SDSU/UCSD Joint Doctoral Program in Clinical Psychology, 6363 Alvarado Court, #103, San Diego State, San Diego, CA 92120, USA
The Interior Design Program, Department of Consumer Affairs, College of Human Sciences, 308 Spidle Hall, Auburn University, AL 36849, USA
The Children's Hospital at Scott & White, Department of Pediatrics, Texas A&M University Health Science Center, 2401 South 31st Street, Temple, TX 76508, USA
Department of Pediatrics, College of Medicine, Department of Landscape Architecture and Urban Planning, College of Architecture, Texas A&M University, 3137 TAMU, College Station, TX 77843-3137, USA
Abstract
Background
The PedsQL™ Present Functioning Visual Analogue Scales (PedsQL™ VAS) were designed as an ecological momentary assessment (EMA) instrument to rapidly measure present or at-the-moment functioning in children and adolescents. The PedsQL™ VAS assess child self-report and parent-proxy report of anxiety, sadness, anger, worry, fatigue, and pain utilizing six developmentally appropriate visual analogue scales based on the well-established Varni/Thompson Pediatric Pain Questionnaire (PPQ) Pain Intensity VAS format.
Methods
The six-item PedsQL™ VAS was administered to 70 pediatric patients ages 5–17 and their parents upon admittance to the hospital environment (Time 1: T1) and again two hours later (Time 2: T2). It was hypothesized that the PedsQL™ VAS Emotional Distress Summary Score (anxiety, sadness, anger, worry) and the fatigue VAS would demonstrate moderate to large effect size correlations with the PPQ Pain Intensity VAS, and that patient" parent concordance would increase over time.
Results
Test-retest reliability was demonstrated from T1 to T2 in the large effect size range. Internal consistency reliability was demonstrated for the PedsQL™ VAS Total Symptom Score (patient self-report: T1 alpha = .72, T2 alpha = .80; parent proxy-report: T1 alpha = .80, T2 alpha = .84) and Emotional Distress Summary Score (patient self-report: T1 alpha = .74, T2 alpha = .73; parent proxy-report: T1 alpha = .76, T2 alpha = .81). As hypothesized, the Emotional Distress Summary Score and Fatigue VAS were significantly correlated with the PPQ Pain VAS in the medium to large effect size range, and patient and parent concordance increased from T1 to T2.
Conclusion
The results demonstrate preliminary test-retest and internal consistency reliability and construct validity of the PedsQL™ Present Functioning VAS instrument for both pediatric patient self-report and parent proxy-report. Further field testing is required to extend these initial findings to other ecologically relevant pediatric environments.
Background
Patient-reported outcomes (PROs) are self-report instruments that directly measure the patient's perceptions of the impact of disease and treatment as clinical trial endpoints, and include multi-item health-related quality of life (HRQOL) instruments, as well as single-item measures (e.g., pain visual analogue scale), daily diaries, treatment adherence, and healthcare satisfaction
The PedsQL™ Measurement Model was designed as a modular approach to measuring pediatric PROs, developed to integrate the relative merits of generic and disease-specific approaches
The PedsQL™ includes child self-report for ages 5–18 and parent proxy-report for ages 2–18
Developments in ecological momentary assessment (EMA) suggest the benefits of measuring symptoms at-the-moment in ecologically relevant environments
As a continuous measurement scale, the VAS potentially avoids the clustering of symptom reports that may occur with single-item categorical response methods
A 10 cm (100 mm) line length has been found to have the smallest measurement error in comparison to line lengths of 5 and 20 cm
The VAS has been shown to be a reliable and valid PRO measure of pediatric patients' pain intensity in children as young as 5 years of age
The experience of hospitalization entails many of the "precipitants" (disease, injury, stress, medical procedures) of pain and other symptoms posited by the Biobehavioral Model of Pediatric Pain
One of the major positive changes in the typical pediatric hospitalization experience has been in the routine implementation of a policy of open visitation rights for parents, including overnight stays, which has resulted in parental social support and coping guidance throughout the hospitalization experience, resulting in a significant attenuation of many of the emotional distress symptoms previously documented in the older pediatric hospitalization literature
Based on the extant pediatric hospitalization stress and coping literature
Method
Participants and settings
As part of a larger architecture doctoral dissertation study on the effects of the hospital environment on pediatric patients, all children that were admitted to the hospital in the 5–17 age group and their parents during the recruitment period were asked to participate. Seventy-five families were approached, and 70 families agreed to participate (93% participation rate). The reasons for declining participation included that the child was too emotionally upset or in pain (secondary to sickle cell anemia crisis) to participate.
