Overdose and prescribed opioids: Associations among chronic non-cancer pain patients

Abstract

In response to growing awareness of chronic pain as a significant patient concern, chronic opioid therapy is prescribed with increased frequency,(1-3) with over 3% of adults now receiving chronic opioid therapy for chronic non-cancer pain (CNCP).(​2) Concurrently, death rates from opioid analgesic poisoning have increased.(4-8). From 1995-2004, opioid-related poisoning hospitalizations doubled in Washington State.(9) A recent study in West Virginia reported that less than half (44%) of autopsy-identified unintentional prescription drug overdose fatalities had received opioids from a physician, suggesting that overdose typically resulted from drug diversion.(10;11) However, overdose risks in patients receiving medically prescribed opioids have not been studied. Some hold that the rise in poisonings is related to excessive use of opioid analgesics in community practice.(12) Others express concern that such interpretations may lead to under-prescribing of opioids for CNCP patients.(13) The association of prescription opioid exposure and overdose risk has been inferred from: uncontrolled case series of autopsies subject to selection biases or ecological time series studies where individual-level associations cannot be examined. While opioids provide partial pain relief for chronic pain.(14-15), the balance of long-term risks and benefits is poorly understood.(16-21) Large-scale epidemiologic studies assessing patient use of prescribed opioids are needed to assess whether there is a relationship between receiving medically prescribed opioids and opioid-related poisonings. A key unanswered question is whether overdose risk differs by opioid dose among patients receiving chronic opioid therapy. The objectives of this report are: 1) to estimate overall overdose rates (non-fatal and fatal) among persons receiving opioids long-term for CNCP from medical sources; and, 2) to compare risks of opioid overdose among patients recently receiving chronic opioid therapy at differing dosage levels.