# Developing and assessing the measurement properties of an instrument to assess the impact of musculoskeletal pain in children aged 9 to 12—the pediatric musculoskeletal pain impact summary score

## TL;DR

This paper introduces a new tool to measure the impact of musculoskeletal pain in children aged 9 to 12, finding it can distinguish between frequent and infrequent pain despite some limitations.

## Contribution

The paper presents a novel instrument, the Pediatric MSK Pain Impact summary score, tailored for assessing musculoskeletal pain impact in school-aged children.

## Key findings

- The instrument has limited internal consistency but shows adequate discriminative validity between frequent and infrequent MSK pain.
- It correlates appropriately with quality of life, care-seeking, and medication intake.
- The tool is short and convenient for use in clinical and research settings.

## Abstract

•MSK pain in children and adolescents is highly prevalent, yet instruments are scarce to measure MSK pain outcomes in children.•The Pediatric MSK Pain Impact summary score is a short and easy instrument to assess MSK pain impact in school-aged children (aged 9 to 12) with MSK pain.•The result of internal consistency was limited, and the construct validity showed borderline estimates of adequacy. However, the discriminative validity results showed that the instrument differentiates between children with frequent and infrequent MSK pain.

MSK pain in children and adolescents is highly prevalent, yet instruments are scarce to measure MSK pain outcomes in children.

The Pediatric MSK Pain Impact summary score is a short and easy instrument to assess MSK pain impact in school-aged children (aged 9 to 12) with MSK pain.

The result of internal consistency was limited, and the construct validity showed borderline estimates of adequacy. However, the discriminative validity results showed that the instrument differentiates between children with frequent and infrequent MSK pain.

Despite the high prevalence of musculoskeletal (MSK) pain in children, there is a lack of instruments to measure the impact of MSK pain on children's activity and participation.

To assess the reliability and construct validity of the Pediatric MSK Pain Impact summary score in school children (aged 9 to 12) with MSK pain.

We used a pragmatic approach in a reflective framework to assess internal consistency, structural validity, convergent validity, and discriminative validity in a sample of 615 children with MSK pain.

The confirmatory factor analysis results indicate that the summary score has limited internal consistency and construct validity. The estimated Cronbach's alpha was 0.63, and most goodness of fit indices met the recommended thresholds (SRMR = 0.030; GFI = 0.993, CFI = 0.955, RMSEA 0.073), although they were close to the lower bounds of the thresholds. The convergent validity showed appropriate correlation of the summary score with quality of life (r = -0.33), care-seeking (r = 0.45), and medication intake (r = 0.37). Discriminative validity showed that the instrument can discriminate between the impact of pain on children with frequent and infrequent (2.93; 95% CI: 2.36 - 3.50) MSK pain.

The Pediatric MSK Pain Impact summary showed limited internal consistency and construct validity; however, it can discriminate between children with frequent and infrequent pain. The results are promising for clinical and research practices as it is a short and convenient tool to be used in school-aged children.