Seventy children and their parents completed the PedsQL™ Present Functioning Visual Analogue Scales. The children were ages 5–17 (Mean age = 10.61, S.D. = 3.54; 40 boys, 30 girls), No ethnicity data were collected. The children were hospitalized for treatment of acute (e.g., infections, accidents, injuries) and chronic (e.g., cystic fibrosis respiratory treatment, sickle cell anemia) conditions as reported by the inpatient nursing staff. However, the larger architecture doctoral dissertation study of which these data are derived from did not have access to individual patient medical records, and thus it was not possible to link patient characteristics regarding medical condition to the VAS data. Pediatric patients and their parents were approached for permission to be part of the study once they had been admitted into their hospital room.
Pediatric patients and their parents completed the PedsQL™ VAS upon admittance, after they had consented to be part of the study, and then two hours later, before any medical procedures were performed. Data were collected concurrently at two sites: Scott & White Memorial Hospital in Temple, Texas, and Christus St. Elizabeth's Hospital in Beaumont, Texas. The length of recruitment was 3 weeks for the Scott & White Memorial Hospital and 6 weeks for the Christus St. Elizabeth's Hospital. Institutional Review Board approval was obtained from both of these institutions prior to data collection.
PedsQL™ Present Functioning Visual Analogue Scales
The PedsQL™ VAS instrument contains six items that measure anxiety, sadness, anger, worry, fatigue, and pain at the present moment, and where derived from the PedsQL™ Emotional Functioning Scale items
Varni/Thompson Pediatric Pain Questionnaire VAS
The Varni/Thompson Pediatric Pain Questionnaire (PPQ) Pain Intensity VAS measurement properties were initially tested in pediatric rheumatology patients as young as 5 years old and their parents, demonstrating greater perceived pain intensity associated with greater rheumatic disease activity
Statistical analysis
Test-retest reliability was evaluated by computing both Pearson Product Moment Correlation coefficients and Intraclass Correlations (ICC) for each item and scale from Time 1 to Time 2. Pearson Product Moment Correlation coefficient effect sizes are designated as small (.10–.29), medium (.30–.49), and large (≥.50)
Construct validity for the PedsQL™ VAS was investigated through an analysis of the intercorrelations among the emotional distress and fatigue items with the benchmark PPQ Pain Intensity VAS criterion. Computing the intercorrelations among scales provides initial information on the construct validity of an instrument
The concordance between patient self-report and parent proxy-report was determined through computing both Pearson Product Moment Correlation coefficients and Intraclass Correlations (ICC) at both Time 1 and Time 2. Given no significant differences between sites in terms of VAS scores after a Bonferroni correction for the number of tests conducted, data were pooled across sites. Statistical analyses were conducted with SPSS.
