Doctor shopping reveals geographical variations in opioid abuse.

BACKGROUND Prescription opioid abuse is not homogeneous due to varying patterns of use and different geographic preferences. Because doctor shopping is one of the main sources of diversion, it has previously been used to estimate drug abuse. OBJECTIVES The aim of this study was to describe and compare opioid abuse in 2008 using doctor shopping to estimate abuse in 3 French regions. SETTING Data for this study came from the General Health Insurance (GHI) reimbursement database, which covers 77% of the French population. All individuals living in Provence-Alpes-Cote d'Azur-Corse (PACA), Rhone-Alpes (RA), or Midi-Pyrenees (MP) that received at least one reimbursement for oral opioids from the GHI in 2008 were included. METHODS Oral opioids under study were opioids for mild to moderate pain (dextropropoxyphene, codeine, tramadol, dihydrocodeine), opoids for moderately severe to severe pain (oral morphine, oxycodone, buprenorphine painkiller, hydromorphone), and opioid maintenance treatments (buprenorphine maintenance, methadone). For a given opioid, the Doctor Shopping Quantity (DSQ) is the quantity obtained by overlapping prescriptions from several prescribers. It is used to estimate the magnitude of abuse. The Doctor Shopping Indicator (DSI) is the DSQ divided by the total dispensed quantity. It is used to estimate the abuse corrected for use. RESULTS The total DSQ for opioids in PACA (213.3 DDD/1,000 inhabitants) was twofold superior to that in RA (115.1 DDD/1,000) and in MP (106.2 DDD/1,000). The DSQ of opioids for mild to moderate pain was 75.5DDD/1000 (DSI=1.1%), 19.7DDD/1,000 (DSI=5.0%) for opioids for moderately severe to severe pain, and 55.3DDD/1,000 (DSI=6.2%) for opioid maintenance treatments. Emergent signals of abuse have been observed at a regional level for oxycodone in MP and dihydrocodeine in RA and MP. LIMITATIONS The main limitation of this study is that the GHI reimbursement database provides information about dispensed and reimbursed prescription drugs, and not necessarily the actual quantity used. CONCLUSION These results confirm important variations in the 3 French regions despite them being geographically close. Besides, they highlight different rates of opioid abuse between opioids for mild to moderate pain, opioids for moderately severe to severe pain, and opioid maintenance treatments, as well as differences within these groups.