Patient Characteristics and Risk of Fall-Related Injuries Among New Users of Opioids in Denmark: A Longitudinal Descriptive Study

Purpose
To assess the 1-year risk of fall-related injuries among new users of opioids in Denmark.

Methods
Using Danish health registers, we identified all new adult users of opioids between 2010 and 2022 (first time use within 5 years). We performed logistic regression and applied marginal comparisons to estimate risk ratios (RRs) associating baseline risk factors to any fall-related injury and fall-related fractures specifically. Patients were followed after opioid initiation until fall-related injury, death, leaving the country, or 1-year follow-up, whichever occurred first.

Results
We identified 1 638 358 unique new users of opioids (54% women; median age 58 years). The 1-year risk of fall-related injuries and fall-related fractures was 8.6% and 3.6%, respectively. The risk of fall-related injuries was highest during the first weeks following opioid initiation. Increasing age, depression, Parkinson's disease, osteoporosis, and prior fall-related injuries were all associated with new fall-related injuries in the multivariable analysis. Prior fall-related injuries was a predictor of new fall-related injuries (RR 2.15; 95% CI: 2.12–2.18) and fall-related fractures (RR 1.35; 95% CI: 1.31–1.40). Prior fall-related fractures was a predictor of new fall-related injuries (RR 1.96; 95% CI: 1.93–1.99) and fall-related fractures (RR 6.47; 95% CI: 6.29–6.65).

Conclusion
The 1-year risk for any fall-related injuries and fractures was 8.6% and 3.6%, respectively, and highest in the first weeks following opioid initiation. Several important risk factors associated with new fall-related injuries were identified. Physicians should be aware of patient characteristics related to fall risk when prescribing opioids.