PEDIATRIC EPM-ROM SCALE: AN REDUCED JOINT COUNT SCALE TO BE USED IN JUVENILE RHEUMATOID ARTHRITIS DAILY PRACTICE AND CLINICAL TRIALS
Introduction. Different instruments are available to measurement of functional status in JRA; however, none of them is based on the evaluation of joint range of motion (ROM). The aim of this study was to design and evaluate a ROM scale to be used as a complementary instrument in JRA trials.
Methods. The 10 joint movements of the Pediatric EPM-ROM scale were derived from 25 initial movements. The selection was based on two criteria: 1) consensus among 3 pediatric rheumatologists, 1 physiotherapist and 1 occupational therapist, and 2) choice of movements that presented the highest scores in a pilot study involving JRA patients. The score for each joint ranges from 0 (full movement) to 3 (severe limitation) and the cut-off degrees of motion are in general, based on the lack of ability to perform some determined activities of daily living. The test-retest reliability was assessed by administering the scale twice by the same observer, 4 to 10 days apart, always in the morning. The inter-observer reliability was evaluated in the same day by two independent observers. Cross-sectional construct validity was also assessed by correlating the mean values of some clinical parameters with the mean Pediatric EPM-ROM scale score.
Results. The instrument was applied to 34 JRA patients, 11 systemic, 11 poly and 12 pauci. The mean EPM-ROM score was 0.57 (SD = 0.54, min. = 0, max. = 2.05). The test-retest and inter-observer correlation coefficients were 0.96 and 0.98, respectively. The Pearson’s correlation coefficients between the scores of the Pediatric EPM-ROM Scale and other parameters were satisfactory: Childhood Health Assessment Questionnaire, r = 0.553 (p < 0.001), American College of Rheumatology global functional class, r = 0.558 (p < 0.001) and number of involved joints, r = 0.652 (p < 0.001).
Conclusion. Our results provide evidence that the Pediatric EPM-ROM scale is a valid instrument to measure joint ROM in JRA patients.
Key Indexing Terms: juvenile rheumatoid arthritis, outcome assessment, range of movement, functional ability.
From the Division of Allergy, Clinical Immunology and Rheumatology, Department of Pediatrics and Division of Rheumatology, Department of Medicine, Sao Paulo Federal University - Escola Paulista de Medicina, Sao Paulo, Brazil.
C. Len, M.D.: Division of Allergy, Clinical Immunology and Rheumatology, Department of Pediatrics.
M. B. Ferraz, M.D.: Associate Professor, Division of Rheumatology, Department of Medicine.
J. Goldenberg, M.D.: Associate Professor and Head, Division of Rheumatology, Department of Medicine.
L. M. Oliveira: PT: Division of Rheumatology, Department of Medicine.
P. P. Araujo: OT.: Division of Rheumatology, Department of Medicine.
M. R. Quaresma, M.D.: Division of Rheumatology, Department of Medicine.
M. T. Terreri, M.D.: Division of Allergy, Clinical Immunology and Rheumatology, Department of Pediatrics.
M. O. E. Hilário, M.D.: Associate Professor and Head, Division of Allergy, Clinical Immunology and Rheumatology, Department of Pediatrics.
Address for correspondence and reprint requests:
Claudio Len, MD
Division of Allergy, Clinical Immunology and Rheumatology
Department of Pediatrics
Av. Brig. Faria Lima, 1826 cj. 205
CEP 01451-908
São Paulo, SP, Brazil
FAX 5511-2128340
INTRODUCTION
Interest in the outcome assessment of patients with juvenile rheumatoid arthritis (JRA) has increased significantly over the past decade. This is specially due to the difficulty of accurately measuring the effects of arthritis (or its treatment) with commonly used endpoints (clinical and laboratory), and also due to the importance of the physical function in the rehabilitation of children with JRA.
