Objectives
To compare the risk of fracture associated with initiating opioids vs. non-steroidal anti-inflammatory drugs (NSAIDs), and the variation in risk by opioid dose, duration of action, and duration of use.
Design
Retrospective Cohort Study.
Setting
Enrollees in two statewide pharmaceutical benefit programs for persons aged 65 and older.
Participants
12,436 initiators of opioids and 4,874 initiators of NSAIDs began treatment between 1/1/1999 and 12/31/2006. The mean age at initiation of analgesia was 81 years, 85% were female, and all had arthritis.
Measurements
Cox proportional hazard models, adjusted for several potential confounders, quantified fracture risk. Study outcomes were fractures of the hip, humerus/ulna, or wrist, identified by a combination of diagnosis (CD-9CM codes) and procedure (CPT codes).
Results
There were 587 fracture events among the patients initiating opioids (120 fractures per 1,000 person-years) and 38 fracture events among patients initiating NSAIDs (25 fractures per 1,000 person-years), hazard ratio [HR], 4.9 [95% CI, 3.5 to 6.9]. Fracture risk increased with opioid dose. Risk was higher for short-acting opioids (HR, 5.1, [CI, 3.7 to 7.1]) than for long-acting opioids (HR, 2.6, [CI, 1.5 to 4.4]), even among patients taking equianalgesic doses, with differential fracture risk apparent for the first two weeks after starting opioids, but not thereafter.
Conclusion
Older patients with arthritis who initiate therapy with opioids are more likely to suffer a fracture, compared with patients who initiate NSAIDs. For the first two weeks after initiating opioid therapy, but not thereafter, short-acting opioids are associated with a higher risk of fracture than are long-acting opioids.