African Americans with cancer pain are more likely to receive an analgesic with toxic metabolite despite clinical risks: a mediation analysis study.

PURPOSE: Renal impairment is highly prevalent among patients with cancer, and many patients have undiagnosed chronic kidney disease (CKD) from underlying disease, treatment, or both. African American individuals have disproportionate risk factors (diabetes, hypertension) predisposing them to CKD. We investigated whether African American patients are more likely than white patients to receive morphine with 3- and 6-glucuronide metabolites, which are known to be neurotoxic and accumulate in CKD; whether insurance type mediates the relationship between race and the prescriber's opioid selection; and whether the chosen opioid has a resultant negative effect according to race.

PATIENTS AND METHODS: Patients (N = 182) were recruited from oncology clinics within the University of Pennsylvania Health System. Inclusion was based on self-identified African American or white race, age older than 18 years, and the presence of cancer-related pain plus a prescription for morphine or oxycodone. Kidney function was estimated using the abbreviated Modification of Diet in Renal Disease formula.

RESULTS: Patients with CKD who received morphine reported a greater severity of analgesic-related adverse effects than patients with CKD who received oxycodone (P = .010). Controlling for health insurance type, African American patients had 71% lower odds of receiving a prescription of oxycodone than white patients (P < .001). Limiting analysis to those with CKD, the effect of private insurance became insignificant. However, race still remained a significant predictor of the prescribed opioid selection. Race was a strong predictor of adverse effect severity in the presence of CKD, and the type of opioid selection partially mediated this relationship.

CONCLUSION: Reducing racial disparities in the type of opioid prescription and understanding mechanisms of disproportionate opioid-related adverse effects in African American patients might decrease the clinical disparities in cancer pain outcomes.