Patterns and trends in long-term opioid use for non-cancer pain in British Columbia, 2005-2012.

Objectives: We aimed to calculate trends in incidence and prevalence rates of long-term opioid use for non-cancer pain, as well as to describe the characteristics of long-term opioid users and their patterns of opioid use.

Methods: We used population-based linked health care and socio-demographic administrative data for British Columbia (BC) between 2005 and 2012. We included individuals who had at least one episode of long-term opioid use during the study period and who were not cancer or palliative care patients.

Results: Long-term users comprised only 10% of all individuals prescribed opioids for non-cancer pain, but accounted for 64% of all opioid prescriptions and 87% of all morphine equivalents dispensed in BC during this period. While the incidence rate did not significantly change, the prevalence rate increased by 27% for men and 22% for women. In 2012, there were 3.80 (3.72-3.88) new long-term opioid users per 1,000 men and 4.42 (4.34-4.51) new users per 1,000 women. At the same time, there were 18.3 (95% CI 18.1-18.5) existing long-term users per 1,000 men and 21.7 users (95% CI 21.5-21.9) per 1,000 women. Overall, 2.4% of BC residents were long-term users of prescription opioids in 2012. Most long-term users had one continuous episode of use spanning multiple years. Almost two thirds took opioids every other day or more frequently.

Conclusion: There is a growing population of long-term opioid users for non-cancer pain in BC, with higher incidence and prevalence rates observed among women than among men.