Background
Childhood physical disability refers to intrinsic biological or acquired conditions (e.g., cerebral palsy, spina bifida, traumatic brain injury, spinal cord injury, amputation) causing impairments which result in disability and limited participation in day-to-day activities. Increasingly, outcomes of health and rehabilitation services for children and youth with disabilities include assessments of health status and well-being, known as health-related quality of life. Health-related quality of Life (HRQoL) is defined as “perceived physical and mental health over time” [
1]. HRQoL measures are defined as multi-dimensional assessments of health status and well-being that include items about functional status (physical, psychological and social), well-being, and general health [
2]. HRQoL assessments measure these domains from the perspective of the child/youth and/or their parents. For children with physical disabilities, health-related quality of life includes not only their functioning and participation in daily living, but also the impact of their disability on the family.
The Child Health Questionnaire (CHQ) is a self-administered or parent proxy assessment of physical, psychological and social health status of children 5–18 years of age [
3]. To date, studies using the CHQ have focused primarily on cross sectional studies of children with cerebral palsy, arthritis or brain injury. In this paper, we describe parents’ perceptions of their child’s health-related quality of life (HRQoL) for 427 children with physical disabilities, the change of these perceptions across an 18-month period of time and the factors that affect amount and direction of change.
Measurement of health outcomes typically focuses on the nature and extent of functional limitations in physical, social, and psychological domains classified in ICIDH-2 [
4]. The CHQ measures Health Related Quality of Life (HRQoL) across these domains [
3,
5]. This measure has been shown to have good reliability, validity and discriminant validity [
6‐
8], is easy to administer [
6], has normative data [
4,
6], and has both a parent proxy version as well as a child- completed version to allow for assessment of the perspectives of children and parents [
9].
The CHQ has been used to measure the HRQoL of children with musculoskeletal or neurologically-based conditions. For musculoskeletal conditions, Selvaag et al. [
10] measured the health status in a sample of 116 children with juvenile idiopathic arthritis (JIA) using the CHQ and the Childhood Health Assessment Questionnaire (CHAQ) and compared results against the results of 116 matched controls. Participants with JIA had significantly poorer physical and psychosocial health scores than healthy children. This study found that the CHQ differentiated between healthy children and children with early juvenile idiopathic arthritis and was able to measure clinical changes in children with arthritis. In another study of children with JIA, the CHQ discriminated between healthy and unhealthy children, but was not sensitive to differences between JIA subtypes [
11].
Oliveira et al. [
12] and Gutierrez-Suarez et al. [
13] reported results from a large multinational (30 countries), cross sectional study of children (3,324 with JIA and 3,315 healthy). Results were similar to those of Selvaag et al. [
10], with physical scores on the CHQ significantly lower and psychosocial scores being slightly lower than those of healthy children. Lower physical functioning scores correlated with the level of functional impairment while the intensity of pain correlated with lower psychosocial scores [
12,
13].
Studies with the CHQ for children with neurologically based conditions have primarily centered on children with cerebral palsy. Liptak et al. [
14] examined parent reported health status of 235 children (ages 2-18) with moderate to severe cerebral palsy. Children in this study had significantly lower CHQ scores than their healthy peers in the following areas: pain, general health, physical functioning, and impact on parents. Children with more severe cerebral palsy had significantly lower scores than those with less severe cerebral palsy in each of the areas. Liptak’s study had few children with mild cerebral palsy and did not provide mean scores to compare with other studies. To address this limitation, Wake et al. [
8] compared data on 80 children with CP across the severity spectrum to data of typically developing children from the same sample population base (taken 2 years prior). As with Liptak et al. [
14], their results showed that parents of children with CP reported significantly lower CHQ scores for physical health and parent and family impact. The psychosocial health of the children with cerebral palsy was similar to that of and for healthy children, but the parents of children with CP reported lower psychosocial well-being and activity scores than did parents of typically developing children.
