Background/Purpose:   The Patient Reported Outcomes Measurement Information System(PROMIS) is a publicly available assessment system offering multiple measures to assess physical, mental and social health. PROMIS measures are developed based on a rigorous mixed-methods approach, and modern measurement methods, including use of item response theory (IRT). Measures are developed for use across a spectrum of chronic conditions. The purpose of the project is development and calibation of instruments to measure aspects of pain in children as part of PROMIS. PROMIS Pediatric Pain Interference, Pain Behavior and Pain Quality measures were previously developed. The primary objective of this study is to evaluate the dimensionality and validity of the PROMIS Pediatric Pain Intensity Scale. 

Methods:   The initial pool of the pediatric PROMIS pain related items were developed based on literature reviews, clinician interviews, and qualitative research with patients with pain. In addition to the three item banks previously developed to assess various dimensions of pain in children, four items were identified as pain intensity items measuring worst pain, usual pain, average pain and current pain on a 5-point likert scale. We conducted confirmatory factor analysis (CFA) to assess dimensionality of these 4 items and looked correlations of the pain intensity scale with other pediatric PROMIS pain scales (pain interference and pain behavior), as well as a legacy pain intensity numeric rating scale.

Results:   The sample populations included pediatric patients with juvenile idiopathic arthritis, fibromyalgia, and sickle cell disease, ages 8 to 18 recruited from outpatient hospital clinics in Ohio, Pennsylvania, and Georgia for a total sample size of N = 447. CFA shows good fit of the four items to a unidimensional model: comparative fix index (CFI)=1.00, Tucker-Lewis index (TLI)=1.00, and root mean square error of approximation (RMSEA)=0.013. The IRT slope parameters of the four items were 1.55, 2.06, 1.51, and 1.15. The category threshold parameters ranged from -2.92 to 2.97. Correlation with legacy pain intensity numeric rating scale is r = .94. Correlations with PROMIS pain interference short form is r = .75 and with PROMIS pain behavior short form is r = .74. “Usual” and “average” pain items provided similar information. Based on cognitive debriefing with study participants, the item worded with reference to “usual pain” was preferred over the“average pain” item. The measure perfomed well after exclusion of the “average pain” item, yielding a three item scale.

Conclusion:  The pediatric PROMIS pain intensity scale provides a short, three-item unidimensional measure of pain and demonstrates convergent validity with other PROMIS pain measures. The pediatric PROMIS pain intensity scale provides a measure of self-reported pain intensity that can be used in pediatric clinical research or clinical practice settings.

« Back to 2016 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/initial-validation-of-the-patient-reported-outcomes-measurement-information-system-pediatric-pain-intensity-scale-in-juvenile-idiopathic-arthritis-juvenile-fibromyalgia-and-sickle-cell-disease/