Trends in use of opioids by chronic non-cancer pain type and number, among Arkansas Medicaid and Wellpoint enrollees: results from the TROUP study

The use of prescription opioids for chronic non-cancer pain is becoming an increasingly more common treatment strategy, and rates of use have increased significantly. We sought to examine trends in opioid prescribing for individuals with chronic non-cancer pain conditions (arthritis, back pain, neck pain, headaches, HIV/AIDS), by type and number of pain diagnoses. Data were obtained from claims records for the years 2000 through 2005 from two health plans: Wellpoint (N=3,768,223) and Arkansas Medicaid (N=154,371). Doses from opioid prescriptions dispensed were converted to morphine equivalents, and the total per patient per year was compared across years and pain types. The percent of enrollees with any opioid use, days supply and mean total opioid dose increased between 2000 and 2005 for all pain diagnosis types and with increasing number of pain diagnoses. Among Arkansas Medicaid enrollees in 2005, mean days supply by pain type ranged from 84.6 (HIV/AIDS) to 134.2 (neck pain), and total mean opioid dose ranged from 5352.7 (HIV/AIDS) to 8575.7 (neck pain) mg morphine equivalents. Mean days supply increased from 69.4 for one pain diagnosis to 191.1 for four pain diagnoses, and the corresponding mean total opioid dose increased from 3827.9 to 11,974.4 mg morphine equivalents. Among Wellpoint enrollees in 2005, mean days supply by pain type ranged from 54.4 (arthritis) to 78.8 (headaches), and mean total opioid dose ranged from 3537.6 (arthritis) to 5041.8 (back pain) mg morphine equivalents. Mean days supply increased from 36.4 for one pain diagnosis to 147.7 for four pain diagnoses, and the corresponding mean total opioid dose increased from 2111.0 to 9332.3 mg morphine equivalents. The greatest percent increases in mean days supply and dose between 2000 and 2005 in both plans occurred among those with back and/or neck pain, and three or four pain diagnoses.