Promise of Composite Pain Index as a single pain outcome for sickle cell disease across the lifespan.

Abstract

This study aimed to validate a Composite Pain Index (CPI) as a single pain outcome measure for sickle cell disease (SCD) across the lifespan from 8years of age. This prospective, cross-sectional study included 55 participants with SCD who completed the PAINReportIt tool and Adolescent Pediatric Pain Tool (APPT) in random order during outpatient visits to derive respective CPI scores for comparison. Of the 55 participants with SCD, 46 (84%) had HgbSS, eight (15%) HgbSC, and one (2%) HgbSβ0+. The mean age of all participants was 17.5±2.6years, and 28 (51%) were female, 52 (95%) were Black, 42 (98%) were non-Hispanic, and 39 (71%) had a ninth grade or higher education. Correlation analyses between the APPT and PAINReportIt revealed positive associations for the number of pain sites (r=.57, p<.001), pain intensity (r=.46, p<.001), pain quality (r=.74, p<.001), and pain pattern (r=.34, p=.01). Patients' mean CPI scores derived from the PAINReportIt was slightly higher than the APPT; 34.2 (SD=14.7) and 30.0 (SD=19.0), respectively. Regression analyses showed that the APPT CPI significantly predicted the PAINReportIt CPI (B=.497, t(53)=6.051, p<.001). This finding holds true even when accounting for the order of measurement or patient's age. The initial validation of CPI as a single pain outcome measure represents a significant advancement in pain assessment for SCD. Further validation is warranted for the CPI as a measure is for both clinicians and researchers to enable longitudinal pain assessment from age 8years across the lifespan as children age into adult care.