Clinical cut-points for the Child Activity Limitations Interview-9 in a large sample of youth with chronic pain

Youth with chronic pain often experience pain-related activity limitations characterized by difficulties in daily physical, social, recreational, and school activities. The Child Activity Limitations Interview-9 (CALI-9) is a validated measure of pain-related activity limitations in youth with chronic pain. However, the development of clinical cut-points is needed to improve score interpretation and utility in clinical and research settings. Participants included 1825 patients presenting to a multidisciplinary chronic pain clinic for initial evaluation. Patient reported outcomes included anxiety and depressive symptoms, pain characteristics, quality of life, and widespread pain. Distribution-based quartile and tertile groupings were derived and compared across all patient reported outcomes. CALI-9 total scores ranged from 0-100 (33.47 ± 22.62). Analyses involving the whole sample supported a tertile solution, resulting in three levels of pain-related activity limitations. Similarly, separate analyses supported a tertile solution for data on children (≤ 12 years) [Minimal (CALI-9 ≤ 14); Moderate (CALI-9 = 15-36); Severe (CALI-9 ≥ 37)] and adolescents (≥ 13 years) [Minimal (CALI-9 ≤ 24); Moderate (CALI-9 = 25-44); Severe (CALI-9 ≥ 45)]. Post hoc pairwise comparisons indicated the tertile solutions yielded a clearer distinction between groups than the quartile solutions. Further analysis of the whole sample tertile solution involved comparing group proportions of patients with elevated anxiety and depressive symptoms, in addition to proportions of patients with widespread pain. Differences across groups provided further support for the tertile solutions. The addition of clinical cut-points will allow for improvements to the clinical and research utility of the CALI-9. PERSPECTIVE: In this article, three levels of pain-related activity limitations (Minimal, Moderate, and Severe) were identified for the CALI-9, using patient reported outcomes from youth with chronic pain. These cut-points can improve the clinical and research utility of the CALI-9.