The authors developed estimates of geographic variation among states and counties in the prevalence of opioid prescribing using data from a large (135 million) representative national sample of opioid prescriptions dispensed during 2008 by 37,000 retail pharmacies. The authors used statistical analyses to estimate the extent to which county variation is explained by characteristics of resident populations, their healthcare utilization, proxy measures of morbidity, availability of healthcare resources, and prescription monitoring laws.

The data shows that geographic variation in prevalence of prescribed opioids is large, greater than the variation observed for other healthcare services. Counties having the highest prescribing rates for opioids were disproportionately located in Appalachia and in southern and western states. Calls for increased government regulation are growing as patients' demands for treatment have increased and more potent opioids have become available, causing an epidemic of abuse.