Do health outcomes following pain service utilization vary for young people experiencing chronic pain according to pain phenotype? An exploratory analysis using the electronic Persistent Pain Outcomes Collaboration database.

Abstract

The prevalence of chronic pain in young people increases with age, approaching rates observed in adults. Utilizing Australiasian electronic Persistent Pain Outcomes Collaboration (ePPOC) data for young people, we previously derived three phenotypes ("low", "moderate", "high") characterized by an increasing symptom-severity gradient in multi-dimensional pain-related variables measured at referral to pain service. In this study, we explored whether health outcomes varied by phenotypes at the end of care episode. We included young people captured in the Australian adult ePPOC data registry representing 80 tertiary and private pain services, within a 5-year period (2018 to 2022) if previously phenotyped and had episode end patient reported outcome measures. Self-reported global rating of change was measured at episode end, while pain severity and interference, pain-related worry (quasisurrogate 'catastrophizing'), emotional functioning and pain self-efficacy were measured at referral and episode end. Differences in outcomes across phenotypes were estimated using logistic regression for binary indicators and clinically significant improvements, and linear regression for mean change. Of 3518 young people initially phenotyped from adult service data, 477 (13.6%) aged 15-25 years had episode end outcomes. The proportion of participants reporting meaningful improvement in outcomes ranged from 24.0%-74.2%, with differences observed across phenotypes. Although the limited proportion of participants with episode end data may have introduced bias, those with and without end episode outcomes were broadly comparable on baseline demographics. Results suggests tailoring care to symptom-severity may be important for optimising outcomes, particularly for young people with "high" symptom-severity whose care needs are more complex. PERSPECTIVE: This study reports unique exploration of whether the outcomes following specialized pain service care supporting young people living with chronic pain varied according to their symptom-severity phenotype. This evidence provides impetus for system and service improvements to more equitably and efficiently meet young people's needs by providing timely, differential care.