Results
Descriptives
Means and standard deviations for pediatric patient self-report and parent proxy-report across the different age groups are presented in Table
PedsQL™ Present Functioning Visual Analogue Scales Descriptives (N = 70)
Ages 5–7 (n = 18)
Ages 8–12 (n = 31)
Ages 13–17 (n = 21)
PedsQL™ Items
Patient Self-Report
Parent Proxy-Report
Patient Self-Report
Parent Proxy-Report
Patient Self-Report
Parent Proxy-Report
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Time 1 Scores
Total Score
25.60
19.04
29.92
18.28
28.17
20.70
38.88
22.10
28.87
19.54
35.99
20.89
Emotional Distress Summary Score
21.60
23.82
23.76
16.90
19.31
19.48
33.77
21.73
20.86
19.67
31.37
21.55
Anxiety VAS
25.00
36.10
23.61
26.83
17.26
22.94
30.48
24.54
25.57
28.02
30.71
29.25
Sadness VAS
22.78
35.45
17.83
24.04
17.58
24.22
38.39
34.67
15.00
17.39
30.48
27.15
Anger VAS
2.22
4.92
7.22
11.40
9.42
16.59
15.23
20.22
6.90
13.82
20.95
24.52
Worry VAS
36.39
41.33
46.39
26.33
32.97
36.52
50.97
29.62
35.95
34.77
43.33
32.07
Fatigue VAS
38.89
41.50
39.17
35.16
54.19
35.59
55.32
33.96
46.90
35.93
44.52
32.94
Pain VAS
28.33
34.13
45.28
34.75
37.58
35.91
42.90
34.27
42.86
30.72
45.95
31.37
Time 2 Scores
Total Score
20.65
22.21
20.62
23.78
23.02
21.58
31.48
21.81
24.56
14.68
29.29
16.15
Emotional Distress Summary Score
17.43
21.02
17.32
22.91
17.84
20.34
25.60
22.73
17.38
16.77
23.10
15.51
Anxiety VAS
13.89
26.04
18.06
28.03
15.78
24.59
23.71
25.92
17.62
22.67
23.47
23.46
Sadness VAS
22.78
33.96
20.83
33.62
14.68
25.91
22.10
28.04
15.00
18.44
19.52
17.60
Anger VAS
3.06
3.89
6.11
10.23
10.32
21.68
20.48
28.59
5.48
6.87
15.71
22.21
Worry VAS
30.00
39.78
24.28
28.03
30.48
34.98
36.13
29.12
31.43
28.95
33.57
27.21
Fatigue VAS
27.78
35.45
26.94
32.36
35.16
32.42
47.58
36.67
42.62
28.18
43.57
25.65
Pain VAS
26.39
37.57
27.50
37.54
31.61
32.54
38.87
32.63
35.24
25.37
39.76
23.21
Note: 0–100 VAS scores; higher values = higher symptom levels.
Test-retest reliability
Test-retest reliability from Time 1 to Time 2 demonstrated mainly moderate to larger effect sizes for patient self-report and parent proxy-report (Table
PedsQL™ Present Functioning Visual Analogue Scales Test-Retest Reliability.
Item
Patient Report
Parent Report
Total Score
.73**
.85
.65**
.79
Emotional Distress Summary Score
.65**
.78
.61**
.76
Anxiety
.53**
.69
.52**
.69
Sadness
.53**
.70
.55**
.70
Anger
.36**
.52
.74**
.84
Worry
.64**
.78
.45**
.62
Fatigue
.59**
.74
.53**
.69
Pain
.60**
.75
.73**
.84
Patient Self-Report and Parent Proxy-Report Time 1 to Time 2 Correlations.
*p < .05, **p < .01 (2-tailed).
Note: Effect sizes are designated as small (.10–.29), medium (.30–.49), and large (≥.50) for Pearson Product Moment Correlations. Intraclass Correlations (ICCs) are designated as ≤ 0.40 poor to fair agreement, 0.41–0.60 moderate agreement, 0.61–0.80 good agreement, and 0.81–1.00 excellent agreement. Intraclass Correlation Coefficients are listed in bold below Pearson Product Moment Correlations.
Internal consistency reliability
Internal consistency reliability alpha coefficients for the PedsQL™ VAS are presented in Table
PedsQL™ Present Functioning Scales Internal Consistency Reliability for Patient Self-Report and Parent Proxy-Report
Ages 5–7 (n = 18)
Ages 8–12 (n = 31)
Ages 13–17 (n = 21)
Total N = 70
Time 1
Total Score
0.54
0.79
0.79
0.72
Emotional Distress Summary Score
0.70
0.74
0.80
0.74
Time 2
Total Score
0.79
0.84
0.71
0.80
Emotional Distress Summary Score
0.69
0.74
0.82
0.73
Time 1
Total Score
0.80
0.83
0.80
0.80
Emotional Distress Summary Score
0.71
0.79
0.76
0.76
Time 2
Total Score
0.84
0.81
0.78
0.84
Emotional Distress Summary Score
0.89
0.83
0.61
0.81
Construct validity
Tables
PedsQL™ Present Functioning Visual Analogue Scales Time 1 Correlations: Patient Self-Report Above the Diagonal, Parent Proxy-Report Below the Diagonal, Patient/Parent Correlations on the Diagonal.”