Vargus-Adams [
15] surveyed 177 parents of children with CP, stratifying severity of the child’s CP using the Gross Motor Function Classification System (GMFCS), and compared the study results with the results by McCarthy et al. [
5] and Liptak et al. [
14]. Results indicated that scores on the CHQ were lower for children with CP (compared to healthy children) in the areas of physical functioning and parental impact, but few differences were found for psychosocial functioning between groups. In a large study of 818 children with cerebral palsy ages 8 to 12 years, Beckung et al. [
16] confirmed significantly lower CHQ scores as compared to normative data. Other studies of the CHQ with children with spina bifida [
17], hip dysplasia [
18], admission to hospital due to injury [
19,
20], and chronic pain – not specified [
21] report that scores on the CHQ physical functioning were lower in their samples compared with healthy children.
Changes in CHQ scores over time for children with disabilities have been examined in three studies. Vargus-Adams [
22] found no significant changes over one year in 177 children (ages 3-18) with cerebral palsy. Using a longer timeframe of 2.5 years, McCullough, Parkes, Kerr & McDowell [
23] examined changes in the CHQ for 184 children with cerebral palsy aged 4 to 17 years. Their findings indicate that scores for the domains of Behavior and Family Activities increased over that time period. Other domains in the measure did not change significantly. Selvaag et al. [
24] found improvement in health status post intervention for 197 children with juvenile rheumatoid arthritis and juvenile spondyloarthropathy in all areas of HRQoL, except for pain, over a 3 year period. Two studies have examined changes in health-related quality of life using other measures. Janssen, Voorman, Becher, Dallmeijer & Schuengel [
25] used the TNO-AZL measure with 91 children with cerebral palsy aged 8 to 14 years and found that health-related quality of life remained stable except for an increase in autonomy scores. In a study of 185 adolescents with cerebral palsy, Livingston and Rosenbaum [
26] demonstrated that group scores on the Quality of Life measure and the Health Utilities Index Mark 3 (HUI3) were stable over one year. Scores on the HUI3 showed more variability, at moderate levels in speech, vision, dexterity, cognition and hearing and higher levels for pain and emotion.
Research about child-related predictors of psychosocial HRQoL indicates significant relationships for measures of child behavior [
8,
10,
24,
27], and disability level [
12,
14,
15,
17,
22]. From a family and community perspective, significant predictors of psychosocial HRQoL include parent impact [
15,
22], family support [
28], school environmental supports [
17], parenting styles [
29], parent’s emotional health [
20] and parent’s rating of general health [
12,
13]. Although these findings are from cross-sectional studies, they do indicate the potential that amount and direction of change in psychosocial HRQoL over time is explained by child behavior, disability level, impact on family, family support, parents health, parenting styles and perceptions of environmental supports.
Predictors of physical HRQoL found in previous research for children with disabilities include gross motor function [
14,
22,
23,
25], disability level [
8,
10‐
13,
17,
22,
24], parents’ ratings of general health [
12] and neurologic examination results [
27]. We hypothesized that children’s health and physical functioning, environmental supports, and parent’s general health would be significantly related to a measure of physical HRQoL.
In summary, there is little information regarding change in the CHQ over time with children with physical disabilities, which is important to know because patterns of changes as well as predictors of change can inform potential interventions focused on health and well-being. This study examines change in a large sample of children with musculoskeletal or neurological disabilities, thus enabling the exploration of the effect of child, family, and environmental variables on physical and psychosocial CHQ scores.
Results
Mean CHQ scale and total summary scores across three data collection points over 18 months are summarized in Table
2. In Table
3, we report the mean percentile score for each CHQ subscale and summary score, as well as the percentage of children in the study who fall below the 25
th, 50
th and 75
th percentiles for the USA normative population as published in the CHQ manual. Except for Family Cohesion, all of the percentile scores are significantly below normative values, meaning that the sample of children with disabilities had lower scores than the normative population. As shown in Table
4, the summary scales and all subscales of the CHQ, except Family Cohesion, are significantly different for this sample as compared to the CHQ normative sample.
