379: Evaluating a Pain Numerical Rating Scale for Pain Intensity in Brazilian Children and Adolescents

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Acute musculoskeletal pain, Pain in special populations (e.g. neonates, children, teens, elderly, neurodegenerative diseases)

Background and Aims: Musculoskeletal pain is common across the lifespan and can affect functioning. A third of children and adolescents’ population report having musculoskeletal pain. In children and adolescents, pain may interfere with school and physical activities and increase the risk of chronic pain in adulthood. Pain intensity is an relevant outcome in pediatric pain research. However, the evidence supporting measurement properties of the Pain Numerical Rating Scale (PNRS) in young populations with musculoskeletal pain, particularly in middle-income countries, remains limited. This study aimed to evaluate the reliability, construct validity, and interpretability of the PNRS in children and adolescents with musculoskeletal pain.

Methods: This observational methodological measurement properties study followed Consensus-based Standards for the selection of health status Measurement Instruments (COSMIN) recommendations. Children and adolescents aged 8-18 years with self-reported musculoskeletal pain from public schools in São Paulo, Brazil, completed the PNRS, Brief Pain Inventory(BPI), and PIP-Kids questionnaire at two time points (test–retest), with a 24–48-hour interval between assessments. Reliability, measurement error, construct validity through hypothesis testing, floor and ceiling effects were evaluated using predefined hypotheses and COSMIN guidelines.

Results: Of 767 invited students, 153 (19.9%) children and adolescents with musculoskeletal pain were included. The sample was predominantly female, with a mean age of 16.0 (standard deviation: 2.7) years. The PNRS demonstrated adequate test-retest reliability (Intraclass Correlation Coefficient: 0.71). The Standard Error of Measurement was 1.74 (15.8%) with an Minimum Detectable Change of 3.66 points. Construct validity was adequate, as nine out of the 10 pre-specified hypotheses (90%) regarding the correlations between the PNRS and the BPI were confirmed. No floor and ceiling effects were observed.

Conclusions: The PNRS is a reliable and valid instrument for assessing pain intensity in children and adolescents with musculoskeletal pain. Its simplicity supports its use in clinical and research settings, particularly in middle-income countries.

References: Henschke N, Kamper SJ, Maher CG. (2015) The epidemiology and economic consequences of pain.
Hestbaek L, Leboeuf-Yde C, Kyvik KO. (2006) Is comorbidity in adolescence a predictor for adult low back pain? A prospective study of a young population.
Birnie KA, Hundert AS, Lalloo C, et al. (2019) Recommendations for selection of self-report pain intensity measures in children and adolescents: a systematic review and quality assessment of measurement properties.
Mokkink LB, Terwee CB, Patrick DL, et al. (2010) The COSMIN study reached international consensus on taxonomy, terminology, and definitions of measurement properties for health-related patient-reported outcomes.

Presenting Author: Yasmin Brasileiro de Souza
Submitting Author: Yasmin Souza

Senior Author: Tiê Parma Yamato

IASP 2026 Global Year theme of Neuropathic Pain: No

• Verônica Souza Santos: Postdoctoral (ongoing) - 1Physical Therapy Department, Universidade Cidade de São Paulo, São Paulo, Brazil. 2School of Rehabilitation Science, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.3Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
• Gisela Cristiane Miyamoto: Postdoctoral - Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
• Tiê Parma Yamato: Postdoctoral - 1Nepean Blue Mountains Local Health District, NSW, Australia. 2Faculty of Medicine and Health, University of Sydney, Australia.