Porthole
A Novel Use of the Front-Door Formula to Estimate the Causal Effect of Chronic Pain on Mortality through Opioid Prescriptions (307834)
Onyebuchi Arah, UCLA*Kosuke Inoue, UCLA
Beate Ritz, UCLA
Keywords: Front-door formula, chronic pain, opioids, death
We investigated the effect of chronic pain on mortality that might be mediated by opioid prescriptions in the general population. We included 13,886 adults in the U.S. National Health and Nutrition Examination Survey 1999-2004 with linkage to mortality databases through 2015. We used Pearl’s front-door formula within the structural causal model to investigate the average effect of chronic pain on all-cause mortality mediated by opioid prescriptions. The front-door formula allowed us to estimate the path-specific effect of the chronic pain on the mortality through opioids in the presence of uncontrolled confounding of its total effect. Opioid prescriptions increased the risk of 3-year mortality with an estimated odds ratio [OR] = 1.47 (95% confidence interval [CI] = 1.12-1.93). Front-door adjustment revealed that chronic pain increased the risk of 3-year mortality mediated by opioid prescriptions with an OR = 1.06 (95% CI = 1.01-1.11). In this nationally representative U.S. database, we found that chronic pain increased mortality risk through opioid prescriptions. This underscores the importance of guideline-based and policy-informed chronic pain management.