Opioid Use among Patients with Early Inflammatory Arthritides Compared to the General Population

Objective. To assess to what extent the worldwide opioid epidemic affects Finnish patients with early inflammatory arthritis (IA).

Methods. From the nationwide register maintained by the Social Insurance Institution of Finland, we collected all incident adult patients with newly onset seropositive and seronegative rheumatoid arthritis (RA+ and RA–) and undifferentiated arthritis (UA) between 2010 and 2014. For each case, 3 general population (GP) controls were matched according to age, sex, and place of residence. Drug purchases between 2009 and 2015 were evaluated 1 year before and after the index date (date of IA diagnosis), further dividing this time into 3-month periods.

Results. A total of 12,115 patients (66% women) were identified. At least 1 opioid purchase was done by 23–27% of the patients 1 year before and 15–20% one year after the index date. Relative risk (RR) of opioid purchases compared to GP was highest during the last 3-month time period before the index date [RR 2.81 (95% CI 2.55–3.09), 3.06 (2.68-3.49), and 4.04 (3.51–4.65) for RA+, RA–, and UA, respectively] but decreased after the index date [RR 1.38 (1.23–1.58), 1.91 (1.63–2.24), and 2.51 (2.15–2.93)]. Up to 4% of the patients were longterm users both before and after the diagnosis.

Conclusion. During 2009–15 in Finland, opioid use peaked just before the diagnosis of IA but decreased rapidly after that, suggesting effective disease control, especially in seropositive RA. Further, opioids were used to treat arthritis pain of patients with incident RA and UA less often than previously reported from other countries.