Table 2
CHQ scores over the 3 measurement points
Family cohesion | Mean | 71.87 | 72.12 | 71.85 |
SD | 22.02 | 22.37 | 22.34 |
Physical functioning | Mean | 65.38 | 65.19 | 65.72 |
SD | 32.63 | 32.94 | 34.22 |
Role/social emotional/behavioral | Mean | 72.39 | 75.32 | 77.23 |
SD | 33.05 | 31.91 | 32.15 |
Role/social-physical | Mean | 68.62 | 71.25 | 71.28 |
SD | 83.33 | 33.72 | 34.64 |
Bodily pain | Mean | 70.33 | 69.90 | 68.85 |
SD | 25.81 | 26.15 | 26.31 |
Behavior | Mean | 67.71 | 68.91 | 69.10 |
SD | 18.29 | 19.14 | 18.77 |
Mental health | Mean | 69.21 | 70.09 | 69.35 |
SD | 14.16 | 14.43 | 15.63 |
Self esteem | Mean | 70.03 | 70.05 | 68.58 |
SD | 18.84 | 19.04 | 19.56 |
General health perceptions | Mean | 60.88 | 61.21 | 62.11 |
SD | 21.00 | 20.94 | 21.53 |
Parental impact-emotional | Mean | 53.38 | 56.02 | 56.61 |
SD | 26.13 | 26.01 | 24.97 |
Parental impact -time | Mean | 70.14 | 71.53 | 74.66 |
SD | 27.68 | 27.09 | 26.33 |
Family activities | Mean | 68.03 | 69.22 | 69.96 |
SD | 23.36 | 24.03 | 23.85 |
Physical summary score | Mean | 38.32 | 38.68 | 39.05 |
SD | 15.90 | 16.54 | 16.71 |
Psychosocial summary score | Mean | 44.16 | 45.09 | 45.21 |
SD | 11.15 | 11.33 | 11.21 |
Table 3
Percent (%) below percentile cutoff scores at Time 1 for CHQ-PF50 subscales and summary scores
Family Cohesion (FC) | 12.2 | 45.1 | 45.1 | 45.1 |
Physical Functioning (PF) | 76.0 | 76.0 | 76.0 | 76.0 |
Role/Social Emotional/Behavioral (REB) | 54.4 | 54.4 | 54.4 | 54.4 |
Role/Social Physical (RP) | 56.8 | 56.8 | 56.8 | 56.8 |
Bodily Pain and Discomfort Scale (BP) | 40.4 | 52.6 | 71.4 | 66.7 |
Behavior Scale (BE) | 43.2 | 71.1 | 83.8 | 60.3 |
Mental Health Scale (MH) | 44.4 | 68.5 | 95.5 | 68.5 |
Self Esteem Scale (SE) | 43.9 | 66.7 | 92.0 | 66.7 |
General Health Perceptions Scale (GH) | 55.9 | 77.5 | 88.7 | 70.2 |
Emotional Impact on Parent Scale (PE) | 72.5 | 81.0 | 95.1 | 81.0 |
Parental Impact Time Scale (PT) | 61.5 | 73.2 | 73.2 | 61.5 |
Family Activities (FA) | 88.3 | 88.3 | 71.1 | 75.8 |
Physical Summary Score (Phs) | 76.7 | 84.0 | 91.0 | 79.5 |
Psychosocial Summary Score (PsS) | 57.1 | 76.9 | 90.1 | 69.3 |
Table 4
CHQ results at Time 1 – Comparison to normative sample
Family Cohesion (FC) | 71.9 (22.0) | 72.3 (21.6) | 0.68 (0.018) | -2.5 to 1.6 |
Physical Functioning (PF) | 65.4 (32.6) | 96.1 (13.9 | 0.0001 (1.22) | -33.8 to -27.6 |
Role/Social Emotional/Behavioral (REB) | 72.4 (33.0) | 92.5 (18.6) | 0.0001 (0.75) | -23.2 to -16.9 |
Role/Social Physical (RP) | 68.6 (34.9) | 93.6 (18.6) | 0.0001 (0.89) | -28.3 to -21.6 |
Bodily Pain and Discomfort Scale (BP) | 70.3 (25.8) | 81.7 (19.0) | 0.0001 (0.5) | -13.8 to -8.9 |
Behavior Scale (BE) | 67.7 (18.3) | 75.6 (16.7) | 0.0001 (0.45) | -9.6 to -6.1 |
Mental Health Scale (MH) | 69.2 (14.2) | 78.5 (13.2) | 0.0001 (0.67) | -10.6 to -7.9 |
Self Esteem Scale (SE) | 70.0 (18.8) | 79.8 (17.5) | 0.0001 (0.53) | -11.6 to -8.0 |
General Health Perceptions Scale (GH) | 60.9 (21.0) | 73.0 (17.3) | 0.0001 (0.62) | -14.1 to -10.1 |
Emotional Impact on Parent Scale (PE) | 53.4 (26.1) | 80.3 (19.1) | 0.0001 (1.17) | -29.4 to -24.4 |
Parental Impact Time Scale (PT) | 70.1 (23.3) | 87.8 (19.9) | 0.0001 (0.81) | -20.3 to -15.0 |
