Trends in long-term use of prescribed opioids in Norway 2010-2019

Background Since 2008, patients with chronic, non-malignant pain conditions can get reimbursement for analgesic opioids. There is limited evidence of analgesic effect of opioids when used over a long time period while the risk of adverse effects is increasing. Thus, closely monitoring of opioid consumption at the population level to detect signs of escalation is needed. Objectives To investigate whether there has been a change in the number of long-term users of prescribed opioids over time and according to reimbursement scheme (reimbursed opioids for palliative care, reimbursed opioids for chronic, non-malignant pain, or non-reimbursable opioids). Methods Data were retrieved from the Norwegian Prescription Database. The study population consisted of all individuals filling at least one prescription of an opioid (ATC N02A) during 2010-2019. Long-term use was defined as being dispensed more than 180 defined daily doses or more than 4500 mg oral morphine equivalents of opioids a given year and filling prescriptions in at least 3 quarters of the year. Individuals were divided into mutually exclusive groups according to reimbursement scheme in a hierarchical manner; reimbursed opioids for palliative care > reimbursed opioids for chronic, non-malignant pain > non-reimbursable opioids. The proportion of long-term opioid users according to reimbursement scheme was calculated. Results The number of long-term opioid users increased from 49,993 in 2010 to 59,996 in 2019. The increase over time was almost solely attributed to an increase among chronic, non-malignant pain patients. The number of long-term users receiving non-reimbursable opioids and opioids for palliative care remained stable over time. In 2019, the majority of the 59,996 long-term users received non-reimbursable opioids only (n=38,006), followed by long-term users receiving opioids for chronic, non-malignant pain (n=14,812), and long-term users receiving palliative care (n=7,178). Conclusions The number of long-term opioid users have increased by 20% (10,000 individuals) over an 11 years period in Norway due to an increase in number of long-term users receiving reimbursed opioids to treat chronic, non-malignant pain. More studies are needed to understand whether the introduction of the reimbursement scheme for chronic pain patients has been a contributing factor to the observed increase in number of long-term opioid users and why the majority of the long-term opioid users do not receive opioids according to the reimbursement scheme for chronic, non-malignant pain.