Opioid Prescribing Patterns, Sonoma County, CA Residents, 2014

BACKGROUND: Drug overdose (poisoning) is the leading cause of injury death in Sonoma County, California (CA), where the drug poisoning death rate has historically exceeded that of the State. Opioid misuse and its associated health consequences increased in the last decade in Sonoma County, and the rate of non-fatal, treat and release, emergency department (ED) visits for unintentional drug poisoning due to opiates recently increased 73% from 10.0 in 2009-11 to 17.3 per 100,000 population in 2012-14. Sonoma County healthcare providers convened in 2015 to establish uniform opioid prescribing guidelines, recognizing guidelines as an important clinical tool to reduce opioid morbidity and mortality. This coalition sought data on local prescribing patterns, information previously unavailable in Sonoma County. 

METHODS:  We analyzed CA’s Controlled Substance Utilization Review and Evaluation System (CURES) data on opioid prescriptions dispensed to Sonoma County residents in 2014 to determine the prevalence of opioid prescription users. Opioid prescription users were stratified by age, gender, and place of residence. We calculated the mean daily dosage of different opioid drug products in morphine milligram equivalents (MMEs) to determine “high risk” patients receiving greater than 100 MMEs per day. Sonoma County residents who filled opioid prescriptions from four or more prescribers at four or more pharmacies in 2014 were analyzed to identify potential “doctor-shopping” behavior.

RESULTS: Results below are for the 2014 calendar year. Approximately 459,000 opioid prescriptions were prescribed by 9,310 unique prescribers for about 126,000 unique Sonoma County residents, or 25% of all county residents. The highest prevalence of opioid prescription users occurred among seniors (41%), and decreased with age. Geographic disparities in the prevalence of opioid prescription users by home city or town ranged from 18% to 47%. Hydrocodone (57%) and oxycodone (18%) were the most frequently prescribed opioids; the annual mean daily dosage per hydrocodone prescription was 41 MMEs and 110 MMEs for oxycodone. About 0.4% (n=524) of all Sonoma County residents who filled an opioid prescription in 2014 were identified as “doctor shoppers.”

CONCLUSIONS:   This descriptive analysis yielded the first local information on Sonoma County opioid prescription users, finding that one in four, or 126,000 Sonoma County residents filled an opioid prescription in 2014. This study is a first effort to contextualize opioid prescription users in Sonoma County. Findings have guided a local coalition of healthcare providers in establishing opioid prescribing guidelines and will be used to track local changes in prescribing patterns.