Family Activities (FA) | 68.0 (23.3) | 89.7 (18.6) | 0.0001 (1.02) | -23.9 to -19.4 |
Results of the linear mixed-effects model to evaluate change over time in the CHQ physical and psychosocial summary scores are reported in Tables
5,
6 and
7. The Level-1 model, presented in Table
5, tested the effect of time. On average, children did not change significantly over time for physical health scores. The average change per time in psychosocial health is small (0.6 points) and statistically significant. Table
5 also reports the standard deviations (transformed into 50% ranges) for the between child differences in Time 1 score and change over time. They give the predicted ranges within which 50% of children’s intercepts and slopes are expected to fall. For both physical and psychosocial function, children vary considerably in their predicted Time 1 scores, as well as in expected change over time. Thus, notwithstanding the lack of average change in CHQ scores, there was evidence of heterogeneity among children that was worth examining.
Table 5
The effect of time on rates of change in physical and psychosocial scores (level-1 model)
Average scores at Time 1 | 38.3 | 44.2 |
95% CI | [36.8, 39.8] | [43.2, 45.3] |
SD of between-child differences | 13.8 | 9.4 |
50% range of differences | 29.0, 47.6 | 37.9, 50.6 |
Average change per time | 0.3 | 0.6 |
95% CI | [–0.3, 0.9] | [0.2., 1.0] |
SD of between-child differences | 5.0 | 1.9 |
50% range of differences | -1.2, 1.8 | -0.7, 1.9 |
Within-child residual SD | 8.4 | 5.7 |
Table 6
The effect of child factors on rates of change in physical and psychosocial scores (level-2 model)
Child factors
| | | | | | |
SDQ
| Intercept | | 41.12** | 1.78 | 59.07** | 0.81 |
Age | | 1.79 | 1.63 | 1.07 | 0.89 |
SDQ | | -0.28** | 0.12 | -1.18** | 0.05 |
Time | 1 | -3.53 | 2.04 | 0.26 | 1.25 |
Time | 2 | -3.62** | 1.71 | 0.48 | 0.95 |
SDQ*time | 1 | 0.28** | 0.14 | -0.08 | 0.08 |
SDQ*time | 2 | 0.22 | 0.12 | -0.05 | 0.06 |
SF-36
| Intercept | | 31.69** | 2.75 | 39.14** | 1.80 |
Age | | 1.96 | 1.64 | 2.12 | 1.13 |
SF-36 | | 0.08** | 0.03 | 0.08** | 0.02 |
Time | 1 | 1.57 | 3.44 | -0.38 | 2.4 |
Time | 2 | 1.21 | 3.04 | 0.75 | 2.02 |
SF-36*time | 1 | -0.02 | 0.04 | -0.02 | 0.03 |
SF-36*time | 2 | -0.03 | 0.04 | -0.02 | 0.02 |
ASK
| Intercept | | 10.45** | 2.39 | 43.89** | 1.84 |
Age | | 2.80 | 1.53 | 2.14 | 1.14 |
ASK | | 0.36** | 0.03 | 0.01 | 0.02 |
Time | 1 | 3.10 | 2.87 | -1.31 | 2.05 |
Time | 2 | -0.26 | 2.47 | 0.76 | 1.67 |
ASK*time | 1 | -0.03 | 0.03 | -0.01 | 0.02 |
ASK*time | 2 | -0.001 | 0.03 | -0.01 | 0.02 |
Table 7
The effect of family and environmental factors on rates of change in physical and psychosocial scores
Family factors
| | | | | | |
Impact on family
| Intercept | | 62.45** | 2.71 | ++ | |
| Age | | 1.68 | 1.61 | | |
| Impact | | -1.20** | 0.12 | | |
| Time | 1 | -11.38** | 3.68 | | |
| Time | 2 | -9.42** | 3.08 | | |
| Impact *time | 1 | 0.55** | 0.16 | | |
| Impact *time | 2 | 0.42** | 0.13 | | |
Environmental factors
| | | | | | |
Overall barriers
| Intercept | | 44.9** | 1.14 | 49.44** | 0.75 |
| Age | | 1.26 | 1.58 | 1.64 | 1.06 |
| Barriers | | -5.8** | 0.6 | 3.83** | 0.38 |
