioning scale scores, and with two of the four PedsQL disease-specific scale scores. There was also a significant negative relationship between the seek social support score and the PedsQL emotional functioning, social functioning, daily activities and treatment scale scores.

The use of effect sizes provides a simple method of rating the strength of the standardized coefficients shown in Tables 3 and 4. For parents’ reports, the effect sizes for the univariate relationships between the pain score and the PedsQL physical functioning, emotional functioning, social functioning and treatment scores were in the medium to large range, as was the relationship with the CHAQ score. After adjustment for the effect of the coping variable, strive to rest and be alone, the effect size describing the relationship between pain and emotional functioning was in the small range. However, the relationship between pain levels and the other PedsQL scores remained in the medium to large range after adjustment for relevant coping variables. For children's reports the pattern was very similar with the most obvious change again being the weaker relationship between pain and emotional functioning after adjustment for the coping variable, seek social support.


    Discussion
 Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 References
 
The scores reported by children on the PedsQL in the present study are similar to those reported by Varni et al. [6] while those reported by parents are somewhat lower. Children with JIA and their parents in both studies reported significantly lower scores on all the PedsQL scales than those reported by the ‘healthy sample’ in the study by Varni et al. [8]. This suggests that children with JIA not only have more problems with their physical functioning than healthy children but they also have more emotional problems, more difficulties with peer relationships and more problems with their schooling. Reports from the children with JIA also highlighted the difficulty they have communicating about their problems with health professionals. This is an important issue as good quality communication between children and clinicians is an essential prerequisite to the provision of effective help for children with problems in these areas.

The results in the present study also show that pain and several pain coping strategies have a significant and independent relationship with several domains which comprise the HRQL of children with JIA. For example, reports from parents and children showed that children with higher levels of pain experienced more problems with their physical, emotional and social functioning. However, reports from both informants showed a weaker relationship between the pain intensity score and the scores on the PedQL school functioning scale. The latter assesses children's ability to concentrate and keep up with school work, and the amount of school missed due to the illness and its treatment. Reports from both parents and children showed a significant negative relationship between children's experience of pain and the score on the PedsQL treatment scale. This scale assesses the extent to which children have problems managing their treatment, and experience anxiety or worry about treatment-related activities. The results suggest that children with higher levels of pain experience more problems in these areas.

Reports from parents showed a significant negative relationship between greater use of the coping strategy strive to rest and be alone and the level of children's HRQL. This coping strategy includes activities such as lying down to rest or sleep, going to bed and asking to be alone. Children reported less use of the strategy strive to rest and be alone than was reported by their parents. There was also no significant relationship between any of the child-reported HRQL domains and this coping strategy. Reports from children showed a significant negative relationship between use of the coping strategy seek social support and several domains of HRQL, a relationship not identified in parent reports. Children who reported greater use of this coping strategy also reported more problems with their emotional and social functioning, their daily activities and the management of their treatment.

Varni et al. [7] suggested that where greater use of a coping strategy is associated with higher levels of pain and more psychological problems, it should be considered as maladaptive. However, in cross-sectional studies it is difficult to interpret the causal paths amongst variables showing a significant relationship. Two explanations are possible for the negative relationship between the use of the coping strategies and the level of children's HRQL, and the positive relationship with their pain levels in the present study. One is that these are ineffective strategies which are associated with failure to manage pain levels adequately and a poorer HRQL. The alternative, and perhaps more plausible explanation, is that children with JIA who have more pain find themselves in greater need of these coping strategies to maintain their HRQL.

It is difficult to explain the isolated finding of a significant positive relationship between use of the coping strategy cognitive self-instruction and children's social functioning. An examination of the scatter plot of scores from the two scales confirmed the positive linear relationship between the two variables. It is possible that greater use of this coping strategy did facilitate better social functioning, however, such a suggestion must remain speculative on the basis of results from this study.

Strengths of the present study are its use of reports from parents and children obtained using valid and reliable measures. Limitations are the relatively low proportion of children with polyarthritis, the inclusion of children who, on average, had only mild to moderate levels of pain and disability, and the inclusion of children who were all attending the same rheumatology clinic. As a result, it is necessary to be cautious when generalizing the results of this study to children receiving treatment in other settings and to children with more severe pain and disability. It should also be noted that only parents completed the CHAQ. The findings on the PedsQL physical functioning and daily activities scales suggest that parents may assess children with JIA as having more problems in several areas assessed by the CHAQ than is reported by children.

In conclusion, differences in the reports obtained from parents and children highlight the importance of clinicians obtaining information about the broader functioning of children with JIA from both children and their parents. However, in the present study reports from children also suggested that they may have difficulty communicating with others about their illness. It is important that clinicians receive adequate training to ensure that they have the skills necessary to interview children. Although the perspectives of parents and children may differ, each informant is a potentially valuable source of clinical information about childhood HRQL.


    Acknowledgments
 
The authors would like to thank J. Carbone, J. Clark and M. Freeman for their assistance with the study. The study was funded by a grant from the Women's and Children's Hospital Foundation.

Dr Varni holds the copyright for the PedsQLTM.


    References
 Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 References
 

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Submitted 22 April 2003; Accepted 14 August 2003