Establishing Clinical Cut-points on the Pediatric PROMIS-Pain Interference Scale in Youth With Abdominal Pain

Objective: Abdominal pain is a common presenting complaint in youth seeking medical care and can be debilitating. Therefore, it is important to understand the impact of pain on functioning using a clinically sensitive approach. The National Institutes of Health has established a common core of psychometrically precise measures through the Patient-Reported Outcomes Measurement Information System (PROMIS) initiative. The Pediatric PROMIS-Pain Interference (PPPI) scale was developed to measure pain-related interference, drawing from existing legacy measures. However, its clinical validity has not been thoroughly established in clinical populations. The current study sought to develop clinical cut-points and investigate the validity of the PPPI in a large sample (N=5281) of youth presenting to gastroenterological care with abdominal pain symptoms.

Materials and methods: Convergent validity of the PPPI was investigated. Quartile and tertile groupings of the PPPI were calculated and compared with cut-points derived from healthy populations and mixed convenience samples on clinical outcomes via multivariate analyses of variance.

Results: There was good evidence of convergent validity. The tertile solution was superior in classifying different levels of pain-related outcomes as compared with other cut-points. The tertile solution suggested the following PPPI groupings: minimal (≤51), moderate (52 to 59), and severe (≥60).

Discussion: Results suggest the PPPI is a valid measure with clinically meaningful cut-points to assess pain-related interference in youth with abdominal pain.