RESUMO
BACKGROUND: Opioid use has increased substantially as a treatment for chronic pain, although harms from long-term opioid therapy outweigh the benefits. More knowledge about factors associated with long-term opioid use is needed. We aimed to investigate the association between socioeconomic status and long-term opioid use in the period 2010-2019. METHODS: This was a nested case-control study in which the cases were all persons ≥18 years with long-term opioid use, that is use of opioids for more than 3 months (N = 215,642). Cases were matched on gender, age and index year (first long-term use period) with four controls who filled at least one opioid prescription, but never developed long-term opioid use in the study period (N = 862,568). We performed a logistic regression analysis adjusted for relevant confounders, stratified on age groups (18-67 years and 68 years and above). RESULTS: In the younger age group, long-term opioid use was associated with low education (adjusted odds ratio, aOR = 1.54; 95% confidence interval, CI [1.51-1.57]), low income (1.33 [1.31-1.36]), being unemployed (1.40 [1.38-1.42]) and receiving disability pension (1.36 [1.33-1.38]). Weaker associations were found for living in a single-person household or in a dense geographical area. Similar associations were found for the older age group. CONCLUSION: We found that low socioeconomic status was associated with long-term opioid use both among people in working age and older people. These results indicate a need for social and financial support for non-pharmacological treatment of chronic pain among people with lower socioeconomic status. SIGNIFICANCE: This study shows that people with low socioeconomic status are at higher risk of developing long-term opioid use. In the clinical setting, physicians should consider socioeconomic status when prescribing opioids for chronic pain. Non-pharmacological treatment options funded by public health services should be prioritized to those with low socioeconomic status as long-term opioid use in chronic pain patients is not recommended.