Examining the burden of opioid prescribing for non-cancer pain considering socio-economic differences, in Wales. A retrospective database study examining trends between 2005 and 2015

Objectives: To use a proxy-measure of oral morphine equivalent dose (OMED) to determine trends in opioid burden in people with non-cancer pain and explore differences related to deprivation status. Design, setting and participants: Retrospective cohort study using cross-sectional and longitudinal trend analyses of opioid prescribing data from 78% of Welsh Primary Care General Practices, whose data is shared with the Secure Anonymised Information Linkage (SAIL) databank. Anonymised data for the period 2005 to 2015, for people aged 18 or over, without a recorded cancer diagnosis and who received at least one prescription for an opioid medicine was included. Primary and Secondary outcomes: A proxy-measure of oral morphine equivalence dose (OMED) was used to describe trends in opioid burden over the study period. OMED burden was stratified by 8 drug groups and deprivation, based on the quintile measures of the Welsh Index of Multiple Deprivation 2011 (WIMD2011). Result: In the 11 years examined, 22 641 424 prescriptions for opioids were issued from 345 primary care general practices in Wales. Daily OMED per 1000 population increased by 94.7% (from 16 266 mg to 31 665 mg). Twenty-eight percent of opioid prescribing occurred in the most deprived quintile. More than 100 000 000mg more OMED was prescribed in the most deprived areas of Wales, compared to the least deprived. Codeine prescribing accounted for 35% of the OMED burden in Wales over the study period. Conclusions: Whilst opioid prescription numbers increased 44% between 2005 and 2015, the OMED burden nearly doubled, with a disproportionate OMED load in the most deprived communities in Wales. Using OMED provides an insightful representation of opioid burden, more so than prescription numbers alone. Socio-economic differences are likely to affect pain presentation, access to support services and increase the likelihood of receiving an opioid prescription.