Contributions of Pain Interference and Affect to Patient-Reported Opioid Benefit in Chronic Pain Management

Background: Despite known deleterious consequences associated with long-term opioid use, many individuals with chronic pain assert opioid benefits and advocate for continued opioid use. However, relative to non-opioid using chronic pain patients, opioid-using patients typically report greater pain severity and depression. Moreover, there appears to be no significant association between pain severity or interference and perceived opioid benefit among chronic pain patients. Thus, pain reduction itself might not directly relate to patient perceptions of opioid benefit. Given extensive prior research revealing significant overlaps between pain and affect, it is prudent to examine contributions of affective disturbances, alongside pain-related factors, to perceived opioid benefits. In the present study, we examined the hierarchical contributions of pain interference and positive affect in predicting self-reported opioid benefit. We hypothesized that positive affect combined with pain interference would best predict opioid benefit. Methods: We examined multisite, cross-sectional data collected from females with fibromyalgia who were using opioids long-term (n = 40) and who were not regularly using opioids but had used them acutely (< 30 days) at least once previously (n = 25). Patients completed a set of questionnaires, including the Positive and Negative Affect Schedule, the Brief Pain Inventory, and a novel measure querying perceived opioid benefit on a 0-10 Likert scale (0 = not at all, 10 = completely). We examined relationships between pain interference, positive affect, and patient-reported opioid benefit using logistic regression. Results: Among opioid-using patients, pain interference combined with positive affect was a better model for opioid benefit (AIC = 52.15) compared to pain interference alone (AIC = 57.80). However, among non-opioid using patients, pain interference alone was a better model for opioid benefit (AIC = 28.00) than pain interference combined with positive affect (AIC = 28.12). Conclusions: Among patients using opioids long-term, affective factors may be primary drivers of perceived opioid benefit. Positive affect combined with pain interference modeled opioid benefit better than pain interference alone among opioid-using chronic pain patients, but not among non-opioid-using chronic pain patients. Importantly, post-hoc analyses examining the contributions of negative affect further validated the main findings; positive affect out-performed negative affect in all models. Thus, perceived opioid benefit may be a function of cumulative opioid-induced enhancements in positive affect. Based on these results, examination of factors besides pain reduction may be critical to understanding perceived opioid benefit among chronic pain patients; this understanding is essential for development of effective, opioid-sparing treatments.