Recently, Giannini et al (1) had proposed a core set of outcome variables to help standardize the management and the results of therapeutic clinical trials, and allow practitioners to assess JRA patients response to clinical and physical therapy. The core set is composed of the following variables: 1) physician global assessment of disease activity; 2) parent/patient assessment of overall well-being; 3) functional ability; 4) number of joints with active arthritis; 5) number of joints with limited range of motion (ROM); and 6) erythrocyte sedimentation rate (ESR).
ROM measurement is a simple method of assessing joint alignment and disease activity and an easy reference for treatment planning. In addition, it provides information on the different degrees of motion and unables the physician and therapist an opportunity to assess joint status in general and functional ability (2). The evaluation of joints with limited ROM during physical examination requires a great deal of observer time and effort. It is not easy to quantify the ROM of all joints; therefore the joint examination reliability tends to be difficult. Several attempts have been made in reducing the number of joints necessary to assess. Although some reduced joint scales have specially been developed to evaluate the ROM of patients with RA (3,4), there are no specific scales for children with JRA.
The aim of our study was to develop a pediatric instrument based on ROM and to evaluate its measurement properties.
MATERIAL AND METHODS
Instrument construction. The Pediatric Escola Paulista de Medicina (EPM)-ROM scale was based on the adult EPM-ROM scale, developed by Ferraz et al (3). Modifications were performed to permit the use in JRA patients, mainly because of the pattern of articular involvement, different from the one observed in patients with RA.
The methodological frameworks for assessing health indices proposed by Kirshner and Guyatt (5) and Juniper et al (6) was used as well as the guidelines for instrument development and testing (7).
Item generation. The development of a new instrument requires generation of a comprehensive list of items that might be appropriate to include (5). A multidisciplinary panel was set up and comprised of 3 pediatric rheumatologists, one physiotherapist and one occupational therapist (both of them with large experience in pediatric patients) . In the first meeting, the panel of experts identified all the movements which would be suitable for inclusion in the Pediatric EPM-ROM scale. Initially, 25 movements were included in the preliminary scale. The method chosen for measuring joint ROM was based on the procedures for measuring and recording developed or recommended by the American Academy of Orthopedic Surgeons in 1966 (8). All ROM measurements were performed with a goniometer from a starting position defined as 0 degree.
The patients’ active-assisted ROM was evaluated, i.e., the examinator assisted the patient in the active movement of each joint.
Item scaling. The scores of each joint movement ranged from 0 (no limitation) to 3 (severe limitation); the cut-off degree of motion were, usually, based on the lack of ability to perform some activities of daily living (ADLs), i.e., the minimal ROM required to perform the specific functions.
The final score for each joint movement was defined as the sum of the left and right ROM score divided by 2.
Item reduction. The reduction of the number of joint movements from 25 (preliminary scale) to 10 (definitive scale) was based on 3 steps:
1) 1st consensus of the multidisciplinary panel (3 pediatric rheumatologists, one physiotherapist and one occupational therapist): selection of 10 joint movements from the preliminary scale, that according to the experience of them, were the most frequently affected in JRA patients.
2) Pilot study: selection of 10 joint movements which presented the highest scores in a pilot study that enrolled 34 consecutive JRA patients (19 boys, 15 girls), ages 2 - 17 years (mean 10.7 years), diagnosed according to the American College of Rheumatology criteria (9). The mean disease duration was 4.8 years. The onset type was systemic in 11, polyarticular in 11 and pauciarticular in 12.
3) 2nd and final consensus of the multidisciplinary panel: consensus of the 10 definitive joint movements, based on the 1st consensus and the pilot study.
Evaluation of the measurement properties. In the reliability study the 34 JRA patients were assessed twice, 4 days apart, by 2 investigators: 1st day = investigators 1 and 2; 4th day = investigator 1. The assessments were performed in a calm place, always at the same time of the day (between 10 and 10:30 a.m.).
