Socioeconomic risk factors for long-term prescription opioid use: A national registry-linkage study
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 prescription opioid use is needed to inform clinical practice. We aimed to investigate the association between socioeconomic status and development of long-term prescription opioid use in the period 2010-2019.
Methods: Nested case-control study using linked nationwide health-and population registers in Norway. Cases were all persons aged 18 years or older with long-term opioid use, i.e., use of prescription opioids for more than three months (N = 215,642). Cases were matched on sex, age, and index year 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 logistic regression analysis for the association between socioeconomic variables and long-term opioid use adjusting for relevant confounders and stratifying on age groups (18-44, 45-67, 18-67, 68 years and above).
Results: For those aged 18-67 years, long-term opioid use was associated with low education (adjusted odds ratio = 1.54; 95% confidence interval [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 those aged 68 years or older. Immigrants in the age group 18-44 years had lower odds of long-term opioid use when compared to natives (0.75 [0.72-0.77]), whereas immigrants in the middle-aged group (44-67 years) had slightly higher odds (1.05 [1.02-1.08]). No association was observed for the oldest age group (68 years and above). In the youngest age group, the strength of the association differed between people born in Africa (0.56 [0.52-0.61]), Central- or South America (0.70 [0.61-0.79]), Europe outside the EU (0.71 [0.65-0.77]), Asia including Turkey (0.80 [0.77-0.84]), and EU/EEA (0.81 [0.77-0.85]) when compared to those born in Norway. For the age group 45-67 years, increased odds were found for immigrants born in North America (1.26 [1.13-1.40]) and the EU/EEA (1.13 [1.09-1.18]).
Conclusions: Low socioeconomic status was associated with long-term prescription opioid use both in the younger (18-67 years) and older (68 years and above) age groups. Young immigrants (18-44 years) were less likely, middle-aged immigrants (45-67 years) more likely, and older immigrants (68 years and above) as likely to develop long-term prescription opioid use when compared to natives. The estimates varied between regions of birth and may be explained by cultural differences in attitudes towards pain and use of medicines and healthcare, as well as barriers in access to health care.