| Time | 1 | -2.01 | 1.4 | -1.06 | 0.94 |
| Time | 2 | -1.48 | 1.2 | -0.86 | 0.78 |
| Barriers *time | 1 | 1.63* | 0.8 | -0.57 | 0.55 |
| Barriers *time | 2 | 0.6 | 0.7 | 0.34 | 0.44 |
The Level-2 model, testing the effect of time as a function of child, family and environmental characteristics, is presented in Tables
6 and
7. The coefficients indicated that environmental barriers had a negative and significant association with physical QoL (-5.8, p < 0.001). The significant interaction term of Barriers and Time 1 indicates that the effect of time on change in physical scores was dependent on levels of environmental barriers. That is, the relationship between the CHIEF total score and physical summary score at Time 1, compared with time 3, was significantly different. For example, when looking at the effect of environmental barriers on rates of change of CHQ physical score (Table
7), the mean initial physical score was 44.9; environmental barriers have a negative effect (beta = -5.8) on physical score. Comparing to time 3, the physical score at time 1 is significantly lower (beta = -2.01) and this change over time, i.e., 18 months, is dependent on levels of environmental barriers (beta = 0.163). In other words, environmental barriers explain the differences in physical rates (or slope) along the three data collection time points. Children with lower time 1 environmental barrier scores display greater changes in physical summary scores over time.
Behavioral difficulties had a significant and negative (-0.28, p = 0.002; -1.2) association with physical scores. The interaction effect was significant and indicated that change in physical scores over time was dependent on child’s behavioral difficulties. In other words, the relationships between behavioral difficulties and physical scores at Time 1 were different compared to Time 3. The parent’s general health and child physical functioning had a significant and positive association with physical score (β = .08, p = 0.02, β = .36, p = 0.0001 respectively) but not over time.
For change in psychosocial score (measured by CHQ), all predictors, with the exception of children physical functioning (measure by ASK), had a significant association with baseline psychosocial scores. However, none of these factors, i.e., child and environmental factors, served as predictors of psychosocial score at Times 2 or 3 and did not explain rates of change in psychosocial score over time.
Discussion
Similar to previous studies, this study found that the health-related quality of life of children with physical disabilities was significantly less than typically developing children in the normative CHQ sample. Previous research described significant differences in the CHQ subscales of physical functioning, role functioning, parental impact and family activities, pain, and general health [
8,
10,
12‐
14,
23]. In the current study, there were significant differences from the normative sample across all subscales except Family Cohesion. Similar to previous studies, psychosocial scores in this sample were only slightly lower than the normative sample, a difference that is statistically significant, but may not be clinically important.