The instrument appeared to be sensible to both investigators and clinicians interested in applying it in the assessment of patients in clinical practice (face validity). Regarding the construct validity, we evaluated the Pearson’s correlation coefficient between the definitive Pediatric EPM-ROM scale and the functional class (American College of Rheumatology - ACR) (10), between the definitive Pediatric EPM-ROM scale and physical ability dimension of the Childhood Health Assessment Questionnaire (11), and between the definitive Pediatric EPM-ROM scale and the number of joints with limited ROM.
RESULTS
Patients. The clinical and demographic characteristics of the
JRA patients that were assessed in the pilot study and in the evaluation of the
measurement properties are presented in Table 1. We observed a slight
male predominance (55.9%). Regarding the type of disease, 7 out of 11 patients with the
systemic type of onset, followed up with polyarticular disease.
Item reduction. Table 2 presents the 10 joint movements
selected from the preliminary scale in the 1st consensus, and the 10 joint movements that
reached the highest scores in the pilot study (and respective mean scores).
In five movements: wrist - extension, ankle - dorsiflexion, knee - extension, hip - lateral rotation and hip - medial rotation an agreement between the 1st consensus and the pilot study was observed. All these movements were included in the definitive Pediatric EPM-ROM scale . The five remaining joint movements were selected at the 2nd consensus, 4 of them from the pilot study (ankle - plantar flexion, wrist - flexion, thumb/metacarpophalangeal - flexion and shoulder - abduction), and one from the 1st consensus (cervical spine - lateral rotation). The multidisciplinary panel decided to include the lateral rotation of cervical spine in the definitive scale due to the importance of this movement in JRA patients. It is important to emphasize that the lateral rotation of the cervical spine was the 11th movement selected in the pilot study.
Evaluation of the measurement properties. The test-retest and inter-observer reliability correlation coefficient were 0.96 (p < 0.001) and 0.99 (p < 0.001), respectively. Regarding the construct validity, the Pearson’s product moment correlation between the Pediatric EPM-ROM scale and the functional class (ACR) was 0.59 (p < 0.05), between the Pediatric EPM-RPM scale and the physical ability dimension of the Childhood HAQ was 0.55 (p < 0.05), and between the Pediatric EPM-ROM scale and the number of joints with limited ROM was 0.65 (p < 0.05).
In addition, its important to emphasize that the Pediatric EPM-ROM scale is easy to use, not time consuming (taking no more than 5 minutes to complete), requires minimal resources and almost no inconvenience to the patients.
DISCUSSION
In the era of evidence based medicine, we must be cautious in the selection of an instrument for use in clinical research, and should closely examine if it is appropriate for the target population and study objective. Several tools were developed to evaluate functional status of JRA patients (12,13,14), but none of them were developed specifically for the assessment of articular status of these patients. The Pediatric EPM-ROM scale was designed for the assessment of articular ROM in JRA patients, and should be used as an outcome instrument in daily practice as well as in clinical trials.
It is important to emphasize that the pattern of articular involvement and functional disability in children with JRA and adults with RA is different. In pediatric patients, the most frequently affected joints are the knees, ankles, wrists and hips (15). Otherwise, among the RA patients, the most frequently involved joints are the metacarpophalangeals, proximal interphalangeals, wrists and knees (16). In accordance with this, the use of simplified ROM scales and health status questionnaires specifically developed for use in adults may not be suitable for use in pediatric patients, and sometimes may result in distortions.
The current preliminary recommendations for assessment methods to be included in JRA clinical trials do not include measures of deformity or limitation of motion (1). The use of ROM scales, such as the Pediatric EPM-ROM scale could help standardization of the assessment of the articular ROM. Certainly, in a clinical trial, one will wish to have a baseline evaluation of joint limitation.
In the Pediatric EPM-ROM scale different weights are assigned to different joints. As known, some joints, such as the hips and the wrists, contributes to a decrease in the patient’s functional capacity, leading to a negative impact on their quality of life. Among the 10 movements of the Pediatric EPM-ROM scale, 2 (20%) are related to the hip involvement (lateral and medial rotation), and 2 (20%) are related to the wrist (flexion and extension). Therefore, by using the scale, we can assign different scores to a single joint, according to the degree of limitation (mild, moderate and severe limitation). Using the limited joint simple count this is not possible.
