UNLABELLED Factors associated with high-dose opioid therapy for noncancer pain are poorly understood. We documented the prevalence of high-dose opioid use as well as associated demographic, clinical, and health service utilization correlates among low back pain patients. Patients prescribed higher doses of opioids (≥100 mg/day morphine equivalent at last dispensing; n = 453) and receiving opioids for 90+ consecutive days were compared to 2 groups: lower-dose opioid group (1-99 mg/day; n = 4,815) or no-opioid group (n = 10,184). Higher-dose opioid use occurred in 2.9% of patients who received any opioids and in 8.6% of patients who received opioids long-term. The median dose in the higher-dose group was 180.0 mg/day. Compared to the no-opioid group, higher-dose users reported poorer health. Compared to either comparison group, patients in the higher-dose group had higher rates of mental health and substance use disorders, concurrent sedative-hypnotic use (60.5%; n = 274), and health service utilization. After adjusting for select covariates, male gender (odds ratio [OR] = 1.68, 95% confidence interval [CI] = 1.37-2.06), higher comorbidity, Medicare coverage (OR = 1.65, 95% CI = 1.22-2.23), any mental health or substance use diagnosis (OR = 1.58, 95% CI = 1.28-1.95), co-prescriptions of sedative-hypnotics (OR = 1.75, 95% CI = 1.42-2.16), and more emergency department and specialty pain clinic visits were associated with higher likelihood of high-dose prescriptions. PERSPECTIVE Higher-dose opioid therapy is being prescribed to 8.6% of back pain patients who receive long-term opioids. These patients had higher mental health and medical comorbidities and co-prescriptions of sedative-hypnotics, raising potential safety concerns.