RESULTS: Of the sampled patients, 207 patients lived in ZIP codes with median incomes > $51,294; 515 in ZIP codes with median incomes between $40,083 and $51,294; 332 in ZIP  codes with median incomes between $30,625 and $40,083; and 95 in ZIP codes with median incomes < $30,625. Groups differed in age (P = 0.047), race (P < 0.001), body mass index (BMI) (P = 0.019), utilization of opioid medications (P = 0.011), morphine milligram equivalents (MME) on first visit (P = 0.036), and utilization of membrane stabilizers such as gabapentin (P = 0.019). There were no significant differences among groups in terms of gender (P = 0.531), type of pain experienced (P = 0.679), or time since pain onset (P = 0.174). Groups were treated similarly, with no statistically significant differences in the proportions of patients who had taken various nonopioid medications throughout their treatment course other than membrane stabilizers, the number of patients who received interventional pain management procedures, or MME at last visit. Average pretreatment numeric rating scale pain scores were not significantly different among quartiles (P = 0.079), posttreatment pain scores (P = 0.767), and subjective percent improvement (P = 0.434).