This study represents one of very few examinations of the stability of CHQ scores longitudinally. In analyzing group results, children did not change significantly over time on Physical summary scores of the CHQ. Psychosocial summary scores changed significantly over the study period of 18 months, but these changes were small and not likely to be of substantial clinical importance. Vargus-Adams [
22] also found no significant changes in CHQ physical HRQoL for children with cerebral palsy over a one-year time period. In a sample of children with juvenile rheumatoid arthritis and juvenile spondyloarthropathy, Selvaag et al. [
24] recorded significant improvements in health related quality of life, except for pain, over a 3-year period. These findings may be different because they are the result of an arthritis intervention study rather than an examination of naturalistic stability. The sample in this current study has predominantly central nervous system-based physical disabilities so it is not surprising that the results are more similar to the findings of Vargus-Adams [
22].
These findings are similar to other studies that have explored quality-of-life measurement in children and youth with disabilities [
26,
45]. This result may reflect the complexity of the children's condition and their typical association with additional health or development conditions such as problems with vision, hearing, or cognition. The presence of several health or development conditions can have a greater impact on the family and is often associated with lower physical functioning. Thus, there can be considerable variability across children with similar primary health conditions. This finding may also reflect the complexity of quality-of-life and the lack of direct explanatory relationships between quality-of-life scores and child and youth functioning [
46]. As well, the role of health interventions received during the study timeframe was not examined. Change in health status may be more likely in children with a less complex health condition with fewer associated neurological problems [
24].
Although there was little average change in CHQ Physical summary scores, there is evidence of heterogeneity and less stability among children. The presence of heterogeneity in slopes (steepness of change over time) and intercepts (time 1 scores) was tested in level-1 model and those findings led to level-2 model analyses to identify characteristics that explained these variances. Findings indicate that heterogeneity of individual trajectories for Physical scores within this sample is explained by presence of environmental barriers, impact on family, child’s behavior and child’s physical functioning. While environmental barriers and behavior had a negative influence, physical functioning had a positive influence. In planning programs and services, these factors can be taken into account and potentially serve as entry points for intervention. For example, intervention could focus on changing environmental barriers or providing children and families with strategies to manage and change behavioral difficulties. Providing support to families in addressing issues of behavioral difficulties and environmental barriers, as well as direct support such as funding, has the potential to positively impact physical and psychosocial QoL, and should be studied further.
The sample of children with musculoskeletal-based disabilities in this study was small, comprising only 20% of the total sample and thus limiting the validity of any subgroup analyses. With so few studies examining change over time for the CHQ, it is difficult to conclude whether the measure is not responsive for children with neurologically-based disabilities or whether that population is not changing appreciably in HRQoL over time. The CHQ is a generic measure of health status so its responsiveness to change may be less than diagnostic specific measures. The advantage of this study is that linear mixed-effects models estimate both the average linear pattern of change, and the degree of heterogeneity in change among children. Thus, while scores on a group basis on the CHQ do not change significantly over time in this sample, there is less stability of scores amongst individual children. Further research regarding the ability of the CHQ to measure change over time and the best methods to analyze longitudinal health-related quality of life data is required.
The findings of this study are based on a sample from the Canadian population and must be interpreted within that context. They also reflect predominantly the perspective of mothers, who were the primary study respondents. A limitation of the study is the smaller subgroup sample size of children with musculoskeletal conditions. Further research can compare HRQoL between children with musculoskeletal versus central nervous system-based disabilities. The CHQ-PF50 was found to have low reliability for ambulant children with cerebral palsy in the domains of Behavior and General Health [
23]. Although the current sample did not include a majority of children with ambulant cerebral palsy, this is a potential limitation to the study.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
ML, GK, SH and MK participated in the design and implementation of the study. ML, DA and GK examined the literature to develop predictive hypotheses for the study. SH and DA supervised the statistical analyses which were carried out by LX. All authors helped draft the manuscript, read and approved the final manuscript.