In our study, we established the reliability and validity of the Pediatric EPM-ROM scale. It is important to emphasize that the Pediatric EPM-ROM scale was developed to complement the other instruments, and the scale is not redundant (17). We did not observed redundancy among the scores of the scale and other parameters commonly used in the assessment of clinical response in JRA, i.e., American College of Rheumatology functional class (r = 0.59), physical ability dimension of the Childhood HAQ (r = 0.55) and number of joints with limited ROM (r = 0.65), all of them reached a coefficient below 0.70.
Vlieland et al (18) determined the sensitivity to changes of the adult EPM-ROM scale (3). These authors evaluated 25 hospitalized rheumatoid arthritis patients, and correlated the change of the EPM-ROM score with changes in other variables (Childhood HAQ - r = 0.48, p = 0.008, and grip strength - r = -0.39, p = 0.026). Studies concerning the longitudinal construct validity of the Pediatric EPM-ROM are currently in progress.
Finally, the Pediatric EPM-ROM scale is potentially useful for evaluating a wide range of interventions, in particular those involving physical therapy. Further applications of the Pediatric EPM-ROM scale should show the usefulness and value of the scale.
ACKNOWLEDGMENT
We thank Dr. J. van der Net, Ph.D., from the Department of Pediatric Physical Therapy, Wilhelmina Children’s Hospital, The Nederlands, for his excellent suggestions during the development of the Pediatric EPM-ROM scale.
REFERENCES
Table 1. Clinical and demographic characteristics of the JRA patients that were assessed in the pilot study and in the evaluation of the measurement properties.
JRA patients (n = 34) |
||
| Male / female |
19 (55.9%) / 15 (44.1%) |
|
| Age (years) / (range) | 10.7 (2.0 - 17.4) |
|
| Disease duration (years) / (range) | 4.8 (0.4 - 16.2) |
|
| Type of onset | ||
| Pauciarticular | 12 (35.4%) |
|
| Polyarticular | 11 (32.3%) |
|
| Systemic | 11 (32.3%) |
|
| Course of disease | ||
| Pauciarticular | 11 (32.3%) |
|
| Polyarticular | 20 (58.9%) |
|
| Systemic | 3 (8.8%) |
|
| Patients with active disease | 23 (66%) |
|
| Functional class (ACR) | ||
| I | 8 (23.6%) |
|
| II | 20 (58.8%) |
|
| III | 3 (8.8%) |
|
| IV | 3 (8.8%) |
|
| CHAQ - mean (SD) | 0.78 (0.77) |
|
| Number of joints with limited
ROM mean (SD) |
7.8 (8.3) |
|
JRA = juvenile rheumatoid arthritis
ACR = American College of Rheumatology
CHAQ = Childhood Health Assessment Questionnaire
Table 2. Joint movements selected in the 1st consensus and pilot study.
1st consensus |
Pilot study (n = 34) |
||
Joint movements |
Score (mean) |
||
1st |
Knee / flexion |
Wrist / extension |
1.12 |
2nd |
Knee / extension |
Ankle / plantar flexion |
0.78 |
3rd |
Wrist / extension |
Wrist / flexion |
0.68 |
4th |
Metacarpophalangeal (average) / flexion |
Thumb (metacarpophalangeal) / flexion |
0.63 |
5th |
Proximal interphalangeal (average)/ flexion |
Ankle / dorsiflexion |
0.54 |
6th |
Hip / lateral rotation |
Knee / extension |
0.52 |
7th |
Hip / medial rotation |
Hip / lateral rotation |
0.51 |
8th |
Ankle / dorsiflexion |
Hip / lateral rotation |
0.40 |
9th |
Elbow / extension |
Hip / abduction |
0.37 |
10th |
Cervical spine / lateral rotation |
Shoulder / abduction |
0.36 |