Total
Emotional
Anxiety
Sadness
Anger
Worry
Fatigue
Pain
Total
.89**
.68**
.71**
.48**
.78**
.55**
.74**
Score
.62
Emotional
.93**
.81**
.77**
.56**
.85**
.19**
.48**
Distress Summary Score
.57
Anxiety
.75**
.81**
.51**
.34**
.56**
.04
.35**
VAS
.50
Sadness
.75**
.79**
.47**
.38**
.48**
.12
.48**
VAS
.58
Anger
.56**
.65**
.40**
.44**
.35**
.09
.23
VAS
.31
Worry
.77**
.81**
.63**
.46**
.31**
.26*
.39**
VAS
.54
Fatigue
.67**
.43**
.30*
.38**
.11
.46**
.37**
VAS
.32
Pain
.76**
.57**
.49**
.47**
.40**
.41**
.44**
VAS
.55
*p < .05, **p < .01 (2-tailed).
Note: Effect sizes are designated as small (.10–.29), medium (.30–.49), and large (≥.50) for Pearson Product Moment Correlations. Intraclass Correlations (ICCs) are designated as ≤ 0.40 poor to fair agreement, 0.41–0.60 moderate agreement, 0.61–0.80 good agreement, and 0.81–1.00 excellent agreement. Intraclass Correlation Coefficients are listed in bold below Pearson Product Moment Correlations.
PedsQL™ Present Functioning Visual Analogue Scales Time 2 Correlations: Patient Self-Report Above the Diagonal, Parent Proxy-Report Below the Diagonal, Patient/Parent Correlations on the Diagonal
Total
Emotional
Anxiety
Sadness
Anger
Worry
Fatigue
Pain
Total
.92**
.70**
.75**
.40**
.82**
.69**
.81**
Score
.80
Emotional
.93**
.77**
.83**
.44**
.88**
.40**
.58**
Distress Summary Score
.73
Anxiety
.79**
.86**
.49**
.13
.59**
.27*
.46**
VAS
.69
Sadness
.80**
.81**
.63**
.30*
.62**
.25*
.54**
VAS
.60
Anger
.59**
.66**
.37**
.41**
.22
.16
.25*
VAS
.67
Worry
.80**
.85**
.75**
.55**
.39**
.45**
.47**
VAS
.74
Fatigue
.75**
.53**
.46**
.49**
.21
.52**
.60**
VAS
.75
Pain
.74**
.53**
.38**
.54**
.38**
.39**
.54**
VAS
.70
.75
. *p < .05, **p < .01 (2-tailed).
Note: Effect sizes are designated as small (.10–.29), medium (.30–.49), and large (≥.50) for Pearson Product Moment Correlations. Intraclass Correlations (ICCs) are designated as ≤ 0.40 poor to fair agreement, 0.41–0.60 moderate agreement, 0.61–0.80 good agreement, and 0.81–1.00 excellent agreement. Intraclass Correlation Coefficients are listed in bold below Pearson Product Moment Correlation.
