Determinants of Opioid Prescribing for Nonmalignant Chronic Pain in US Outpatient Settings

Study Objectives. Identify prescribing trends for opioid use in non-malignant chronic pain (NMCP) from the National Ambulatory Medical Care Survey (NAMCS). Determine predictors of opioid use based on patient-specific factors. Design. This cross-sectional study analyzed NAMCS data from 2000 to 2007. Pain medications prescribed were retrieved using NAMCS drug codes. Multivariate logistic models examined determinants of opioid prescribing among NMCP patients. Subjects. Patients included in the study were age 18 years or older with NMCP diagnosis based on ICD-9 codes identified as reason for visits. Results. Approximately 690 million weighted outpatient visits related to NMCP were reported in the US between 2000 to 2007. Reported opioid use was 14.3%. Compared with patients age 18 to 34 years, patients age 35 to 49 years were 1.47 times more likely (odds ratio [OR] = 1.47, 95% confidence interval [CI] = 1.17-1.86) and patients age 65 years or older were 0.61 times less likely (OR = 0.39, 95% C I= 0.27-0.55] to receive opioids. Patient visits from primary care physicians were 1.83 times more likely to report opioids (OR = 1.83, 95% CI = 1.50-2.25) than specialty physicians. Hispanic ethnicity and patients with private insurance were less likely to receive opioids, while patients having five or more medications, publicly funded insurance, the ICD-9 code of general chronic pain, established patients, and the southern prescribing region were more likely to receive opioids. Conclusions. Differences exist between those prescribed and not prescribed opioids. Results from this study paired with increased education and further research regarding the appropriate prescribing and monitoring of opioids may help enhance awareness, diminish treatment disparities and improve safe and appropriate use of opioids in the NMCP population.