Table
PedsQL™ Present Functioning Visual Analogue Scores: Time 1 to Time 2 Differences
Time 1
Time 2
Item
N
Mean
SD
Mean
SD
Difference
Effect Size
t
Child Report
Total
70
27.72
19.70
22.87
19.72
-4.85
.25
2.81**
Emotional Distress Summary Score
70
20.36
20.43
17.60
19.25
-2.76
.13
NS
Anxiety
70
21.74
28.17
15.89
24.10
-5.85
.21
NS
Sadness
70
18.14
25.71
16.86
26.21
-1.28
.05
NS
Anger
70
6.81
13.76
7.00
15.21
+0.19
.01
NS
Worry
70
34.74
36.79
30.64
34.13
-4.10
.11
NS
Fatigue
70
48.07
37.26
35.50
32.06
-12.57
.33
3.31***
Pain
70
36.79
33.93
31.36
31.71
-5.43
.15
NS
Parent Report
Total
70
35.71
20.85
28.03
21.02
-7.68
.37
3.69***
Emotional Distress Summary Score
70
30.48
20.67
22.72
20.85
-7.76
.38
3.53***
Anxiety
70
28.79
26.39
22.21
25.52
-6.58
.25
2.17*
Sadness
70
30.73
30.80
21.00
26.67
-9.73
.32
2.95**
Anger
70
14.89
20.27
15.36
23.63
+0.47
.02
NS
Worry
70
47.50
29.35
32.31
28.30
-15.19
.52
4.18***
Fatigue
70
47.93
34.17
41.07
33.27
-6.86
.20
NS
Pain
70
44.43
33.10
36.21
31.51
-8.22
.25
2.88**
*p < .05, **p < .01, ***p < .001.
Note: Effect sizes are designated as small (.20), medium (.50), and large (.80).
Parent/Child concordance
The parent/child concordance intercorrelations matrix is shown in Tables
Discussion
This study presents the preliminary test-retest and internal consistency reliability and construct validity of the PedsQL™ Present Functioning Visual Analogue Scales for anxiety, sadness, anger, worry, fatigue and pain. Most test-retest reliabilities were in the large effect size range. The majority of internal consistency reliabilities met or exceeded the recommended minimum alpha coefficient standard of 0.70 for group comparisons. Preliminary construct validity of the PedsQL™ Present Functioning VAS was demonstrated through the intercorrelations among the emotional distress and fatigue VAS rating with the well-established PPQ VAS pain intensity criterion.
These findings have certain limitations. The data presented here were collected in the context of a larger architecture doctoral dissertation study investigating the effects of the hospital environment on children. As such, the larger study was not specifically designed to test the measurement properties or establish the validity of the PedsQL™ Present Functioning VAS. For optimal testing of a present functioning scale, it would be useful to test for subject characteristics that might predict VAS scores, such as injury severity and chronic health condition. Since these data were not collected, it was not possible to separate the patients into known groups in order to determine whether the VAS was able to differentiate patients based on established diagnostic criteria. The 2-hour interval was selected to minimize the probability of the occurrence of medical procedures which would have substantially affected the test-retest reliability calculations. However, the short test-retest interval may have potentially inflated the test-retest reliability and attenuated possible changes in scores from Time 1 to Time 2. Further, given that previous research with the PPQ Pain Intensity VAS has demonstrated a relationship to children's coping strategies
As ecological momentary assessment (EMA) research with adult patients demonstrates the utility of at-the-moment assessment in disentangling the interrelationships between such diverse constructs as pain, mood, fatigue, coping, and social support through a daily process analysis, the application of these methods and technologies to the pediatric population will requirement measurement instruments that are developmentally appropriate. The PedsQL™ Present Functioning Visual Analogue Scales represent one approach to meeting that need.
Conclusion
This study demonstrates preliminary reliability and validity of the PedsQL™ Present Functioning Visual Analogue Scales for both child self-report and parent-proxy report. The PedsQL™ VAS was designed as a pediatric measurement instrument for the ecological momentary assessment of anxiety, sadness, anger, worry, fatigue, and pain in pediatric patients ages 5–18.
Abbreviations
PedsQL™ Pediatric Quality of Life Inventory™
PRO Patient-Reported Outcomes
HRQOL Health-Related Quality of Life
VAS Visual Analogue Scale
Competing interests
The author(s) declare that they have no competing interests.
Authors' contributions
JWV and SAS designed the instrument. SAS and JWV drafted the manuscript. SAS performed the statistical analyses. SJE conceptualized the rationale and design of the original dissertation study from which the data were collected. JWV and TMB consulted on the statistical analyses. TMB participated in manuscript preparation. All authors read and approved the final manuscript.
Acknowledgements
Dr. Varni holds the copyright and the trademark for the PedsQL™ and receives financial compensation from the Mapi Research Trust, which is a nonprofit research institute that charges distribution fees to for-profit companies that use the Pediatric Quality of Life Inventory™.